Seasonal Influenza: An Overview

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Li, Christina; Freedman, Marian

2009-01-01

Seasonal influenza is a major cause of morbidity and mortality in the United States. It also has major social and economic consequences in the form of high rates of absenteeism from school and work as well as significant treatment and hospitalization costs. In fact, annual influenza epidemics and the resulting deaths and lost days of productivity…

Modeling Influenza Transmission Using Environmental Parameters

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Soebiyanto, Radina P.; Kiang, Richard K.

2010-01-01

Influenza is an acute viral respiratory disease that has significant mortality, morbidity and economic burden worldwide. It infects approximately 5-15% of the world population, and causes 250,000 500,000 deaths each year. The role of environments on influenza is often drawn upon the latitude variability of influenza seasonality pattern. In regions with temperate climate, influenza epidemics exhibit clear seasonal pattern that peak during winter months, but it is not as evident in the tropics. Toward this end, we developed mathematical model and forecasting capabilities for influenza in regions characterized by warm climate Hong Kong (China) and Maricopa County (Arizona, USA). The best model for Hong Kong uses Land Surface Temperature (LST), precipitation and relative humidity as its covariates. Whereas for Maricopa County, we found that weekly influenza cases can be best modelled using mean air temperature as its covariates. Our forecasts can further guides public health organizations in targeting influenza prevention and control measures such as vaccination.

Protocol: Transmission and prevention of influenza in Hutterites: Zoonotic transmission of influenza A: swine & swine workers

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Loeb Mark

2009-11-01

Full Text Available Abstract Background Among swine, reassortment of influenza virus genes from birds, pigs, and humans could generate influenza viruses with pandemic potential. Humans with acute infection might also be a source of infection for swine production units. This article describes the study design and methods being used to assess influenza A transmission between swine workers and pigs. We hypothesize that transmission of swine influenza viruses to humans, transmission of human influenza viruses to swine, and reassortment of human and swine influenza A viruses is occurring. The project is part of a Team Grant; all Team Grant studies include active surveillance for influenza among Hutterite swine farmers in Alberta, Canada. This project also includes non-Hutterite swine farms that are experiencing swine respiratory illness. Methods/Design Nurses conduct active surveillance for influenza-like-illness (ILI, visiting participating communally owned and operated Hutterite swine farms twice weekly. Nasopharyngeal swabs and acute and convalescent sera are obtained from persons with any two such symptoms. Swabs are tested for influenza A and B by a real time RT-PCR (reverse transcriptase polymerase chain reaction at the Alberta Provincial Laboratory for Public Health (ProvLab. Test-positive participants are advised that they have influenza. The occurrence of test-positive swine workers triggers sampling (swabbing, acute and convalescent serology of the swine herd by veterinarians. Specimens obtained from swine are couriered to St. Jude Children's Research Hospital, Memphis, TN for testing. Veterinarians and herd owners are notified if animal specimens are test-positive for influenza. If swine ILI occurs, veterinarians obtain samples from the pigs; test-positives from the animals trigger nurses to obtain specimens (swabbing, acute and convalescent serology from the swine workers. ProvLab cultures influenza virus from human specimens, freezes these cultures and

Influence of Media on Seasonal Influenza Epidemic Curves.

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Saito, Satoshi; Saito, Norihiro; Itoga, Masamichi; Ozaki, Hiromi; Kimura, Toshiyuki; Okamura, Yuji; Murakami, Hiroshi; Kayaba, Hiroyuki

2016-09-01

Theoretical investigations predicting the epidemic curves of seasonal influenza have been demonstrated so far; however, there is little empirical research using ever accumulated epidemic curves. The effects of vaccine coverage and information distribution on influenza epidemics were evaluated. Four indices for epidemics (i.e., onset-peak duration, onset-end duration, ratio of the onset-peak duration to onset-end duration and steepness of epidemic curves) were defined, and the correlations between these indices and anti-flu drug prescription dose, vaccine coverage, the volume of media and search trend on influenza through internet were analyzed. Epidemiological data on seasonal influenza epidemics from 2002/2003 to 2013/2014 excluding 2009/2010 season were collected from National Institute of Infectious Diseases of Japan. The onset-peak duration and its ratio to onset-end duration correlated inversely with the volume of anti-flu drug prescription. Onset-peak duration correlated positively with media information volume on influenza. The steepness of the epidemic curve, and anti-flu drug prescription dose inversely correlated with the volume of media information. Pre-epidemic search trend and media volume on influenza correlated with the vaccine coverage in the season. Vaccine coverage had no strong effect on epidemic curve. Education through media has an effect on the epidemic curve of seasonal influenza. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Seasonal influenza activity for 2005-2006 season seems to be ending in most European countries.

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Paget, W.J.; Meijer, A.; Falcao, J.M.; Jong, J.C. de; Kyncl, J.; Meerhoff, T.J.; Meuwissen, L.E.; Nicoll, A.; Velden, J. van der

2006-01-01

During the 2005-2006 season, seasonal influenza epidemics started late in countries across Europe. Clinical influenza activity has only reached moderate levels and has mainly been associated with influenza B viruses. There has been co-circulation of influenza A and B viruses in many countries, and

Influenza in workplaces: transmission, workers' adherence to sick leave advice and European sick leave recommendations.

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Edwards, Christina Hansen; Tomba, Gianpaolo Scalia; de Blasio, Birgitte Freiesleben

2016-06-01

Knowledge about influenza transmission in the workplace and whether staying home from work when experiencing influenza-like illness can reduce the spread of influenza is crucial for the design of efficient public health initiatives. This review synthesizes current literature on sickness presenteeism and influenza transmission in the workplace and provides an overview of sick leave recommendations in Europe for influenza. A search was performed on Medline, Embase, PsychINFO, Cinahl, Web of Science, Scopus and SweMed to identify studies related to workplace contacts, -transmission, -interventions and compliance with recommendations to take sick leave. A web-based survey on national recommendations and policies for sick leave during influenza was issued to 31 European countries. Twenty-two articles (9 surveys; 13 modelling articles) were eligible for this review. Results from social mixing studies suggest that 20-25% of weekly contacts are made in the workplace, while modelling studies suggest that on average 16% (range 9-33%) of influenza transmission occurs in the workplace. The effectiveness of interventions to reduce workplace presenteeism is largely unknown. Finally, estimates from studies reporting expected compliance with sick leave recommendations ranged from 71 to 95%. Overall, 18 countries participated in the survey of which nine (50%) had issued recommendations encouraging sick employees to stay at home during the 2009 A(H1N1) pandemic, while only one country had official recommendations for seasonal influenza. During the 2009 A(H1N1) pandemic, many European countries recommended ill employees to take sick leave. Further research is warranted to quantify the effect of reduced presenteeism during influenza illness. © The Author 2016. Published by Oxford University Press on behalf of the European Public Health Association.

Influenza in workplaces: transmission, workers’ adherence to sick leave advice and European sick leave recommendations

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Tomba, Gianpaolo Scalia; de Blasio, Birgitte Freiesleben

2016-01-01

Background: Knowledge about influenza transmission in the workplace and whether staying home from work when experiencing influenza-like illness can reduce the spread of influenza is crucial for the design of efficient public health initiatives. Aim: This review synthesizes current literature on sickness presenteeism and influenza transmission in the workplace and provides an overview of sick leave recommendations in Europe for influenza. Methods: A search was performed on Medline, Embase, PsychINFO, Cinahl, Web of Science, Scopus and SweMed to identify studies related to workplace contacts, -transmission, -interventions and compliance with recommendations to take sick leave. A web-based survey on national recommendations and policies for sick leave during influenza was issued to 31 European countries. Results: Twenty-two articles (9 surveys; 13 modelling articles) were eligible for this review. Results from social mixing studies suggest that 20–25% of weekly contacts are made in the workplace, while modelling studies suggest that on average 16% (range 9–33%) of influenza transmission occurs in the workplace. The effectiveness of interventions to reduce workplace presenteeism is largely unknown. Finally, estimates from studies reporting expected compliance with sick leave recommendations ranged from 71 to 95%. Overall, 18 countries participated in the survey of which nine (50%) had issued recommendations encouraging sick employees to stay at home during the 2009 A(H1N1) pandemic, while only one country had official recommendations for seasonal influenza. Conclusions: During the 2009 A(H1N1) pandemic, many European countries recommended ill employees to take sick leave. Further research is warranted to quantify the effect of reduced presenteeism during influenza illness. PMID:27060594

[Influenza surveillance in nine consecutive seasons, 2003-2012: results from National Influenza Reference Laboratory, Istanbul Faculty Of Medicine, Turkey].

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Akçay Ciblak, Meral; Kanturvardar Tütenyurd, Melis; Asar, Serkan; Tulunoğlu, Merve; Fındıkçı, Nurcihan; Badur, Selim

2012-10-01

Influenza is a public health problem that affects 5-20% of the world population annually causing high morbidity and mortality especially in risk groups. In addition to determining prevention and treatment strategies with vaccines and antivirals, surveillance data plays an important role in combat against influenza. Surveillance provides valuable data on characteristics of influenza activity, on types, sub-types, antigenic properties and antiviral resistance profile of circulating viruses in a given region. The first influenza surveillance was initiated as a pilot study in 2003 by now named National Influenza Reference Laboratory, Istanbul Faculty of Medicine. Surveillance was launched at national level by Ministry of Health in 2004 and two National Influenza Laboratories, one in Istanbul and the other in Ankara, have been conducting surveillance in Turkey. Surveillance data obtained for nine consecutive years, 2003-2012, by National Influenza Reference Laboratory in Istanbul Faculty of Medicine have been summarized in this report. During 2003-2012 influenza surveillance seasons, a total of 11.077 nasal swabs collected in viral transport medium were sent to the National Influenza Reference Laboratory, Istanbul for analysis. Immun-capture ELISA followed by MDCK cell culture was used for detection of influenza viruses before 2009 and real-time RT-PCR was used thereafter. Antigenic characterizations were done by hemagglutination inhibition assay with the reactives supplied by World Health Organization. Analysis of the results showed that influenza B viruses have entered the circulation in 2005-2006 seasons, and have contributed to the epidemics at increasing rates every year except in the 2009 pandemic season. Influenza B Victoria and Yamagata lineages were cocirculating for two seasons. For other seasons either lineage was in circulation. Antigenic characterization revealed that circulating B viruses matched the vaccine composition either partially or totally for only

Fluorescent immunochromatography for rapid and sensitive typing of seasonal influenza viruses.

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Akira Sakurai

Full Text Available Lateral flow tests also known as Immunochromatography (IC is an antigen-detection method conducted on a nitrocellulose membrane that can be completed in less than 20 min. IC has been used as an important rapid test for clinical diagnosis and surveillance of influenza viruses, but the IC sensitivity is relatively low (approximately 60% and the limit of detection (LOD is as low as 10³ pfu per reaction. Recently, we reported an improved IC assay using antibodies conjugated with fluorescent beads (fluorescent immunochromatography; FLIC for subtyping H5 influenza viruses (FLIC-H5. Although the FLIC strip must be scanned using a fluorescent reader, the sensitivity (LOD is significantly improved over that of conventional IC methods. In addition, the antibodies which are specific against the subtypes of influenza viruses cannot be available for the detection of other subtypes when the major antigenicity will be changed. In this study, we established the use of FLIC to type seasonal influenza A and B viruses (FLIC-AB. This method has improved sensitivity to 100-fold higher than that of conventional IC methods when we used several strains of influenza viruses. In addition, FLIC-AB demonstrated the ability to detect influenza type A and influenza type B viruses from clinical samples with high sensitivity and specificity (Type A: sensitivity 98.7% (74/75, specificity 100% (54/54, Type B: sensitivity 100% (90/90, specificity 98.2% (54/55 in nasal swab samples in comparison to the results of qRT-PCR. And furthermore, FLIC-AB performs better in the detection of early stage infection (under 13 h than other conventional IC methods. Our results provide new strategies to prevent the early-stage transmission of influenza viruses in humans during both seasonal outbreaks and pandemics.

Influenza in the immediate post-pandemic era : A comparison with seasonal and pandemic influenza in hospitalized patients

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Rahamat-Langendoen, J. C.; Tutuhatunewa, E. D.; Scholvinck, E. H.; Hak, E.; Koopmans, M.; Niesters, H. G. M.; Riezebos-Brilman, A.

Background: Comparative data on severity and treatment of seasonal, pandemic and post-pandemic influenza virus infections are scarce. Objectives: To systematically analyze characteristics of hospitalized patients with influenza in the post-pandemic period compared to seasonal and pandemic influenza.

Influenza epidemiology and influenza vaccine effectiveness during the 2014–2015 season: annual report from the Global Influenza Hospital Surveillance Network

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Joan Puig-Barberà

2016-08-01

Full Text Available Abstract The Global Influenza Hospital Surveillance Network (GIHSN has established a prospective, active surveillance, hospital-based epidemiological study to collect epidemiological and virological data for the Northern and Southern Hemispheres over several consecutive seasons. It focuses exclusively on severe cases of influenza requiring hospitalization. A standard protocol is shared between sites allowing comparison and pooling of results. During the 2014–2015 influenza season, the GIHSN included seven coordinating sites from six countries (St. Petersburg and Moscow, Russian Federation; Prague, Czech Republic; Istanbul, Turkey; Beijing, China; Valencia, Spain; and Rio de Janeiro, Brazil. Here, we present the detailed epidemiological and influenza vaccine effectiveness findings for the Northern Hemisphere 2014–2015 influenza season.

Key issues for estimating the impact and cost-effectiveness of seasonal influenza vaccination strategies.

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Jit, Mark; Newall, Anthony T; Beutels, Philippe

2013-04-01

Many countries have considered or are considering modifying their seasonal influenza immunization policies. Estimating the impact of such changes requires understanding the existing clinical and economic burden of influenza, as well as the potential impact of different vaccination options. Previous studies suggest that vaccinating clinical risk groups, health care workers, children and the elderly may be cost-effective. However, challenges in such estimation include: (1) potential cases are not usually virologically tested; (2) cases have non-specific symptoms and are rarely reported to surveillance systems; (3) endpoints for influenza proxies (such as influenza-like illness) need to be matched to case definitions for treatment costs, (4) disease burden estimates vary from year to year with strain transmissibility, virulence and prior immunity, (5) methods to estimate productivity losses due to influenza vary, (6) vaccine efficacy estimates from trials differ due to variation in subtype prevalence, vaccine match and case ascertainment, and (7) indirect (herd) protection from vaccination depends on setting-specific variables that are difficult to directly measure. Given the importance of knowing the impact of changes to influenza policy, such complexities need careful treatment using tools such as population-based trial designs, meta-analyses, time-series analyses and transmission dynamic models.

Understanding influenza vaccine protection in the community: an assessment of the 2013 influenza season in Victoria, Australia.

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Carville, Kylie S; Grant, Kristina A; Sullivan, Sheena G; Fielding, James E; Lane, Courtney R; Franklin, Lucinda; Druce, Julian; Kelly, Heath A

2015-01-03

The influenza virus undergoes frequent antigenic drift, necessitating annual review of the composition of the influenza vaccine. Vaccination is an important strategy for reducing the impact and burden of influenza, and estimating vaccine effectiveness (VE) each year informs surveillance and preventative measures. We aimed to describe the influenza season and to estimate the effectiveness of the influenza vaccine in Victoria, Australia, in 2013. Routine laboratory notifications, general practitioner sentinel surveillance (including a medical deputising service) data, and sentinel hospital admission surveillance data for the influenza season (29 April to 27 October 2013) were collated in Victoria, Australia, to describe influenza-like illness or confirmed influenza during the season. General practitioner sentinel surveillance data were used to estimate VE against medically-attended laboratory confirmed influenza. VE was estimated using the case test negative design as 1-adjusted odds ratio (odds of vaccination in cases compared with controls) × 100%. Cases tested positive for influenza while non-cases (controls) tested negative. Estimates were adjusted for age group, week of onset, time to swabbing and co-morbidities. The 2013 influenza season was characterised by relatively low activity with a late peak. Influenza B circulation preceded that of influenza A(H1)pdm09, with very little influenza A(H3) circulation. Adjusted VE for all influenza was 55% (95%CI: -11, 82), for influenza A(H1)pdm09 was 43% (95%CI: -132, 86), and for influenza B was 56% (95%CI: -51, 87) Imputation of missing data raised the influenza VE point estimate to 64% (95%CI: 13, 85). Clinicians can continue to promote a positive approach to influenza vaccination, understanding that inactivated influenza vaccines prevent at least 50% of laboratory-confirmed outcomes in hospitals and the community. Copyright © 2014 Elsevier Ltd. All rights reserved.

Rapid detection of pandemic influenza in the presence of seasonal influenza

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2010-01-01

Background Key to the control of pandemic influenza are surveillance systems that raise alarms rapidly and sensitively. In addition, they must minimise false alarms during a normal influenza season. We develop a method that uses historical syndromic influenza data from the existing surveillance system 'SERVIS' (Scottish Enhanced Respiratory Virus Infection Surveillance) for influenza-like illness (ILI) in Scotland. Methods We develop an algorithm based on the weekly case ratio (WCR) of reported ILI cases to generate an alarm for pandemic influenza. From the seasonal influenza data from 13 Scottish health boards, we estimate the joint probability distribution of the country-level WCR and the number of health boards showing synchronous increases in reported influenza cases over the previous week. Pandemic cases are sampled with various case reporting rates from simulated pandemic influenza infections and overlaid with seasonal SERVIS data from 2001 to 2007. Using this combined time series we test our method for speed of detection, sensitivity and specificity. Also, the 2008-09 SERVIS ILI cases are used for testing detection performances of the three methods with a real pandemic data. Results We compare our method, based on our simulation study, to the moving-average Cumulative Sums (Mov-Avg Cusum) and ILI rate threshold methods and find it to be more sensitive and rapid. For 1% case reporting and detection specificity of 95%, our method is 100% sensitive and has median detection time (MDT) of 4 weeks while the Mov-Avg Cusum and ILI rate threshold methods are, respectively, 97% and 100% sensitive with MDT of 5 weeks. At 99% specificity, our method remains 100% sensitive with MDT of 5 weeks. Although the threshold method maintains its sensitivity of 100% with MDT of 5 weeks, sensitivity of Mov-Avg Cusum declines to 92% with increased MDT of 6 weeks. For a two-fold decrease in the case reporting rate (0.5%) and 99% specificity, the WCR and threshold methods

Characterization of regional influenza seasonality patterns in China and implications for vaccination strategies: spatio-temporal modeling of surveillance data.

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Hongjie Yu

2013-11-01

-latitude provinces, given the complexity of seasonal patterns in this region. More broadly, our findings are consistent with the role of climatic factors on influenza transmission dynamics. Please see later in the article for the Editors' Summary.

Modeling Seasonal Influenza Transmission and Its Association with Climate Factors in Thailand Using Time-Series and ARIMAX Analyses.

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Chadsuthi, Sudarat; Iamsirithaworn, Sopon; Triampo, Wannapong; Modchang, Charin

2015-01-01

Influenza is a worldwide respiratory infectious disease that easily spreads from one person to another. Previous research has found that the influenza transmission process is often associated with climate variables. In this study, we used autocorrelation and partial autocorrelation plots to determine the appropriate autoregressive integrated moving average (ARIMA) model for influenza transmission in the central and southern regions of Thailand. The relationships between reported influenza cases and the climate data, such as the amount of rainfall, average temperature, average maximum relative humidity, average minimum relative humidity, and average relative humidity, were evaluated using cross-correlation function. Based on the available data of suspected influenza cases and climate variables, the most appropriate ARIMA(X) model for each region was obtained. We found that the average temperature correlated with influenza cases in both central and southern regions, but average minimum relative humidity played an important role only in the southern region. The ARIMAX model that includes the average temperature with a 4-month lag and the minimum relative humidity with a 2-month lag is the appropriate model for the central region, whereas including the minimum relative humidity with a 4-month lag results in the best model for the southern region.

Modes of transmission of influenza B virus in households.

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Benjamin J Cowling

Full Text Available While influenza A and B viruses can be transmitted via respiratory droplets, the importance of small droplet nuclei "aerosols" in transmission is controversial.In Hong Kong and Bangkok, in 2008-11, subjects were recruited from outpatient clinics if they had recent onset of acute respiratory illness and none of their household contacts were ill. Following a positive rapid influenza diagnostic test result, subjects were randomly allocated to one of three household-based interventions: hand hygiene, hand hygiene plus face masks, and a control group. Index cases plus their household contacts were followed for 7-10 days to identify secondary infections by reverse transcription polymerase chain reaction (RT-PCR testing of respiratory specimens. Index cases with RT-PCR-confirmed influenza B were included in the present analyses. We used a mathematical model to make inferences on the modes of transmission, facilitated by apparent differences in clinical presentation of secondary infections resulting from aerosol transmission. We estimated that approximately 37% and 26% of influenza B virus transmission was via the aerosol mode in households in Hong Kong and Bangkok, respectively. In the fitted model, influenza B virus infections were associated with a 56%-72% risk of fever plus cough if infected via aerosol route, and a 23%-31% risk of fever plus cough if infected via the other two modes of transmission.Aerosol transmission may be an important mode of spread of influenza B virus. The point estimates of aerosol transmission were slightly lower for influenza B virus compared to previously published estimates for influenza A virus in both Hong Kong and Bangkok. Caution should be taken in interpreting these findings because of the multiple assumptions inherent in the model, including that there is limited biological evidence to date supporting a difference in the clinical features of influenza B virus infection by different modes.

Host adaptation and transmission of influenza A viruses in mammals

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Schrauwen, Eefje JA; Fouchier, Ron AM

2014-01-01

A wide range of influenza A viruses of pigs and birds have infected humans in the last decade, sometimes with severe clinical consequences. Each of these so-called zoonotic infections provides an opportunity for virus adaptation to the new host. Fortunately, most of these human infections do not yield viruses with the ability of sustained human-to-human transmission. However, animal influenza viruses have acquired the ability of sustained transmission between humans to cause pandemics on rare occasions in the past, and therefore, influenza virus zoonoses continue to represent threats to public health. Numerous recent studies have shed new light on the mechanisms of adaptation and transmission of avian and swine influenza A viruses in mammals. In particular, several studies provided insights into the genetic and phenotypic traits of influenza A viruses that may determine airborne transmission. Here, we summarize recent studies on molecular determinants of virulence and adaptation of animal influenza A virus and discuss the phenotypic traits associated with airborne transmission of newly emerging influenza A viruses. Increased understanding of the determinants and mechanisms of virulence and transmission may aid in assessing the risks posed by animal influenza viruses to human health, and preparedness for such risks. PMID:26038511

Case-based reported mortality associated with laboratory-confirmed influenza A(H1N1 2009 virus infection in the Netherlands: the 2009-2010 pandemic season versus the 2010-2011 influenza season

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Timen Aura

2011-10-01

Full Text Available Abstract Background In contrast to seasonal influenza epidemics, where the majority of deaths occur amongst elderly, a considerable part of the 2009 pandemic influenza related deaths concerned relatively young people. In the Netherlands, all deaths associated with laboratory-confirmed influenza A(H1N1 2009 virus infection had to be notified, both during the 2009-2010 pandemic season and the 2010-2011 influenza season. To assess whether and to what extent pandemic mortality patterns were reverting back to seasonal patterns, a retrospective analyses of all notified fatal cases associated with laboratory-confirmed influenza A(H1N1 2009 virus infection was performed. Methods The notification database, including detailed information about the clinical characteristics of all notified deaths, was used to perform a comprehensive analysis of all deceased patients with a laboratory-confirmed influenza A(H1N1 2009 virus infection. Characteristics of the fatalities with respect to age and underlying medical conditions were analysed, comparing the 2009-2010 pandemic and the 2010-2011 influenza season. Results A total of 65 fatalities with a laboratory-confirmed influenza A(H1N1 2009 virus infection were notified in 2009-2010 and 38 in 2010-2011. During the pandemic season, the population mortality rates peaked in persons aged 0-15 and 55-64 years. In the 2010-2011 influenza season, peaks in mortality were seen in persons aged 0-15 and 75-84 years. During the 2010-2011 influenza season, the height of first peak was lower compared to that during the pandemic season. Underlying immunological disorders were more common in the pandemic season compared to the 2010-2011 season (p = 0.02, and cardiovascular disorders were more common in the 2010-2011 season (p = 0.005. Conclusions The mortality pattern in the 2010-2011 influenza season still resembled the 2009-2010 pandemic season with a peak in relatively young age groups, but concurrently a clear shift toward

CD206+ Cell Number Differentiates Influenza A (H1N1pdm09 from Seasonal Influenza A Virus in Fatal Cases

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Heidi G. Rodriguez-Ramirez

2014-01-01

Full Text Available In 2009, a new influenza A (H1N1 virus affected many persons around the world. There is an urgent need for finding biomarkers to distinguish between influenza A (H1N1pdm09 and seasonal influenza virus. We investigated these possible biomarkers in the lung of fatal cases of confirmed influenza A (H1N1pdm09. Cytokines (inflammatory and anti-inflammatory and cellular markers (macrophages and lymphocytes subpopulation markers were analyzed in lung tissue from both influenza A (H1N1pdm09 and seasonal influenza virus. High levels of IL-17, IFN-γ, and TNF-α positive cells were identical in lung tissue from the influenza A (H1N1pdm09 and seasonal cases when compared with healthy lung tissue (P<0.05. Increased IL-4+ cells, and CD4+ and CD14+ cells were also found in high levels in both influenza A (H1N1pdm09 and seasonal influenza virus (P<0.05. Low levels of CD206+ cells (marker of alternatively activated macrophages marker in lung were found in influenza A (H1N1pdm09 when compared with seasonal influenza virus (P<0.05, and the ratio of CD206/CD14+ cells was 2.5-fold higher in seasonal and noninfluenza group compared with influenza A (H1N1pdm09 (P<0.05. In conclusion, CD206+ cells differentiate between influenza A (H1N1pdm09 and seasonal influenza virus in lung tissue of fatal cases.

Rapid detection of pandemic influenza in the presence of seasonal influenza

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Robertson Chris

2010-11-01

Full Text Available Abstract Background Key to the control of pandemic influenza are surveillance systems that raise alarms rapidly and sensitively. In addition, they must minimise false alarms during a normal influenza season. We develop a method that uses historical syndromic influenza data from the existing surveillance system 'SERVIS' (Scottish Enhanced Respiratory Virus Infection Surveillance for influenza-like illness (ILI in Scotland. Methods We develop an algorithm based on the weekly case ratio (WCR of reported ILI cases to generate an alarm for pandemic influenza. From the seasonal influenza data from 13 Scottish health boards, we estimate the joint probability distribution of the country-level WCR and the number of health boards showing synchronous increases in reported influenza cases over the previous week. Pandemic cases are sampled with various case reporting rates from simulated pandemic influenza infections and overlaid with seasonal SERVIS data from 2001 to 2007. Using this combined time series we test our method for speed of detection, sensitivity and specificity. Also, the 2008-09 SERVIS ILI cases are used for testing detection performances of the three methods with a real pandemic data. Results We compare our method, based on our simulation study, to the moving-average Cumulative Sums (Mov-Avg Cusum and ILI rate threshold methods and find it to be more sensitive and rapid. For 1% case reporting and detection specificity of 95%, our method is 100% sensitive and has median detection time (MDT of 4 weeks while the Mov-Avg Cusum and ILI rate threshold methods are, respectively, 97% and 100% sensitive with MDT of 5 weeks. At 99% specificity, our method remains 100% sensitive with MDT of 5 weeks. Although the threshold method maintains its sensitivity of 100% with MDT of 5 weeks, sensitivity of Mov-Avg Cusum declines to 92% with increased MDT of 6 weeks. For a two-fold decrease in the case reporting rate (0.5% and 99% specificity, the WCR and

Performance of the Quidel Sofia Rapid Influenza Diagnostic Test During the 2012-2013 and 2013-2014 Influenza Seasons

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2016-03-23

Performance of the Quidel Sofia rapid influenza diagnostic test during the 2012–2013 and 2013–2014 influenza seasons Peter E. Kammerer, Jennifer M... Influenza A+B Fluorescent Immunoassay was used to test nasal swab specimens from patients with influenza -like illness at US–Mexico border-area clinics in...the 2012–2013 and 2013–2014 influenza seasons. Compared with real-time reverse transcription polymerase chain reaction, the overall sensitivities and

Influenza in Poland in 2013 and 2013/2014 epidemic season

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Kondratiuk, Katarzyna; Czarkowski, Mirosław P; Hallmann-Szelińska, Ewelina; Staszewska, Ewa; Bednarska, Karolina; Cielebąk, Ewa; Brydak, Lidia B

2016-01-01

Analysis of epidemiological situation of influenza in Poland in 2013 and 2013/14 epidemic season in reference to previous years and seasons. Analysis was based on: 1) data collected within influenza routine surveillance system in Poland, including data published in annual bulletins “Infectious diseases and poisonings in Poland” as well as unpublished data gathered in the Department of Epidemiology of the NIPH-NIH; 2) data collected within influenza system - Sentinel, and beyond this system, concerning results of virological tests carried out in 2013/14 epidemic season in the Department of Influenza Research, National Influenza Center in the NIPHNIH and/or laboratories of provincial sanitary and epidemiological stations which are gathered in the National Influenza Center. Compared to 2012, the number of influenza and influenza-like cases increased more than twofold in 2013 in Poland. A total of 3 164 405 cases were reported. Incidence was 8 218.7 per 100,000 population (33 733.2 in 0-4 age group). As many as 0.45% of patients were referred to hospitals. According to the data of the Central Statistical Office, 115 deaths due to influenza were notified. Based on the data of the sanitary inspection (incomplete data), the percentage of population vaccinated against influenza was 2.4% (7.7% of persons aged more than 64 years). A total of 2 780 945 cases were registered in 2013/14 epidemic season. Its peak was reported in March 2014. Incidence was 7 224.0 per 100,000 population (35 172.8 in 0-4 age group). Compared to 2012/13 epidemic season, it was lower by 8.0%. Incidence rates ranged from 29 339.6 in pomorskie voivodeship to 1 306.5 in lubuskie voivodeship. Nearly a half of all cases (48.7%) were registered in children and adolescents up to 15 years. As many as 0.34% of patients were referred to hospitals (0.87% of persons aged more than 64 years). From the data of the Central Statistical Office transpires that 8 deaths due to influenza were reported in epidemic

Transmission of influenza A viruses between pigs and people, Iowa, 2002-2004.

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Terebuh, Pauline; Olsen, Christopher W; Wright, Jennifer; Klimov, Alexander; Karasin, Alexander; Todd, Karla; Zhou, Hong; Hall, Henrietta; Xu, Xiyan; Kniffen, Tim; Madsen, David; Garten, Rebecca; Bridges, Carolyn B

2010-11-01

Triple-reassortant (tr) viruses of human, avian, and swine origin, including H1N1, H1N2, and H3N2 subtypes, emerged in North American swine herds in 1998 and have become predominant. While sporadic human infections with classical influenza A (H1N1) and with tr-swine influenza viruses have been reported, relatively few have been documented in occupationally exposed swine workers (SW). We conducted a 2-year (2002-2004) prospective cohort study of transmission of influenza viruses between pigs and SW from a single pork production company in Iowa. Respiratory samples were collected and tested for influenza viruses from SW and from pigs under their care through surveillance for influenza-like illnesses (ILI). Serial blood samples from study participants were tested by hemagglutination inhibition (HI) for antibody seroconversion against human and swine influenza viruses (SIV), and antibody seroprevalence was compared to age-matched urban Iowa blood donors. During the first year, 15 of 88 SW had ILI and were sampled; all were culture-negative for influenza. During the second year, 11 of 76 SW had ILI and were sampled; one was culture-positive for a human seasonal H3N2 virus. Among 20 swine herd ILI outbreaks sampled, influenza A virus was detected by rRT-PCR from 17 with 11 trH1N1 and five trH3N2 virus isolates cultured. During both years, HI geometric mean titers were significantly higher among SW compared to blood donor controls for three SIV: classical swine Sw/WI/238/97 (H1N1), tr Sw/IN/9K035/99 (H1N2), and trSw/IA/H02NJ56371/02 (H1N1)] (P influenza viruses and were exposed to diverse influenza virus strains circulating in pigs. Influenza virus surveillance among pigs and SW should be encouraged to better understand cross-species transmission and diversity of influenza viruses at the human-swine interface. © 2010 Blackwell Publishing Ltd.

Influenza Vaccine Effectiveness: Maintained Protection Throughout the Duration of Influenza Seasons 2010-2011 through 2013-2014

Science.gov (United States)

2016-06-08

effectiveness: Maintained protection throughout the duration of influenza seasons 2010–2011 through 2013–2014http://dx.doi.org/10.1016/j.vaccine...Unfortunately, we did not have data on the proportion who received the higher-dose vaccine. Another limitation of our study is that we did not conduct a...significant protection against influenza infection for the duration of the influenza season or up to 6 months postvac- cination. Since the start of the

Contact transmission of influenza virus between ferrets imposes a looser bottleneck than respiratory droplet transmission allowing propagation of antiviral resistance

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Frise, Rebecca; Bradley, Konrad; van Doremalen, Neeltje; Galiano, Monica; Elderfield, Ruth A.; Stilwell, Peter; Ashcroft, Jonathan W.; Fernandez-Alonso, Mirian; Miah, Shahjahan; Lackenby, Angie; Roberts, Kim L.; Donnelly, Christl A.; Barclay, Wendy S.

2016-01-01

Influenza viruses cause annual seasonal epidemics and occasional pandemics. It is important to elucidate the stringency of bottlenecks during transmission to shed light on mechanisms that underlie the evolution and propagation of antigenic drift, host range switching or drug resistance. The virus spreads between people by different routes, including through the air in droplets and aerosols, and by direct contact. By housing ferrets under different conditions, it is possible to mimic various routes of transmission. Here, we inoculated donor animals with a mixture of two viruses whose genomes differed by one or two reverse engineered synonymous mutations, and measured the transmission of the mixture to exposed sentinel animals. Transmission through the air imposed a tight bottleneck since most recipient animals became infected by only one virus. In contrast, a direct contact transmission chain propagated a mixture of viruses suggesting the dose transferred by this route was higher. From animals with a mixed infection of viruses that were resistant and sensitive to the antiviral drug oseltamivir, resistance was propagated through contact transmission but not by air. These data imply that transmission events with a looser bottleneck can propagate minority variants and may be an important route for influenza evolution. PMID:27430528

Influenza seasonality in Madagascar: the mysterious African free-runner.

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Alonso, Wladimir Jimenez; Guillebaud, Julia; Viboud, Cecile; Razanajatovo, Norosoa Harline; Orelle, Arnaud; Zhou, Steven Zhixiang; Randrianasolo, Laurence; Heraud, Jean-Michel

2015-05-01

The seasonal drivers of influenza activity remain debated in tropical settings where epidemics are not clearly phased. Antananarivo is a particularly interesting case study because it is in Madagascar, an island situated in the tropics and with quantifiable connectivity levels to other countries. We aimed at disentangling the role of environmental forcing and population fluxes on influenza seasonality in Madagascar. We compiled weekly counts of laboratory-confirmed influenza-positive specimens for the period 2002 to 2012 collected in Antananarivo, with data available from sub-Saharan countries and countries contributing most foreign travelers to Madagascar. Daily climate indicators were compiled for the study period. Overall, influenza activity detected in Antananarivo predated that identified in temperate Northern Hemisphere locations. This activity presented poor temporal matching with viral activity in other countries from the African continent or countries highly connected to Madagascar excepted for A(H1N1)pdm09. Influenza detection in Antananarivo was not associated with travel activity and, although it was positively correlated with all climatic variables studied, such association was weak. The timing of influenza activity in Antananarivo is irregular, is not driven by climate, and does not align with that of countries in geographic proximity or highly connected to Madagascar. This work opens fresh questions regarding the drivers of influenza seasonality globally particularly in mid-latitude and less-connected regions to tailor vaccine strategies locally. © 2015 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

Effect of the one-child policy on influenza transmission in China: a stochastic transmission model.

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Fengchen Liu

Full Text Available BACKGROUND: China's one-child-per-couple policy, introduced in 1979, led to profound demographic changes for nearly a quarter of the world's population. Several decades later, the consequences include decreased fertility rates, population aging, decreased household sizes, changes in family structure, and imbalanced sex ratios. The epidemiology of communicable diseases may have been affected by these changes since the transmission dynamics of infectious diseases depend on demographic characteristics of the population. Of particular interest is influenza because China and Southeast Asia lie at the center of a global transmission network of influenza. Moreover, changes in household structure may affect influenza transmission. Is it possible that the pronounced demographic changes that have occurred in China have affected influenza transmission? METHODS AND FINDINGS: To address this question, we developed a continuous-time, stochastic, individual-based simulation model for influenza transmission. With this model, we simulated 30 years of influenza transmission and compared influenza transmission rates in populations with and without the one-child policy control. We found that the average annual attack rate is reduced by 6.08% (SD 2.21% in the presence of the one-child policy compared to a population in which no demographic changes occurred. There was no discernible difference in the secondary attack rate, -0.15% (SD 1.85%, between the populations with and without a one-child policy. We also forecasted influenza transmission over a ten-year time period in a population with a two-child policy under a hypothesis that a two-child-per-couple policy will be carried out in 2015, and found a negligible difference in the average annual attack rate compared to the population with the one-child policy. CONCLUSIONS: This study found that the average annual attack rate is slightly lowered in a population with a one-child policy, which may have resulted from a

Factors associated with seasonal influenza vaccine uptake among children in Japan.

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Shono, Aiko; Kondo, Masahide

2015-02-18

Seasonal influenza vaccine was once part of the routine immunization schedule that is routinely offered to all children in Japan, but it is now excluded from the schedule. This study aimed to investigate factors influential to parents' decision to have their children receive seasonal influenza vaccine, as well as types of seasonal influenza vaccine information that is given to parents. We conducted a cross-sectional online survey of 555 participants who have at least one child younger than 13 years of age. Respondents were asked to categorize the history of influenza vaccination of their youngest child as either 'annual' , 'sometimes' , or 'never'. Participants were also asked about potentially influential factors in their decision to have their children receive a seasonal influenza vaccine. A total of 75% of respondents answered that their youngest child had received a seasonal influenza vaccine, and 57% of respondents answered that their child receives the vaccine every year. The higher income group was more likely than the lowest income group to have a history of influenza vaccine uptake. A recommendation from a pediatrician or school/nursery to have their child vaccinated was also positively associated with a history of influenza vaccine uptake. The most common reason for a pediatrician's recommendation was 'it leads to milder symptoms if infected'. The main finding of the study is a significant association between household income and influenza vaccination of the youngest child in the household. We also found that cost could be a barrier to vaccinating children in low income households and that information from pediatricians and schools/nurseries could motivate parents to have their children vaccinated.

Role of Temperature, Humidity and Rainfall on Influenza Transmission in Guatemala, El Salvador and Panama

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Soebiyanto, Radina P.; Bonilla, Luis; Jara, Jorge; McCracken, John; Azziz?-Baumgartner, Eduardo; Widdowson, Marc-Alain; Kiang, Richard

2012-01-01

Worldwide, seasonal influenza causes about 500,000 deaths and 5 million severe illnesses per year. The environmental drivers of influenza transmission are poorly understood especially in the tropics. We aimed to identify meteorological factors for influenza transmission in tropical Central America. We gathered laboratory-confirmed influenza case-counts by week from Guatemala City, San Salvador Department (El Salvador) and Panama Province from 2006 to 2010. The average total cases per year were: 390 (Guatemala), 99 (San Salvador) and 129 (Panama). Meteorological factors including daily air temperature, rainfall, relative and absolute humidity (RH, AH) were obtained from ground stations, NASA satellites and land models. For these factors, we computed weekly averages and their deviation from the 5-yr means. We assessed the relationship between the number of influenza case-counts and the meteorological factors, including effects lagged by 1 to 4 weeks, using Poisson regression for each site. Our results showed influenza in San Salvador would increase by 1 case within a week of every 1 day with RH>75% (Relative Risk (RR)= 1.32, p=.001) and every 1C increase in minimum temperature (RR=1.29, p=.007) but it would decrease by 1 case for every 1mm-above mean weekly rainfall (RR=0.93,pGuatemala had 1 case increase for every 1C increase in minimum temperature in the previous week (RR=1.21, p<.001), and for every 1mm/day-above normal increase of rainfall rate (RR=1.03, p=.03) (model pseudo-R2=0.54). Our findings that cases increase with temperature and humidity differ from some temperate-zone studies. But they indicate that climate parameters such as humidity and temperature could be predictive of influenza activity and should be incorporated into country-specific influenza transmission models

Influenza vaccine effectiveness assessment through sentinel virological data in three post-pandemic seasons

Science.gov (United States)

Torner, Núria; Martínez, Ana; Basile, Luca; Marcos, M Angeles; Antón, Andrés; Mar Mosquera, M; Isanta, Ricard; Cabezas, Carmen; Jané, Mireia; Domínguez, Angela; Program of Catalonia, the PIDIRAC Sentinel Surveillance

2014-01-01

Influenza vaccination aims at reducing the incidence of serious disease, complications and death among those with the most risk of severe influenza disease. Influenza vaccine effectiveness (VE) through sentinel surveillance data from the PIDIRAC program (Daily Acute Respiratory Infection Surveillance of Catalonia) during 2010–2011, 2011–2012, and 2012–2013 influenza seasons, with three different predominant circulating influenza virus (IV) types [A(H1N1)pdm09, A(H3N2) and B, respectively] was assessed. The total number of sentinel samples with known vaccination background collected during the study period was 3173, 14.7% of which had received the corresponding seasonal influenza vaccine. 1117 samples (35.2%) were positive for IV. A retrospective negative case control design was used to assess vaccine effectiveness (VE) for the entire period and for each epidemic influenza season. An overall VE of 58.1% (95% CI:46.8–67) was obtained. Differences in VE according to epidemic season were observed, being highest for the 2012–2013 season with predominance of IV type B (69.7% ;95% CI:51.5–81) and for the 2010–2011 season, with predominance of the A(H1N1)pdm09 influenza virus strain (67.2% ;95%CI:49.5–78.8) and lowest for the 2011–2012 season with A(H3N2) subtype predominance (34.2% ;95%CI:4.5–54.6). Influenza vaccination prevents a substantial number of influenza-associated illnesses. Although vaccines with increased effectiveness are needed and the search for a universal vaccine that is not subject to genetic modifications might increase VE, nowadays only the efforts to increase vaccination rates of high-risk population and healthcare personnel let reduce the burden of influenza and its complications. PMID:25483540

Transmission characteristics of the 2009 H1N1 influenza pandemic: comparison of 8 Southern hemisphere countries.

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Lulla Opatowski

2011-09-01

Full Text Available While in Northern hemisphere countries, the pandemic H1N1 virus (H1N1pdm was introduced outside of the typical influenza season, Southern hemisphere countries experienced a single wave of transmission during their 2009 winter season. This provides a unique opportunity to compare the spread of a single virus in different countries and study the factors influencing its transmission. Here, we estimate and compare transmission characteristics of H1N1pdm for eight Southern hemisphere countries/states: Argentina, Australia, Bolivia, Brazil, Chile, New Zealand, South Africa and Victoria (Australia. Weekly incidence of cases and age-distribution of cumulative cases were extracted from public reports of countries' surveillance systems. Estimates of the reproduction numbers, R(0, empirically derived from the country-epidemics' early exponential phase, were positively associated with the proportion of children in the populations (p = 0.004. To explore the role of demography in explaining differences in transmission intensity, we then fitted a dynamic age-structured model of influenza transmission to available incidence data for each country independently, and for all the countries simultaneously. Posterior median estimates of R₀ ranged 1.2-1.8 for the country-specific fits, and 1.29-1.47 for the global fits. Corresponding estimates for overall attack-rate were in the range 20-50%. All model fits indicated a significant decrease in susceptibility to infection with age. These results confirm the transmissibility of the 2009 H1N1 pandemic virus was relatively low compared with past pandemics. The pattern of age-dependent susceptibility found confirms that older populations had substantial--though partial--pre-existing immunity, presumably due to exposure to heterologous influenza strains. Our analysis indicates that between-country-differences in transmission were at least partly due to differences in population demography.

Safety, efficacy, and immunogenicity of an inactivated influenza vaccine in healthy adults: a randomized, placebo-controlled trial over two influenza seasons

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Bouveret Nancy

2010-03-01

Full Text Available Abstract Background Seasonal influenza imposes a substantial personal morbidity and societal cost burden. Vaccination is the major strategy for influenza prevention; however, because antigenically drifted influenza A and B viruses circulate annually, influenza vaccines must be updated to provide protection against the predicted prevalent strains for the next influenza season. The aim of this study was to assess the efficacy, safety, reactogenicity, and immunogenicity of a trivalent inactivated split virion influenza vaccine (TIV in healthy adults over two influenza seasons in the US. Methods The primary endpoint of this double-blind, randomized study was the average efficacy of TIV versus placebo for the prevention of vaccine-matched, culture-confirmed influenza (VMCCI across the 2005-2006 and 2006-2007 influenza seasons. Secondary endpoints included the prevention of laboratory-confirmed (defined by culture and/or serology influenza, as well as safety, reactogenicity, immunogenicity, and consistency between three consecutive vaccine lots. Participants were assessed actively during both influenza seasons, and nasopharyngeal swabs were collected for viral culture from individuals with influenza-like illness. Blood specimens were obtained for serology one month after vaccination and at the end of each influenza season's surveillance period. Results Although the point estimate for efficacy in the prevention of all laboratory-confirmed influenza was 63.2% (97.5% confidence interval [CI] lower bound of 48.2%, the point estimate for the primary endpoint, efficacy of TIV against VMCCI across both influenza seasons, was 46.3% with a 97.5% CI lower bound of 9.8%. This did not satisfy the pre-specified success criterion of a one-sided 97.5% CI lower bound of >35% for vaccine efficacy. The VMCCI attack rates were very low overall at 0.6% and 1.2% in the TIV and placebo groups, respectively. Apart from a mismatch for influenza B virus lineage in 2005

Detecting emerging transmissibility of avian influenza virus in human households.

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Michiel van Boven

2007-07-01

Full Text Available Accumulating infections of highly pathogenic H5N1 avian influenza in humans underlines the need to track the ability of these viruses to spread among humans. A human-transmissible avian influenza virus is expected to cause clusters of infections in humans living in close contact. Therefore, epidemiological analysis of infection clusters in human households is of key importance. Infection clusters may arise from transmission events from (i the animal reservoir, (ii humans who were infected by animals (primary human-to-human transmission, or (iii humans who were infected by humans (secondary human-to-human transmission. Here we propose a method of analysing household infection data to detect changes in the transmissibility of avian influenza viruses in humans at an early stage. The method is applied to an outbreak of H7N7 avian influenza virus in The Netherlands that was the cause of more than 30 human-to-human transmission events. The analyses indicate that secondary human-to-human transmission is plausible for the Dutch household infection data. Based on the estimates of the within-household transmission parameters, we evaluate the effectiveness of antiviral prophylaxis, and conclude that it is unlikely that all household infections can be prevented with current antiviral drugs. We discuss the applicability of our method for the detection of emerging human-to-human transmission of avian influenza viruses in particular, and for the analysis of within-household infection data in general.

The 2009-2010 influenza pandemic: effects on pandemic and seasonal vaccine uptake and lessons learned for seasonal vaccination campaigns.

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Poland, Gregory A

2010-09-07

Individual and national/cultural differences were apparent in response to the 2009-2010 influenza pandemic. Overall pandemic influenza immunization rates were low across all nations, including among healthcare workers. Among the reasons for the low coverage rates may have been a lack of concern about the individual risk of influenza, which may translate into a lack of willingness or urgency to be vaccinated, particularly if there is mistrust of information provided by public health or governmental authorities. Intuitively, a link between willingness to be vaccinated against seasonal influenza and against pandemic influenza exists, given the similarities in decision-making for this infection. As such, the public is likely to share common concerns regarding pandemic and seasonal influenza vaccination, particularly in the areas of vaccine safety and side effects, and personal risk. Given the public's perception of the low level of virulence of the recent pandemic influenza virus, there is concern that the perception of a lack of personal risk of infection and risk of vaccine side effects could adversely affect seasonal vaccine uptake. While governments are more often concerned about public anxiety and panic, as well as absenteeism of healthcare and other essential workers during a pandemic, convincing the public of the threat posed by pandemic or seasonal influenza is often the more difficult, and underappreciated task. Thus, appropriate, timely, and data-driven health information are very important issues in increasing influenza vaccine coverage, perhaps even more so in western societies where trust in government and public health reports may be lower than in other countries. This article explores what has been learned about cross-cultural responses to pandemic influenza, and seeks to apply those lessons to seasonal influenza immunization programs. 2010 Elsevier Ltd. All rights reserved.

Seasonal trivalent inactivated influenza vaccine protects against 1918 Spanish influenza virus in ferrets

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The influenza H1N1 pandemic of 1918 was one of the worst medical disasters in human history. Recent studies have demonstrated that the hemagglutinin (HA) protein of the 1918 virus and 2009 H1N1 pandemic virus, the latter now a component of the seasonal trivalent inactivated influenza vaccine (TIV),...

Economic evaluation of the vaccination program against seasonal and pandemic A/H1N1 influenza among customs officers in Greece.

Science.gov (United States)

Mamma, Maria; Spandidos, Demetrios A

2013-01-01

Health policies from many countries recommend influenza vaccination of "high-priority" professional groups, including customs officers. Our aim was to estimate the economic impact of the vaccination program against influenza among customs officers in Greece during the 2009/2010 period. We developed a decision analytical computational simulation model including dynamic transmission elements that estimated the economic impact of various scenarios with different attack rates, symptomatic percentages and vaccination participation among customs officers. We also assessed in real-time the economic impact of the national 2009/2010 campaign against seasonal and pandemic A/H1N1 influenza. Implementing a seasonal and pandemic A/H1N1 influenza vaccination program among customs officers in Greece with a participation rate of 30%, influenza vaccination was not cost-saving in any of the studied influenza scenarios. When the participation rate reached 100%, the program was cost-saving, when the influenza attack rate was 30% and the symptomatic rate 65%. The real-time estimated mean net cost-benefit value in 2009/2010 period was -7.3 euros/custom officer. With different clinical scenarios, providing a vaccination program against seasonal and pandemic A/H1N1 influenza can incur a substantial net benefit for customs offices. However, the size of the benefit strongly depends upon the attack rate of influenza, the symptomatic rate as well as the participation rate of the customs officers in the program. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Seasonal influenza vaccine effectiveness against influenza in 2012-2013 : A hospital-based case-control study in Lithuania

NARCIS (Netherlands)

Gefenaite, Giedre; Rahamat-Langendoen, Janette; Ambrozaitis, Arvydas; Mickiene, Aukse; Jancoriene, Ligita; Kuliese, Monika; Velyvyte, Daiva; Niesters, Hubert; Stolk, Ronald P.; Zagminas, Kestutis; Hak, Eelko

2014-01-01

BACKGROUND: Due to scarce information on seasonal influenza vaccine effectiveness (SIVE) against severe clinical influenza outcomes in risk populations, we conducted a case-control study to assess its effects against laboratory-confirmed influenza in hospitalized patients during the 2012-2013

AS03-adjuvanted versus non-adjuvanted inactivated trivalent influenza vaccine against seasonal influenza in elderly people: a phase 3 randomised trial

NARCIS (Netherlands)

McElhaney, J.E.; Beran, J.; Devaster, J.M.; Esen, M.; Launay, O.; Leroux-Roels, G.; Ruiz-Palacios, G.M.; Essen, G.A. van; Caplanusi, A.; Claeys, C.; Durand, C.; Duval, X.; Idrissi, M. El; Falsey, A.R.; Feldman, G.; Frey, S.E.; Galtier, F.; Hwang, S.J.; Innis, B.L.; Kovac, M.; Kremsner, P.; McNeil, S.; Nowakowski, A.; Richardus, J.H.; Trofa, A.; Oostvogels, L.; Verheugt, F.W.; et al.,

2013-01-01

BACKGROUND: We aimed to compare AS03-adjuvanted inactivated trivalent influenza vaccine (TIV) with non-adjuvanted TIV for seasonal influenza prevention in elderly people. METHODS: We did a randomised trial in 15 countries worldwide during the 2008-09 (year 1) and 2009-10 (year 2) influenza seasons.

Analysis of Economic Burden of Seasonal Influenza: An Actuarial Based Conceptual Model

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S. S. N. Perera

2017-01-01

Full Text Available Analysing the economic burden of the seasonal influenza is highly essential due to the large number of outbreaks in recent years. Mathematical and actuarial models can be considered as management tools to understand the dynamical behavior, predict the risk, and compute it. This study is an attempt to develop conceptual model to investigate the economic burden due to seasonal influenza. The compartment SIS (susceptible-infected-susceptible model is used to capture the dynamical behavior of influenza. Considering the current investment and future medical care expenditure as premium payment and benefit (claim, respectively, the insurance and actuarial based conceptual model is proposed to model the present economic burden due to the spread of influenza. Simulation is carried out to demonstrate the variation of the present economic burden with respect to model parameters. The sensitivity of the present economic burden is studied with respect to the risk of disease spread. The basic reproduction is used to identify the risk of disease spread. Impact of the seasonality is studied by introducing the seasonally varying infection rate. The proposed model provides theoretical background to investigate the economic burden of seasonal influenza.

Transmission of Influenza A Viruses

Science.gov (United States)

Neumann, Gabriele; Kawaoka, Yoshihiro

2015-01-01

Influenza A viruses cause respiratory infections that range from asymptomatic to deadly in humans. Widespread outbreaks (pandemics) are attributable to ‘novel’ viruses that possess a viral hemagglutinin (HA) gene to which humans lack immunity. After a pandemic, these novel viruses form stable virus lineages in humans and circulate until they are replaced by other novel viruses. The factors and mechanisms that facilitate virus transmission among hosts and the establishment of novel lineages are not completely understood, but the HA and basic polymerase 2 (PB2) proteins are thought to play essential roles in these processes by enabling avian influenza viruses to infect mammals and replicate efficiently in their new host. Here, we summarize our current knowledge of the contributions of HA, PB2, and other viral components to virus transmission and the formation of new virus lineages. PMID:25812763

Statistical estimates of absenteeism attributable to seasonal and pandemic influenza from the Canadian Labour Force Survey.

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Schanzer, Dena L; Zheng, Hui; Gilmore, Jason

2011-04-12

As many respiratory viruses are responsible for influenza like symptoms, accurate measures of the disease burden are not available and estimates are generally based on statistical methods. The objective of this study was to estimate absenteeism rates and hours lost due to seasonal influenza and compare these estimates with estimates of absenteeism attributable to the two H1N1 pandemic waves that occurred in 2009. Key absenteeism variables were extracted from Statistics Canada's monthly labour force survey (LFS). Absenteeism and the proportion of hours lost due to own illness or disability were modelled as a function of trend, seasonality and proxy variables for influenza activity from 1998 to 2009. Hours lost due to the H1N1/09 pandemic strain were elevated compared to seasonal influenza, accounting for a loss of 0.2% of potential hours worked annually. In comparison, an estimated 0.08% of hours worked annually were lost due to seasonal influenza illnesses. Absenteeism rates due to influenza were estimated at 12% per year for seasonal influenza over the 1997/98 to 2008/09 seasons, and 13% for the two H1N1/09 pandemic waves. Employees who took time off due to a seasonal influenza infection took an average of 14 hours off. For the pandemic strain, the average absence was 25 hours. This study confirms that absenteeism due to seasonal influenza has typically ranged from 5% to 20%, with higher rates associated with multiple circulating strains. Absenteeism rates for the 2009 pandemic were similar to those occurring for seasonal influenza. Employees took more time off due to the pandemic strain than was typical for seasonal influenza.

Statistical estimates of absenteeism attributable to seasonal and pandemic influenza from the Canadian Labour Force Survey

Science.gov (United States)

2011-01-01

Background As many respiratory viruses are responsible for influenza like symptoms, accurate measures of the disease burden are not available and estimates are generally based on statistical methods. The objective of this study was to estimate absenteeism rates and hours lost due to seasonal influenza and compare these estimates with estimates of absenteeism attributable to the two H1N1 pandemic waves that occurred in 2009. Methods Key absenteeism variables were extracted from Statistics Canada's monthly labour force survey (LFS). Absenteeism and the proportion of hours lost due to own illness or disability were modelled as a function of trend, seasonality and proxy variables for influenza activity from 1998 to 2009. Results Hours lost due to the H1N1/09 pandemic strain were elevated compared to seasonal influenza, accounting for a loss of 0.2% of potential hours worked annually. In comparison, an estimated 0.08% of hours worked annually were lost due to seasonal influenza illnesses. Absenteeism rates due to influenza were estimated at 12% per year for seasonal influenza over the 1997/98 to 2008/09 seasons, and 13% for the two H1N1/09 pandemic waves. Employees who took time off due to a seasonal influenza infection took an average of 14 hours off. For the pandemic strain, the average absence was 25 hours. Conclusions This study confirms that absenteeism due to seasonal influenza has typically ranged from 5% to 20%, with higher rates associated with multiple circulating strains. Absenteeism rates for the 2009 pandemic were similar to those occurring for seasonal influenza. Employees took more time off due to the pandemic strain than was typical for seasonal influenza. PMID:21486453

Morbidity, Mortality, and Seasonality of Influenza Hospitalizations in Egypt, November 2007-November 2014.

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Amr Kandeel

Full Text Available Influenza typically comprises a substantial portion of acute respiratory infections, a leading cause of mortality worldwide. However, influenza epidemiology data are lacking in Egypt. We describe seven years of Egypt's influenza hospitalizations from a multi-site influenza surveillance system.Syndromic case definitions identified individuals with severe acute respiratory infection (SARI admitted to eight hospitals in Egypt. Standardized demographic and clinical data were collected. Nasopharyngeal and oropharyngeal swabs were tested for influenza using real-time reverse transcription polymerase chain reaction and typed as influenza A or B, and influenza A specimens subtyped.From November 2007-November 2014, 2,936/17,441 (17% SARI cases were influenza-positive. Influenza-positive patients were more likely to be older, female, pregnant, and have chronic condition(s (all p<0.05. Among them, 53 (2% died, and death was associated with older age, five or more days from symptom onset to hospitalization, chronic condition(s, and influenza A (all p<0.05. An annual seasonal influenza pattern occurred from July-June. Each season, the proportion of the season's influenza-positive cases peaked during November-May (19-41%.In Egypt, influenza causes considerable morbidity and mortality and influenza SARI hospitalization patterns mirror those of the Northern Hemisphere. Additional assessment of influenza epidemiology in Egypt may better guide disease control activities and vaccine policy.

Comparison between pandemic H1N1 2009 influenza pneumonia and seasonal influenza pneumonia in adults

International Nuclear Information System (INIS)

Ishiguro, Takashi; Takayanagi, Noboru; Yoneda, Koichiro

2011-01-01

We compared 126 cases of seasonal influenza pneumonia (seasonal flu) reported between January, 1996 and March, 2009, with 10 cases of laboratory-confirmed pandemic influenza (H1N1) 2009 influenza virus pneumonia (novel flu), based on clinical condition, computed tomography (CT) findings, severity, treatment, and prognosis, to clarify the characteristics of this novel flu. The mean age of subjects was 52.4 years in the novel flu group and 64 years in the seasonal flu group, and novel flu patients were younger than seasonal flu patients. Seasonal flu patients had more underlying diseases than did novel flu patients. The median duration from illness onset to hospitalization was 4 days in both groups. Primary viral pneumonia was present in 70% of novel flu cases and 31% of seasonal flu cases. The proportion of primary virus pneumonia was higher in novel flu patients, and the disease severity of the seasonal flu group was more severe than that of the novel flu group. White blood cell and lymphocyte counts were lower in novel flu patients, and chest CT images showed bilateral shadows and pure ground-glass opacities more frequently in the novel flu cases. There were no differences in treatment, number of days required for the fever to subside, or mortality between the groups. (author)

The impact of the pandemic influenza A(H1N1) 2009 virus on seasonal influenza A viruses in the southern hemisphere, 2009.

Science.gov (United States)

Blyth, C C; Kelso, A; McPhie, K A; Ratnamohan, V M; Catton, M; Druce, J D; Smith, D W; Williams, S H; Huang, Q S; Lopez, L; Schoub, B D; Venter, M; Dwyer, D E

2010-08-05

Data collected over winter 2009 by five World Health Organisation National Influenza Centres in the southern hemisphere were used to examine the circulation of pandemic and seasonal influenza A strains during the first pandemic wave in the southern hemisphere.There is compelling evidence that the pandemic influenza A(H1N1) 2009 virus significantly displaced seasonal influenza A(H1N1) and, to a lesser extent, A(H3N2) viruses circulating in the southern hemisphere. Complete replacement of seasonal influenza A strains, however, was not observed during the first pandemic wave.

Physician's knowledge, attitudes, and practices regarding seasonal influenza, pandemic influenza, and highly pathogenic avian influenza A (H5N1) virus infections of humans in Indonesia

OpenAIRE

Mangiri, Amalya; Iuliano, A. Danielle; Wahyuningrum, Yunita; Praptiningsih, Catharina Y.; Lafond, Kathryn E.; Storms, Aaron D.; Samaan, Gina; Ariawan, Iwan; Soeharno, Nugroho; Kreslake, Jennifer M.; Storey, J. Douglas; Uyeki, Timothy M.

2016-01-01

Indonesia has reported highest number of fatal human cases of highly pathogenic avian influenza (HPAI) A (H5N1) virus infection worldwide since 2005. There are limited data available on seasonal and pandemic influenza in Indonesia. During 2012, we conducted a survey of clinicians in two districts in western Java, Indonesia, to assess knowledge, attitudes, and practices (KAP) of clinical diagnosis, testing, and treatment of patients with seasonal influenza, pandemic influenza, or HPAI H5N1 vir...

Defining the sizes of airborne particles that mediate influenza transmission in ferrets.

Science.gov (United States)

Zhou, Jie; Wei, Jianjian; Choy, Ka-Tim; Sia, Sin Fun; Rowlands, Dewi K; Yu, Dan; Wu, Chung-Yi; Lindsley, William G; Cowling, Benjamin J; McDevitt, James; Peiris, Malik; Li, Yuguo; Yen, Hui-Ling

2018-03-06

Epidemics and pandemics of influenza are characterized by rapid global spread mediated by non-mutually exclusive transmission modes. The relative significance between contact, droplet, and airborne transmission is yet to be defined, a knowledge gap for implementing evidence-based infection control measures. We devised a transmission chamber that separates virus-laden particles by size and determined the particle sizes mediating transmission of influenza among ferrets through the air. Ferret-to-ferret transmission was mediated by airborne particles larger than 1.5 µm, consistent with the quantity and size of virus-laden particles released by the donors. Onward transmission by donors was most efficient before fever onset and may continue for 5 days after inoculation. Multiple virus gene segments enhanced the transmissibility of a swine influenza virus among ferrets by increasing the release of virus-laden particles into the air. We provide direct experimental evidence of influenza transmission via droplets and fine droplet nuclei, albeit at different efficiency. Copyright © 2018 the Author(s). Published by PNAS.

Statistical estimates of absenteeism attributable to seasonal and pandemic influenza from the Canadian Labour Force Survey

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Zheng Hui

2011-04-01

Full Text Available Abstract Background As many respiratory viruses are responsible for influenza like symptoms, accurate measures of the disease burden are not available and estimates are generally based on statistical methods. The objective of this study was to estimate absenteeism rates and hours lost due to seasonal influenza and compare these estimates with estimates of absenteeism attributable to the two H1N1 pandemic waves that occurred in 2009. Methods Key absenteeism variables were extracted from Statistics Canada's monthly labour force survey (LFS. Absenteeism and the proportion of hours lost due to own illness or disability were modelled as a function of trend, seasonality and proxy variables for influenza activity from 1998 to 2009. Results Hours lost due to the H1N1/09 pandemic strain were elevated compared to seasonal influenza, accounting for a loss of 0.2% of potential hours worked annually. In comparison, an estimated 0.08% of hours worked annually were lost due to seasonal influenza illnesses. Absenteeism rates due to influenza were estimated at 12% per year for seasonal influenza over the 1997/98 to 2008/09 seasons, and 13% for the two H1N1/09 pandemic waves. Employees who took time off due to a seasonal influenza infection took an average of 14 hours off. For the pandemic strain, the average absence was 25 hours. Conclusions This study confirms that absenteeism due to seasonal influenza has typically ranged from 5% to 20%, with higher rates associated with multiple circulating strains. Absenteeism rates for the 2009 pandemic were similar to those occurring for seasonal influenza. Employees took more time off due to the pandemic strain than was typical for seasonal influenza.

Molecular characterization of influenza viruses circulating in Northern Italy during two seasons (2005/2006 and 2006/2007) of low influenza activity.

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Pariani, Elena; Amendola, Antonella; Zappa, Alessandra; Bianchi, Silvia; Colzani, Daniela; Anselmi, Giovanni; Zanetti, Alessandro; Tanzi, Elisabetta

2008-11-01

The influenza activity and circulation of influenza viruses in Lombardy (the most populous Italian region) were observed during two consecutive seasons (2005/2006 and 2006/2007) characterized by low influenza activity by the Italian Influenza Surveillance Network. The molecular characteristics of circulating viruses were analyzed to evaluate the introduction of new variants and emergence of vaccine-escape viruses. In both seasons, the epidemic in Lombardy was sustained almost exclusively by influenza A viruses, accounting for 80.5% and 93.6% of total detections, respectively, and the co-circulation of A/H3 viruses belonging to distinct phylogenetic groups was observed. The A/H1N1 viruses isolated during the 2005/2006 season were closely related to A/New Caledonia/20/99, while the hemagglutinin (HA) sequences of the A/H1N1 viruses from the 2006/2007 season exhibited a greater diversity. These viruses were A/Solomon Islands/3/2006-like and showed several variants. All B isolates were similar to B/Malaysia/2506/2004 belonging to the B/Victoria/2/87-lineage. Influenza B virus was the dominant virus in Europe in the 2005/2006 season and accounted for the 20% of total detections in Lombardy. Overall, the viruses studied presented heterogeneity in their HA sequences suggesting the circulation of a miscellaneous set of variants during the two seasons notwithstanding the medium-low activity of influenza. The importance of virological surveillance of influenza viruses is recognized widely and the molecular characterization of the viruses, especially in vaccinated subjects, is of particular importance to evaluate the introduction and circulation of new variants. 2008 Wiley-Liss, Inc.

Influenza-like illness in an urban community of Salvador, Brazil: incidence, seasonality and risk factors.

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Oliveira, Carlos R; Costa, Gisela S R; Paploski, Igor A D; Kikuti, Mariana; Kasper, Amelia M; Silva, Monaise M O; Tavares, Aline S; Cruz, Jaqueline S; Queiroz, Tássia L; Lima, Helena C A V; Calcagno, Juan; Reis, Mitermayer G; Weinberger, Daniel M; Shapiro, Eugene D; Ko, Albert I; Ribeiro, Guilherme S

2016-03-15

with the number of school days, indicating that children may play a role in the timing of seasonal influenza transmission.

Effectiveness of seasonal trivalent inactivated influenza vaccine in preventing influenza hospitalisations and primary care visits in Auckland, New Zealand, in 2013.

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Turner, N; Pierse, N; Bissielo, A; Huang, Qs; Radke, S; Baker, Mg; Widdowson, Ma; Kelly, H

2014-08-28

This study reports the first vaccine effectiveness (VE) estimates for the prevention of general practice visits and hospitalisations for laboratory-confirmed influenza from an urban population in Auckland, New Zealand, in the same influenza season (2013). A case test-negative design was used to estimate propensity-adjusted VE in both hospital and community settings. Patients with a severe acute respiratory infection (SARI) or influenza-like illness (ILI) were defined as requiring hospitalisation (SARI) or attending a general practice (ILI) with a history of fever or measured temperature ≥38 °C, cough and onset within the past 10 days. Those who tested positive for influenza virus were cases while those who tested negative were controls. Results were analysed to 7 days post symptom onset and adjusted for the propensity to be vaccinated and the timing during the influenza season. Influenza vaccination provided 52% (95% CI: 32 to 66) protection against laboratory-confirmed influenza hospitalisation and 56% (95% CI: 34 to 70) against presenting to general practice with influenza. VE estimates were similar for all types and subtypes. This study found moderate effectiveness of influenza vaccine against medically attended and hospitalised influenza in New Zealand, a temperate, southern hemisphere country during the 2013 winter season.

Estimated incidence and number of outpatient visits for seasonal influenza in 2015-2016 in Beijing, China.

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Wu, S; Van Asten, L; Wang, L; McDonald, S A; Pan, Y; Duan, W; Zhang, L; Sun, Y; Zhang, Y; Zhang, X; Pilot, E; Krafft, T; Van Der Hoek, W; Van Der Sande, M A B; Yang, P; Wang, Q

2017-01-01

Information on morbidity burden of seasonal influenza in China is limited. A multiplier model was used to estimate the incidence and number of outpatient visits for seasonal influenza by age group for the 2015-2016 season in Beijing, the capital of China, based on reported numbers of influenza-like

Influenza epidemics, seasonality, and the effects of cold weather on cardiac mortality

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2012-01-01

Background More people die in the winter from cardiac disease, and there are competing hypotheses to explain this. The authors conducted a study in 48 US cities to determine how much of the seasonal pattern in cardiac deaths could be explained by influenza epidemics, whether that allowed a more parsimonious control for season than traditional spline models, and whether such control changed the short term association with temperature. Methods The authors obtained counts of daily cardiac deaths and of emergency hospital admissions of the elderly for influenza during 1992–2000. Quasi-Poisson regression models were conducted estimating the association between daily cardiac mortality, and temperature. Results Controlling for influenza admissions provided a more parsimonious model with better Generalized Cross-Validation, lower residual serial correlation, and better captured Winter peaks. The temperature-response function was not greatly affected by adjusting for influenza. The pooled estimated increase in risk for a temperature decrease from 0 to −5°C was 1.6% (95% confidence interval (CI) 1.1-2.1%). Influenza accounted for 2.3% of cardiac deaths over this period. Conclusions The results suggest that including epidemic data explained most of the irregular seasonal pattern (about 18% of the total seasonal variation), allowing more parsimonious models than when adjusting for seasonality only with smooth functions of time. The effect of cold temperature is not confounded by epidemics. PMID:23025494

Serological response to influenza vaccination among children vaccinated for multiple influenza seasons.

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Sajjad Rafiq

Full Text Available To evaluate if, among children aged 3 to 15 years, influenza vaccination for multiple seasons affects the proportion sero-protected.Participants were 131 healthy children aged 3-15 years. Participants were vaccinated with trivalent inactivated seasonal influenza vaccine (TIV over the 2005-06, 2006-07 and 2007-8 seasons. Number of seasons vaccinated were categorized as one (2007-08; two (2007-08 and 2006-07 or 2007-08 and 2005-06 or three (2005-06, 2006-07, and 2007-08. Pre- and post-vaccination sera were collected four weeks apart. Antibody titres were determined by hemagglutination inhibition (HAI assay using antigens to A/Solomon Islands/03/06 (H1N1, A/Wisconsin/67/05 (H3N2 and B/Malaysia/2506/04. The proportions sero-protected were compared by number of seasons vaccinated using cut-points for seroprotection of 1:40 vs. 1:320. The proportions of children sero-protected against H1N1 and H3N2 was high (>85% regardless of number of seasons vaccinated and regardless of cut-point for seroprotection. For B Malaysia there was no change in proportions sero-protected by number of seasons vaccinated; however the proportions protected were lower than for H1N1 and H3N2, and there was a lower proportion sero-protected when the higher, compared to lower, cut-point was used for sero-protection.The proportion of children sero-protected is not affected by number of seasons vaccinated.

Vaccination against seasonal influenza

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GS Department

2010-01-01

This year, as usual, the Medical Service is helping to promote vaccination against seasonal influenza. Vaccination against seasonal flu is especially recommended for anyone who suffers from chronic pulmonary, cardio-vascular or kidney disease or diabetes, is recovering from a serious illness or major surgery, or is over 65 years of age. The flu virus is transmitted through the air and through contact with contaminated surfaces, so frequent hand-washing with soap and/or an antiseptic hand wash is of great importance. As soon as the first symptoms appear (fever above 38°, shivering, coughing, muscle and/or joint pains, generalised weakness), you are strongly recommended to stay at home to avoid spreading the virus. Anyone working on the CERN site who wishes to be vaccinated against seasonal flu should go to the Infirmary (Building 57, ground floor), with their dose of vaccine. The Medical Service will issue a prescription on the day of the vaccination for the purposes of reimbursement through UNIQA...

Characteristics and management of patients with influenza in a German hospital during the 2014/2015 influenza season.

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Hagel, Stefan; Ludewig, Katrin; Moeser, Anne; Baier, Michael; Löffler, Bettina; Schleenvoigt, Benjamin; Forstner, Christina; Pletz, Mathias W

2016-10-01

The objective of this study was to review the management of patients with influenza during the influenza season 2014/2015 (n = 197). Our study revealed a high rate of healthcare-associated influenza infection (35.5 %) and a correlation between the total number of patients with HA influenza and the number of nurses on sick leave. The results of the study underline the importance of strict hygiene management. Furthermore, widespread influenza vaccination for both high-risk patients and health care workers is recommended.

Effectiveness of influenza vaccine against laboratory-confirmed influenza, in the late 2011–2012 season in Spain, among population targeted for vaccination

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2013-01-01

Background In Spain, the influenza vaccine effectiveness (VE) was estimated in the last three seasons using the observational study cycEVA conducted in the frame of the existing Spanish Influenza Sentinel Surveillance System. The objective of the study was to estimate influenza vaccine effectiveness (VE) against medically attended, laboratory-confirmed influenza-like illness (ILI) among the target groups for vaccination in Spain in the 2011–2012 season. We also studied influenza VE in the early (weeks 52/2011-7/2012) and late (weeks 8-14/2012) phases of the epidemic and according to time since vaccination. Methods Medically attended patients with ILI were systematically swabbed to collect information on exposure, laboratory outcome and confounding factors. Patients belonging to target groups for vaccination and who were swabbed 4 months, respectively, since vaccination. A decrease in VE with time since vaccination was only observed in individuals aged ≥ 65 years. Regarding the phase of the season, decreasing point estimates were only observed in the early phase, whereas very low or null estimates were obtained in the late phase for the shortest time interval. Conclusions The 2011–2012 influenza vaccine showed a low-to-moderate protective effect against medically attended, laboratory-confirmed influenza in the target groups for vaccination, in a late season and with a limited match between the vaccine and circulating strains. The suggested decrease in influenza VE with time since vaccination was mostly observed in the elderly population. The decreasing protective effect of the vaccine in the late part of the season could be related to waning vaccine protection because no viral changes were identified throughout the season. PMID:24053661

Burden of medically attended influenza infection and cases averted by vaccination — United States, 2013/14 through 2015/16 influenza seasons

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Jackson, Michael L.; Phillips, C. Hallie; Benoit, Joyce; Jackson, Lisa A.; Gaglani, Manjusha; Murthy, Kempapura; McLean, Huong Q.; Belongia, Edward A.; Malosh, Ryan; Zimmerman, Richard; Flannery, Brendan

2018-01-01

Background In addition to preventing hospitalizations and deaths due to influenza, influenza vaccination programs can reduce the burden of outpatient visits for influenza. We estimated the incidence of medically-attended influenza at three geographically diverse sites in the United States, and the cases averted by vaccination, for the 2013/14 through 2015/16 influenza seasons. Methods We defined surveillance populations at three sites from the United States Influenza Vaccine Effectiveness Network. Among these populations, we identified outpatient visits laboratory-confirmed influenza via active surveillance, and identified all outpatient visits for acute respiratory illness from healthcare databases. We extrapolated the total number of outpatient visits for influenza from the proportion of surveillance visits with a positive influenza test. We combined estimates of incidence, vaccine coverage, and vaccine effectiveness to estimate outpatient visits averted by vaccination. Results Across the three sites and seasons, incidence of medically attended influenza ranged from 14 to 54 per 1,000 population. Incidence was highest in children aged 6 months to 9 years (33 to 70 per 1,000) and lowest in adults aged 18-49 years (21 to 27 per 1,000). Cases averted ranged from 9 per 1,000 vaccinees (Washington, 2014/15) to 28 per 1,000 (Wisconsin, 2013/14). Discussion Seasonal influenza epidemics cause a considerable burden of outpatient medical visits. The United States influenza vaccination program has caused meaningful reductions in outpatient visits for influenza, even in years when the vaccine is not well-matched to the dominant circulating influenza strain. PMID:29249545

Clinical outcomes of seasonal influenza and pandemic influenza A (H1N1 in pediatric inpatients

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Budd Alicia

2010-10-01

Full Text Available Abstract Background In April 2009, a novel influenza A H1N1 (nH1N1 virus emerged and spread rapidly worldwide. News of the pandemic led to a heightened awareness of the consequences of influenza and generally resulted in enhanced infection control practices and strengthened vaccination efforts for both healthcare workers and the general population. Seasonal influenza (SI illness in the pediatric population has been previously shown to result in significant morbidity, mortality, and substantial hospital resource utilization. Although influenza pandemics have the possibility of resulting in considerable illness, we must not ignore the impact that we can experience annually with SI. Methods We compared the outcomes of pediatric patients ≤18 years of age at a large urban hospital with laboratory confirmed influenza and an influenza-like illness (ILI during the 2009 pandemic and two prior influenza seasons. The primary outcome measure was hospital length of stay (LOS. All variables potentially associated with LOS based on univariable analysis, previous studies, or hypothesized relationships were included in the regression models to ensure adjustment for their effects. Results There were 133 pediatric cases of nH1N1 admitted during 2009 and 133 cases of SI admitted during the prior 2 influenza seasons (2007-8 and 2008-9. Thirty-six percent of children with SI and 18% of children with nH1N1 had no preexisting medical conditions (p = 0.14. Children admitted with SI had 1.73 times longer adjusted LOS than children admitted for nH1N1 (95% CI 1.35 - 2.13. There was a trend towards more children with SI requiring mechanical ventilation compared with nH1N1 (16 vs.7, p = 0.08. Conclusions This study strengthens the growing body of evidence demonstrating that SI results in significant morbidity in the pediatric population. Pandemic H1N1 received considerable attention with strong media messages urging people to undergo vaccination and encouraging improved

Late diagnosis of influenza in adult patients during a seasonal outbreak.

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Choi, Seong-Ho; Chung, Jin-Won; Kim, Tark; Park, Ki-Ho; Lee, Mi Suk; Kwak, Yee Gyung

2018-03-01

Due to advances in diagnostic techniques, clinicians are more frequently performing influenza diagnostic tests and referring to their test results ahead of the administration of neuraminidase inhibitors (NAIs). To investigate the clinical significance of the time from symptom onset to laboratory diagnosis, we reviewed the clinical characteristics of adult patients with influenza who had an early laboratory diagnosis (ED) or a late laboratory diagnosis (LD) at one of four tertiary care centers during a seasonal outbreak of influenza. Clinical data were collected from 1,405 adults during the 2013 to 2014 influenza season. A patient was regarded as receiving an ED or LD if he/she received an influenza diagnostic test at 0 to 1 or 4 to 7 days after symptom onset, respectively. Early NAI therapy and late NAI therapy were defined as the administration of NAI ≤ 2 or > 2 days after symptom onset, respectively. Nearly half of the patients (47.0%) received an ED (n = 661), whereas 13.5% (n = 190) received a LD. Patients with a LD had initial symptoms of cough, sputum production, and dyspnea and experienced pneumonia, antibiotic therapy, hospitalization, and admission to the intensive care unit more often than those with an ED. NAI therapy and early NAI therapy were less frequent in patients with a LD than those with an ED. Of the analyzed baseline characteristics, age ≥ 50 years, influenza B infection, and diagnosis using a polymerase chain reaction test were significantly associated with a LD. LD was associated with inappropriate antiviral therapy and complicated presenting features in adult patients with seasonal influenza. ED of influenza should be emphasized, especially for older adults.

Comparative community burden and severity of seasonal and pandemic influenza: results of the Flu Watch cohort study.

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Hayward, Andrew C; Fragaszy, Ellen B; Bermingham, Alison; Wang, Lili; Copas, Andrew; Edmunds, W John; Ferguson, Neil; Goonetilleke, Nilu; Harvey, Gabrielle; Kovar, Jana; Lim, Megan S C; McMichael, Andrew; Millett, Elizabeth R C; Nguyen-Van-Tam, Jonathan S; Nazareth, Irwin; Pebody, Richard; Tabassum, Faiza; Watson, John M; Wurie, Fatima B; Johnson, Anne M; Zambon, Maria

2014-06-01

Assessment of the effect of influenza on populations, including risk of infection, illness if infected, illness severity, and consultation rates, is essential to inform future control and prevention. We aimed to compare the community burden and severity of seasonal and pandemic influenza across different age groups and study years and gain insight into the extent to which traditional surveillance underestimates this burden. Using preseason and postseason serology, weekly illness reporting, and RT-PCR identification of influenza from nasal swabs, we tracked the course of seasonal and pandemic influenza over five successive cohorts (England 2006-11; 5448 person-seasons' follow-up). We compared burden and severity of seasonal and pandemic strains. We weighted analyses to the age and regional structure of England to give nationally representative estimates. We compared symptom profiles over the first week of illness for different strains of PCR-confirmed influenza and non-influenza viruses using ordinal logistic regression with symptom severity grade as the outcome variable. Based on four-fold titre rises in strain-specific serology, on average influenza infected 18% (95% CI 16-22) of unvaccinated people each winter. Of those infected there were 69 respiratory illnesses per 100 person-influenza-seasons compared with 44 per 100 in those not infected with influenza. The age-adjusted attributable rate of illness if infected was 23 illnesses per 100 person-seasons (13-34), suggesting most influenza infections are asymptomatic. 25% (18-35) of all people with serologically confirmed infections had PCR-confirmed disease. 17% (10-26) of people with PCR-confirmed influenza had medically attended illness. These figures did not differ significantly when comparing pandemic with seasonal influenza. Of PCR-confirmed cases, people infected with the 2009 pandemic strain had markedly less severe symptoms than those infected with seasonal H3N2. Seasonal influenza and the 2009 pandemic

Recombinant IgA Is Sufficient To Prevent Influenza Virus Transmission in Guinea Pigs

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Seibert, Christopher W.; Rahmat, Saad; Krause, Jens C.; Eggink, Dirk; Albrecht, Randy A.; Goff, Peter H.; Krammer, Florian; Duty, J. Andrew; Bouvier, Nicole M.; García-Sastre, Adolfo

2013-01-01

A serum hemagglutination inhibition (HAI) titer of 40 or greater is thought to be associated with reduced influenza virus pathogenesis in humans and is often used as a correlate of protection in influenza vaccine studies. We have previously demonstrated that intramuscular vaccination of guinea pigs with inactivated influenza virus generates HAI titers greater than 300 but does not protect vaccinated animals from becoming infected with influenza virus by transmission from an infected cage mate. Only guinea pigs intranasally inoculated with a live influenza virus or a live attenuated virus vaccine, prior to challenge, were protected from transmission (A. C. Lowen et al., J. Virol. 83:2803–2818, 2009.). Because the serum HAI titer is mostly determined by IgG content, these results led us to speculate that prevention of viral transmission may require IgA antibodies or cellular immune responses. To evaluate this hypothesis, guinea pigs and ferrets were administered a potent, neutralizing mouse IgG monoclonal antibody, 30D1 (Ms 30D1 IgG), against the A/California/04/2009 (H1N1) virus hemagglutinin and exposed to respiratory droplets from animals infected with this virus. Even though HAI titers were greater than 160 1 day postadministration, Ms 30D1 IgG did not prevent airborne transmission to passively immunized recipient animals. In contrast, intramuscular administration of recombinant 30D1 IgA (Ms 30D1 IgA) prevented transmission to 88% of recipient guinea pigs, and Ms 30D1 IgA was detected in animal nasal washes. Ms 30D1 IgG administered intranasally also prevented transmission, suggesting the importance of mucosal immunity in preventing influenza virus transmission. Collectively, our data indicate that IgG antibodies may prevent pathogenesis associated with influenza virus infection but do not protect from virus infection by airborne transmission, while IgA antibodies are more important for preventing transmission of influenza viruses. PMID:23698296

Incidence of influenza-like illness and severe acute respiratory infection during three influenza seasons in Bangladesh, 2008–2010

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Alamgir, ASM; Rahman, Mustafizur; Homaira, Nusrat; Sohel, Badrul Munir; Sharker, MA Yushuf; Zaman, Rashid Uz; Dee, Jacob; Gurley, Emily S; Al Mamun, Abdullah; Mah-E-Muneer, Syeda; Fry, Alicia M; Widdowson, Marc-Alain; Bresee, Joseph; Lindstrom, Stephen; Azim, Tasnim; Brooks, Abdullah; Podder, Goutam; Hossain, M Jahangir; Rahman, Mahmudur; Luby, Stephen P

2012-01-01

Abstract Objective To determine how much influenza contributes to severe acute respiratory illness (SARI), a leading cause of death in children, among people of all ages in Bangladesh. Methods Physicians obtained nasal and throat swabs to test for influenza virus from patients who were hospitalized within 7 days of the onset of severe acute respiratory infection (SARI) or who consulted as outpatients for influenza-like illness (ILI). A community health care utilization survey was conducted to determine the proportion of hospital catchment area residents who sought care at study hospitals and calculate the incidence of influenza using this denominator. Findings The estimated incidence of SARI associated with influenza in children < 5 years old was 6.7 (95% confidence interval, CI: 0–18.3); 4.4 (95% CI: 0–13.4) and 6.5 per 1000 person–years (95% CI: 0–8.3/1000) during the 2008, 2009 and 2010 influenza seasons, respectively. The incidence of SARI in people aged ≥ 5 years was 1.1 (95% CI: 0.4–2.0) and 1.3 (95% CI: 0.5–2.2) per 10 000 person–years during 2009 and 2010, respectively. The incidence of medically attended, laboratory-confirmed seasonal influenza in outpatients with ILI was 10 (95% CI: 8–14), 6.6 (95% CI: 5–9) and 17 per 100 person–years (95% CI: 13–22) during the 2008, 2009 and 2010 influenza seasons, respectively. Conclusion Influenza-like illness is a frequent cause of consultation in the outpatient setting in Bangladesh. Children aged less than 5 years are hospitalized for influenza in greater proportions than children in other age groups. PMID:22271960

Suboptimal effectiveness of the 2011-2012 seasonal influenza vaccine in adult Korean populations.

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Won Suk Choi

Full Text Available The effectiveness of the 2011-2012 seasonal influenza vaccine was evaluated in adult Korean populations with regard to how well it could prevent laboratory-confirmed influenza and influenza-related complications.A retrospective case-control and retrospective cohort study was conducted among patients who visited four selected hospitals from September 2011 to May 2012. The analysis included 1,130 laboratory-confirmed influenza patients. For each influenza case, one control patient was chosen at a ratio of 1:1. A control was defined as an age group-matched patient who visited the same hospital with influenza-like illness within 48 hours of symptom onset but for whom laboratory tests were negative for influenza. Age group and visit date were matched between the cases and controls. Vaccine effectiveness (VE was defined as [100 × (1-odds ratio for influenza in vaccinated versus non-vaccinated persons]. The patients with laboratory-confirmed influenza were followed for at least one month through reviewing the medical records and conducting a telephone interview.The VE of the 2011-2012 seasonal influenza vaccine was 3.8% [95% confidence interval (CI, -16.5% to 20.6%] for preventing laboratory-confirmed influenza, -16.1% (95% CI, -48.3 to 9.1 for influenza A and 26.2% (95% CI, -2.6 to 46.2 for influenza B. The age-specific adjusted VE was 0.3% (95% CI, -29.4 to 23.1 among participants aged 19 to 49 years, 11.9% (95% CI, -34.3 to 42.2 among those aged 50 to 64 years and -3.9% (-60.1 to 32.5 among those aged ≥65 years. The adjusted VE for preventing any influenza-related complications was -10.7% (95% CI, -41.1% to 42.2%.The 2011-2012 seasonal influenza vaccine was not effective in preventing laboratory-confirmed influenza or influenza-related complications in adult Korean populations.

Assessing parents' knowledge and attitudes towards seasonal influenza vaccination of children before and after a seasonal influenza vaccination effectiveness study in low-income urban and rural Kenya, 2010-2011.

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Oria, Prisca Adhiambo; Arunga, Geoffrey; Lebo, Emmaculate; Wong, Joshua M; Emukule, Gideon; Muthoka, Philip; Otieno, Nancy; Mutonga, David; Breiman, Robert F; Katz, Mark A

2013-04-25

Influenza vaccine is rarely used in Kenya, and little is known about attitudes towards the vaccine. From June-September 2010, free seasonal influenza vaccine was offered to children between 6 months and 10 years old in two Population-Based Infectious Disease Surveillance (PBIDS) sites. This survey assessed attitudes about influenza, uptake of the vaccine and experiences with childhood influenza vaccination. We administered a questionnaire and held focus group discussions with parents of children of enrollment age in the two sites before and after first year of the vaccine campaign. For pre-vaccination focus group discussions, we randomly selected mothers and fathers who had an eligible child from the PBIDS database to participate. For the post-vaccination focus group discussions we stratified parents whose children were eligible for vaccination into fully vaccinated, partially vaccinated and non-vaccinated groups. Overall, 5284 and 5755 people completed pre and post-vaccination questionnaires, respectively, in Kibera and Lwak. From pre-vaccination questionnaire results, among parents who were planning on vaccinating their children, 2219 (77.6%) in Kibera and 1780 (89.6%) in Lwak said the main reason was to protect the children from seasonal influenza. In the pre-vaccination discussions, no parent had heard of the seasonal influenza vaccine. At the end of the vaccine campaign, of 18,652 eligible children, 5,817 (31.2%) were fully vaccinated, 2,073 (11.1%) were partially vaccinated and, 10,762 (57.7%) were not vaccinated. In focus group discussions, parents who declined vaccine were concerned about vaccine safety or believed seasonal influenza illness was not severe enough to warrant vaccination. Parents who declined the vaccine were mainly too busy [251(25%) in Kibera and 95 (10.5%) in Lwak], or their child was away during the vaccination period [199(19.8%) in Kibera; 94(10.4%) in Lwak]. If influenza vaccine were to be introduced more broadly in Kenya, effective

The effectiveness of seasonal trivalent inactivated influenza vaccine in preventing laboratory confirmed influenza hospitalisations in Auckland, New Zealand in 2012.

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Turner, Nikki; Pierse, Nevil; Bissielo, Ange; Huang, Q Sue; Baker, Michael G; Widdowson, Marc-Alain; Kelly, Heath

2014-06-17

Few studies report the effectiveness of trivalent inactivated influenza vaccine (TIV) in preventing hospitalisation for influenza-confirmed respiratory infections. Using a prospective surveillance platform, this study reports the first such estimate from a well-defined ethnically diverse population in New Zealand (NZ). A case test-negative design was used to estimate propensity adjusted vaccine effectiveness. Patients with a severe acute respiratory infection (SARI), defined as a patient of any age requiring hospitalisation with a history of a fever or a measured temperature ≥38°C and cough and onset within the past 7 days, admitted to public hospitals in South and Central Auckland were eligible for inclusion in the study. Cases were SARI patients who tested positive for influenza, while non-cases (controls) were SARI patients who tested negative. Results were adjusted for the propensity to be vaccinated and the timing of the influenza season. The propensity and season adjusted vaccine effectiveness (VE) was estimated as 39% (95% CI 16;56). The VE point estimate against influenza A (H1N1) was lower than for influenza B or influenza A (H3N2) but confidence intervals were wide and overlapping. Estimated VE was 59% (95% CI 26;77) in patients aged 45-64 years but only 8% (-78;53) in those aged 65 years and above. Prospective surveillance for SARI has been successfully established in NZ. This study for the first year, the 2012 influenza season, has shown low to moderate protection by TIV against influenza positive hospitalisation. Copyright © 2014 Elsevier Ltd. All rights reserved.

The effectiveness of seasonal trivalent inactivated influenza vaccine in preventing laboratory confirmed influenza hospitalisations in Auckland, New Zealand in 2012

Science.gov (United States)

Turner, Nikki; Pierse, Nevil; Bissielo, Ange; Huang, Q Sue; Baker, Michael; Widdowson, Marc-Alain; Kelly, Heath

2015-01-01

Background Few studies report the effectiveness of trivalent inactivated influenza vaccine (TIV) in preventing hospitalisation for influenza-confirmed respiratory infections. Using a prospective surveillance platform, this study reports the first such estimate from a well-defined ethnically diverse population in New Zealand (NZ). Methods A case test-negative study was used to estimate propensity adjusted vaccine effectiveness. Patients with a severe acute respiratory infection (SARI), defined as a patient of any age requiring hospitalization with a history of a fever or a measured temperature ≥38°C and cough and onset within the past 7 days, admitted to public hospitals in Central, South and East Auckland were eligible for inclusion in the study. Cases were SARI patients who tested positive for influenza, while non-cases (controls) were SARI patients who tested negative. Results were adjusted for the propensity to be vaccinated and the timing of the influenza season Results The propensity and season adjusted vaccine effectiveness (VE) was estimated as 37% (95% CI 18;51). The VE point estimate against influenza A (H1N1) was higher than for influenza B or influenza A (H3N2) but confidence intervals were wide and overlapping. Estimated VE was 51% (95% CI 28;67) in patients aged 18-64 years but only 6% (95% CI -51;42) in those aged 65 years and above. Conclusion Prospective surveillance for SARI has been successfully established in NZ . This study for the first year, the 2012 influenza season, has shown low to moderate protection by TIV against hospitalisation for laboratory-confirmed influenza. PMID:24768730

Morbidity, Mortality, and Seasonality of Influenza Hospitalizations in Egypt, November 2007-November 2014

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Kandeel, Amr; Labib, Manal; Said, Mayar; El-Refai, Samir; El-Gohari, Amani; Talaat, Maha

2016-01-01

Background Influenza typically comprises a substantial portion of acute respiratory infections, a leading cause of mortality worldwide. However, influenza epidemiology data are lacking in Egypt. We describe seven years of Egypt’s influenza hospitalizations from a multi-site influenza surveillance system. Methods Syndromic case definitions identified individuals with severe acute respiratory infection (SARI) admitted to eight hospitals in Egypt. Standardized demographic and clinical data were collected. Nasopharyngeal and oropharyngeal swabs were tested for influenza using real-time reverse transcription polymerase chain reaction and typed as influenza A or B, and influenza A specimens subtyped. Results From November 2007–November 2014, 2,936/17,441 (17%) SARI cases were influenza-positive. Influenza-positive patients were more likely to be older, female, pregnant, and have chronic condition(s) (all p<0.05). Among them, 53 (2%) died, and death was associated with older age, five or more days from symptom onset to hospitalization, chronic condition(s), and influenza A (all p<0.05). An annual seasonal influenza pattern occurred from July–June. Each season, the proportion of the season’s influenza-positive cases peaked during November–May (19–41%). Conclusions In Egypt, influenza causes considerable morbidity and mortality and influenza SARI hospitalization patterns mirror those of the Northern Hemisphere. Additional assessment of influenza epidemiology in Egypt may better guide disease control activities and vaccine policy. PMID:27607330

Seasonal influenza vaccination during pregnancy and the risks of preterm delivery and small for gestational age birth.

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Ahrens, Katherine A; Louik, Carol; Kerr, Stephen; Mitchell, Allen A; Werler, Martha M

2014-11-01

Influenza vaccination is routinely recommended for pregnant women, yet information on perinatal outcomes is sparse. We investigated the associations between trivalent (seasonal) influenza vaccination during pregnancy and the risks of preterm delivery (PTD, live birth vaccination and PTD and SGA were assessed using Cox and logistic regression models, respectively, with propensity scores used to adjust for confounding. Women vaccinated against pandemic H1N1 were excluded from the analysis. Influenza vaccination during pregnancy showed a near null association with PTD for influenza seasons 2006-07 through 2008-09 compared with unvaccinated women [adjusted hazard ratios (aHR) ranged from 0.79 [95% confidence interval (CI) 0.28, 2.21] in 2007-08 to 1.08 [95% CI: 0.40, 2.95] in 2008-09]. For 2009-10, the risk of PTD was higher in vaccinated women (aHR, 7.81 [95% CI: 2.66, 23.0]). Influenza vaccination was not associated with appreciable risks for SGA for all seasons with sufficient numbers of exposed SGA. Though limited by study size, these findings add support to previous observations of little or no increased risk of PTD or SGA associated with seasonal influenza vaccination for three of the four influenza seasons in our study. The increased risk of PTD observed for the 2009-10 influenza season warrants further investigation. © 2014 John Wiley & Sons Ltd.

Influenza virus infection among pediatric patients reporting diarrhea and influenza-like illness

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Uyeki Timothy M

2010-01-01

Full Text Available Abstract Background Influenza is a major cause of morbidity and hospitalization among children. While less often reported in adults, gastrointestinal symptoms have been associated with influenza in children, including abdominal pain, nausea, vomiting, and diarrhea. Methods From September 2005 and April 2008, pediatric patients in Indonesia presenting with concurrent diarrhea and influenza-like illness were enrolled in a study to determine the frequency of influenza virus infection in young patients presenting with symptoms less commonly associated with an upper respiratory tract infection (URTI. Stool specimens and upper respiratory swabs were assayed for the presence of influenza virus. Results Seasonal influenza A or influenza B viral RNA was detected in 85 (11.6% upper respiratory specimens and 21 (2.9% of stool specimens. Viable influenza B virus was isolated from the stool specimen of one case. During the time of this study, human infections with highly pathogenic avian influenza A (H5N1 virus were common in the survey area. However, among 733 enrolled subjects, none had evidence of H5N1 virus infection. Conclusions The detection of influenza viral RNA and viable influenza virus from stool suggests that influenza virus may be localized in the gastrointestinal tract of children, may be associated with pediatric diarrhea and may serve as a potential mode of transmission during seasonal and epidemic influenza outbreaks.

Burden and characteristics of influenza A and B in Danish intensive care units during the 2009/10 and 2010/11 influenza seasons

DEFF Research Database (Denmark)

Gubbels, S; Krause, Tyra Grove; Bragstad, Karoline

2013-01-01

SUMMARY Influenza surveillance in Danish intensive care units (ICUs) was performed during the 2009/10 and 2010/11 influenza seasons to monitor the burden on ICUs. All 44 Danish ICUs reported aggregate data for incidence and point prevalence, and case-based demographical and clinical parameters....... Additional data on microbiological testing, vaccination and death were obtained from national registers. Ninety-six patients with influenza A(H1N1)pdm09 were recorded in 2009/10; 106 with influenza A and 42 with influenza B in 2010/11. The mean age of influenza A patients was higher in 2010/11 than in 2009....../10, 53 vs. 44 years (P=0·004). No differences in other demographic and clinical parameters were detected between influenza A and B patients. In conclusion, the number of patients with severe influenza was higher in Denmark during the 2010/11 than the 2009/10 season with a shift towards older age groups...

Risk of influenza transmission in a hospital emergency department during the week of highest incidence.

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Esteve-Esteve, Miguel; Bautista-Rentero, Daniel; Zanón-Viguer, Vicente

2018-02-01

To estimate the risk of influenza transmission in patients coming to a hospital emergency department during the week of highest incidence and to analyze factors associated with transmission. Retrospective observational analysis of a cohort of patients treated in the emergency room during the 2014-2015 flu season. The following variables were collected from records: recorded influenza diagnosis, results of a rapid influenza confirmation test, point of exposure (emergency department, outpatient clinic, or the community), age, sex, flu vaccination or not, number of emergency visits, time spent in the waiting room, and total time in the hospital. We compiled descriptive statistics and performed bivariate and multivariate analyses by means of a Poisson regression to estimate relative risk (RR) and 95% CIs. The emergency department patients had a RR of contracting influenza 3.29 times that of the communityexposed population (95% CI, 1.53-7.08, P=.002); their risk was 2.05 times greater than that of outpatient clinic visitors (95% CI, 1.04-4.02, P=.036). Emergency patients under the age of 15 years had a 5.27 greater risk than older patients (95% CI, 1.59-17.51; P=.007). The RR of patients visiting more than once was 11.43 times greater (95% CI, 3.58-36.44; P<.001). The risk attributable to visiting the emergency department risk was 70.5%, whereas risk attributable to community exposure was 2%. The risk of contracting influenza is greater for emergency department patients than for the general population or for patients coming to the hospital for outpatient clinic visits. Patients under the age of 15 years incur greater risk.

Seasonality of Influenza and Respiratory Syncytial Viruses and the Effect of Climate Factors in Subtropical-Tropical Asia Using Influenza-Like Illness Surveillance Data, 2010 -2012.

Science.gov (United States)

Kamigaki, Taro; Chaw, Liling; Tan, Alvin G; Tamaki, Raita; Alday, Portia P; Javier, Jenaline B; Olveda, Remigio M; Oshitani, Hitoshi; Tallo, Veronica L

2016-01-01

The seasonality of influenza and respiratory syncytial virus (RSV) is well known, and many analyses have been conducted in temperate countries; however, this is still not well understood in tropical countries. Previous studies suggest that climate factors are involved in the seasonality of these viruses. However, the extent of the effect of each climate variable is yet to be defined. We investigated the pattern of seasonality and the effect of climate variables on influenza and RSV at three sites of different latitudes: the Eastern Visayas region and Baguio City in the Philippines, and Okinawa Prefecture in Japan. Wavelet analysis and the dynamic linear regression model were applied. Climate variables used in the analysis included mean temperature, relative and specific humidity, precipitation, and number of rainy days. The Akaike Information Criterion estimated in each model was used to test the improvement of fit in comparison with the baseline model. At all three study sites, annual seasonal peaks were observed in influenza A and RSV; peaks were unclear for influenza B. Ranges of climate variables at the two Philippine sites were narrower and mean variables were significantly different among the three sites. Whereas all climate variables except the number of rainy days improved model fit to the local trend model, their contributions were modest. Mean temperature and specific humidity were positively associated with influenza and RSV at the Philippine sites and negatively associated with influenza A in Okinawa. Precipitation also improved model fit for influenza and RSV at both Philippine sites, except for the influenza A model in the Eastern Visayas. Annual seasonal peaks were observed for influenza A and RSV but were less clear for influenza B at all three study sites. Including additional data from subsequent more years would help to ascertain these findings. Annual amplitude and variation in climate variables are more important than their absolute values for

Seasonality of Influenza and Respiratory Syncytial Viruses and the Effect of Climate Factors in Subtropical-Tropical Asia Using Influenza-Like Illness Surveillance Data, 2010 -2012.

Directory of Open Access Journals (Sweden)

Taro Kamigaki

Full Text Available The seasonality of influenza and respiratory syncytial virus (RSV is well known, and many analyses have been conducted in temperate countries; however, this is still not well understood in tropical countries. Previous studies suggest that climate factors are involved in the seasonality of these viruses. However, the extent of the effect of each climate variable is yet to be defined.We investigated the pattern of seasonality and the effect of climate variables on influenza and RSV at three sites of different latitudes: the Eastern Visayas region and Baguio City in the Philippines, and Okinawa Prefecture in Japan. Wavelet analysis and the dynamic linear regression model were applied. Climate variables used in the analysis included mean temperature, relative and specific humidity, precipitation, and number of rainy days. The Akaike Information Criterion estimated in each model was used to test the improvement of fit in comparison with the baseline model.At all three study sites, annual seasonal peaks were observed in influenza A and RSV; peaks were unclear for influenza B. Ranges of climate variables at the two Philippine sites were narrower and mean variables were significantly different among the three sites. Whereas all climate variables except the number of rainy days improved model fit to the local trend model, their contributions were modest. Mean temperature and specific humidity were positively associated with influenza and RSV at the Philippine sites and negatively associated with influenza A in Okinawa. Precipitation also improved model fit for influenza and RSV at both Philippine sites, except for the influenza A model in the Eastern Visayas.Annual seasonal peaks were observed for influenza A and RSV but were less clear for influenza B at all three study sites. Including additional data from subsequent more years would help to ascertain these findings. Annual amplitude and variation in climate variables are more important than their

Inferring influenza global transmission networks without complete phylogenetic information.

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Aris-Brosou, Stéphane

2014-03-01

Influenza is one of the most severe respiratory infections affecting humans throughout the world, yet the dynamics of its global transmission network are still contentious. Here, I describe a novel combination of phylogenetics, time series, and graph theory to analyze 14.25 years of data stratified in space and in time, focusing on the main target of the human immune response, the hemagglutinin gene. While bypassing the complete phylogenetic inference of huge data sets, the method still extracts information suggesting that waves of genetic or of nucleotide diversity circulate continuously around the globe for subtypes that undergo sustained transmission over several seasons, such as H3N2 and pandemic H1N1/09, while diversity of prepandemic H1N1 viruses had until 2009 a noncontinuous transmission pattern consistent with a source/sink model. Irrespective of the shift in the structure of H1N1 diversity circulation with the emergence of the pandemic H1N1/09 strain, US prevalence peaks during the winter months when genetic diversity is at its lowest. This suggests that a dominant strain is generally responsible for epidemics and that monitoring genetic and/or nucleotide diversity in real time could provide public health agencies with an indirect estimate of prevalence.

Vaccine effectiveness against medically attended laboratory-confirmed influenza in Japan, 2011-2012 Season.

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Motoi Suzuki

Full Text Available The objective of this study was to estimate influenza vaccine effectiveness (VE against medically attended, laboratory-confirmed influenza during the 2011-2012 season in Japan using a test-negative case-control study design. The effect of co-circulating non-influenza respiratory viruses (NIRVs on VE estimates was also explored. Nasopharyngeal swab samples were collected from outpatients with influenza-like illnesses (ILIs in a community hospital in Nagasaki, Japan. Thirteen respiratory viruses (RVs, including influenza A and B, were identified from the samples using a multiplex polymerase chain reaction. The difference in VE point estimates was assessed using three different controls: ILI patients that tested negative for influenza, those that tested negative for all RVs, and those that tested positive for NIRVs. The adjusted VE against medically attended, laboratory-confirmed influenza using all influenza-negative controls was 5.3% (95% confidence interval [CI], -60.5 to 44.1. The adjusted VEs using RV-negative and NIRV-positive controls were -1.5% (95% CI, -74.7 to 41 and 50% (95% CI, -43.2 to 82.5, respectively. Influenza VE was limited in Japan during the 2011-2012 season. Although the evidence is not conclusive, co-circulating NIRVs may affect influenza VE estimates in test-negative case-control studies.

Cost-effectiveness of inactivated seasonal influenza vaccination in a cohort of Thai children ≤60 months of age.

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Kittikraisak, Wanitchaya; Suntarattiwong, Piyarat; Ditsungnoen, Darunee; Pallas, Sarah E; Abimbola, Taiwo O; Klungthong, Chonticha; Fernandez, Stefan; Srisarang, Suchada; Chotpitayasunondh, Tawee; Dawood, Fatimah S; Olsen, Sonja J; Lindblade, Kim A

2017-01-01

Vaccination is the best measure to prevent influenza. We conducted a cost-effectiveness evaluation of trivalent inactivated seasonal influenza vaccination, compared to no vaccination, in children ≤60 months of age participating in a prospective cohort study in Bangkok, Thailand. A static decision tree model was constructed to simulate the population of children in the cohort. Proportions of children with laboratory-confirmed influenza were derived from children followed weekly. The societal perspective and one-year analytic horizon were used for each influenza season; the model was repeated for three influenza seasons (2012-2014). Direct and indirect costs associated with influenza illness were collected and summed. Cost of the trivalent inactivated seasonal influenza vaccine (IIV3) including promotion, administration, and supervision cost was added for children who were vaccinated. Quality-adjusted life years (QALY), derived from literature, were used to quantify health outcomes. The incremental cost-effectiveness ratio (ICER) was calculated as the difference in the expected total costs between the vaccinated and unvaccinated groups divided by the difference in QALYs for both groups. Compared to no vaccination, IIV3 vaccination among children ≤60 months in our cohort was not cost-effective in the introductory year (2012 season; 24,450 USD/QALY gained), highly cost-effective in the 2013 season (554 USD/QALY gained), and cost-effective in the 2014 season (16,200 USD/QALY gained). The cost-effectiveness of IIV3 vaccination among children participating in the cohort study varied by influenza season, with vaccine cost and proportion of high-risk children demonstrating the greatest influence in sensitivity analyses. Vaccinating children against influenza can be economically favorable depending on the maturity of the program, influenza vaccine performance, and target population.

Cost-effectiveness of inactivated seasonal influenza vaccination in a cohort of Thai children ≤60 months of age.

Directory of Open Access Journals (Sweden)

Wanitchaya Kittikraisak

Full Text Available Vaccination is the best measure to prevent influenza. We conducted a cost-effectiveness evaluation of trivalent inactivated seasonal influenza vaccination, compared to no vaccination, in children ≤60 months of age participating in a prospective cohort study in Bangkok, Thailand.A static decision tree model was constructed to simulate the population of children in the cohort. Proportions of children with laboratory-confirmed influenza were derived from children followed weekly. The societal perspective and one-year analytic horizon were used for each influenza season; the model was repeated for three influenza seasons (2012-2014. Direct and indirect costs associated with influenza illness were collected and summed. Cost of the trivalent inactivated seasonal influenza vaccine (IIV3 including promotion, administration, and supervision cost was added for children who were vaccinated. Quality-adjusted life years (QALY, derived from literature, were used to quantify health outcomes. The incremental cost-effectiveness ratio (ICER was calculated as the difference in the expected total costs between the vaccinated and unvaccinated groups divided by the difference in QALYs for both groups.Compared to no vaccination, IIV3 vaccination among children ≤60 months in our cohort was not cost-effective in the introductory year (2012 season; 24,450 USD/QALY gained, highly cost-effective in the 2013 season (554 USD/QALY gained, and cost-effective in the 2014 season (16,200 USD/QALY gained.The cost-effectiveness of IIV3 vaccination among children participating in the cohort study varied by influenza season, with vaccine cost and proportion of high-risk children demonstrating the greatest influence in sensitivity analyses. Vaccinating children against influenza can be economically favorable depending on the maturity of the program, influenza vaccine performance, and target population.

Network information analysis reveals risk perception transmission in a behaviour-influenza dynamics system.

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Liao, C-M; You, S-H; Cheng, Y-H

2015-01-01

Influenza poses a significant public health burden worldwide. Understanding how and to what extent people would change their behaviour in response to influenza outbreaks is critical for formulating public health policies. We incorporated the information-theoretic framework into a behaviour-influenza (BI) transmission dynamics system in order to understand the effects of individual behavioural change on influenza epidemics. We showed that information transmission of risk perception played a crucial role in the spread of health-seeking behaviour throughout influenza epidemics. Here a network BI model provides a new approach for understanding the risk perception spread and human behavioural change during disease outbreaks. Our study allows simultaneous consideration of epidemiological, psychological, and social factors as predictors of individual perception rates in behaviour-disease transmission systems. We suggest that a monitoring system with precise information on risk perception should be constructed to effectively promote health behaviours in preparation for emerging disease outbreaks.

Incidence of medically attended influenza infection and cases averted by vaccination, 2011/12 and 2012/13 influenza seasons

Science.gov (United States)

Jackson, Michael L.; Jackson, Lisa A.; Kieke, Burney; McClure, David; Gaglani, Manjusha; Murthy, Kempapura; Malosh, Ryan; Monto, Arnold; Zimmerman, Richard K.; Foppa, Ivo M.; Flannery, Brendan; Thompson, Mark G.

2018-01-01

Background We estimated the burden of outpatient influenza and cases prevented by vaccination during the 2011/12 and 2012/13 influenza seasons using data from the United States Influenza Vaccine Effectiveness (US Flu VE) Network. Methods We defined source populations of persons who could seek care for acute respiratory illness (ARI) at each of the five US Flu VE Network sites. We identified all members of the source population who were tested for influenza during US Flu VE influenza surveillance. Each influenza-positive subject received a sampling weight based on the proportion of source population members who were tested for influenza, stratified by site, age, and other factors. We used the sampling weights to estimate the cumulative incidence of medically attended influenza in the source populations. We estimated cases averted by vaccination using estimates of cumulative incidence, vaccine coverage, and vaccine effectiveness. Results Cumulative incidence of medically attended influenza ranged from 0.8% to 2.8% across sites during 2011/12 and from 2.6% to 6.5% during the 2012/13 season. Stratified by age, incidence ranged from 1.2% among adults 50 years of age and older in 2011/12 to 10.9% among children 6 months to 8 years of age in 2012/13. Cases averted by vaccination ranged from 4 to 41 per 1,000 vaccinees, depending on the study site and year. Conclusions The incidence of medically attended influenza varies greatly by year and even by geographic region within the same year. The number of cases averted by vaccination varies greatly based on overall incidence and on vaccine coverage. PMID:26271827

Analysis of Seasonal Influenza Vaccine Uptake among Children and Adolescents with an Intellectual Disability

Science.gov (United States)

Yen, Chia-Feng; Hsu, Shang-Wei; Loh, Ching-Hui; Fang, Wen-Hui; Wu, Chia-Ling; Chu, Cordia M.; Lin, Jin-Ding

2012-01-01

The aim of the present study was to describe the seasonal influenza vaccination rate and to examine its determinants for children and adolescents with intellectual disabilities (ID) living in the community. A cross-sectional survey was conducted to analyze the data on seasonal influenza vaccination rate among 1055 ID individuals between the ages…

Characterization of Seasonal Influenza Virus Type and Subtypes Isolated from Influenza Like Illness Cases of 2012.

Science.gov (United States)

Upadhyay, B P; Ghimire, P; Tashiro, M; Banjara, M R

Background Seasonal influenza is one of the increasing public health burdens in Nepal. Objective The objective of this study was to isolate and characterize the influenza virus type and subtypes of Nepal. Method A total of 1536 throat swab specimens were collected from January to December 2012. Total ribonucleic acid was extracted using Qiagen viral nucleic acid extraction kit and polymerase chain reaction assay was performed following the US; CDC Real-time PCR protocol. Ten percent of positive specimens were inoculated onto Madin-Darby Canine Kidney cells. Isolates were characterized by using reference ferret antisera. Result Of the total specimens (n=1536), influenza virus type A was detected in 196 (22%) cases; of which 194 (99%) were influenza A (H1N1) pdm09 and 2 (1 %) were influenza A/H3 subtype. Influenza B was detected in 684 (76.9%) cases. Influenza A (H1N1) pdm09, A/H3 and influenza B virus were antigenically similar to the recommended influenza virus vaccine candidate of the year 2012. Although sporadic cases of influenza were observed throughout the year, peak was observed during July to November. Conclusion Similar to other tropical countries, A (H1N1) pdm09, A/H3 and influenza B viruses were co-circulated in Nepal.

Detecting emerging transmissibility of avian influenza virus in human households

NARCIS (Netherlands)

Boven, M. van; Koopmans, M.; Du Ry van Beest Holle, M.; Meijer, Adam; Klinkenberg, D.; Donnelly, C.A.; Heesterbeek, J.A.P.

Accumulating infections of highly pathogenic H5N1 avian influenza in humans underlines the need to track the ability of these viruses to spread among humans. A human-transmissible avian influenza virus is expected to cause clusters of infections in humans living in close contact. Therefore,

Detecting emerging transmissibility of avian influenza virus in human households

NARCIS (Netherlands)

Boven, van R.M.; Koopmans, M.; Du Ry Beest Holle, van M.; Meijer, A.; Klinkenberg, D.; Donnelly, C.; Heesterbeek, J.A.P.

2007-01-01

Accumulating infections of highly pathogenic H5N1 avian influenza in humans underlines the need to track the ability of these viruses to spread among humans. A human-transmissible avian influenza virus is expected to cause clusters of infections in humans living in close contact. Therefore,

Case of seasonal reassortant A(H1N2) influenza virus infection, the Netherlands, March 2018.

NARCIS (Netherlands)

Meijer, A.; Swaan, C.M.; Voerknecht, M.; Jusic, E.; Brink, S. van den; Wijsman, L.A.; Voordouw, B.C.G.; Donker, G.A.; Sleven, J.; Dorigo-Zetsma, W.W.; Svraka, S.; Boven, M. van; Haverkate, M.R.; Timen, A.; Dissel, J.T. van; Koopmans, M.P.G.; Besteboer, T.M.; Fouchier, R.A.M.

2018-01-01

A seasonal reassortant A(H1N2) influenza virus harbouring genome segments from seasonal influenza viruses A(H1N1)pdm09 (HA and NS) and A(H3N2) (PB2, PB1, PA, NP, NA and M) was identified in March 2018 in a 19-months-old patient with influenza-like illness (ILI) who presented to a general

Case of seasonal reassortant A(H1N2) influenza virus infection, the Netherlands, March 2018.

NARCIS (Netherlands)

Meijer, Adam; Swaan, Corien M; Voerknecht, Martin; Jusic, Edin; van den Brink, Sharon; Wijsman, Lisa A; Voordouw, Bettie Cg; Donker, Gé A; Sleven, Jacqueline; Dorigo-Zetsma, Wendelien W; Svraka, Sanela; van Boven, Michiel; Haverkate, Manon R; Timen, Aura; van Dissel, Jaap T; Koopmans, Marion Pg; Bestebroer, Theo M; Fouchier, Ron Am

A seasonal reassortant A(H1N2) influenza virus harbouring genome segments from seasonal influenza viruses A(H1N1)pdm09 (HA and NS) and A(H3N2) (PB2, PB1, PA, NP, NA and M) was identified in March 2018 in a 19-months-old patient with influenza-like illness (ILI) who presented to a general

Is the association between hip fractures and seasonality modified by influenza vaccination? An ecological study.

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Fraenkel, M; Yitshak-Sade, M; Beacher, L; Carmeli, M; Mandelboim, M; Siris, E; Novack, V

2017-09-01

Osteoporotic hip fractures in 4344 patients were more common during winter. Lower temperatures were associated with higher rates of fracture only in those not vaccinated for influenza. Influenza outbreaks increased the risk of hip fractures. Further studies are needed to assess whether influenza vaccination can prevent hip fractures. Winter seasonality of osteoporotic hip fracture incidence has been demonstrated, yet the explanation for the association is lacking. We hypothesize that the seasonality of osteoporotic hip fracture can be explained by an association between hip fractures and seasonal influenza outbreaks. This retrospective cohort study included all patients admitted to Soroka University Medical Center with a diagnosis of osteoporotic hip fracture (ICD-9 code 820) between the years 2001 and 2013. Patients with malignancies, trauma, and age under 50 were excluded. In a time series analysis, we examined the association between hip fracture incidence and seasonality adjusted for meteorological factors, and population rates of influenza infection and vaccination using Poisson models. Four thousand three hundred forty-four patients with a hip fracture were included (69% females, mean age 78). Daily fracture rates were significantly higher in winter (1.1 fractures/day) compared to summer, fall, and spring (0.79, 0.90, and 0.91; p risk only in those not vaccinated for influenza (n = 2939, for every decrease of 5 °C, RR 1.08, CI 1.02-1.16; p risk for hip fracture, adjusted for seasons and temperature, was 1.26 2 weeks following a week with high infection burden (CI 1.05;1.51 p = 0.01), while the temperature was not significantly associated with the fracture risk. Under dry and warm desert climate, winter hip fracture incidence increase might be associated with influenza infection, and this effect can be negated by influenza vaccination.

Modeling and Statistical Analysis of the Spatio-Temporal Patterns of Seasonal Influenza in Israel

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Katriel, Guy; Yaari, Rami; Roll, Uri; Stone, Lewi

2012-01-01

Background Seasonal influenza outbreaks are a serious burden for public health worldwide and cause morbidity to millions of people each year. In the temperate zone influenza is predominantly seasonal, with epidemics occurring every winter, but the severity of the outbreaks vary substantially between years. In this study we used a highly detailed database, which gave us both temporal and spatial information of influenza dynamics in Israel in the years 1998–2009. We use a discrete-time stochastic epidemic SIR model to find estimates and credible confidence intervals of key epidemiological parameters. Findings Despite the biological complexity of the disease we found that a simple SIR-type model can be fitted successfully to the seasonal influenza data. This was true at both the national levels and at the scale of single cities.The effective reproductive number Re varies between the different years both nationally and among Israeli cities. However, we did not find differences in Re between different Israeli cities within a year. R e was positively correlated to the strength of the spatial synchronization in Israel. For those years in which the disease was more “infectious”, then outbreaks in different cities tended to occur with smaller time lags. Our spatial analysis demonstrates that both the timing and the strength of the outbreak within a year are highly synchronized between the Israeli cities. We extend the spatial analysis to demonstrate the existence of high synchrony between Israeli and French influenza outbreaks. Conclusions The data analysis combined with mathematical modeling provided a better understanding of the spatio-temporal and synchronization dynamics of influenza in Israel and between Israel and France. Altogether, we show that despite major differences in demography and weather conditions intra-annual influenza epidemics are tightly synchronized in both their timing and magnitude, while they may vary greatly between years. The predominance of

2009–2010 Seasonal Influenza Vaccination Coverage Among College Students From 8 Universities in North Carolina

Science.gov (United States)

Poehling, Katherine A.; Blocker, Jill; Ip, Edward H.; Peters, Timothy R.; Wolfson, Mark

2012-01-01

Objective We sought to describe the 2009–2010 seasonal influenza vaccine coverage of college students. Participants 4090 college students from eight North Carolina universities participated in a confidential, web-based survey in October-November 2009. Methods Associations between self-reported 2009–2010 seasonal influenza vaccination and demographic characteristics, campus activities, parental education, and email usage were assessed by bivariate analyses and by a mixed-effects model adjusting for clustering by university. Results Overall, 20% of students (range 14%–30% by university) reported receiving 2009–2010 seasonal influenza vaccine. Being a freshman, attending a private university, having a college-educated parent, and participating in academic clubs/honor societies predicted receipt of influenza vaccine in the mixed-effects model. Conclusions The self-reported 2009–2010 influenza vaccine coverage was one-quarter of the 2020 Healthy People goal (80%) for healthy persons 18–64 years of age. College campuses have the opportunity to enhance influenza vaccine coverage among its diverse student populations. PMID:23157195

Seasonal influenza vaccine policies, recommendations and use in the World Health Organization’s Western Pacific Region Original Research

Directory of Open Access Journals (Sweden)

Members of the Western Pacific Region Global Influenza Surveillance and Response System

2013-09-01

Full Text Available Objective: Vaccination is the most effective way to prevent seasonal influenza and its severe outcomes. The objective of our study was to synthesize information on seasonal influenza vaccination policies, recommendations and practices in place in 2011 for all countries and areas in the Western Pacific Region of the World Health Organization (WHO. Methods: Data were collected via a questionnaire on seasonal influenza vaccination policies, recommendations and practices in place in 2011. Results: Thirty-six of the 37 countries and areas (97% responded to the survey. Eighteen (50% reported having established seasonal influenza vaccination policies, an additional seven (19% reported having recommendations for risk groups for seasonal influenza vaccination only and 11 (30% reported having no policies or recommendations in place. Of the 25 countries and areas with policies or recommendations, health-care workers and the elderly were most frequently recommended for vaccination; 24 (96% countries and areas recommended vaccinating these groups, followed by pregnant women (19 [76%], people with chronic illness (18 [72%] and children (15 [60%]. Twenty-six (72% countries and areas reported having seasonal influenza vaccines available through public funding, private market purchase or both. Most of these countries and areas purchased only enough vaccine to cover 25% or less of their populations. Discussion: In light of the new WHO position paper on influenza vaccines published in 2012 and the increasing availability of country-specific data, countries and areas should consider reviewing or developing their seasonal influenza vaccination policies to reduce morbidity and mortality associated with annual epidemics and as part of ongoing efforts for pandemic preparedness.

National seasonal influenza vaccination survey in Europe, 2008.

LENUS (Irish Health Repository)

Mereckiene, J

2008-10-23

A cross-sectional survey was undertaken with the European Union (EU) Member States and Norway and Iceland to describe seasonal influenza immunisation in the 2006-7 season, in particular to identify country-specific recommendations for risk groups, obtain vaccine uptake information and allow comparison with global recommendations. A standardised questionnaire was completed electronically by each country\\'s project gatekeeper. Of the 29 countries surveyed, 28 recommended seasonal influenza vaccination for older age groups (22 for those aged > 65 years), and in one country vaccine was recommended for all age groups. All countries recommended vaccinating patients with chronic pulmonary and cardiovascular diseases and most countries advised to immunise patients with haematologic or metabolic disorders (n=28), immunologic disorders (n=27) and renal disease (n=27), as well as residents of long-term care facilities (n=24). Most countries recommended vaccination for staff in hospitals (n=25), long-term care facilities (n=25) and outpatient clinics (n=23), and one-third had such recommendations for workers in essential (n=10), military (n=10) and veterinary services (n=10) and poultry industry (n=13). Eight countries recommended vaccine for pregnant women; and five advised to vaccinate children (with age limits ranging from 6 months to 5 years). Twenty countries measured influenza vaccine uptake among those aged > 65 years (range 1.8%-82.1%), seven reported uptake in healthcare workers (range 14%-48%) and seven assessed coverage in persons with underlying medical conditions (range 27.6%-75.2%). The data provided by this study can assist EU states to assess and compare their influenza vaccination programme performance with other countries. The information provides a comprehensive overview of policies and programmes and their outcomes and can be used to inform joint discussions on how the national policies in the EU might be standardised in the future to achieve optimal

National seasonal influenza vaccination survey in Europe, 2008.

Science.gov (United States)

Mereckiene, J; Cotter, S; Nicoll, A; Levy-Bruhl, D; Ferro, A; Tridente, G; Zanoni, G; Berra, P; Salmaso, S; O'Flanagan, D; O Flanagan, D

2008-10-23

A cross-sectional survey was undertaken with the European Union (EU) Member States and Norway and Iceland to describe seasonal influenza immunisation in the 2006-7 season, in particular to identify country-specific recommendations for risk groups, obtain vaccine uptake information and allow comparison with global recommendations. A standardised questionnaire was completed electronically by each country's project gatekeeper. Of the 29 countries surveyed, 28 recommended seasonal influenza vaccination for older age groups (22 for those aged > 65 years), and in one country vaccine was recommended for all age groups. All countries recommended vaccinating patients with chronic pulmonary and cardiovascular diseases and most countries advised to immunise patients with haematologic or metabolic disorders (n=28), immunologic disorders (n=27) and renal disease (n=27), as well as residents of long-term care facilities (n=24). Most countries recommended vaccination for staff in hospitals (n=25), long-term care facilities (n=25) and outpatient clinics (n=23), and one-third had such recommendations for workers in essential (n=10), military (n=10) and veterinary services (n=10) and poultry industry (n=13). Eight countries recommended vaccine for pregnant women; and five advised to vaccinate children (with age limits ranging from 6 months to 5 years). Twenty countries measured influenza vaccine uptake among those aged > 65 years (range 1.8%-82.1%), seven reported uptake in healthcare workers (range 14%-48%) and seven assessed coverage in persons with underlying medical conditions (range 27.6%-75.2%). The data provided by this study can assist EU states to assess and compare their influenza vaccination programme performance with other countries. The information provides a comprehensive overview of policies and programmes and their outcomes and can be used to inform joint discussions on how the national policies in the EU might be standardised in the future to achieve optimal

Case of seasonal reassortant a(H1N2) influenza virus infection, the Netherlands, March 2018

NARCIS (Netherlands)

Meijer, A. (Adam); C. Swaan (Corien); Voerknecht, M. (Martin); E. Jusic (Edin); van den Brink, S. (Sharon); Wijsman, L.A. (Lisa A.); A.C.G. Voordouw (Bettie); G.A. Donker (Gé); Sleven, J. (Jacqueline); Dorigo-Zetsma, W.W. (Wendelien W.); S. Svraka-Latifovic (Sanela); M. van Boven (Michiel); Haverkate, M.R. (Manon R.); A. Timen (Aura); J.T. van Dissel (Jaap); M.P.G. Koopmans D.V.M. (Marion); T.M. Bestebroer (Theo); R.A.M. Fouchier (Ron)

2018-01-01

textabstractA seasonal reassortant A(H1N2) influenza virus harbouring genome segments from seasonal influenza viruses A(H1N1)pdm09 (HA and NS) and A(H3N2) (PB2, PB1, PA, NP, NA and M) was identified in March 2018 in a 19-months-old patient with influenza-like illness (ILI) who presented to a general

Risk of Guillain-Barré syndrome after seasonal influenza vaccination and influenza health-care encounters: a self-controlled study.

Science.gov (United States)

Kwong, Jeffrey C; Vasa, Priya P; Campitelli, Michael A; Hawken, Steven; Wilson, Kumanan; Rosella, Laura C; Stukel, Therese A; Crowcroft, Natasha S; McGeer, Allison J; Zinman, Lorne; Deeks, Shelley L

2013-09-01

The possible risk of Guillain-Barré syndrome from influenza vaccines remains a potential obstacle to achieving high vaccination coverage. However, influenza infection might also be associated with Guillain-Barré syndrome. We aimed to assess the risk of Guillain-Barré syndrome after seasonal influenza vaccination and after influenza-coded health-care encounters. We used the self-controlled risk interval design and linked universal health-care system databases from Ontario, Canada, with data obtained between 1993 and 2011. We used physician billing claims for influenza vaccination and influenza-coded health-care encounters to ascertain exposures. Using fixed-effects conditional Poisson regression, we estimated the relative incidence of hospitalisation for primary-coded Guillain-Barré syndrome during the risk interval compared with the control interval. We identified 2831 incident admissions for Guillain-Barré syndrome; 330 received an influenza vaccine and 109 had an influenza-coded health-care encounter within 42 weeks before hospitalisation. The risk of Guillain-Barré syndrome within 6 weeks of vaccination was 52% higher than in the control interval of 9-42 weeks (relative incidence 1·52; 95% CI 1·17-1·99), with the greatest risk during weeks 2-4 after vaccination. The risk of Guillain-Barré syndrome within 6 weeks of an influenza-coded health-care encounter was greater than for vaccination (15·81; 10·28-24·32). The attributable risks were 1·03 Guillain-Barré syndrome admissions per million vaccinations, compared with 17·2 Guillain-Barré syndrome admissions per million influenza-coded health-care encounters. The relative and attributable risks of Guillain-Barré syndrome after seasonal influenza vaccination are lower than those after influenza illness. Patients considering immunisation should be fully informed of the risks of Guillain-Barré syndrome from both influenza vaccines and influenza illness. Canadian Institutes of Health Research

Avian influenza viruses in humans.

Science.gov (United States)

Malik Peiris, J S

2009-04-01

Past pandemics arose from low pathogenic avian influenza (LPAI) viruses. In more recent times, highly pathogenic avian influenza (HPAI) H5N1, LPAI H9N2 and both HPAI and LPAI H7 viruses have repeatedly caused zoonotic disease in humans. Such infections did not lead to sustained human-to-human transmission. Experimental infection of human volunteers and seroepidemiological studies suggest that avian influenza viruses of other subtypes may also infect humans. Viruses of the H7 subtype appear to have a predilection to cause conjunctivitis and influenza-like illness (ILI), although HPAI H7N7 virus has also caused fatal respiratory disease. Low pathogenic H9N2 viruses have caused mild ILI and its occurrence may be under-recognised for this reason. In contrast, contemporary HPAI H5N1 viruses are exceptional in their virulence for humans and differ from human seasonal influenza viruses in their pathogenesis. Patients have a primary viral pneumonia progressing to acute respiratory distress syndrome (ARDS) and multiple organ dysfunction syndrome. Over 380 human cases have been confirmed to date, with an overall case fatality of 63%. The zoonotic transmission of avian influenza is a rare occurrence, butthe greater public health concern is the adaptation of such viruses to efficient human transmission, which could lead to a pandemic. A better understanding of the ecology of avian influenza viruses and the biological determinants of transmissibility and pathogenicity in humans is important for pandemic preparedness.

Seasonal and pandemic human influenza viruses attach better to human upper respiratory tract epithelium than avian influenza viruses

NARCIS (Netherlands)

D.A.J. van Riel (Debby); M.A. den Bakker (Michael); L.M.E. Leijten (Lonneke); S. Chutinimitkul (Salin); V.J. Munster (Vincent); E. de Wit (Emmie); G.F. Rimmelzwaan (Guus); R.A.M. Fouchier (Ron); A.D.M.E. Osterhaus (Albert); T. Kuiken (Thijs)

2010-01-01

textabstractInfluenza viruses vary markedly in their efficiency of human-to-human transmission. This variation has been speculated to be determined in part by the tropism of influenza virus for the human upper respiratory tract. To study this tropism, we determined the pattern of virus attachment by

Mortality Attributable to Seasonal Influenza A and B Infections in Thailand, 2005–2009: A Longitudinal Study

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Cooper, Ben S.; Kotirum, Surachai; Kulpeng, Wantanee; Praditsitthikorn, Naiyana; Chittaganpitch, Malinee; Limmathurotsakul, Direk; Day, Nicholas P. J.; Coker, Richard; Teerawattananon, Yot; Meeyai, Aronrag

2015-01-01

Influenza epidemiology differs substantially in tropical and temperate zones, but estimates of seasonal influenza mortality in developing countries in the tropics are lacking. We aimed to quantify mortality due to seasonal influenza in Thailand, a tropical middle-income country. Time series of polymerase chain reaction–confirmed influenza infections between 2005 and 2009 were constructed from a sentinel surveillance network. These were combined with influenza-like illness data to derive measures of influenza activity and relationships to mortality by using a Bayesian regression framework. We estimated 6.1 (95% credible interval: 0.5, 12.4) annual deaths per 100,000 population attributable to influenza A and B, predominantly in those aged ≥60 years, with the largest contribution from influenza A(H1N1) in 3 out of 4 years. For A(H3N2), the relationship between influenza activity and mortality varied over time. Influenza was associated with increases in deaths classified as resulting from respiratory disease (posterior probability of positive association, 99.8%), cancer (98.6%), renal disease (98.0%), and liver disease (99.2%). No association with circulatory disease mortality was found. Seasonal influenza infections are associated with substantial mortality in Thailand, but evidence for the strong relationship between influenza activity and circulatory disease mortality reported in temperate countries is lacking. PMID:25899091

Monitoring receipt of seasonal influenza vaccines with BRFSS and NHIS data: challenges and solutions.

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Burger, Andrew E; Reither, Eric N

2014-06-30

Despite the availability of vaccines that mitigate the health risks associated with seasonal influenza, most individuals in the U.S. remain unvaccinated. Monitoring vaccination uptake for seasonal influenza, especially among disadvantaged or high-risk groups, is therefore an important public health activity. The Behavioral Risk Factor Surveillance System (BRFSS) - the largest telephone-based health surveillance system in the world - is an important resource in monitoring population health trends, including influenza vaccination. However, due to limitations in the question that measures influenza vaccination status, difficulties arise in estimating seasonal vaccination rates. Although researchers have proposed various methodologies to address this issue, no systematic review of these methodologies exists. By subjecting these methods to tests of sensitivity and specificity, we identify their strengths and weaknesses and advance a new method for estimating national and state-level vaccination rates with BRFSS data. To ensure that our findings are not anomalous to the BRFSS, we also analyze data from the National Health Interview Survey (NHIS). For both studies, we find that restricting the sample to interviews conducted between January and September offers the best balance of sensitivity (>90% on average), specificity (>90% on average), and statistical power (retention of 92.2% of vaccinations from the target flu season) over other proposed methods. We conclude that including survey participants from these months provides a simple and effective way to estimate seasonal influenza vaccination rates with BRFSS and NHIS data, and we discuss potential ways to better estimate vaccination rates in future epidemiologic surveys. Copyright © 2014 Elsevier Ltd. All rights reserved.

Parents’ Perception and their Decision on their Children's Vaccination Against Seasonal Influenza in Guangzhou

Science.gov (United States)

He, Lei; Liao, Qiu-Yan; Huang, You-Qi; Feng, Shuo; Zhuang, Xiao-Ming

2015-01-01

Background: Seasonal influenza epidemic occurs every year in Guangzhou, which can affect all age groups. Young children are the most susceptible targets. Parents can decide whether to vaccinate their children or not based on their own consideration in China. The aim of this study was to identify factors that are important for parental decisions on vaccinating their children against seasonal influenza based on a modified health belief model (HBM). Methods: A cross-sectional study was conducted in Guangzhou, China. A total of 335 parents who had at least on child aged between 6 months and 3 years were recruited from women and children's hospital in Guangzhou, China. Each eligible subject was invited for a face-to-face interview based on a standardized questionnaire. Results: Uptake of seasonal influenza within the preceding 12 months among the target children who aged between 6 months and 36 months was 47.7%. Around 62.4% parents indicated as being “likely/very likely” to take their children for seasonal influenza vaccination in the next 12 months. The hierarchical logistic regression model showed that children's age (odds ratio [OR] =2.59, 95% confidence interval [CI]: 1.44–4.68), social norm (OR = 2.08, 95% CI: 1.06–4.06) and perceived control (OR = 2.96, 95% CI: 1.60–5.50) were significantly and positively associated with children's vaccination uptake within the preceding 12 months; children with a history of taking seasonal influenza vaccine (OR = 2.50, 95% CI: 1.31–4.76), perceived children's health status (OR = 3.36, 95% CI: 1.68–6.74), worry/anxious about their children influenza infection (OR = 2.31, 95% CI: 1.19–4.48) and perceived control (OR = 3.21, 95% CI: 1.65–6.22) were positively association with parental intention to vaccinate their children in the future 12 months. However, anticipated more regret about taking children for the vaccination was associated with less likely to vaccinate children within the preceding 12 months (OR = 0

DNA priming for seasonal influenza vaccine: a phase 1b double-blind randomized clinical trial.

Directory of Open Access Journals (Sweden)

Julie E Ledgerwood

Full Text Available The efficacy of current influenza vaccines is limited in vulnerable populations. DNA vaccines can be produced rapidly, and may offer a potential strategy to improve vaccine immunogenicity, indicated by studies with H5 influenza DNA vaccine prime followed by inactivated vaccine boost.Four sites enrolled healthy adults, randomized to receive 2011/12 seasonal influenza DNA vaccine prime (n=65 or phosphate buffered saline (PBS (n=66 administered intramuscularly with Biojector. All subjects received the 2012/13 seasonal inactivated influenza vaccine, trivalent (IIV3 36 weeks after the priming injection. Vaccine safety and tolerability was the primary objective and measurement of antibody response by hemagglutination inhibition (HAI was the secondary objective.The DNA vaccine prime-IIV3 boost regimen was safe and well tolerated. Significant differences in HAI responses between the DNA vaccine prime and the PBS prime groups were not detected in this study.While DNA priming significantly improved the response to a conventional monovalent H5 vaccine in a previous study, it was not effective in adults using seasonal influenza strains, possibly due to pre-existing immunity to the prime, unmatched prime and boost antigens, or the lengthy 36 week boost interval. Careful optimization of the DNA prime-IIV3 boost regimen as related to antigen matching, interval between vaccinations, and pre-existing immune responses to influenza is likely to be needed in further evaluations of this vaccine strategy. In particular, testing this concept in younger age groups with less prior exposure to seasonal influenza strains may be informative.ClinicalTrials.gov NCT01498718.

Seasonal influenza split vaccines confer partial cross-protection against heterologous influenza virus in ferrets when combined with the CAF01 adjuvant

DEFF Research Database (Denmark)

Christensen, Dennis; Christensen, Jan P.; Korsholm, Karen S.

2018-01-01

Influenza epidemics occur annually, and estimated 5-10% of the adult population and 20-30% of children will become ill from influenza infection. Seasonal vaccines primarily work through the induction of neutralizing antibodies against the principal surface antigen hemagglutinin (HA). This important...... role of HA-specific antibodies explains why previous pandemics have emerged when new HAs have appeared in circulating human viruses. It has long been recognized that influenza virus-specific CD4(+) T cells are important in protection from infection through direct effector mechanisms or by providing...... help to B cells and CD8(+) T cells. However, the seasonal influenza vaccine is poor at inducing CD4(+) T-cell responses and needs to be combined with an adjuvant facilitating this response. In this study, we applied the ferret model to investigate the cross-protective efficacy of a heterologous...

Predictors of seasonal influenza vaccination among healthcare workers in hospitals : a descriptive meta-analysis

NARCIS (Netherlands)

Riphagen-Dalhuisen, Josien; Gefenaite, Giedre; Hak, Eelko

Objective Vaccinating healthcare workers (HCWs) against influenza is one of the most important methods of decreasing influenza transmission among at-risk patients in healthcare facilities. However, despite recommendations, the rate of uptake of influenza vaccine among HCWs remains low. The objective

Characterization of influenza a outbreaks in Minnesota swine herds and measures taken to reduce the risk of zoonotic transmission.

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Beaudoin, A; Johnson, S; Davies, P; Bender, J; Gramer, M

2012-03-01

Influenza A virus infections commonly cause respiratory disease in swine and can be transmitted between people and pigs, with potentially novel strains introduced into herds and spilling back into the human population. The goals of this study were to characterize influenza infections in Minnesota pigs and assess biosecurity measures used by swine workers. Veterinarians submitting influenza-positive swine samples to the University of Minnesota Veterinary Diagnostic Laboratory between October 2007 and April 2009 were surveyed regarding disease-related information and biosecurity procedures at each farm. Influenza-positive samples were submitted year-round, peaking in spring and fall. H1N1 was the most commonly detected subtype (56%), followed by H3N2 (14%) and H1N2 (12%). Most positive submissions were associated with illness in growing pigs (median age 8.8 weeks, IQR 5-15). Median morbidity and mortality were 25% (IQR 10-48) and 2% (IQR 0.5-3.5), respectively. Vaccination of sows and growing pigs was conducted at 71% and 7.9% of the swine farms, respectively. Specialized footwear was reported as the most common form of protective equipment used by workers. Employee vaccination for seasonal influenza was 19%. The sow vaccination rate in this study is consistent with national data, although growing pig vaccination is lower than the national average. Seasonal and age trends identified here may provide diagnostic guidance when growing pigs experience respiratory disease. Inconsistent use of protective equipment and employee vaccination at swine farms indicates the need for further discussion and research of approaches to minimize interspecies influenza transmission on swine farms. © 2011 Blackwell Verlag GmbH.

Severe influenza cases in paediatric intensive care units in Germany during the pre-pandemic seasons 2005 to 2008

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Liese Johannes G

2011-08-01

Full Text Available Abstract Background Data on complications in children with seasonal influenza virus infection are limited. We initiated a nation-wide three-year surveillance of children who were admitted to a paediatric intensive care unit (PICU with severe seasonal influenza. Methods From October 2005 to July 2008, active surveillance was performed using an established reporting system for rare diseases (ESPED including all paediatric hospitals in Germany. Cases to be reported were hospitalized children Results Twenty severe influenza-associated cases were reported from 14 PICUs during three pre-pandemic influenza seasons (2005-2008. The median age of the patients (12 males/8 females was 7.5 years (range 0.1-15 years. None had received vaccination against influenza. In 14 (70% patients, the infection had been caused by influenza A and in five (25% by influenza B; in one child (5% the influenza type was not reported. Patients spent a median of 19 (IQR 12-38 days in the hospital and a median of 11 days (IQR 6-18 days in the PICU; 10 (50% needed mechanical ventilation. Most frequent diagnoses were influenza-associated pneumonia (60%, bronchitis/bronchiolitis (30%, encephalitis/encephalopathy (25%, secondary bacterial pneumonia (25%, and ARDS (25%. Eleven (55% children had chronic underlying medical conditions, including 8 (40% with chronic pulmonary diseases. Two influenza A- associated deaths were reported: i an 8-year old boy with pneumococcal encephalopathy following influenza infection died from cerebral edema, ii a 14-year-old boy with asthma bronchiale, cardiac malformation and Addison's disease died from cardiac and respiratory failure. For nine (45% patients, possibly permanent sequelae were reported (3 neurological, 3 pulmonary, 3 other sequelae. Conclusions Influenza-associated pneumonia and secondary bacterial infections are relevant complications of seasonal influenza in Germany. The incidence of severe influenza cases in PICUs was relatively low

Qualitative motivators and barriers to pandemic vs. seasonal influenza vaccination among healthcare workers: a content analysis.

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Prematunge, Chatura; Corace, Kimberly; McCarthy, Anne; Nair, Rama C; Roth, Virginia; Suh, Kathryn N; Garber, Gary

2014-12-12

Influenza is a major concern across healthcare environments. Annual vaccination of healthcare workers (HCW) remains a key mode of influenza prevention in healthcare settings. Yet influenza vaccine coverage among HCWs continues to be below recommended targets, in pandemic and non-pandemic settings. Thus, the primary objective of this analysis is to identify motivators and barriers to pandemic (panINFLU) and seasonal influenza vaccination (sINFLU) through the qualitative analysis of HCW provided reasons driving HCW's personal vaccination decisions. Data were collected from a multi-professional sample of HCWs via a cross-sectional survey study, conducted at a tertiary-care hospital in Ontario, Canada. HCW provided and ranked qualitative reasons for personal (1) panINFLU (pH1N1) and (2) sINFLU (2008/2009 season) vaccine uptake and avoidance were used to identify key vaccination motivators and barriers through content analysis methodology. Most HCW vaccination motivators and barriers were found to be similar for panINFLU and sINFLU vaccines. Personal motivators had the greatest impact on vaccination (panINFLU 29.9% and sINFLU 33.9%). Other motivators included preventing influenza in loved ones, patients, and community, and awareness of HCW role in influenza transmission. In contrast, concerns of vaccine safety and limited HCW knowledge of influenza vaccines (panINFLU 46.2% and sINFLU 37.3%). HCW vaccination during the pandemic was motivated by panINFLU related fear, epidemiology, and workplace pro-vaccination policies. HCW perceptions of accelerated panINFLU vaccine development and vaccine safety compromises, negative views of external sources (i.e. media, pharmaceutical companies, and regulatory agencies) and pandemic management strategies were barriers specific to panINFLU vaccine. HCW panINFLU and sINFLU vaccine coverage can increase if future vaccination programs (1) highlight personal vaccination benefits (2) emphasize the impact HCW non-vaccination on family

Influenza Transmission in the Mother-Infant Dyad Leads to Severe Disease, Mammary Gland Infection, and Pathogenesis by Regulating Host Responses.

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Paquette, Stéphane G; Banner, David; Huang, Stephen S H; Almansa, Raquel; Leon, Alberto; Xu, Luoling; Bartoszko, Jessica; Kelvin, David J; Kelvin, Alyson A

2015-10-01

Seasonal influenza viruses are typically restricted to the human upper respiratory tract whereas influenza viruses with greater pathogenic potential often also target extra-pulmonary organs. Infants, pregnant women, and breastfeeding mothers are highly susceptible to severe respiratory disease following influenza virus infection but the mechanisms of disease severity in the mother-infant dyad are poorly understood. Here we investigated 2009 H1N1 influenza virus infection and transmission in breastfeeding mothers and infants utilizing our developed infant-mother ferret influenza model. Infants acquired severe disease and mortality following infection. Transmission of the virus from infants to mother ferrets led to infection in the lungs and mother mortality. Live virus was also found in mammary gland tissue and expressed milk of the mothers which eventually led to milk cessation. Histopathology showed destruction of acini glandular architecture with the absence of milk. The virus was localized in mammary epithelial cells of positive glands. To understand the molecular mechanisms of mammary gland infection, we performed global transcript analysis which showed downregulation of milk production genes such as Prolactin and increased breast involution pathways indicated by a STAT5 to STAT3 signaling shift. Genes associated with cancer development were also significantly increased including JUN, FOS and M2 macrophage markers. Immune responses within the mammary gland were characterized by decreased lymphocyte-associated genes CD3e, IL2Ra, CD4 with IL1β upregulation. Direct inoculation of H1N1 into the mammary gland led to infant respiratory infection and infant mortality suggesting the influenza virus was able to replicate in mammary tissue and transmission is possible through breastfeeding. In vitro infection studies with human breast cells showed susceptibility to H1N1 virus infection. Together, we have shown that the host-pathogen interactions of influenza virus

The risk of airborne influenza transmission in passenger cars.

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Knibbs, L D; Morawska, L; Bell, S C

2012-03-01

Travel in passenger cars is a ubiquitous aspect of the daily activities of many people. During the 2009 influenza A(H1N1) pandemic a case of probable transmission during car travel was reported in Australia, to which spread via the airborne route may have contributed. However, there are no data to indicate the likely risks of such events, and how they may vary and be mitigated. To address this knowledge gap, we estimated the risk of airborne influenza transmission in two cars (1989 model and 2005 model) by employing ventilation measurements and a variation of the Wells-Riley model. Results suggested that infection risk can be reduced by not recirculating air; however, estimated risk ranged from 59% to 99·9% for a 90-min trip when air was recirculated in the newer vehicle. These results have implications for interrupting in-car transmission of other illnesses spread by the airborne route.

Detecting signals of seasonal influenza severity through age dynamics

DEFF Research Database (Denmark)

Lee, Elizabeth C.; Viboud, Cécile; Simonsen, Lone

2015-01-01

stages of an outbreak. To address the limitations of traditional indicators, we propose a novel severity index based on influenza age dynamics estimated from routine physician diagnosis data that can be used retrospectively and for early warning. METHODS: We developed a quantitative 'ground truth......' severity benchmark that synthesizes multiple traditional severity indicators from publicly available influenza surveillance data in the United States. Observing that the age distribution of cases may signal severity early in an epidemic, we constructed novel retrospective and early warning severity indexes....... The retrospective index was well correlated with the severity benchmark and correctly identified the two most severe seasons. The early warning index performance varied, but it projected 2007-08 as relatively severe 10 weeks prior to the epidemic peak. Influenza severity varied significantly among states within...

Exceptional influenza morbidity in summer season of 2017 in Israel may predict the vaccine efficiency in the coming winter.

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Pando, Rakefet; Sharabi, Sivan; Mandelboim, Michal

2018-03-07

Influenza infections are the leading cause of respiratory viral infections worldwide, and are mostly common in the winter season. The seasonal influenza vaccine is currently the most effective preventive modality against influenza infection. Immediately following each winter season the World Health Organization (WHO) announces the vaccine composition for the following winter. Unexpectedly, during the summer of 2017, in Israel, we observed in hospitalized patients, an exceptionally high numbers of Influenza positive cases. The majority of the influenza B infections were caused by influenza B/Yamagata lineage, which did not circulate in Israel in the previous winter, and most of the influenza A infections were caused by influenza A/H3N2, a strain similar to the strain that circulated in Israel in the previous winter. We therefore predict that these two viruses will circulate in the coming winter of 2017/18 and that the trivalent vaccine, which includes antigenically different viruses will be inefficient. Copyright © 2018 Elsevier Ltd. All rights reserved.

Seasonal influenza vaccination coverage rate of target groups in selected cities and provinces in China by season (2009/10 to 2011/12.

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Lei Zhou

Full Text Available BACKGROUND: The objectives of the survey were to identify the level of influenza vaccination coverage in China in three influenza seasons 2009/10 to 2011/12, and to find out potential predictors for seasonal influenza vaccination. METHODS: In September and October 2011, representative urban household telephone surveys were conducted in five provinces in China with a response rate of 6%. Four target groups were defined for analysis: 1 children ≤ 5 years old; 2 elderly persons aged ≥ 60 years old; 3 health care workers (persons working in the medical field and 4 chronically ill persons. RESULTS: The overall mean vaccination rate was 9.0%. Among the four target groups, the rate of vaccination of children aged ≤ 5 years old (mean = 26% was highest and the rate of elderly people aged ≥ 60 years old (mean = 7.4% was the lowest, while the rates of persons who suffer from a chronic illness (mean = 9.4% and health care workers (9.5% were similar. A subsidy for influenza vaccination, age group, health care workers, suffering from a chronic illness and living in Eastern China were independent significant predictors for influenza vaccination. CONCLUSIONS: The seasonal influenza vaccination coverage rates among urban populations in selected cities and provinces in China were far below previously reported rates in developed countries. Influenza vaccination coverage rates differed widely between different target groups and provinces in China. Subsidy policy might have a positive effect on influenza vaccination rate, but further cost-effectiveness studies, as well as the vaccination rate associated factors studies are still needed to inform strategies to increase coverage.

Trends of influenza B during the 2010-2016 seasons in 2 regions of north and south Italy: The impact of the vaccine mismatch on influenza immunisation strategy.

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Orsi, Andrea; Colomba, Giuseppina Maria Elena; Pojero, Fanny; Calamusa, Giuseppe; Alicino, Cristiano; Trucchi, Cecilia; Canepa, Paola; Ansaldi, Filippo; Vitale, Francesco; Tramuto, Fabio

2018-03-04

Influenza A and B viruses are responsible for respiratory infections, representing globally seasonal threats to human health. The 2 viral types often co-circulate and influenza B plays an important role in the spread of infection. A 6-year retrospective surveillance study was conducted between 2010 and 2016 in 2 large administrative regions of Italy, located in the north (Liguria) and in the south (Sicily) of the country, to describe the burden and epidemiology of both B/Victoria and B/Yamagata lineages in different healthcare settings. Influenza B viruses were detected in 5 of 6 seasonal outbreaks, exceeding influenza A during the season 2012-2013. Most of influenza B infections were found in children aged ≤ 14 y and significant differences were observed in the age-groups infected by the different lineages. B/Victoria strains prevailed in younger population than B/Yamagata, but also were more frequently found in the community setting. Conversely, B/Yamagata viruses were prevalent among hospitalized cases suggesting their potential role in the development of more severe disease. The relative proportions of viral lineages varied from year to year, resulting in different lineage-level mismatch for the B component of trivalent influenza vaccine. Our findings confirmed the need for continuous virological surveillance of seasonal epidemics and bring attention to the adoption of universal influenza immunization program in the childhood. The use of tetravalent vaccine formulations may be useful to improve the prevention and control of the influenza burden in general population.

Associations between seasonal influenza and meteorological parameters in Costa Rica, Honduras and Nicaragua.

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Soebiyanto, Radina P; Clara, Wilfrido A; Jara, Jorge; Balmaseda, Angel; Lara, Jenny; Lopez Moya, Mariel; Palekar, Rakhee; Widdowson, Marc-Alain; Azziz-Baumgartner, Eduardo; Kiang, Richard K

2015-11-04

Seasonal influenza affects a considerable proportion of the global population each year. We assessed the association between subnational influenza activity and temperature, specific humidity and rainfall in three Central America countries, i.e. Costa Rica, Honduras and Nicaragua. Using virologic data from each country's national influenza centre, rainfall from the Tropical Rainfall Measuring Mission and air temperature and specific humidity data from the Global Land Data Assimilation System, we applied logistic regression methods for each of the five sub-national locations studied. Influenza activity was represented by the weekly proportion of respiratory specimens that tested positive for influenza. The models were adjusted for the potentially confounding co-circulating respiratory viruses, seasonality and previous weeks' influenza activity. We found that influenza activity was proportionally associated (P<0.05) with specific humidity in all locations [odds ratio (OR) 1.21-1.56 per g/kg], while associations with temperature (OR 0.69-0.81 per °C) and rainfall (OR 1.01-1.06 per mm/day) were location-dependent. Among the meteorological parameters, specific humidity had the highest contribution (~3-15%) to the model in all but one location. As model validation, we estimated influenza activity for periods, in which the data was not used in training the models. The correlation coefficients between the estimates and the observed were ≤0.1 in 2 locations and between 0.6-0.86 in three others. In conclusion, our study revealed a proportional association between influenza activity and specific humidity in selected areas from the three Central America countries.

The Use of Ambient Humidity Conditions to Improve Influenza Forecast

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Shaman, J. L.; Kandula, S.; Yang, W.; Karspeck, A. R.

2017-12-01

Laboratory and epidemiological evidence indicate that ambient humidity modulates the survival and transmission of influenza. Here we explore whether the inclusion of humidity forcing in mathematical models describing influenza transmission improves the accuracy of forecasts generated with those models. We generate retrospective forecasts for 95 cities over 10 seasons in the United States and assess both forecast accuracy and error. Overall, we find that humidity forcing improves forecast performance and that forecasts generated using daily climatological humidity forcing generally outperform forecasts that utilize daily observed humidity forcing. These findings hold for predictions of outbreak peak intensity, peak timing, and incidence over 2- and 4-week horizons. The results indicate that use of climatological humidity forcing is warranted for current operational influenza forecast and provide further evidence that humidity modulates rates of influenza transmission.

Targeted vaccination in healthy school children - Can primary school vaccination alone control influenza?

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Thorrington, Dominic; Jit, Mark; Eames, Ken

2015-10-05

The UK commenced an extension to the seasonal influenza vaccination policy in autumn 2014 that will eventually see all healthy children between the ages of 2-16 years offered annual influenza vaccination. Models suggest that the new policy will be both highly effective at reducing the burden of influenza as well as cost-effective. We explore whether targeting vaccination at either primary or secondary schools would be more effective and/or cost-effective than the current strategy. An age-structured deterministic transmission dynamic SEIR-type mathematical model was used to simulate a national influenza outbreak in England. Costs including GP consultations, hospitalisations due to influenza and vaccinations were compared to potential gains in quality-adjusted life years achieved through vaccinating healthy children. Costs and benefits of the new JCVI vaccination policy were estimated over a single season, and compared to the hypothesised new policies of targeted and heterogeneous vaccination. All potential vaccination policies were highly cost-effective. Influenza transmission can be eliminated for a particular season by vaccinating both primary and secondary school children, but not by vaccinating only one group. The most cost-effective policy overall is heterogeneous vaccination coverage with 48% uptake in primary schools and 34% in secondary schools. The Joint Committee on Vaccination and Immunisation can consider a modification to their policy of offering seasonal influenza vaccinations to all healthy children of ages 2-16 years. Copyright © 2015 Elsevier Ltd. All rights reserved.

Spatial modeling of wild bird risk factors to investigate highly pathogenic A(H5N1) avian influenza virus transmission

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Prosser, Diann J.; Hungerford, Laura L.; Erwin, R. Michael; Ottinger, Mary Ann; Takekawa, John Y.; Newman, Scott H.; Xiao, Xianming; Ellis, Erie C.

2016-01-01

One of the longest-persisting avian influenza viruses in history, highly pathogenic avian influenza virus (HPAIV) A(H5N1), continues to evolve after 18 years, advancing the threat of a global pandemic. Wild waterfowl (family Anatidae), are reported as secondary transmitters of HPAIV, and primary reservoirs for low-pathogenic avian influenza viruses, yet spatial inputs for disease risk modeling for this group have been lacking. Using GIS and Monte Carlo simulations, we developed geospatial indices of waterfowl abundance at 1 and 30 km resolutions and for the breeding and wintering seasons for China, the epicenter of H5N1. Two spatial layers were developed: cumulative waterfowl abundance (WAB), a measure of predicted abundance across species, and cumulative abundance weighted by H5N1 prevalence (WPR), whereby abundance for each species was adjusted based on prevalence values then totaled across species. Spatial patterns of the model output differed between seasons, with higher WAB and WPR in the northern and western regions of China for the breeding season and in the southeast for the wintering season. Uncertainty measures indicated highest error in southeastern China for both WAB and WPR. We also explored the effect of resampling waterfowl layers from 1 km to 30 km resolution for multi-scale risk modeling. Results indicated low average difference (less than 0.16 and 0.01 standard deviations for WAB and WPR, respectively), with greatest differences in the north for the breeding season and southeast for the wintering season. This work provides the first geospatial models of waterfowl abundance available for China. The indices provide important inputs for modeling disease transmission risk at the interface of poultry and wild birds. These models are easily adaptable, have broad utility to both disease and conservation needs, and will be available to the scientific community for advanced modeling applications.

Mapping risk of avian influenza transmission at the interface of domestic poultry and wild birds

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Prosser, Diann J.; Hungerford, Laura L.; Erwin, R. Michael; Ottinger, Mary Ann; Takekawa, John Y.; Ellis, Erle C.

2013-01-01

Emergence of avian influenza viruses with high lethality to humans, such as the currently circulating highly pathogenic A(H5N1) (emerged in 1996) and A(H7N9) cause serious concern for the global economic and public health sectors. Understanding the spatial and temporal interface between wild and domestic populations, from which these viruses emerge, is fundamental to taking action. This information, however, is rarely considered in influenza risk models, partly due to a lack of data. We aim to identify areas of high transmission risk between domestic poultry and wild waterfowl in China, the epicenter of both viruses. Two levels of models were developed: one that predicts hotspots of novel virus emergence between domestic and wild birds, and one that incorporates H5N1 risk factors, for which input data exists. Models were produced at 1 and 30 km spatial resolution, and two temporal seasons. Patterns of risk varied between seasons with higher risk in the northeast, central-east, and western regions of China during spring and summer, and in the central and southeastern regions during winter. Monte-Carlo uncertainty analyses indicated varying levels of model confidence, with lowest errors in the densely populated regions of eastern and southern China. Applications and limitations of the models are discussed within.

Seasonal influenza vaccination of healthcare workers: systematic review of qualitative evidence

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Theo Lorenc

2017-11-01

Full Text Available Abstract Background Most countries recommend that healthcare workers (HCWs are vaccinated seasonally against influenza in order to protect themselves and patients. However, in many cases coverage remains low. A range of strategies have been implemented to increase uptake. Qualitative evidence can help in understanding the context of interventions, including why interventions may fail to achieve the desired effect. This study aimed to synthesise evidence on HCWs’ perceptions and experiences of vaccination for seasonal influenza. Methods Systematic review of qualitative evidence. We searched MEDLINE, EMBASE and CINAHL and included English-language studies which reported substantive qualitative data on the vaccination of HCWs for seasonal influenza. Findings were synthesised thematically. Results Twenty-five studies were included in the review. HCWs may be motivated to accept vaccination to protect themselves and their patients against infection. However, a range of beliefs may act as barriers to vaccine uptake, including concerns about side-effects, scepticism about vaccine effectiveness, and the belief that influenza is not a serious illness. HCWs value their autonomy and professional responsibility in making decisions about vaccination. The implementation of interventions to promote vaccination uptake may face barriers both from HCWs’ personal beliefs and from the relationships between management and employees within the targeted organisations. Conclusions HCWs’ vaccination behaviour needs to be understood in the context of HCWs’ relationships with each other, with management and with patients. Interventions to promote vaccination should take into account both the individual beliefs of targeted HCWs and the organisational context within which they are implemented.

Parents′ Perception and their Decision on their Children′s Vaccination Against Seasonal Influenza in Guangzhou

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Lei He

2015-01-01

Full Text Available Background: Seasonal influenza epidemic occurs every year in Guangzhou, which can affect all age groups. Young children are the most susceptible targets. Parents can decide whether to vaccinate their children or not based on their own consideration in China. The aim of this study was to identify factors that are important for parental decisions on vaccinating their children against seasonal influenza based on a modified health belief model (HBM. Methods: A cross-sectional study was conducted in Guangzhou, China. A total of 335 parents who had at least on child aged between 6 months and 3 years were recruited from women and children′s hospital in Guangzhou, China. Each eligible subject was invited for a face-to-face interview based on a standardized questionnaire. Results: Uptake of seasonal influenza within the preceding 12 months among the target children who aged between 6 months and 36 months was 47.7%. Around 62.4% parents indicated as being "likely/very likely" to take their children for seasonal influenza vaccination in the next 12 months. The hierarchical logistic regression model showed that children′s age (odds ratio [OR] =2.59, 95% confidence interval [CI]: 1.44-4.68, social norm (OR = 2.08, 95% CI: 1.06-4.06 and perceived control (OR = 2.96, 95% CI: 1.60-5.50 were significantly and positively associated with children′s vaccination uptake within the preceding 12 months; children with a history of taking seasonal influenza vaccine (OR = 2.50, 95% CI: 1.31-4.76, perceived children′s health status (OR = 3.36, 95% CI: 1.68-6.74, worry/anxious about their children influenza infection (OR = 2.31, 95% CI: 1.19-4.48 and perceived control (OR = 3.21, 95% CI: 1.65-6.22 were positively association with parental intention to vaccinate their children in the future 12 months. However, anticipated more regret about taking children for the vaccination was associated with less likely to vaccinate children within the preceding 12 months (OR = 0

The cost-effectiveness of vaccinating pregnant women against seasonal influenza in England and Wales.

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Jit, Mark; Cromer, Deborah; Baguelin, Marc; Stowe, Julia; Andrews, Nick; Miller, Elizabeth

2010-12-10

We assessed the cost-effectiveness of vaccinating pregnant women against seasonal influenza in England and Wales, taking into account the timing of vaccination relative to both the influenza season and trimester of pregnancy. Women were assumed to be vaccinated in their second or third trimester. Vaccination between September and December was found to have an incremental cost-effectiveness ratio of £23,000 per quality adjusted life year (QALY) (95% CI £10,000-£140,000) if it is assumed that infants are partially protected through their mothers, and of £28,000 per QALY gained (95% CI £13,000-£200,000) if infants are not protected. If some vaccine protection lasts for a second season, then the ratio is only £15,000 per QALY gained (95% CI £6,000-£93,000). Most of the benefit of vaccination is in preventing symptomatic episodes, regardless of health care resource use. Extending vaccination beyond December is unlikely to be cost-effective unless there is good protection into a second influenza season. Key sources of uncertainty are the cost of vaccine delivery and the quality of life detriment due to a clinically apparent episode of confirmed influenza. The cost of vaccine purchase itself is relatively low. Copyright © 2010 Elsevier Ltd. All rights reserved.

Virulence determinants of pandemic influenza viruses

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Tscherne, Donna M.; García-Sastre, Adolfo

2011-01-01

Influenza A viruses cause recurrent, seasonal epidemics and occasional global pandemics with devastating levels of morbidity and mortality. The ability of influenza A viruses to adapt to various hosts and undergo reassortment events ensures constant generation of new strains with unpredictable degrees of pathogenicity, transmissibility, and pandemic potential. Currently, the combination of factors that drives the emergence of pandemic influenza is unclear, making it impossible to foresee the details of a future outbreak. Identification and characterization of influenza A virus virulence determinants may provide insight into genotypic signatures of pathogenicity as well as a more thorough understanding of the factors that give rise to pandemics. PMID:21206092

Assessing exposure risks for aquatic organisms posed by Tamiflu use under seasonal influenza and pandemic conditions

International Nuclear Information System (INIS)

Chen, Wei-Yu; Lin, Chia-Jung; Liao, Chung-Min

2014-01-01

Environmental pollution by anti-influenza drugs is increasingly recognized as a threat to aquatic environments. However, little is known about empirical data on risk effects posed by environmentally relevant concentrations of anti-influenza drug based on recently published ecotoxicological researches in Taiwan. Here we linked ecotoxicology models with an epidemiological scheme to assess exposure risks of aquatic organisms and environmental hazards posed by antiviral oseltamivir (Tamiflu) use in Taiwan. Built on published bioassays, we used probabilistic risk assessment model to estimate potential threats of environmentally relevant hazards on algae, daphnid, and zerbrafish. We found that Tamiflu use was unlikely to pose a significant chronic environmental risk to daphnia and zebrafish during seasonal influenza. However, the chronic environmental risk posed by Tamiflu use during pandemic was alarming. We conclude that no significant risk to algal growth was found during seasonal influenza and high pandemic Tamiflu use. -- Highlights: • Environmentally relevant concentrations of anti-influenza drug have ecotoxicologically important effects. • Tamiflu is unlikely to pose a significant chronic environmental risk during seasonal influenza. • Chronic environmental risk posed by Tamiflu during pandemic is alarming. • Tertiary process in sewage treatment plants is crucial in mitigating Tamiflu exposure risk. -- A probabilistic framework can be used for assessing exposure risks posed by environmentally relevant concentrations of anti-influenza drug in aquatic ecosystems

Case of seasonal reassortant A(H1N2) influenza virus infection, the Netherlands, March 2018.

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Meijer, Adam; Swaan, Corien M; Voerknecht, Martin; Jusic, Edin; van den Brink, Sharon; Wijsman, Lisa A; Voordouw, Bettie Cg; Donker, Gé A; Sleven, Jacqueline; Dorigo-Zetsma, Wendelien W; Svraka, Sanela; van Boven, Michiel; Haverkate, Manon R; Timen, Aura; van Dissel, Jaap T; Koopmans, Marion Pg; Bestebroer, Theo M; Fouchier, Ron Am

2018-04-01

A seasonal reassortant A(H1N2) influenza virus harbouring genome segments from seasonal influenza viruses A(H1N1)pdm09 (HA and NS) and A(H3N2) (PB2, PB1, PA, NP, NA and M) was identified in March 2018 in a 19-months-old patient with influenza-like illness (ILI) who presented to a general practitioner participating in the routine sentinel surveillance of ILI in the Netherlands. The patient recovered fully. Further epidemiological and virological investigation did not reveal additional cases.

Transmission and reassortment of avian influenza viruses at the Asian-North American interface.

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Ramey, Andrew M; Pearce, John M; Ely, Craig R; Guy, Lisa M Sheffield; Irons, David B; Derksen, Dirk V; Ip, Hon S

2010-10-25

Twenty avian influenza viruses were isolated from seven wild migratory bird species sampled at St. Lawrence Island, Alaska. We tested predictions based on previous phylogenetic analyses of avian influenza viruses that support spatially dependent trans-hemispheric gene flow and frequent interspecies transmission at a location situated at the Asian-North American interface. Through the application of phylogenetic and genotypic approaches, our data support functional dilution by distance of trans-hemispheric reassortants and interspecific virus transmission. Our study confirms infection of divergent avian taxa with nearly identical avian influenza strains in the wild. Findings also suggest that H16N3 viruses may contain gene segments with unique phylogenetic positions and that further investigation of how host specificity may impact transmission of H13 and H16 viruses is warranted. Copyright © 2010. Published by Elsevier Inc.

Influenza seasonality goes south in the Yucatan Peninsula: The case for a different influenza vaccine calendar in this Mexican region.

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Ayora-Talavera, Guadalupe; Flores, Gerardo Montalvo-Zurbia; Gómez-Carballo, Jesus; González-Losa, Refugio; Conde-Ferraez, Laura; Puerto-Solís, Marylin; López-Martínez, Irma; Díaz-Quiñonez, Alberto; Barrera-Badillo, Gisela; Acuna-Soto, Rodolfo; Livinski, Alicia A; Alonso, Wladimir J

2017-08-24

While vaccination may be relatively straightforward for regions with a well-defined winter season, the situation is quite different for tropical regions. Influenza activity in tropical regions might be out of phase with the dynamics predicted for their hemispheric group thereby impacting the effectiveness of the immunization campaign. To investigate how the climatic diversity of Mexico hinders its existing influenza immunization strategy and to suggest that the hemispheric vaccine recommendations be tailored to the regional level in order to optimize vaccine effectiveness. We studied the seasonality of influenza throughoutMexico by modeling virological and mortality data.De-trended time series of each Mexican state were analyzed by Fourier decomposition to describe the amplitude and timing of annual influenza epidemic cycles and to compare with each the timing of the WHO's Northern and Southern Hemispheric vaccination schedule. The timings of the primary (major) peaks of both virological and mortality data for most Mexican states are well aligned with the Northern Hemisphere winter (December-February) and vaccine schedule. However, influenza peaks in September in the three states of the Yucatan Peninsula. Influenza-related mortality also peaks in September in Quintana Roo and Yucatan whereas it peaks in May in Campeche. As the current timing of vaccination in Mexico is between October and November, more than half of the annual influenza cases have already occurred in the Yucatan Peninsula states by the time the Northern Hemispheric vaccine is delivered and administered. The current Northern Hemispheric influenza calendar adopted for Mexico is not optimal for the Yucatan Peninsula states thereby likely reducing the effectiveness of the immunization of the population. We recommend that Mexico tailor its immunization strategy to better reflect its climatologic and epidemiological diversity and adopt the WHO Southern Hemisphere influenza vaccine and schedule for the

Effectiveness of seasonal influenza vaccine in preventing influenza primary care visits and hospitalisation in Auckland, New Zealand in 2015: interim estimates.

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Bissielo, A; Pierse, N; Huang, Q S; Thompson, M G; Kelly, H; Mishin, V P; Turner, N

2016-01-01

Preliminary results for influenza vaccine effectiveness (VE) against acute respiratory illness with circulating laboratory-confirmed influenza viruses in New Zealand from 27 April to 26 September 2015, using a case test-negative design were 36% (95% confidence interval (CI): 11-54) for general practice encounters and 50% (95% CI: 20-68) for hospitalisations. VE against hospitalised influenza A(H3N2) illnesses was moderate at 53% (95% CI: 6-76) but improved compared with previous seasons.

Epidemiology of Hospital Admissions with Influenza during the 2013/2014 Northern Hemisphere Influenza Season: Results from the Global Influenza Hospital Surveillance Network

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Puig-Barberà, Joan; Natividad-Sancho, Angels; Trushakova, Svetlana; Sominina, Anna; Pisareva, Maria; Ciblak, Meral A.; Badur, Selim; Yu, Hongjie; Cowling, Benjamin J.; El Guerche-Séblain, Clotilde; Mira-Iglesias, Ainara; Kisteneva, Lidiya; Stolyarov, Kirill; Yurtcu, Kubra; Feng, Luzhao; López-Labrador, Xavier; Burtseva, Elena

2016-01-01

Background The Global Influenza Hospital Surveillance Network was established in 2012 to obtain valid epidemiologic data on hospital admissions with influenza-like illness. Here we describe the epidemiology of admissions with influenza within the Northern Hemisphere sites during the 2013/2014 influenza season, identify risk factors for severe outcomes and complications, and assess the impact of different influenza viruses on clinically relevant outcomes in at-risk populations. Methods Eligible consecutive admissions were screened for inclusion at 19 hospitals in Russia, Turkey, China, and Spain using a prospective, active surveillance approach. Patients that fulfilled a common case definition were enrolled and epidemiological data were collected. Risk factors for hospitalization with laboratory-confirmed influenza were identified by multivariable logistic regression. Findings 5303 of 9507 consecutive admissions were included in the analysis. Of these, 1086 were influenza positive (534 A(H3N2), 362 A(H1N1), 130 B/Yamagata lineage, 3 B/Victoria lineage, 40 untyped A, and 18 untyped B). The risk of hospitalization with influenza (adjusted odds ratio [95% confidence interval]) was elevated for patients with cardiovascular disease (1.63 [1.33–2.02]), asthma (2.25 [1.67–3.03]), immunosuppression (2.25 [1.23–4.11]), renal disease (2.11 [1.48–3.01]), liver disease (1.94 [1.18–3.19], autoimmune disease (2.97 [1.58–5.59]), and pregnancy (3.84 [2.48–5.94]). Patients without comorbidities accounted for 60% of admissions with influenza. The need for intensive care or in-hospital death was not significantly different between patients with or without influenza. Influenza vaccination was associated with a lower risk of confirmed influenza (adjusted odds ratio = 0.61 [0.48–0.77]). Conclusions Influenza infection was detected among hospital admissions with and without known risk factors. Pregnancy and underlying comorbidity increased the risk of detecting influenza

Influenza activity in Cambodia during 2006-2008

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Zhou Weigong

2009-10-01

Full Text Available Abstract Background There is little information about influenza disease among the Cambodian population. To better understand the dynamics of influenza in Cambodia, the Cambodian National Influenza Center (NIC was established in August 2006. To continuously monitor influenza activity, a hospital based sentinel surveillance system for ILI (influenza like illness with a weekly reporting and sampling scheme was established in five sites in 2006. In addition, hospital based surveillance of acute lower respiratory infection (ALRI cases was established in 2 sites. Methods The sentinel sites collect weekly epidemiological data on ILI patients fulfilling the case definition, and take naso-pharyngeal specimens from a defined number of cases per week. The samples are tested in the Virology Unit at the Institut Pasteur in Phnom Penh. From each sample viral RNA was extracted and amplified by a multiplex RT-PCR detecting simultaneously influenza A and influenza B virus. Influenza A viruses were then subtyped and analyzed by hemagglutination inhibition assay. Samples collected by the ALRI system were tested with the same approach. Results From 2006 to 2008, influenza circulation was observed mainly from June to December, with a clear seasonal peak in October shown in the data from 2008. Conclusion Influenza activity in Cambodia occurred during the rainy season, from June to December, and ended before the cool season (extending usually from December to February. Although Cambodia is a tropical country geographically located in the northern hemisphere, influenza activity has a southern hemisphere transmission pattern. Together with the antigenic analysis of the circulating strains, it is now possible to give better influenza vaccination recommendation for Cambodia.

Genetic data provide evidence for wind-mediated transmission of highly pathogenic avian influenza.

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Ypma, Rolf J F; Jonges, Marcel; Bataille, Arnaud; Stegeman, Arjan; Koch, Guus; van Boven, Michiel; Koopmans, Marion; van Ballegooijen, W Marijn; Wallinga, Jacco

2013-03-01

Outbreaks of highly pathogenic avian influenza in poultry can cause severe economic damage and represent a public health threat. Development of efficient containment measures requires an understanding of how these influenza viruses are transmitted between farms. However, the actual mechanisms of interfarm transmission are largely unknown. Dispersal of infectious material by wind has been suggested, but never demonstrated, as a possible cause of transmission between farms. Here we provide statistical evidence that the direction of spread of avian influenza A(H7N7) is correlated with the direction of wind at date of infection. Using detailed genetic and epidemiological data, we found the direction of spread by reconstructing the transmission tree for a large outbreak in the Netherlands in 2003. We conservatively estimate the contribution of a possible wind-mediated mechanism to the total amount of spread during this outbreak to be around 18%.

On the epidemiology of influenza

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Scragg Robert

2008-02-01

Full Text Available Abstract The epidemiology of influenza swarms with incongruities, incongruities exhaustively detailed by the late British epidemiologist, Edgar Hope-Simpson. He was the first to propose a parsimonious theory explaining why influenza is, as Gregg said, "seemingly unmindful of traditional infectious disease behavioral patterns." Recent discoveries indicate vitamin D upregulates the endogenous antibiotics of innate immunity and suggest that the incongruities explored by Hope-Simpson may be secondary to the epidemiology of vitamin D deficiency. We identify – and attempt to explain – nine influenza conundrums: (1 Why is influenza both seasonal and ubiquitous and where is the virus between epidemics? (2 Why are the epidemics so explosive? (3 Why do they end so abruptly? (4 What explains the frequent coincidental timing of epidemics in countries of similar latitude? (5 Why is the serial interval obscure? (6 Why is the secondary attack rate so low? (7 Why did epidemics in previous ages spread so rapidly, despite the lack of modern transport? (8 Why does experimental inoculation of seronegative humans fail to cause illness in all the volunteers? (9 Why has influenza mortality of the aged not declined as their vaccination rates increased? We review recent discoveries about vitamin D's effects on innate immunity, human studies attempting sick-to-well transmission, naturalistic reports of human transmission, studies of serial interval, secondary attack rates, and relevant animal studies. We hypothesize that two factors explain the nine conundrums: vitamin D's seasonal and population effects on innate immunity, and the presence of a subpopulation of "good infectors." If true, our revision of Edgar Hope-Simpson's theory has profound implications for the prevention of influenza.

Hand hygiene to reduce community transmission of influenza and acute respiratory tract infection: a systematic review

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Warren‐Gash, Charlotte; Fragaszy, Ellen; Hayward, Andrew C.

2012-01-01

Please cite this paper as: Warren‐Gash et al. (2012) Hand hygiene to reduce community transmission of influenza and acute respiratory tract infection: a systematic review. Influenza and Other Respiratory Viruses DOI: 10.1111/irv.12015. Hand hygiene may be associated with modest protection against some acute respiratory tract infections, but its specific role in influenza transmission in different settings is unclear. We aimed to review evidence that improving hand hygiene reduces primary and secondary transmission of (i) influenza and (ii) acute respiratory tract infections in community settings. We searched Medline, Embase, Global Health and Cochrane databases up to 13 February 2012 for reports in any language of original research investigating the effect of hand hygiene on influenza or acute respiratory tract infection where aetiology was unspecified in community settings including institutions such as schools, and domestic residences. Data were presented and quality rated across outcomes according to the Grading of Recommendations Assessment, Development and Evaluation system. Sixteen articles met inclusion criteria. There was moderate to low‐quality evidence of a reduction in both influenza and respiratory tract infection with hand hygiene interventions in schools, greatest in a lower–middle‐income setting. There was high‐quality evidence of a small reduction in respiratory infection in childcare settings. There was high‐quality evidence for a large reduction in respiratory infection with a hand hygiene intervention in squatter settlements in a low‐income setting. There was moderate‐ to high‐quality evidence of no effect on secondary transmission of influenza in households that had already experienced an index case. While hand hygiene interventions have potential to reduce transmission of influenza and acute respiratory tract infections, their effectiveness varies depending on setting, context and compliance. PMID:23043518

Hand hygiene to reduce community transmission of influenza and acute respiratory tract infection: a systematic review.

OpenAIRE

Warren-Gash, C; Fragaszy, E; Hayward, AC

2012-01-01

: Please cite this paper as: Warren-Gash et al. (2012) Hand hygiene to reduce community transmission of influenza and acute respiratory tract infection: a systematic review. Influenza and Other Respiratory Viruses DOI: 10.1111/irv.12015. Hand hygiene may be associated with modest protection against some acute respiratory tract infections, but its specific role in influenza transmission in different settings is unclear. We aimed to review evidence that improving hand hygiene reduces primary an...

Predominance of influenza A(H1N1)pdm09 virus genetic subclade 6B.1 and influenza B/Victoria lineage viruses at the start of the 2015/16 influenza season in Europe

DEFF Research Database (Denmark)

Broberg, Eeva; Melidou, Angeliki; Prosenc, Katarina

2016-01-01

Influenza A(H1N1)pdm09 viruses predominated in the European influenza 2015/16 season. Most analysed viruses clustered in a new genetic subclade 6B.1, antigenically similar to the northern hemisphere vaccine component A/California/7/2009. The predominant influenza B lineage was Victoria compared...

A cross-sectional survey to evaluate knowledge, attitudes and practices (KAP regarding seasonal influenza vaccination among European travellers to resource-limited destinations

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Szucs Thomas D

2010-07-01

Full Text Available Abstract Background Influenza is one of the most common vaccine-preventable diseases in travellers. By performing two cross-sectional questionnaire surveys during winter 2009 and winter 2010 among European travellers to resource-limited destinations, we aimed to investigate knowledge, attitudes and practices (KAP regarding seasonal influenza vaccination. Methods Questionnaires were distributed in the waiting room to the visitors of the University of Zurich Centre for Travel' Health (CTH in January and February 2009 and January 2010 prior to travel health counselling (CTH09 and CTH10. Questions included demographic data, travel-related characteristics and KAP regarding influenza vaccination. Data were analysed by using SPSS® version 14.0 for Windows. Differences in proportions were compared using the Chi-square test and the significance level was set at p ≤ 0.05. Predictors for seasonal and pandemic influenza vaccination were determined by multiple logistic regression analyses. Results With a response rate of 96.6%, 906 individuals were enrolled and 868 (92.5% provided complete data. Seasonal influenza vaccination coverage was 13.7% (n = 119. Only 43 (14.2% participants were vaccinated against pandemic influenza A/H1N1, mostly having received both vaccines simultaneously, the seasonal and pandemic one. Job-related purposes (44, 37%, age > 64 yrs (25, 21% and recommendations of the family physician (27, 22.7% were the most often reported reasons for being vaccinated. In the multiple logistic regression analyses of the pooled data increasing age (OR = 1.03, 95% CI 1.01 - 1.04, a business trip (OR = 0.39, 95% CI 0.17 - 0.92 and seasonal influenza vaccination in the previous winter seasons (OR = 12.91, 95% CI 8.09 - 20.58 were independent predictors for seasonal influenza vaccination in 2009 or 2010. Influenza vaccination recommended by the family doctor (327, 37.7%, travel to regions with known high risk of influenza (305, 35.1%, and influenza

Predictors of seasonal influenza vaccination behaviour among nurses and implications for interventions to increase vaccination uptake: A cross-sectional survey.

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Kan, Ting; Ai, Jiaqi; Zhang, Jing; Liu, Xiaohong

2018-03-01

Vaccination has been proven the most effective method to prevent seasonal influenza. Nurses' vaccination can provide protection against influenza not only for themselves but also for patients they take care of. However, vaccination coverage of nurses is suboptimal worldwide, especially in China. The influencing factors need to be explored so as to develop specific, workable strategies to improve nurses' vaccination behaviour. To explore predictors of their vaccination behaviour, identify the motivators and barriers of vaccination, and provide implications for future interventions. A cross-sectional convenience sampling questionnaire survey. Nine hospitals including five tertiary hospitals, two secondary hospitals, and two primary hospitals in Shanghai, China. A total of 1000 nurses from the nine hospitals were invited to participate in this survey. Among them, 921 nurses responded and 895 returned valid questionnaires that were used in data analysis. The Chinese version of the King's Nurses' Influenza Vaccination Questionnaire was used as the survey instrument and distributed to the participants during February-November 2012. Descriptive statistics, univariate analyses, and multivariate analyses were conducted to explore the predictors of nurses' vaccination behaviour. Overall, 8.8% of the respondents received seasonal influenza vaccination in the past influenza season (2011/2012 season). Nurses had averagely received 0.38 ± 0.71 influenza vaccines during the past five influenza seasons (2007/2008 to 2011/2012 season). Predictors of nurses' vaccination status were clinical specialty, knowledge about influenza vaccination [1.331 (1.102, 1.608), p = 0.003], internal health locus of control [0.910 (0.845, 0.980), p = 0.013], chance health locus of control [1.075 (1.023, 1.130), p = 0.004]and powerful others health of locus control [1.166 (1.083, 1.255), p behaviour against seasonal influenza. Vaccination coverage in this population was suboptimal

Calculating the potential for within-flight transmission of influenza A (H1N1

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Blower Sally

2009-12-01

Full Text Available Abstract Background Clearly air travel, by transporting infectious individuals from one geographic location to another, significantly affects the rate of spread of influenza A (H1N1. However, the possibility of within-flight transmission of H1N1 has not been evaluated; although it is known that smallpox, measles, tuberculosis, SARS and seasonal influenza can be transmitted during commercial flights. Here we present the first quantitative risk assessment to assess the potential for within-flight transmission of H1N1. Methods We model airborne transmission of infectious viral particles of H1N1 within a Boeing 747 using methodology from the field of quantitative microbial risk assessment. Results The risk of catching H1N1 will essentially be confined to passengers travelling in the same cabin as the source case. Not surprisingly, we find that the longer the flight the greater the number of infections that can be expected. We calculate that H1N1, even during long flights, poses a low to moderate within-flight transmission risk if the source case travels First Class. Specifically, 0-1 infections could occur during a 5 hour flight, 1-3 during an 11 hour flight and 2-5 during a 17 hour flight. However, within-flight transmission could be significant, particularly during long flights, if the source case travels in Economy Class. Specifically, two to five infections could occur during a 5 hour flight, 5-10 during an 11 hour flight and 7-17 during a 17 hour flight. If the aircraft is only partially loaded, under certain conditions more infections could occur in First Class than in Economy Class. During a 17 hour flight, a greater number of infections would occur in First Class than in Economy if the First Class Cabin is fully occupied, but Economy class is less than 30% full. Conclusions Our results provide insights into the potential utility of air travel restrictions on controlling influenza pandemics in the winter of 2009/2010. They show travel by one

Molecular epidemiology of influenza B virus among hospitalized pediatric patients in Northern Italy during the 2015-16 season.

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Antonio Piralla

Full Text Available The influenza B viruses belong to two lineages distinguished by their genetic and antigenic characteristics, which are referred to as the Yamagata and Victoria lineages, designated after their original isolates, B/Yamagata/16/88 and B/Victoria/2/87. The primary aim of this study was to evaluate the molecular characteristics of influenza B viruses circulating in a region of Northern Italy, Lombardia, during the influenza season of 2015-2016.Influenza B virus was detected using a respiratory virus panel of assays and an influenza B-specific real-time polymerase chain reaction. The complete influenza B hemagglutinin (HA gene was amplified and sequenced directly from clinical specimens. Phylogenetic analysis was performed using nucleotide sequences.A total of 71 hospitalized pediatric patients were influenza B positive. Phylogenetic analysis showed that the great majority of influenza B strains (66/71, 93.0% belonged to the Victoria-lineage and were antigenically like vaccine strain (B/Brisbane/60/2008 included only in the quadrivalent vaccine. In the detected influenza B strains, a series of amino acid changes were observed in the antigenic regions: I117V, V124A, N129D, V146I, N197D, T199A, and A202T. However, only 2 amino acid changes were observed in the HA regions involved in receptor binding or in antibody recognition.All the influenza B strains identified in this study belonged to the influenza B Victoria lineage not included in the trivalent vaccine commonly used by the general population during the 2015-2016 influenza season in Italy. This indicates that protection against influenza B infection in the vaccinated population was in general very poor during the 2015-2016 influenza season.

Fatal Cases of Seasonal Influenza in Russia in 2015-2016.

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Ilyicheva, T; Durymanov, A; Susloparov, I; Kolosova, N; Goncharova, N; Svyatchenko, S; Petrova, O; Bondar, A; Mikheev, V; Ryzhikov, A

2016-01-01

The influenza epidemic in 2015-2016 in Russia is characterized by a sharp increase of influenza cases (beginning from the second week of 2016) with increased fatalities. Influenza was confirmed in 20 fatal cases registered among children (0-10 years), in 5 cases among pregnant women, and in 173 cases among elderly people (60 years and older). Two hundred and ninety nine people died from influenza were patients with some chronic problems. The overwhelming majority among the deceased (more than 98%) were not vaccinated against influenza. We isolated 109 influenza A(H1N1)pdm09 and one A(H3N2) virus strains from 501 autopsy material samples. The antigenic features of the strains were similar to the vaccine strains. A phylogenic analysis of hemagglutinin revealed that influenza A(H1N1)pdm09 virus strains belonged to 6B genetic group that had two main dominant subgroups during the 2015-2016 season. In Russia strains of the first group predominated. We registered an increased proportion of strains with D222G mutation in receptor-binding site. A herd immunity analysis carried out immediately prior to the epidemic showed that 34.4% blood sera samples collected in different regions of Russia were positive to A/California/07/09(H1N1)pdm09. We came to a conclusion that public awareness enhancement is necessary to reduce unreasonable refusals of vaccination.

Probable Tiger-to-Tiger Transmission of Avian Influenza H5N1

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Thanawongnuwech, Roongroje; Amonsin, Alongkorn; Tantilertcharoen, Rachod; Damrongwatanapokin, Sudarat; Theamboonlers, Apiradee; Payungporn, Sunchai; Nanthapornphiphat, Kamonchart; Ratanamungklanon, Somchuan; Tunak, Eakchai; Songserm, Thaweesak; Vivatthanavanich, Veravit; Lekdumrongsak, Thawat; Kesdangsakonwut, Sawang; Tunhikorn, Schwann

2005-01-01

During the second outbreak of avian influenza H5N1 in Thailand, probable horizontal transmission among tigers was demonstrated in the tiger zoo. Sequencing and phylogenetic analysis of those viruses showed no differences from the first isolate obtained in January 2004. This finding has implications for influenza virus epidemiology and pathogenicity in mammals. PMID:15890122

Neuraminidase inhibitor susceptibility profile of human influenza viruses during the 2016-2017 influenza season in Mainland China.

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Huang, Weijuan; Cheng, Yanhui; Li, Xiyan; Tan, Minju; Wei, Hejiang; Zhao, Xiang; Xiao, Ning; Dong, Jie; Wang, Dayan

2018-06-01

To understand the current situation of antiviral-resistance of influenza viruses to neuraminidase inhibitors (NAIs) in Mainland China, The antiviral-resistant surveillance data of the circulating influenza viruses in Mainland China during the 2016-2017 influenza season were analyzed. The total 3215 influenza viruses were studied to determine 50% inhibitory concentration (IC 50 ) for oseltamivir and zanamivir using a fluorescence-based assay. Approximately 0.3% (n = 10) of viruses showed either highly reduced inhibition (HRI) or reduced inhibition (RI) against at least one NAI. The most common neuraminidase (NA) amino acid substitution was H275Y in A (H1N1)pdm09 virus, which confers HRI by oseltamivir. Two A (H1N1)pdm09 viruses contained a new NA amino acid substitution respectively, S110F and D151E, which confers RI by oseltamivir or/and zanamivir. Two B/Victoria-lineage viruses harbored a new NA amino acid substitution respectively, H134Q and S246P, which confers RI by zanamivir. One B/Victoria-lineage virus contained dual amino acid substitution NA P124T and V422I, which confers HRI by zanamivir. One B/Yamagata-lineage virus was a reassortant virus that haemagglutinin (HA) from B/Yamagata-lineage virus and NA from B/Victoria-lineage virus, defined as B/Yamagata-lineage virus confers RI by oseltamivir, but as B/Victoria-lineage virus confers normal inhibition by oseltamivir. All new substitutions that have not been reported before, the correlation of these substitutions and observed changes in IC 50 should be further assessed. During the 2016-2017 influenza season in Mainland China the majority tested viruses were susceptible to oseltamivir and zanamivir. Hence, NAIs remain the recommended antiviral for treatment and prophylaxis of influenza virus infections. Copyright © 2018 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Addressing ethical issues in pandemic influenza planning: equitable access to scare medical resources

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Verweij, M.F.

2007-01-01

It is generally expected that sooner or later a novel influenza A virus subtype, easily transmissible from person to person, will emerge and cause pandemic disease. Humans will have little or no immunity to this virus, which could spread at least as easily as common seasonal influenza and

HI responses induced by seasonal influenza vaccination are associated with clinical protection and with seroprotection against non-homologous strains.

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Luytjes, Willem; Enouf, Vincent; Schipper, Maarten; Gijzen, Karlijn; Liu, Wai Ming; van der Lubben, Mariken; Meijer, Adam; van der Werf, Sylvie; Soethout, Ernst C

2012-07-27

Vaccination against influenza induces homologous as well as cross-specific hemagglutination inhibiting (HI) responses. Induction of cross-specific HI responses may be essential when the influenza strain does not match the vaccine strain, or even to confer a basic immune response against a pandemic influenza virus. We carried out a clinical study to evaluate the immunological responses after seasonal vaccination in healthy adults 18-60 years of age, receiving the yearly voluntary vaccination during the influenza season 2006/2007. Vaccinees of different age groups were followed for laboratory confirmed influenza (LCI) and homologous HI responses as well as cross-specific HI responses against the seasonal H1N1 strain of 2008 and pandemic H1N1 virus of 2009 (H1N1pdm09) were determined. Homologous HI titers that are generally associated with protection (i.e. seroprotective HI titers ≥40) were found in more than 70% of vaccinees. In contrast, low HI titers before and after vaccination were significantly associated with seasonal LCI. Cross-specific HI titers ≥40 against drifted seasonal H1N1 were found in 69% of vaccinees. Cross-specific HI titers ≥40 against H1N1pdm09 were also significantly induced, especially in the youngest age group. More specifically, cross-specific HI titers ≥40 against H1N1pdm09 were inversely correlated with age. We did not find a correlation between the subtype of influenza which was circulating at the age of birth of the vaccinees and cross-specific HI response against H1N1pdm09. These data indicate that the HI titers before and after vaccination determine the vaccination efficacy. In addition, in healthy adults between 18 and 60 years of age, young adults appear to be best able to mount a cross-protective HI response against H1N1pdm09 or drifted seasonal influenza after seasonal vaccination. Copyright © 2012 Elsevier Ltd. All rights reserved.

Swine Influenza/Variant Influenza Viruses

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... Address What's this? Submit What's this? Submit Button Influenza Types Seasonal Avian Swine Variant Pandemic Other Information on Swine Influenza/Variant Influenza Virus Language: English (US) Español Recommend ...

2009 Pandemic Influenza A Virus Subtype H1N1 in Morocco, 2009–2010: Epidemiology, Transmissibility, and Factors Associated With Fatal Cases

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Barakat, Amal; Ihazmad, Hassan; El Falaki, Fatima; Tempia, Stefano; Cherkaoui, Imad; El Aouad, Rajae

2012-01-01

expected influenza season (October–January) in Morocco. We obtained an R0 estimate of 1.44 (95% CI, 1.32–1.56) and a mean serial interval (±SD) of 2.3 ± 1.4 days (95% CI, 1.6–3.0). Conclusion. Widespread but delayed community transmission of A(H1N1)pdm09 occurred in Morocco in 2009, and A(H1N1)pdm09 became the dominant influenza virus subtype during the 2009–2010 influenza season. The transmissibility characteristics were similar to those observed in other countries. PMID:23169979

Cytokine response patterns in severe pandemic 2009 H1N1 and seasonal influenza among hospitalized adults.

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Nelson Lee

Full Text Available BACKGROUND: Studying cytokine/chemokine responses in severe influenza infections caused by different virus subtypes may improve understanding on pathogenesis. METHODS: Adults hospitalized for laboratory-confirmed seasonal and pandemic 2009 A/H1N1 (pH1N1 influenza were studied. Plasma concentrations of 13 cytokines/chemokines were measured at presentation and then serially, using cytometric-bead-array with flow-cytometry and ELISA. PBMCs from influenza patients were studied for cytokine/chemokine expression using ex-vivo culture (Whole Blood Assay,±PHA/LPS stimulation. Clinical variables were prospectively recorded and analyzed. RESULTS: 63 pH1N1 and 53 seasonal influenza patients were studied. pH1N1 patients were younger (mean±S.D. 42.8±19.2 vs 70.5±16.7 years, and fewer had comorbidities. Respiratory/cardiovascular complications were common in both groups (71.4% vs 81.1%, although severe pneumonia with hypoxemia (54.0% vs 28.3% and ICU admissions (25.4% vs 1.9% were more frequent with pH1N1. Hyperactivation of the proinflammatory cytokines IL-6, CXCL8/IL-8, CCL2/MCP-1 and sTNFR-1 was found in pH1N1 pneumonia (2-15 times normal and in complicated seasonal influenza, but not in milder pH1N1 infections. The adaptive-immunity (Th1/Th17-related CXCL10/IP-10, CXCL9/MIG and IL-17A however, were markedly suppressed in severe pH1N1 pneumonia (2-27 times lower than seasonal influenza; P-values<0.01. This pattern was further confirmed with serial measurements. Hypercytokinemia tended to be sustained in pH1N1 pneumonia, associated with a slower viral clearance [PCR-negativity: day 3-4, 55% vs 85%; day 6-7, 67% vs 100%]. Elevated proinflammatory cytokines, particularly IL-6, predicted ICU admission (adjusted OR 12.6, 95%CI 2.6-61.5, per log(10unit increase; P = 0.002, and correlated with fever, tachypnoea, deoxygenation, and length-of-stay (Spearman's rho, P-values<0.01 in influenza infections. PBMCs in seasonal influenza patients were activated and

Natural T Cell-mediated Protection against Seasonal and Pandemic Influenza. Results of the Flu Watch Cohort Study.

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Hayward, Andrew C; Wang, Lili; Goonetilleke, Nilu; Fragaszy, Ellen B; Bermingham, Alison; Copas, Andrew; Dukes, Oliver; Millett, Elizabeth R C; Nazareth, Irwin; Nguyen-Van-Tam, Jonathan S; Watson, John M; Zambon, Maria; Johnson, Anne M; McMichael, Andrew J

2015-06-15

A high proportion of influenza infections are asymptomatic. Animal and human challenge studies and observational studies suggest T cells protect against disease among those infected, but the impact of T-cell immunity at the population level is unknown. To investigate whether naturally preexisting T-cell responses targeting highly conserved internal influenza proteins could provide cross-protective immunity against pandemic and seasonal influenza. We quantified influenza A(H3N2) virus-specific T cells in a population cohort during seasonal and pandemic periods between 2006 and 2010. Follow-up included paired serology, symptom reporting, and polymerase chain reaction (PCR) investigation of symptomatic cases. A total of 1,414 unvaccinated individuals had baseline T-cell measurements (1,703 participant observation sets). T-cell responses to A(H3N2) virus nucleoprotein (NP) dominated and strongly cross-reacted with A(H1N1)pdm09 NP (P < 0.001) in participants lacking antibody to A(H1N1)pdm09. Comparison of paired preseason and post-season sera (1,431 sets) showed 205 (14%) had evidence of infection based on fourfold influenza antibody titer rises. The presence of NP-specific T cells before exposure to virus correlated with less symptomatic, PCR-positive influenza A (overall adjusted odds ratio, 0.27; 95% confidence interval, 0.11-0.68; P = 0.005, during pandemic [P = 0.047] and seasonal [P = 0.049] periods). Protection was independent of baseline antibodies. Influenza-specific T-cell responses were detected in 43%, indicating a substantial population impact. Naturally occurring cross-protective T-cell immunity protects against symptomatic PCR-confirmed disease in those with evidence of infection and helps to explain why many infections do not cause symptoms. Vaccines stimulating T cells may provide important cross-protective immunity.

Natural T Cell–mediated Protection against Seasonal and Pandemic Influenza. Results of the Flu Watch Cohort Study

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Wang, Lili; Goonetilleke, Nilu; Fragaszy, Ellen B.; Bermingham, Alison; Copas, Andrew; Dukes, Oliver; Millett, Elizabeth R. C.; Nazareth, Irwin; Nguyen-Van-Tam, Jonathan S.; Watson, John M.; Zambon, Maria; Johnson, Anne M.; McMichael, Andrew J.

2015-01-01

Rationale: A high proportion of influenza infections are asymptomatic. Animal and human challenge studies and observational studies suggest T cells protect against disease among those infected, but the impact of T-cell immunity at the population level is unknown. Objectives: To investigate whether naturally preexisting T-cell responses targeting highly conserved internal influenza proteins could provide cross-protective immunity against pandemic and seasonal influenza. Methods: We quantified influenza A(H3N2) virus–specific T cells in a population cohort during seasonal and pandemic periods between 2006 and 2010. Follow-up included paired serology, symptom reporting, and polymerase chain reaction (PCR) investigation of symptomatic cases. Measurements and Main Results: A total of 1,414 unvaccinated individuals had baseline T-cell measurements (1,703 participant observation sets). T-cell responses to A(H3N2) virus nucleoprotein (NP) dominated and strongly cross-reacted with A(H1N1)pdm09 NP (P < 0.001) in participants lacking antibody to A(H1N1)pdm09. Comparison of paired preseason and post-season sera (1,431 sets) showed 205 (14%) had evidence of infection based on fourfold influenza antibody titer rises. The presence of NP-specific T cells before exposure to virus correlated with less symptomatic, PCR-positive influenza A (overall adjusted odds ratio, 0.27; 95% confidence interval, 0.11–0.68; P = 0.005, during pandemic [P = 0.047] and seasonal [P = 0.049] periods). Protection was independent of baseline antibodies. Influenza-specific T-cell responses were detected in 43%, indicating a substantial population impact. Conclusions: Naturally occurring cross-protective T-cell immunity protects against symptomatic PCR-confirmed disease in those with evidence of infection and helps to explain why many infections do not cause symptoms. Vaccines stimulating T cells may provide important cross-protective immunity. PMID:25844934

Oseltamivir (Tamiflu® in the environment, resistance development in influenza A viruses of dabbling ducks and the risk of transmission of an oseltamivir-resistant virus to humans – a review

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Josef D. Järhult

2012-06-01

Full Text Available The antiviral drug oseltamivir (Tamiflu® is a cornerstone in influenza pandemic preparedness plans worldwide. However, resistance to the drug is a growing concern. The active metabolite oseltamivir carboxylate (OC is not degraded in surface water or sewage treatment plants and has been detected in river water during seasonal influenza outbreaks. The natural influenza reservoir, dabbling ducks, can thus be exposed to OC in aquatic environments. Environmental-like levels of OC induce resistance development in influenza A/H1N1 virus in mallards. There is a risk of resistance accumulation in influenza viruses circulating among wild birds when oseltamivir is used extensively. By reassortment or direct transmission, oseltamivir resistance can be transmitted to humans potentially causing a resistant pandemic or human-adapted highly-pathogenic avian influenza virus. There is a need for more research on resistance development in the natural influenza reservoir and for a prudent use of antivirals.

Seasonal influenza vaccine policy, use and effectiveness in the tropics and subtropics: a systematic literature review.

NARCIS (Netherlands)

Hirve, S.; Lambach, P.; Paget, J.; Vandemaele, K.; Fitzner, J.; Zhang, W.

2016-01-01

Aim: The evidence needed for tropical countries to take informed decisions on influenza vaccination is scarce. This paper reviews policy, availability, use and effectiveness of seasonal influenza vaccine in tropical and subtropical countries. Method: Global health databases were searched in three

Seasonal influenza vaccine policy, use and effectiveness in the tropics and subtropics - a systematic literature review

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Hirve, S.; Lambach, P.; Paget, J.; Vandemaele, K.; Fitzner, J.; Zhang, W.

2016-01-01

AIM: The evidence needed for tropical countries to take informed decisions on influenza vaccination is scarce. This article reviews policy, availability, use and effectiveness of seasonal influenza vaccine in tropical and subtropical countries. METHOD: Global health databases were searched in three

A data-driven model for influenza transmission incorporating media effects.

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Mitchell, Lewis; Ross, Joshua V

2016-10-01

Numerous studies have attempted to model the effect of mass media on the transmission of diseases such as influenza; however, quantitative data on media engagement has until recently been difficult to obtain. With the recent explosion of 'big data' coming from online social media and the like, large volumes of data on a population's engagement with mass media during an epidemic are becoming available to researchers. In this study, we combine an online dataset comprising millions of shared messages relating to influenza with traditional surveillance data on flu activity to suggest a functional form for the relationship between the two. Using this data, we present a simple deterministic model for influenza dynamics incorporating media effects, and show that such a model helps explain the dynamics of historical influenza outbreaks. Furthermore, through model selection we show that the proposed media function fits historical data better than other media functions proposed in earlier studies.

Uptake and impact of vaccinating school age children against influenza during a season with circulation of drifted influenza A and B strains, England, 2014/15.

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Pebody, Richard G; Green, Helen K; Andrews, Nick; Boddington, Nicola L; Zhao, Hongxin; Yonova, Ivelina; Ellis, Joanna; Steinberger, Sophia; Donati, Matthew; Elliot, Alex J; Hughes, Helen E; Pathirannehelage, Sameera; Mullett, David; Smith, Gillian E; de Lusignan, Simon; Zambon, Maria

2015-01-01

The 2014/15 influenza season was the second season of roll-out of a live attenuated influenza vaccine (LAIV) programme for healthy children in England. During this season, besides offering LAIV to all two to four year olds, several areas piloted vaccination of primary (4-11 years) and secondary (11-13 years) age children. Influenza A(H3N2) circulated, with strains genetically and antigenically distinct from the 2014/15 A(H3N2) vaccine strain, followed by a drifted B strain. We assessed the overall and indirect impact of vaccinating school age children, comparing cumulative disease incidence in targeted and non-targeted age groups in vaccine pilot to non-pilot areas. Uptake levels were 56.8% and 49.8% in primary and secondary school pilot areas respectively. In primary school age pilot areas, cumulative primary care influenza-like consultation, emergency department respiratory attendance, respiratory swab positivity, hospitalisation and excess respiratory mortality were consistently lower in targeted and non-targeted age groups, though less for adults and more severe end-points, compared with non-pilot areas. There was no significant reduction for excess all-cause mortality. Little impact was seen in secondary school age pilot only areas compared with non-pilot areas. Vaccination of healthy primary school age children resulted in population-level impact despite circulation of drifted A and B influenza strains.

Transmission of highly pathogenic avian influenza H7 virus

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Bos, M.E.H.

2009-01-01

Knowledge of the transmission of highly pathogenic avian influenza (HPAI) virus still has gaps, complicating epidemic control. A model was developed to back-calculate the day HPAI virus was introduced into a flock, based on within-flock mortality data of the Dutch HPAI H7N7 epidemic (2003). The

Knowledge, awareness and practices towards seasonal influenza and its vaccine: implications for future vaccination campaigns in Jordan.

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Abu-Rish, Eman Y; Elayeh, Eman R; Mousa, Lubabah A; Butanji, Yasser K; Albsoul-Younes, Abla M

2016-12-01

Influenza is an underestimated contributor to morbidity and mortality. Population knowledge regarding influenza and its vaccination has a key role in enhancing vaccination coverage. This study aimed to identify the gaps of knowledge among Jordanian population towards influenza and its vaccine, and to identify the major determinants of accepting seasonal influenza vaccine in adults and children in Jordan. This was a cross-sectional study that enrolled 941 randomly selected adults in Amman, Jordan. A four-section questionnaire was used which included questions about the sociodemographic characteristics, knowledge about influenza and the factors that affect seasonal influenza vaccine acceptance and refusal. Only 47.3% of the participants were considered knowledgeable. About half of the participants (51.9%) correctly identified the main influenza preventative measures. Lack of knowledge about the important role of seasonal influenza vaccine in disease prevention was observed. Low vaccination rate (20% of adults) was reported. The most critical barrier against vaccination in adults and children was the concern about the safety and the efficacy of the vaccine, while the most important predictors for future vaccination in adults and children were physician recommendation and government role. In children, the inclusion of the vaccine within the national immunization program was an important determinant of vaccine acceptance. Formulating new strategies to improve the population's level of knowledge, assuring the population about the safety and the efficacy of the vaccine and the inclusion of the vaccine within the national immunization program are the essential factors to enhance vaccination coverage in Jordan. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Transmission of equine influenza virus during an outbreak is characterized by frequent mixed infections and loose transmission bottlenecks.

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Joseph Hughes

2012-12-01

Full Text Available The ability of influenza A viruses (IAVs to cross species barriers and evade host immunity is a major public health concern. Studies on the phylodynamics of IAVs across different scales - from the individual to the population - are essential for devising effective measures to predict, prevent or contain influenza emergence. Understanding how IAVs spread and evolve during outbreaks is critical for the management of epidemics. Reconstructing the transmission network during a single outbreak by sampling viral genetic data in time and space can generate insights about these processes. Here, we obtained intra-host viral sequence data from horses infected with equine influenza virus (EIV to reconstruct the spread of EIV during a large outbreak. To this end, we analyzed within-host viral populations from sequences covering 90% of the infected yards. By combining gene sequence analyses with epidemiological data, we inferred a plausible transmission network, in turn enabling the comparison of transmission patterns during the course of the outbreak and revealing important epidemiological features that were not apparent using either approach alone. The EIV populations displayed high levels of genetic diversity, and in many cases we observed distinct viral populations containing a dominant variant and a number of related minor variants that were transmitted between infectious horses. In addition, we found evidence of frequent mixed infections and loose transmission bottlenecks in these naturally occurring populations. These frequent mixed infections likely influence the size of epidemics.

Asymptomatic ratio for seasonal H1N1 influenza infection among schoolchildren in Taiwan.

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Hsieh, Ying-Hen; Tsai, Chen-An; Lin, Chien-Yu; Chen, Jin-Hua; King, Chwan-Chuen; Chao, Day-Yu; Cheng, Kuang-Fu

2014-02-12

Studies indicate that asymptomatic infections do indeed occur frequently for both seasonal and pandemic influenza, accounting for about one-third of influenza infections. Studies carried out during the 2009 pH1N1 pandemic have found significant antibody response against seasonal H1N1 and H3N2 vaccine strains in schoolchildren receiving only pandemic H1N1 monovalent vaccine, yet reported either no symptoms or only mild symptoms. Serum samples of 255 schoolchildren, who had not received vaccination and had pre-season HI Ab serotiters definition of Fever + (cough or sore throat or nose) + ( headache or pain or fatigue). Asymptomatic ratio for children is found to be substantially higher than that of the general population in literature. In providing reasonable quantification of the asymptomatic infected children spreading pathogens to others in a seasonal epidemic or a pandemic, our estimates of symptomatic ratio of infected children has important clinical and public health implications.

Molecular epidemiology of influenza A(H1N1PDM09 hemagglutinin gene circulating in São Paulo State , Brazil: 2016 anticipated influenza season

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Katia Corrêa de Oliveira Santos

Full Text Available ABSTRACT Compared to previous years, seasonal influenza activity commenced early in São Paulo State, Brazil, Southern hemisphere during the 2016 year. In order to investigate the genetic pattern of influenza A(H1N1pdm09 in the State of Sao Paulo a total of 479 respiratory samples, collected in January by Sentinel Surveillance Units, were screened by real-time RT-PCR. A total of 6 Influenza viruses A(H1N1pdm09 presenting ct values ≤ 30 were sequenced following phylogenetic analysis. The present study identified the circulation of the new 6B.1 subgroup (A/Sao Paulo/10-118/2016 and A/Sao Paulo/3032/2016. In addition, influenza A(H1N1pdm09 group 6B has also been identified during January in the State of Sao Paulo. Despite amino acid changes and changes in potential glycosylation motifs, 6B.1 viruses were well inhibited by the reference ferret antiserum against A/California/07/2009 virus, the A(H1N1pdm09 component of the vaccine for the 2016 influenza season.

Epidemiological and molecular surveillance of influenza and respiratory syncytial viruses in children with acute respiratory infections (2004/2005 season

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Alessandra Zappa

2008-03-01

Full Text Available Objective. During the 2004/2005 influenza season an active virological surveillance of influenza viruses and respiratory syncytial virus (RSV was carried out to monitor the epidemiologic trend of acute respiratory infections (ARI in the paediatric community. Materials and methods. 100 patients (51 males, 49 females; mean age: 19 months, either treated at the Emergency Unit or hospitalized in the Pediatric Unit of “San Carlo Borromeo Hospital” (Milan, reporting symptoms related to ARI were enrolled. Pharyngeal swabs were collected for virological investigation by: 1 multiplexnested- PCR for the simultaneous identification of both influenza A and B viruses and RSV; 2 multiplex-nested- PCR for the subtyping of influenza A viruses (H1 and H3. Results. 12% (12/100 subjects were infected with influenza A virus, 4% (4/100 with influenza B virus and 14 (14% with RSV. Of all the 12 influenza A positive samples 4 (33.3% belonged to subtype H1 and 8 (66.7% to subtype H3. Bronchiolitis and bronchitis episodes were significantly higher among RSV-infected subjects than among influenza- infected subjects (42.8% vs 6.2%; p<0.05 and 35.7% vs 6.2%; p<0.05, respectively. Pneumonia episodes occurred similarly both in influenza-infected children and in RSV-infected ones. Conclusions. During the 2004/2005 influenza season, influenza viruses and RSV were liable for high morbidity among paediatric subjects.The present study underlies the importance of planning an active surveillance of respiratory viral infections among paediatric cases requiring hospitalization due to ARI.A thorough analysis of target population features, of viruses antigenic properties and seasonality will be decisive in the evaluation of each clinical event.

Productive infection of human skeletal muscle cells by pandemic and seasonal influenza A(H1N1 viruses.

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Marion Desdouits

Full Text Available Besides the classical respiratory and systemic symptoms, unusual complications of influenza A infection in humans involve the skeletal muscles. Numerous cases of acute myopathy and/or rhabdomyolysis have been reported, particularly following the outbreak of pandemic influenza A(H1N1 in 2009. The pathogenesis of these influenza-associated myopathies (IAM remains unkown, although the direct infection of muscle cells is suspected. Here, we studied the susceptibility of cultured human primary muscle cells to a 2009 pandemic and a 2008 seasonal influenza A(H1N1 isolate. Using cells from different donors, we found that differentiated muscle cells (i. e. myotubes were highly susceptible to infection by both influenza A(H1N1 isolates, whereas undifferentiated cells (i. e. myoblasts were partially resistant. The receptors for influenza viruses, α2-6 and α2-3 linked sialic acids, were detected on the surface of myotubes and myoblasts. Time line of viral nucleoprotein (NP expression and nuclear export showed that the first steps of the viral replication cycle could take place in muscle cells. Infected myotubes and myoblasts exhibited budding virions and nuclear inclusions as observed by transmission electron microscopy and correlative light and electron microscopy. Myotubes, but not myoblasts, yielded infectious virus progeny that could further infect naive muscle cells after proteolytic treatment. Infection led to a cytopathic effect with the lysis of muscle cells, as characterized by the release of lactate dehydrogenase. The secretion of proinflammatory cytokines by muscle cells was not affected following infection. Our results are compatible with the hypothesis of a direct muscle infection causing rhabdomyolysis in IAM patients.

The effect of age and recent influenza vaccination history on the immunogenicity and efficacy of 2009-10 seasonal trivalent inactivated influenza vaccination in children.

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Sophia Ng

Full Text Available There is some evidence that annual vaccination of trivalent inactivated influenza vaccine (TIV may lead to reduced vaccine immunogenicity but evidence is lacking on whether vaccine efficacy is affected by prior vaccination history. The efficacy of one dose of TIV in children 6-8 y of age against influenza B is uncertain. We examined whether immunogenicity and efficacy of influenza vaccination in school-age children varied by age and past vaccination history.We conducted a randomized controlled trial of 2009-10 TIV. Influenza vaccination history in the two preceding years was recorded. Immunogenicity was assessed by comparison of HI titers before and one month after receipt of TIV/placebo. Subjects were followed up for 11 months with symptom diaries, and respiratory specimens were collected during acute respiratory illnesses to permit confirmation of influenza virus infections. We found that previous vaccination was associated with reduced antibody responses to TIV against seasonal A(H1N1 and A(H3N2 particularly in children 9-17 y of age, but increased antibody responses to the same lineage of influenza B virus in children 6-8 y of age. Serological responses to the influenza A vaccine viruses were high regardless of vaccination history. One dose of TIV appeared to be efficacious against confirmed influenza B in children 6-8 y of age regardless of vaccination history.Prior vaccination was associated with lower antibody titer rises following vaccination against seasonal influenza A vaccine viruses, but higher responses to influenza B among individuals primed with viruses from the same lineage in preceding years. In a year in which influenza B virus predominated, no impact of prior vaccination history was observed on vaccine efficacy against influenza B. The strains that circulated in the year of study did not allow us to study the effect of prior vaccination on vaccine efficacy against influenza A.

Hand hygiene to reduce community transmission of influenza and acute respiratory tract infection: a systematic review.

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Warren-Gash, Charlotte; Fragaszy, Ellen; Hayward, Andrew C

2013-09-01

Hand hygiene may be associated with modest protection against some acute respiratory tract infections, but its specific role in influenza transmission in different settings is unclear. We aimed to review evidence that improving hand hygiene reduces primary and secondary transmission of (i) influenza and (ii) acute respiratory tract infections in community settings. We searched Medline, Embase, Global Health and Cochrane databases up to 13 February 2012 for reports in any language of original research investigating the effect of hand hygiene on influenza or acute respiratory tract infection where aetiology was unspecified in community settings including institutions such as schools, and domestic residences. Data were presented and quality rated across outcomes according to the Grading of Recommendations Assessment, Development and Evaluation system. Sixteen articles met inclusion criteria. There was moderate to low-quality evidence of a reduction in both influenza and respiratory tract infection with hand hygiene interventions in schools, greatest in a lower-middle-income setting. There was high-quality evidence of a small reduction in respiratory infection in childcare settings. There was high-quality evidence for a large reduction in respiratory infection with a hand hygiene intervention in squatter settlements in a low-income setting. There was moderate- to high-quality evidence of no effect on secondary transmission of influenza in households that had already experienced an index case. While hand hygiene interventions have potential to reduce transmission of influenza and acute respiratory tract infections, their effectiveness varies depending on setting, context and compliance. © 2012 John Wiley & Sons Ltd.

Seasonal Influenza Vaccination amongst Medical Students: A Social Network Analysis Based on a Cross-Sectional Study.

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Rhiannon Edge

Full Text Available The Chief Medical Officer for England recommends that healthcare workers have a seasonal influenza vaccination in an attempt to protect both patients and NHS staff. Despite this, many healthcare workers do not have a seasonal influenza vaccination. Social network analysis is a well-established research approach that looks at individuals in the context of their social connections. We examine the effects of social networks on influenza vaccination decision and disease dynamics.We used a social network analysis approach to look at vaccination distribution within the network of the Lancaster Medical School students and combined these data with the students' beliefs about vaccination behaviours. We then developed a model which simulated influenza outbreaks to study the effects of preferentially vaccinating individuals within this network.Of the 253 eligible students, 217 (86% provided relational data, and 65% of responders had received a seasonal influenza vaccination. Students who were vaccinated were more likely to think other medical students were vaccinated. However, there was no clustering of vaccinated individuals within the medical student social network. The influenza simulation model demonstrated that vaccination of well-connected individuals may have a disproportional effect on disease dynamics.This medical student population exhibited vaccination coverage levels similar to those seen in other healthcare groups but below recommendations. However, in this population, a lack of vaccination clustering might provide natural protection from influenza outbreaks. An individual student's perception of the vaccination coverage amongst their peers appears to correlate with their own decision to vaccinate, but the directionality of this relationship is not clear. When looking at the spread of disease within a population it is important to include social structures alongside vaccination data. Social networks influence disease epidemiology and

Replication of swine and human influenza viruses in juvenile and layer turkey hens.

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Ali, Ahmed; Yassine, Hadi; Awe, Olusegun O; Ibrahim, Mahmoud; Saif, Yehia M; Lee, Chang-Won

2013-04-12

Since the first reported isolation of swine influenza viruses (SIVs) in turkeys in the 1980s, transmission of SIVs to turkeys was frequently documented. Recently, the 2009 pandemic H1N1 virus, that was thought to be of swine origin, was detected in turkeys with a severe drop in egg production. In this study, we assessed the infectivity of different mammalian influenza viruses including swine, pandemic H1N1 and seasonal human influenza viruses in both juvenile and layer turkeys. In addition, we investigated the potential influenza virus dissemination in the semen of experimentally infected turkey toms. Results showed that all mammalian origin influenza viruses tested can infect turkeys. SIVs were detected in respiratory and digestive tracts of both juvenile and layer turkeys. Variations in replication efficiencies among SIVs were observed especially in the reproductive tract of layer turkeys. Compared to SIVs, limited replication of seasonal human H1N1 and no detectable replication of recent human-like swine H1N2, pandemic H1N1 and seasonal human H3N2 viruses was noticed. All birds seroconverted to all tested viruses regardless of their replication level. In turkey toms, we were able to detect swine H3N2 virus in semen and reproductive tract of infected toms by real-time RT-PCR although virus isolation was not successful. These data suggest that turkey hens could be affected by diverse influenza strains especially SIVs. Moreover, the differences in the replication efficiency we demonstrated among SIVs and between SIV and human influenza viruses in layer turkeys suggest a possible use of turkeys as an animal model to study host tropism and pathogenesis of influenza viruses. Our results also indicate a potential risk of venereal transmission of influenza viruses in turkeys. Copyright © 2012 Elsevier B.V. All rights reserved.

Quantifying the risk of pandemic influenza virus evolution by mutation and re-assortment.

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Reperant, Leslie A; Grenfell, Bryan T; Osterhaus, Albert D M E

2015-12-08

Large outbreaks of zoonotic influenza A virus (IAV) infections may presage an influenza pandemic. However, the likelihood that an airborne-transmissible variant evolves upon zoonotic infection or co-infection with zoonotic and seasonal IAVs remains poorly understood, as does the relative importance of accumulating mutations versus re-assortment in this process. Using discrete-time probabilistic models, we determined quantitative probability ranges that transmissible variants with 1-5 mutations and transmissible re-assortants evolve after a given number of zoonotic IAV infections. The systematic exploration of a large population of model parameter values was designed to account for uncertainty and variability in influenza virus infection, epidemiological and evolutionary processes. The models suggested that immunocompromised individuals are at high risk of generating IAV variants with pandemic potential by accumulation of mutations. Yet, both immunocompetent and immunocompromised individuals could generate high viral loads of single and double mutants, which may facilitate their onward transmission and the subsequent accumulation of additional 1-2 mutations in newly-infected individuals. This may result in the evolution of a full transmissible genotype along short chains of contact transmission. Although co-infection with zoonotic and seasonal IAVs was shown to be a rare event, it consistently resulted in high viral loads of re-assortants, which may facilitate their onward transmission among humans. The prevention or limitation of zoonotic IAV infection in immunocompromised and contact individuals, including health care workers, as well as vaccination against seasonal IAVs-limiting the risk of co-infection-should be considered fundamental tools to thwart the evolution of a novel pandemic IAV by accumulation of mutations and re-assortment. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Reverse Genetics Approaches for the Development of Influenza Vaccines

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Nogales, Aitor; Martínez-Sobrido, Luis

2016-01-01

Influenza viruses cause annual seasonal epidemics and occasional pandemics of human respiratory disease. Influenza virus infections represent a serious public health and economic problem, which are most effectively prevented through vaccination. However, influenza viruses undergo continual antigenic variation, which requires either the annual reformulation of seasonal influenza vaccines or the rapid generation of vaccines against potential pandemic virus strains. The segmented nature of influenza virus allows for the reassortment between two or more viruses within a co-infected cell, and this characteristic has also been harnessed in the laboratory to generate reassortant viruses for their use as either inactivated or live-attenuated influenza vaccines. With the implementation of plasmid-based reverse genetics techniques, it is now possible to engineer recombinant influenza viruses entirely from full-length complementary DNA copies of the viral genome by transfection of susceptible cells. These reverse genetics systems have provided investigators with novel and powerful approaches to answer important questions about the biology of influenza viruses, including the function of viral proteins, their interaction with cellular host factors and the mechanisms of influenza virus transmission and pathogenesis. In addition, reverse genetics techniques have allowed the generation of recombinant influenza viruses, providing a powerful technology to develop both inactivated and live-attenuated influenza vaccines. In this review, we will summarize the current knowledge of state-of-the-art, plasmid-based, influenza reverse genetics approaches and their implementation to provide rapid, convenient, safe and more effective influenza inactivated or live-attenuated vaccines. PMID:28025504

Continental synchronicity of human influenza virus epidemics despite climactic variation.

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Geoghegan, Jemma L; Saavedra, Aldo F; Duchêne, Sebastián; Sullivan, Sheena; Barr, Ian; Holmes, Edward C

2018-01-01

The factors that determine the pattern and rate of spread of influenza virus at a continental-scale are uncertain. Although recent work suggests that influenza epidemics in the United States exhibit a strong geographical correlation, the spatiotemporal dynamics of influenza in Australia, a country and continent of approximately similar size and climate complexity but with a far smaller population, are not known. Using a unique combination of large-scale laboratory-confirmed influenza surveillance comprising >450,000 entries and genomic sequence data we determined the local-level spatial diffusion of this important human pathogen nationwide in Australia. We used laboratory-confirmed influenza data to characterize the spread of influenza virus across Australia during 2007-2016. The onset of established epidemics varied across seasons, with highly synchronized epidemics coinciding with the emergence of antigenically distinct viruses, particularly during the 2009 A/H1N1 pandemic. The onset of epidemics was largely synchronized between the most populous cities, even those separated by distances of >3000 km and those that experience vastly diverse climates. In addition, by analyzing global phylogeographic patterns we show that the synchronized dissemination of influenza across Australian cities involved multiple introductions from the global influenza population, coupled with strong domestic connectivity, rather than through the distinct radial patterns of geographic dispersal that are driven by work-flow transmission as observed in the United States. In addition, by comparing the spatial structure of influenza A and B, we found that these viruses tended to occupy different geographic regions, and peak in different seasons, perhaps indicative of moderate cross-protective immunity or viral interference effects. The highly synchronized outbreaks of influenza virus at a continental-scale revealed here highlight the importance of coordinated public health responses in the

Influenza immunization rates in children and teenagers in Polish cities: conclusions from the 2009/2010 season.

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Kuchar, Ernest; Nitsch-Osuch, Aneta; Zycinska, Katarzyna; Miskiewicz, Katarzyna; Szenborn, Leszek; Wardyn, Kazimierz

2013-01-01

The aim of this study was to determine influenza vaccine coverage among children aged 0-18 years in inner city practices in Poland in the 2009/2010 season and factors that might have influenced low vaccination coverage. A retrospective review of 11,735 vaccination charts of children aged 0-18 from seven randomly selected general practices in the capital city of Warsaw and one large practice in the city of Wroclaw was performed. We calculated the numbers of children who were vaccinated in the 2009/2010 season and analyzed the age distribution of vaccinated children. We also reviewed the vaccination history in patients who were vaccinated against influenza including: previous influenza vaccinations, modification (widening) of standard immunization scheme, and a proportion of children who completed the recommended two-dose schedule of vaccination. In the calculations, 95% confidence intervals were used. Out of the total of 11,735 children surveyed, 362 (3.1%, CI: 2.8-3.4%) were vaccinated against influenza in the 2009/2010 season. For 115 of these 362 (31.8%, CI: 27.0-36.6%) children it was their first vaccination against influenza. The mean age of a vaccinated child was 6.0 ± 4.3 years. Children aged 2-5 were most commonly vaccinated (153/362, 42.3%, CI: 37.2-47.4%), while infants (aged 6-12 months) were vaccinated rarely (15/362, 4.4%, CI: 2.2-6.2%). In the group of children younger than 8 years (86/362 children) who were vaccinated for the first time in their life only 29/86 (33.7%, CI: 23.7-43.7%) completed the recommended two-dose schedule. In conclusion, the importance of vaccinating children against influenza is hugely understated in Poland. General physicians should actively recommend annual influenza immunization of children. Recommendations of National Immunization Program concerning influenza vaccine should be clearer, simpler, and easier to implement.

Computational Identification of Antigenicity-Associated Sites in the Hemagglutinin Protein of A/H1N1 Seasonal Influenza Virus.

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Xiaowei Ren

Full Text Available The antigenic variability of influenza viruses has always made influenza vaccine development challenging. The punctuated nature of antigenic drift of influenza virus suggests that a relatively small number of genetic changes or combinations of genetic changes may drive changes in antigenic phenotype. The present study aimed to identify antigenicity-associated sites in the hemagglutinin protein of A/H1N1 seasonal influenza virus using computational approaches. Random Forest Regression (RFR and Support Vector Regression based on Recursive Feature Elimination (SVR-RFE were applied to H1N1 seasonal influenza viruses and used to analyze the associations between amino acid changes in the HA1 polypeptide and antigenic variation based on hemagglutination-inhibition (HI assay data. Twenty-three and twenty antigenicity-associated sites were identified by RFR and SVR-RFE, respectively, by considering the joint effects of amino acid residues on antigenic drift. Our proposed approaches were further validated with the H3N2 dataset. The prediction models developed in this study can quantitatively predict antigenic differences with high prediction accuracy based only on HA1 sequences. Application of the study results can increase understanding of H1N1 seasonal influenza virus antigenic evolution and accelerate the selection of vaccine strains.

Universal or Specific? A Modeling-Based Comparison of Broad-Spectrum Influenza Vaccines against Conventional, Strain-Matched Vaccines.

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Rahul Subramanian

2016-12-01

Full Text Available Despite the availability of vaccines, influenza remains a major public health challenge. A key reason is the virus capacity for immune escape: ongoing evolution allows the continual circulation of seasonal influenza, while novel influenza viruses invade the human population to cause a pandemic every few decades. Current vaccines have to be updated continually to keep up to date with this antigenic change, but emerging 'universal' vaccines-targeting more conserved components of the influenza virus-offer the potential to act across all influenza A strains and subtypes. Influenza vaccination programmes around the world are steadily increasing in their population coverage. In future, how might intensive, routine immunization with novel vaccines compare against similar mass programmes utilizing conventional vaccines? Specifically, how might novel and conventional vaccines compare, in terms of cumulative incidence and rates of antigenic evolution of seasonal influenza? What are their potential implications for the impact of pandemic emergence? Here we present a new mathematical model, capturing both transmission dynamics and antigenic evolution of influenza in a simple framework, to explore these questions. We find that, even when matched by per-dose efficacy, universal vaccines could dampen population-level transmission over several seasons to a greater extent than conventional vaccines. Moreover, by lowering opportunities for cross-protective immunity in the population, conventional vaccines could allow the increased spread of a novel pandemic strain. Conversely, universal vaccines could mitigate both seasonal and pandemic spread. However, where it is not possible to maintain annual, intensive vaccination coverage, the duration and breadth of immunity raised by universal vaccines are critical determinants of their performance relative to conventional vaccines. In future, conventional and novel vaccines are likely to play complementary roles in

Emergency department and 'Google flu trends' data as syndromic surveillance indicators for seasonal influenza.

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Thompson, L H; Malik, M T; Gumel, A; Strome, T; Mahmud, S M

2014-11-01

We evaluated syndromic indicators of influenza disease activity developed using emergency department (ED) data - total ED visits attributed to influenza-like illness (ILI) ('ED ILI volume') and percentage of visits attributed to ILI ('ED ILI percent') - and Google flu trends (GFT) data (ILI cases/100 000 physician visits). Congruity and correlation among these indicators and between these indicators and weekly count of laboratory-confirmed influenza in Manitoba was assessed graphically using linear regression models. Both ED and GFT data performed well as syndromic indicators of influenza activity, and were highly correlated with each other in real time. The strongest correlations between virological data and ED ILI volume and ED ILI percent, respectively, were 0·77 and 0·71. The strongest correlation of GFT was 0·74. Seasonal influenza activity may be effectively monitored using ED and GFT data.

Educating youth swine exhibitors on influenza A virus transmission at agricultural fairs.

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Nolting, J M; Midla, J; Whittington, M S; Scheer, S D; Bowman, A S

2018-02-01

Influenza A virus (IAV) is a major zoonotic pathogen that threatens global public health. Novel strains of influenza A viruses pose a significant risk to public health due to their pandemic potential, and transmission of influenza A viruses from animals to humans is an important mechanism in the generation and introduction of IAVs that threaten human health. The purpose of this descriptive correlational study was to develop real-life training scenarios to better inform swine exhibitors of the risks they may encounter when influenza A viruses are present in swine. Educational activities were implemented in five Ohio counties where exhibition swine had historically been shedding influenza A viruses during the county fair. A total of 146 youth swine exhibitors participated in the educational programme, and an increase in the knowledge base of these youth was documented. It is expected that educating youth exhibitors about exposure to influenza A virus infections in the swine they are exhibiting will result in altered behaviours and animal husbandry practices that will improve both human and animal health. © 2017 Blackwell Verlag GmbH.

Estimating burden of influenza-associated influenza-like illness and severe acute respiratory infection at public healthcare facilities in Romania during the 2011/12-2015/16 influenza seasons.

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Gefenaite, Giedre; Pistol, Adriana; Popescu, Rodica; Popovici, Odette; Ciurea, Daniel; Dolk, Christiaan; Jit, Mark; Gross, Diane

2018-01-01

Influenza is responsible for substantial morbidity and mortality, but there is limited information on reliable disease burden estimates, especially from middle-income countries in the WHO European Region. To estimate the incidence of medically attended influenza-associated influenza-like illness (ILI) and hospitalizations due to severe acute respiratory infection (SARI) presenting to public healthcare facilities in Romania. Sentinel influenza surveillance data for ILI and SARI from 2011/12-2015/16, including virological data, were used to estimate influenza-associated ILI and SARI incidence/100 000 and their 95% confidence intervals (95% CI). The overall annual incidence of ILI and influenza-associated ILI per 100 000 persons in Romania varied between 68 (95% CI: 61-76) and 318 (95% CI: 298-338) and between 23 (95% CI: 19-29) and 189 (95% CI: 149-240), respectively. The highest ILI and influenza incidence was among children aged 0-4 years. We estimated that SARI incidence per 100 000 persons was 6 (95% CI: 5-7) to 9 (95% CI: 8-10), of which 2 (95% CI: 1-2) to 3 (95% CI: 2-4) were due to influenza. Up to 0.3% of the Romanian population were annually reported with ILI, and 0.01% was hospitalized with SARI, of which as much as one-third could be explained by influenza. This evaluation was the first study estimating influenza burden in Romania. We found that during each influenza season, a substantial number of persons in Romania suffer from influenza-related ILI or are hospitalized due to influenza-associated SARI. © 2017 The World Health Organization. Influenza and Other Respiratory Viruses. Published by John Wiley & Sons Ltd.

Health-seeking behavior and transmission dynamics in the control of influenza infection among different age groups.

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You, Shu-Han; Chen, Szu-Chieh; Liao, Chung-Min

2018-01-01

It has been found that health-seeking behavior has a certain impact on influenza infection. However, behaviors with/without risk perception on the control of influenza transmission among age groups have not been well quantified. The purpose of this study was to assess to what extent, under scenarios of with/without control and preventive/protective behaviors, the age-specific network-driven risk perception influences influenza infection. A behavior-influenza model was used to estimate the spread rate of age-specific risk perception in response to an influenza outbreak. A network-based information model was used to assess the effect of network-driven risk perception information transmission on influenza infection. A probabilistic risk model was used to assess the infection risk effect of risk perception with a health behavior change. The age-specific overlapping percentage was estimated to be 40%-43%, 55%-60%, and 19%-35% for child, teenage and adult, and elderly age groups, respectively. Individuals perceive the preventive behavior to improve risk perception information transmission among teenage and adult and elderly age groups, but not in the child age group. The population with perceived health behaviors could not effectively decrease the percentage of infection risk in the child age group, whereas for the elderly age group, the percentage of decrease in infection risk was more significant, with a 97.5th percentile estimate of 97%. The present integrated behavior-infection model can help health authorities in communicating health messages for an intertwined belief network in which health-seeking behavior plays a key role in controlling influenza infection.

Trivalent inactivated influenza vaccine effective against influenza A(H3N2) variant viruses in children during the 2014/15 season, Japan

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Sugaya, Norio; Shinjoh, Masayoshi; Kawakami, Chiharu; Yamaguchi, Yoshio; Yoshida, Makoto; Baba, Hiroaki; Ishikawa, Mayumi; Kono, Mio; Sekiguchi, Shinichiro; Kimiya, Takahisa; Mitamura, Keiko; Fujino, Motoko; Komiyama, Osamu; Yoshida, Naoko; Tsunematsu, Kenichiro; Narabayashi, Atsushi; Nakata, Yuji; Sato, Akihiro; Taguchi, Nobuhiko; Fujita, Hisayo; Toki, Machiko; Myokai, Michiko; Ookawara, Ichiro; Takahashi, Takao

2016-01-01

The 2014/15 influenza season in Japan was characterised by predominant influenza A(H3N2) activity; 99% of influenza A viruses detected were A(H3N2). Subclade 3C.2a viruses were the major epidemic A(H3N2) viruses, and were genetically distinct from A/New York/39/2012(H3N2) of 2014/15 vaccine strain in Japan, which was classified as clade 3C.1. We assessed vaccine effectiveness (VE) of inactivated influenza vaccine (IIV) in children aged 6 months to 15 years by test-negative case–control design based on influenza rapid diagnostic test. Between November 2014 and March 2015, a total of 3,752 children were enrolled: 1,633 tested positive for influenza A and 42 for influenza B, and 2,077 tested negative. Adjusted VE was 38% (95% confidence intervals (CI): 28 to 46) against influenza virus infection overall, 37% (95% CI: 27 to 45) against influenza A, and 47% (95% CI: -2 to 73) against influenza B. However, IIV was not statistically significantly effective against influenza A in infants aged 6 to 11 months or adolescents aged 13 to 15 years. VE in preventing hospitalisation for influenza A infection was 55% (95% CI: 42 to 64). Trivalent IIV that included A/New York/39/2012(H3N2) was effective against drifted influenza A(H3N2) virus, although vaccine mismatch resulted in low VE. PMID:27784529

Strategies for Pandemic and Seasonal Influenza Vaccination of Schoolchildren in the United States

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Basta, Nicole E.; Chao, Dennis L.; Halloran, M. Elizabeth; Matrajt, Laura; Longini, Ira M.

2009-01-01

Vaccinating school-aged children against influenza can reduce age-specific and population-level illness attack rates. Using a stochastic simulation model of influenza transmission, the authors assessed strategies for vaccinating children in the United States, varying the vaccine type, coverage level, and reproductive number R (average number of secondary cases produced by a typical primary case). Results indicated that vaccinating children can substantially reduce population-level illness att...

Seroprotective antibodies to 2011 variant influenza A(H3N2v) and seasonal influenza A(H3N2) among three age groups of US Department of Defense service members.

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Radin, Jennifer M; Hawksworth, Anthony W; Ortiguerra, Ryan G; Brice, Gary T

2015-01-01

In 2011, a new variant of influenza A(H3N2) emerged that contained a recombination of genes from swine H3N2 viruses and the matrix (M) gene of influenza A(H1N1)pdm09 virus. New combinations and variants of pre-existing influenza viruses are worrisome if there is low or nonexistent immunity in a population, which increases chances for an outbreak or pandemic. Sera collected in 2011 were obtained from US Department of Defense service members in three age groups: 19-21 years, 32-33 years, and 47-48 years. Pre- and post-vaccination samples were available for the youngest age group, and postvaccination samples for the two older groups. Specimens were tested using microneutralization assays for antibody titers against H3N2v (A/Indiana/10/2011) and seasonal H3N2 virus (A/Perth/16/2009). The youngest age group had significantly (p<0.05) higher geometric mean titers for H3N2v with 165 (95% confidence interval [CI]: 105-225) compared with the two older groups, aged 32-33 and 47-48 years, who had geometric mean titers of 68 (95% CI: 55-82) and 46 (95% CI: 24-65), respectively. Similarly, the youngest age group also had the highest geometric mean titers for seasonal H3N2. In the youngest age group, the proportion of patients who seroconverted after vaccination was 12% for H3N2v and 27% for seasonal H3N2. Our results were similar to previous studies that found highest seroprotection among young adults and decreasing titers among older adults. The proportion of 19- to 21-year-olds who seroconverted after seasonal vaccination was low and similar to previous findings. Improving our understanding of H3N2v immunity among different age groups in the United States can help inform vaccination plans if H3N2v becomes more transmissible in the future.

Seasonal influenza vaccination is the strongest correlate of cross-reactive antibody responses in migratory bird handlers.

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Oshansky, Christine M; Wong, Sook-San; Jeevan, Trushar; Smallwood, Heather S; Webby, Richard J; Shafir, Shira C; Thomas, Paul G

2014-12-09

Avian species are reservoirs of influenza A viruses and could harbor viruses with significant pandemic potential. We examined the antibody and cellular immune responses to influenza A viruses in field or laboratory workers with a spectrum of occupational exposure to avian species for evidence of zoonotic infections. We measured the seroprevalence and T cell responses among 95 individuals with various types and degrees of prior field or laboratory occupational exposure to wild North American avian species using whole blood samples collected in 2010. Plasma samples were tested using endpoint enzyme-linked immunosorbent assay (ELISA) and hemagglutination (HA) inhibition (HAI) assays to subtypes H3, H4, H5, H6, H7, H8, and H12 proteins. Detectable antibodies were found against influenza HA antigens in 77% of individuals, while 65% of individuals tested had measurable T cell responses (gamma interferon [IFN-γ] enzyme-linked immunosorbent spot assay [ELISPOT]) to multiple HA antigens of avian origin. To begin defining the observed antibody specificities, Spearman rank correlation analysis showed that ELISA responses, which measure both head- and stalk-binding antibodies, do not predict HAI reactivities, which measure primarily head-binding antibodies. This result suggests that ELISA titers can report cross-reactivity based on the levels of non-head-binding responses. However, the strongest positive correlate of HA-specific ELISA antibody titers was receipt of seasonal influenza virus vaccination. Occupational exposure was largely uncorrelated with serological measures, with the exception of individuals exposed to poultry, who had higher levels of H7-specific antibodies than non-poultry-exposed individuals. While the cohort had antibody and T cell reactivity to a broad range of influenza viruses, only occupational exposure to poultry was associated with a significant difference in antibody levels to a specific subtype (H7). There was no evidence that T cell assays

Delayed norovirus epidemic in the 2009-2010 season in Japan: potential relationship with intensive hand sanitizer use for pandemic influenza.

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Inaida, S; Shobugawa, Y; Matsuno, S; Saito, R; Suzuki, H

2016-09-01

Norovirus (NoV) epidemics normally peak in December in Japan; however, the peak in the 2009-2010 season was delayed until the fourth week of January 2010. We suspected intensive hand hygiene that was conducted for a previous pandemic influenza in 2009 as the cause of this delay. We analysed the NoV epidemic trend, based on national surveillance data, and its associations with monthly output data for hand hygiene products, including alcohol-based skin antiseptics and hand soap. The delayed peak in the NoV incidence in the 2009-2010 season had the lowest number of recorded cases of the five seasons studied (2006-2007 to 2010-2011). GII.4 was the most commonly occurring genotype. The monthly relative risk of NoV and monthly output of both alcohol-based skin antiseptics and hand soap were significantly and negatively correlated. Our findings suggest an association between hand hygiene using these products and prevention of NoV transmission.

Seasonal influenza vaccination coverage and its determinants among nursing homes personnel in western France.

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Elias, Christelle; Fournier, Anna; Vasiliu, Anca; Beix, Nicolas; Demillac, Rémi; Tillaut, Hélène; Guillois, Yvonnick; Eyebe, Serge; Mollo, Bastien; Crépey, Pascal

2017-07-07

Influenza-associated deaths is an important risk for the elderly in nursing homes (NHs) worldwide. Vaccination coverage among residents is high but poorly effective due to immunosenescence. Hence, vaccination of personnel is an efficient way to protect residents. Our objective was to quantify the seasonal influenza vaccination (IV) coverage among NH for elderly workers and identify its determinants in France. We conducted a cross-sectional study in March 2016 in a randomized sample of NHs of the Ille-et-Vilaine department of Brittany, in western France. A standardized questionnaire was administered to a randomized sample of NH workers for face-to-face interviews. General data about the establishment was also collected. Among the 33 NHs surveyed, IV coverage for the 2015-2016 season among permanent workers was estimated at 20% (95% Confidence Interval (CI) 15.3%-26.4%) ranging from 0% to 69% depending on the establishments surveyed. Moreover, IV was associated with having previously experienced a "severe" influenza episode in the past (Prevalence Ratio 1.48, 95% CI 1.01-2.17), and varied by professional categories (p benefits had a significant influence on the IV coverage (p communication tools may be required to be adapted to the various NH professionals to improve influenza prevention.

Influenza A virus transmission via respiratory aerosols or droplets as it relates to pandemic potential

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Richard, Mathilde; Fouchier, Ron A.M.

2015-01-01

Many respiratory viruses of humans originate from animals. For instance, there are now eight paramyxoviruses, four coronaviruses and four orthomxoviruses that cause recurrent epidemics in humans but were once confined to other hosts. In the last decade, several members of the same virus families have jumped the species barrier from animals to humans. Fortunately, these viruses have not become established in humans, because they lacked the ability of sustained transmission between humans. However, these outbreaks highlighted the lack of understanding of what makes a virus transmissible. In part triggered by the relatively high frequency of occurrence of influenza A virus zoonoses and pandemics, the influenza research community has started to investigate the viral genetic and biological traits that drive virus transmission via aerosols or respiratory droplets between mammals. Here we summarize recent discoveries on the genetic and phenotypic traits required for airborne transmission of zoonotic influenza viruses of subtypes H5, H7 and H9 and pandemic viruses of subtypes H1, H2 and H3. Increased understanding of the determinants and mechanisms of respiratory virus transmission is not only key from a basic scientific perspective, but may also aid in assessing the risks posed by zoonotic viruses to human health, and preparedness for such risks. PMID:26385895

Travellers and influenza: risks and prevention.

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Goeijenbier, M; van Genderen, P; Ward, B J; Wilder-Smith, A; Steffen, R; Osterhaus, A D M E

2017-01-01

Influenza viruses are among the major causes of serious human respiratory tract infection worldwide. In line with the high disease burden attributable to influenza, these viruses play an important, but often neglected, role in travel medicine. Guidelines and recommendations regarding prevention and management of influenza in travellers are scarce. Of special interest for travel medicine are risk populations and also circumstances that facilitate influenza virus transmission and spread, like travel by airplane or cruise ship and mass gatherings. We conducted a PUBMED/MEDLINE search for a combination of the MeSH terms Influenza virus, travel, mass gathering, large scale events and cruise ship. In addition we gathered guidelines and recommendations from selected countries and regarding influenza prevention and management in travellers. By reviewing these search results in the light of published knowledge in the fields of influenza prevention and management, we present best practice advice for the prevention and management of influenza in travel medicine. Seasonal influenza is among the most prevalent infectious diseases in travellers. Known host-associated risk factors include extremes of age and being immune-compromised, while the most relevant environmental factors are associated with holiday cruises and mass gatherings. Pre-travel advice should address influenza and its prevention for travellers, whenever appropriate on the basis of the epidemiological situation concerned. Preventative measures should be strongly recommended for travellers at high-risk for developing complications. In addition, seasonal influenza vaccination should be considered for any traveller wishing to reduce the risk of incapacitation, particularly cruise ship crew and passengers, as well as those participating in mass gatherings. Besides advice concerning preventive measures and vaccination, advice on the use of antivirals may be considered for some travellers. © International Society of

Emerging influenza viruses and the prospect of a universal influenza virus vaccine.

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Krammer, Florian

2015-05-01

Influenza viruses cause annual seasonal epidemics and pandemics at irregular intervals. Several cases of human infections with avian and swine influenza viruses have been detected recently, warranting enhanced surveillance and the development of more effective countermeasures to address the pandemic potential of these viruses. The most effective countermeasure against influenza virus infection is the use of prophylactic vaccines. However, vaccines that are currently in use for seasonal influenza viruses have to be re-formulated and re-administered in a cumbersome process every year due to the antigenic drift of the virus. Furthermore, current seasonal vaccines are ineffective against novel pandemic strains. This paper reviews zoonotic influenza viruses with pandemic potential and technological advances towards better vaccines that induce broad and long lasting protection from influenza virus infection. Recent efforts have focused on the development of broadly protective/universal influenza virus vaccines that can provide immunity against drifted seasonal influenza virus strains but also against potential pandemic viruses. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Improving influenza virological surveillance in Europe: strain-based reporting of antigenic and genetic characterisation data, 11 European countries, influenza season 2013/14

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Broberg, Eeva; Hungnes, Olav; Schweiger, Brunhilde; Prosenc, Katarina; Daniels, Rod; Guiomar, Raquel; Ikonen, Niina; Kossyvakis, Athanasios; Pozo, Francisco; Puzelli, Simona; Thomas, Isabelle; Waters, Allison; Wiman, Åsa; Meijer, Adam

2016-01-01

Influenza antigenic and genetic characterisation data are crucial for influenza vaccine composition decision making. Previously, aggregate data were reported to the European Centre for Disease Prevention and Control by European Union/European Economic Area (EU/EEA) countries. A system for collecting case-specific influenza antigenic and genetic characterisation data was established for the 2013/14 influenza season. In a pilot study, 11 EU/EEA countries reported through the new mechanism. We demonstrated feasibility of reporting strain-based antigenic and genetic data and ca 10% of influenza virus-positive specimens were selected for further characterisation. Proportions of characterised virus (sub)types were similar to influenza virus circulation levels. The main genetic clades were represented by A/StPetersburg/27/2011(H1N1)pdm09 and A/Texas/50/2012(H3N2). A(H1N1)pdm09 viruses were more prevalent in age groups (by years) influenza virus circulation among hospitalised patients and substantially improved the reporting of virus characterisation data. Therefore, strain-based reporting of readily available data is recommended to all reporting countries within the EU/EEA. PMID:27762211

The epidemiological impact of childhood influenza vaccination using live-attenuated influenza vaccine (LAIV) in Germany: predictions of a simulation study

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2014-01-01

Background Routine annual influenza vaccination is primarily recommended for all persons aged 60 and above and for people with underlying chronic conditions in Germany. Other countries have already adopted additional childhood influenza immunisation programmes. The objective of this study is to determine the potential epidemiological impact of implementing paediatric influenza vaccination using intranasally administered live-attenuated influenza vaccine (LAIV) in Germany. Methods A deterministic age-structured model is used to simulate the population-level impact of different vaccination strategies on the transmission dynamics of seasonal influenza in Germany. In our base-case analysis, we estimate the effects of adding a LAIV-based immunisation programme targeting children 2 to 17 years of age to the existing influenza vaccination policy. The data used in the model is based on published evidence complemented by expert opinion. Results In our model, additional vaccination of children 2 to 17 years of age with LAIV leads to the prevention of 23.9 million influenza infections and nearly 16 million symptomatic influenza cases within 10 years. This reduction in burden of disease is not restricted to children. About one third of all adult cases can indirectly be prevented by LAIV immunisation of children. Conclusions Our results demonstrate that vaccinating children 2–17 years of age is likely associated with a significant reduction in the burden of paediatric influenza. Furthermore, annual routine childhood vaccination against seasonal influenza is expected to decrease the incidence of influenza among adults and older people due to indirect effects of herd protection. In summary, our model provides data supporting the introduction of a paediatric influenza immunisation programme in Germany. PMID:24450996

The Role of HIV in the Household Introduction and Transmission of Influenza in an Urban Slum, Nairobi, Kenya, 2008-2011.

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Judd, Michael C; Emukule, Gideon O; Njuguna, Henry; McMorrow, Meredith L; Arunga, Geoffrey O; Katz, Mark A; Montgomery, Joel M; Wong, Joshua M; Breiman, Robert F; Mott, Joshua A

2015-09-01

Little is known about how human immunodeficiency virus (HIV) infection affects influenza transmission within homes in sub-Saharan Africa. We used respiratory illness surveillance and HIV testing data gathered in Kibera, an urban slum in Nairobi, Kenya, to examine the impact of HIV status on (1) introducing influenza to the home and (2) transmitting influenza to household contacts. While HIV status did not affect the likelihood of being an influenza index case, household contacts of HIV-infected influenza index cases had twice the risk of developing secondary influenza-like illness than contacts of HIV-negative index cases. HIV-infected influenza index cases may facilitate transmission of influenza within the home. Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Mortality Associated With Seasonal and Pandemic Influenza Among Pregnant and Nonpregnant Women of Childbearing Age in a High-HIV-Prevalence Setting-South Africa, 1999-2009.

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Tempia, Stefano; Walaza, Sibongile; Cohen, Adam L; von Mollendorf, Claire; Moyes, Jocelyn; McAnerney, Johanna M; Cohen, Cheryl

2015-10-01

Information on the mortality burden associated with seasonal and pandemic influenza virus infection among pregnant women is scarce in most settings, particularly in sub-Saharan Africa where pregnancy and maternal mortality rates as well as human immunodeficiency virus (HIV) prevalence are elevated. We used an ecological study design to estimate the seasonal and A(H1N1)pdm09 influenza-associated mortality among pregnant and nonpregnant women of childbearing age (15-49 years) by HIV serostatus during 1999-2009 in South Africa. Mortality rates were expressed per 100 000 person-years. During 1999-2009, the estimated mean annual seasonal influenza-associated mortality rates were 12.6 (123 deaths) and 7.3 (914 deaths) among pregnant and nonpregnant women, respectively. Among pregnant women, the estimated mean annual seasonal influenza-associated mortality rates were 74.9 (109 deaths) among HIV-infected and 1.5 (14 deaths) among HIV-uninfected individuals. Among nonpregnant women, the estimated mean annual seasonal influenza-associated mortality rate was 41.2 (824 deaths) among HIV-infected and 0.9 (90 deaths) among HIV-uninfected individuals. Pregnant women experienced an increased risk of seasonal influenza-associated mortality compared with nonpregnant women (relative risk [RR], 2.8; 95% confidence interval [CI], 1.7-3.9). In 2009, the estimated influenza A(H1N1)pdm09-associated mortality rates were 19.3 (181 deaths) and 9.4 (1189 deaths) among pregnant and nonpregnant women, respectively (RR, 3.2; 95% CI, 2.3-4.1). Among women of childbearing age, the majority of estimated seasonal influenza-associated deaths occurred in HIV-infected individuals. Pregnant women experienced an increased risk of death associated with seasonal and A(H1N1)pdm09 influenza infection compared with nonpregnant women. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Uptake and impact of a new live attenuated influenza vaccine programme in England: early results of a pilot in primary school-age children, 2013/14 influenza season.

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Pebody, R G; Green, H K; Andrews, N; Zhao, H; Boddington, N; Bawa, Z; Durnall, H; Singh, N; Sunderland, A; Letley, L; Ellis, J; Elliot, A J; Donati, M; Smith, G E; de Lusignan, S; Zambon, M

2014-06-05

As part of the introduction and roll-out of a universal childhood live-attenuated influenza vaccination programme, 4–11 year-olds were vaccinated in seven pilot areas in England in the 2013/14 influenza season. This paper presents the uptake and impact of the programme for a range of disease indicators. End-of-season uptake was defined as the number of children in the target population who received at least one dose of influenza vaccine. Between week 40 2013 and week 15 2014, cumulative disease incidence per 100,000 population (general practitioner consultations for influenza-like illness and laboratory-confirmed influenza hospitalisations), cumulative influenza swab positivity in primary and secondary care and cumulative proportion of emergency department respiratory attendances were calculated. Indicators were compared overall and by age group between pilot and non-pilot areas. Direct impact was defined as reduction in cumulative incidence based on residence in pilot relative to non-pilot areas in 4–11 year-olds. Indirect impact was reduction between pilot and non-pilot areas in 11 year-olds. Overall vaccine uptake of 52.5% (104,792/199,475) was achieved. Although influenza activity was low, a consistent, though not statistically significant, decrease in cumulative disease incidence and influenza positivity across different indicators was seen in pilot relative to non-pilot areas in both targeted and non-targeted age groups, except in older age groups, where no difference was observed for secondary care indicators.

Influenza vaccination among healthcare workers and absenteeism from work due to influenza-like illness in a teaching hospital in Palermo

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Emanuele Amodio

2010-09-01

Full Text Available

Background: Annual flu vaccination of healthcare workers (HCWs is recommended worldwide as the best way to prevent influenza and to avoid its transmission. However, in several European Countries, vaccination rate among HCWs is still less than 25%. The aim of this study was to determine the HCW vaccination coverage during a three year period in a large University Hospital, identifying socio demographic and occupational variables involved in the decision to accept influenza vaccination. Moreover, for the 2007-2008 season, we also assessed the effectiveness of influenza vaccination in reducing influenza-related absenteeism.

Methods: During three consecutive influenza seasons (from 2005-2006 to 2007-2008, a cross-sectional study was carried out on all HCWs employed in the “Azienda Ospedaliera Universitaria Policlinico” (AOUP of Palermo (Italy. Socio-demographic and occupational data of HCWs were collected from administrative hospital personnel records and included gender, age, birthplace, residence, profession and the workplace unit. In addition, during the 2007-2008 season, a retrospective study was conducted to evaluate absence from work due to influenza–like illness (ILI in vaccinated versus unvaccinated personnel.

Results: A total of 7,848 HCW-years were observed and 881 vaccines were administered during the study period. Vaccination rate declined from 14.7% in 2005-2006 to 8.2% in 2007-2008 (Chi-square for trend=53.6, p<0.001. Coverage was generally higher among older and male HCWs whereas nurses and workers in surgical areas had lower vaccination rates. In the 2007-2008 season, absenteeism due to ILI in the vaccinated group was significantly less common than unvaccinated HCWs (3.3% vs 7.1%; p=0.04.

Conclusions: Our experience encourages flu vaccination of HCWs and accentuates the importance of annual influenza vaccination programs

Surveillance and vaccine effectiveness of an influenza epidemic predominated by vaccine-mismatched influenza B/Yamagata-lineage viruses in Taiwan, 2011-12 season.

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Yi-Chun Lo

Full Text Available INTRODUCTION: The 2011-12 trivalent influenza vaccine contains a strain of influenza B/Victoria-lineage viruses. Despite free provision of influenza vaccine among target populations, an epidemic predominated by influenza B/Yamagata-lineage viruses occurred during the 2011-12 season in Taiwan. We characterized this vaccine-mismatched epidemic and estimated influenza vaccine effectiveness (VE. METHODS: Influenza activity was monitored through sentinel viral surveillance, emergency department (ED and outpatient influenza-like illness (ILI syndromic surveillance, and case-based surveillance of influenza with complications and deaths. VE against laboratory-confirmed influenza was evaluated through a case-control study on ILI patients enrolled into sentinel viral surveillance. Logistic regression was used to estimate VE adjusted for confounding factors. RESULTS: During July 2011-June 2012, influenza B accounted for 2,382 (72.5% of 3,285 influenza-positive respiratory specimens. Of 329 influenza B viral isolates with antigen characterization, 287 (87.2% were B/Yamagata-lineage viruses. Proportions of ED and outpatient visits being ILI-related increased from November 2011 to January 2012. Of 1,704 confirmed cases of influenza with complications, including 154 (9.0% deaths, influenza B accounted for 1,034 (60.7% of the confirmed cases and 103 (66.9% of the deaths. Reporting rates of confirmed influenza with complications and deaths were 73.5 and 6.6 per 1,000,000, respectively, highest among those aged ≥65 years, 50-64 years, 3-6 years, and 0-2 years. Adjusted VE was -31% (95% CI: -80, 4 against all influenza, 54% (95% CI: 3, 78 against influenza A, and -66% (95% CI: -132, -18 against influenza B. CONCLUSIONS: This influenza epidemic in Taiwan was predominated by B/Yamagata-lineage viruses unprotected by the 2011-12 trivalent vaccine. The morbidity and mortality of this vaccine-mismatched epidemic warrants careful consideration of introducing a

Avian Influenza spread and transmission dynamics

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Bourouiba, Lydia; Gourley, Stephen A.; Liu, Rongsong; Takekawa, John Y.; Wu, Jianhong; Chen, Dongmei; Moulin, Bernard; Wu, Jianhong

2015-01-01

The spread of highly pathogenic avian influenza (HPAI) viruses of type A of subtype H5N1 has been a serious threat to global public health. Understanding the roles of various (migratory, wild, poultry) bird species in the transmission of these viruses is critical for designing and implementing effective control and intervention measures. Developing appropriate models and mathematical techniques to understand these roles and to evaluate the effectiveness of mitigation strategies have been a challenge. Recent development of the global health surveillance (especially satellite tracking and GIS techniques) and the mathematical theory of dynamical systems combined have gradually shown the promise of some cutting-edge methodologies and techniques in mathematical biology to meet this challenge.

Change in settings for early-season influenza vaccination among US adults, 2012 to 2013

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Sarah J. Clark, MPH

2016-12-01

Full Text Available Vaccination in non-medical settings is recommended as a strategy to increase access to seasonal influenza vaccine. To evaluate change in early-season influenza vaccination setting, we analyzed data from the National Internet Flu Survey. Bivariate comparison of respondent characteristics by location of vaccination was assessed using chi-square tests. Multinomial logistic regression was performed to compare the predicted probability of being vaccinated in medical, retail, and mobile settings in 2012 vs 2013. In both 2012 and 2013, vaccination in medical settings was more likely among elderly adults, those with chronic conditions, and adults with a high school education or less. Adults 18–64 without a chronic condition had a lower probability of vaccination in the medical setting, and higher probability of vaccination in a retail or mobile setting, in 2013 compared to 2012. Adults 18–64 with a chronic condition had no change in their location of flu vaccination. Elderly adults had a lower probability of vaccination in the medical setting, and higher probability of vaccination in a retail setting, in 2013 compared to 2012. Non-medical settings continue to play an increasing role in influenza vaccination of adults, particularly for adults without a chronic condition and elderly adults. Retail and mobile settings should continue to be viewed as important mechanisms to ensure broad access to influenza vaccination.

Influenza and other respiratory virus infections in outpatients with medically attended acute respiratory infection during the 2011-12 influenza season.

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Zimmerman, Richard K; Rinaldo, Charles R; Nowalk, Mary Patricia; Gk, Balasubramani; Thompson, Mark G; Moehling, Krissy K; Bullotta, Arlene; Wisniewski, Stephen

2014-07-01

Respiratory tract infections are a major cause of outpatient visits, yet only a portion is tested to determine the etiologic organism. Multiplex reverse transcriptase polymerase chain reaction (MRT-PCR) assays for detection of multiple viruses are being used increasingly in clinical settings. During January-April 2012, outpatients with acute respiratory illness (≤ 7 days) were tested for influenza using singleplex RT-PCR (SRT-PCR). A subset was assayed for 18 viruses using MRT-PCR to compare detection of influenza and examine the distribution of viruses and characteristics of patients using multinomial logistic regression. Among 662 participants (6 months-82 years), detection of influenza was similar between the MRT-PCR and SRT-PCR (κ = 0.83). No virus was identified in 267 (40.3%) samples. Commonly detected viruses were human rhinovirus (HRV, 15.4%), coronavirus (CoV, 10.4%), respiratory syncytial virus (RSV, 8.4%), human metapneumovirus (hMPV, 8.3%), and influenza (6%). Co-detections were infrequent (6.9%) and most commonly occurred among those infections (P = 0.008), nasal congestion was more frequent in CoV, HRV, hMPV, influenza and RSV infections (P = 0.001), and body mass index was higher among those with influenza (P = 0.036). Using MRT-PCR, a viral etiology was found in three-fifths of patients with medically attended outpatient visits for acute respiratory illness during the influenza season; co-detected viruses were infrequent. Symptoms varied by viral etiology. © 2014 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

Swine Influenza Virus (H1N2) Characterization and Transmission in Ferrets, Chile.

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Bravo-Vasquez, Nicolás; Karlsson, Erik A; Jimenez-Bluhm, Pedro; Meliopoulos, Victoria; Kaplan, Bryan; Marvin, Shauna; Cortez, Valerie; Freiden, Pamela; Beck, Melinda A; Hamilton-West, Christopher; Schultz-Cherry, Stacey

2017-02-01

Phylogenetic analysis of the influenza hemagglutinin gene (HA) has suggested that commercial pigs in Chile harbor unique human seasonal H1-like influenza viruses, but further information, including characterization of these viruses, was unavailable. We isolated influenza virus (H1N2) from a swine in a backyard production farm in Central Chile and demonstrated that the HA gene was identical to that in a previous report. Its HA and neuraminidase genes were most similar to human H1 and N2 viruses from the early 1990s and internal segments were similar to influenza A(H1N1)pdm09 virus. The virus replicated efficiently in vitro and in vivo and transmitted in ferrets by respiratory droplet. Antigenically, it was distinct from other swine viruses. Hemagglutination inhibition analysis suggested that antibody titers to the swine Chilean H1N2 virus were decreased in persons born after 1990. Further studies are needed to characterize the potential risk to humans, as well as the ecology of influenza in swine in South America.

Influenza vaccinations of health care personnel

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Aneta Nitsch-Osuch

2013-02-01

Full Text Available Influenza is one of the most common respiratory diseases affecting people of all age groups all over the world. Seasonal influenza leads to substantial morbidity and mortality on a global scale. Vaccines are undeniably one of the most important health advances of the past century, however, managing influenza in working populations remains a difficult issue. Vaccination of health care workers (HCW is an efficient way to reduce the risk of occupational infection and to prevent nosocomial transmission to vulnerable patients. Despite this, achieving high immunization rates among those professionals is a challenge. Knowledge and attitudes of healthcare providers have significant impact on the frequency with which vaccines are offered and accepted, but many HCWs are poorly equipped to make informed recommendations about vaccine merits and risks. Principal reasons for vaccination are the willing not to be infected and avoiding transmission to patients and the family. The main reasons for refusing is lack of time, a feeling of invulnerability to vaccination, conviction of not being at risk, of being too young or in good health. Misconceptions about influenza vaccine efficacy, like adverse effects, and fear of contracting illness from the vaccine are significantly associated with noncompliance with vaccination. Therefore, strategies to increase awareness of the importance of recommending influenza immunization among health professionals are required. Med Pr 2013;64(1:119–129

Avian influenza H5N1 viral and bird migration networks in Asia

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Tian, Huaivu; Zhou, Sen; Dong, Lu; Van Boeckel, Thomas P.; Cui, Yujun; Newman, Scott H.; Takekawa, John Y.; Prosser, Diann J.; Xiao, Xiangming; Wu, Yarong; Cazelles, Bernard; Huang, Shanqian; Yang, Ruifu; Grenfell, Bryan T.; Xu, Bing

2015-01-01

The spatial spread of the highly pathogenic avian influenza virus H5N1 and its long-term persistence in Asia have resulted in avian influenza panzootics and enormous economic losses in the poultry sector. However, an understanding of the regional long-distance transmission and seasonal patterns of the virus is still lacking. In this study, we present a phylogeographic approach to reconstruct the viral migration network. We show that within each wild fowl migratory flyway, the timing of H5N1 outbreaks and viral migrations are closely associated, but little viral transmission was observed between the flyways. The bird migration network is shown to better reflect the observed viral gene sequence data than other networks and contributes to seasonal H5N1 epidemics in local regions and its large-scale transmission along flyways. These findings have potentially far-reaching consequences, improving our understanding of how bird migration drives the periodic reemergence of H5N1 in Asia.

Pandemic vaccination strategies and influenza severe outcomes during the influenza A(H1N1)pdm09 pandemic and the post-pandemic influenza season

DEFF Research Database (Denmark)

Gil Cuesta, Julita; Aavitsland, Preben; Englund, Hélène

2016-01-01

During the 2009/10 influenza A(H1N1)pdm09 pandemic, the five Nordic countries adopted different approaches to pandemic vaccination. We compared pandemic vaccination strategies and severe influenza outcomes, in seasons 2009/10 and 2010/11 in these countries with similar influenza surveillance...... systems. We calculated the cumulative pandemic vaccination coverage in 2009/10 and cumulative incidence rates of laboratory confirmed A(H1N1)pdm09 infections, intensive care unit (ICU) admissions and deaths in 2009/10 and 2010/11. We estimated incidence risk ratios (IRR) in a Poisson regression model...... with the other countries. In 2010/11 Denmark had a significantly higher cumulative incidence of A(H1N1)pdm09 ICU admissions (IRR: 2.4; 95% confidence interval (CI): 1.9-3.0) and deaths (IRR: 8.3; 95% CI: 5.1-13.5). Compared with Denmark, the other countries had higher pandemic vaccination coverage...

Enhancing Seasonal Influenza Surveillance: Topic Analysis of Widely Used Medicinal Drugs Using Twitter Data.

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Kagashe, Ireneus; Yan, Zhijun; Suheryani, Imran

2017-09-12

Uptake of medicinal drugs (preventive or treatment) is among the approaches used to control disease outbreaks, and therefore, it is of vital importance to be aware of the counts or frequencies of most commonly used drugs and trending topics about these drugs from consumers for successful implementation of control measures. Traditional survey methods would have accomplished this study, but they are too costly in terms of resources needed, and they are subject to social desirability bias for topics discovery. Hence, there is a need to use alternative efficient means such as Twitter data and machine learning (ML) techniques. Using Twitter data, the aim of the study was to (1) provide a methodological extension for efficiently extracting widely consumed drugs during seasonal influenza and (2) extract topics from the tweets of these drugs and to infer how the insights provided by these topics can enhance seasonal influenza surveillance. From tweets collected during the 2012-13 flu season, we first identified tweets with mentions of drugs and then constructed an ML classifier using dependency words as features. The classifier was used to extract tweets that evidenced consumption of drugs, out of which we identified the mostly consumed drugs. Finally, we extracted trending topics from each of these widely used drugs' tweets using latent Dirichlet allocation (LDA). Our proposed classifier obtained an F 1 score of 0.82, which significantly outperformed the two benchmark classifiers (ie, Pstrategies for mitigating the severity of seasonal influenza outbreaks. The proposed methods can be extended to the outbreaks of other diseases. ©Ireneus Kagashe, Zhijun Yan, Imran Suheryani. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 12.09.2017.

Knowledge, motivation, and attitudes of Hungarian family physicians toward pandemic influenza vaccination in the 2009/10 influenza season: questionnaire study.

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Rurik, Imre; Langmár, Zoltán; Márton, Hajnalka; Kovács, Eszter; Szigethy, Endre; Ilyés, István

2011-04-15

To evaluate the knowledge, motivation, and attitudes of Hungarian family physicians toward pandemic influenza vaccination in the 2009/10 influenza season. A questionnaire with 20 questions was developed and sent to 232 family physicians in 3 largest Hungarian cities: Budapest, Debrecen, and Miskolc. The study was conducted in December 2009 and January 2010. A hundred and ninety eight (85%) physicians answered the questionnaire adequately. Respondents believed that the influenza outbreak represented less of a threat to their practices than to Hungary or the world as a whole. They mostly agreed that vaccination was important and were frequently dissatisfied with the support from health authorities. The proportion of vaccinated patients ranged between 2% and 53%, without differences according to geographical region, age, sex, and duration of physicians' employment in family practice. Physicians who were satisfied with the payment for procedures and underwent vaccination themselves were more active in vaccination. Health authorities should provide clear and evidence-based professional support to family physicians and should encourage them to get vaccinated against pandemic influenza, while insurance funds have to establish appropriate reimbursement system.

Molecular Markers for Interspecies Transmission of Avian Influenza Viruses in Mammalian Hosts

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Lee, Taehyung

2017-01-01

In the last decade, a wide range of avian influenza viruses (AIVs) have infected various mammalian hosts and continuously threaten both human and animal health. It is a result of overcoming the inter-species barrier which is mostly associated with gene reassortment and accumulation of mutations in their gene segments. Several recent studies have shed insights into the phenotypic and genetic changes that are involved in the interspecies transmission of AIVs. These studies have a major focus on transmission from avian to mammalian species due to the high zoonotic potential of the viruses. As more mammalian species have been infected with these viruses, there is higher risk of genetic evolution of these viruses that may lead to the next human pandemic which represents and raises public health concern. Thus, understanding the mechanism of interspecies transmission and molecular determinants through which the emerging AIVs can acquire the ability to transmit to humans and other mammals is an important key in evaluating the potential risk caused by AIVs among humans. Here, we summarize previous and recent studies on molecular markers that are specifically involved in the transmission of avian-derived influenza viruses to various mammalian hosts including humans, pigs, horses, dogs, and marine mammals. PMID:29236050

Microstructure of atmospheric particles revealed by TXM and a new mode of influenza virus transmission

Energy Technology Data Exchange (ETDEWEB)

Bao, L.M., E-mail: baoliangman@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhang, G.L., E-mail: zhangguilin@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Lei, Q.T.; Li, Y.; Li, X.L. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Hwu, Y.K. [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Yi, J.M. [Advanced Photon Source, Argonne National Laboratory, Argonne 60439 (United States)

2015-09-15

For control of influenza, firstly it is important to find the real virus transmission media. Atmospheric aerosol particles are presumably one of the media. In this study, three typical atmospheric inhaled particles in Shanghai were studied by the synchrotron based transmission X-ray microscopes (TXM). Three dimensional microstructure of the particles reveals that there are many pores contained in, particularly the coal combustion fly particles which may be possible virus carrier. The particles can transport over long distance and cause long-range infections due to its light weight. We suggest a mode which is droplet combining with aerosol mode. By this mode the transmission of global and pandemic influenzas and infection between inland avian far from population and poultry or human living in cities along coast may be explained.

Influenza (Flu) Viruses

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... Types Seasonal Avian Swine Variant Pandemic Other Influenza (Flu) Viruses Language: English (US) Español Recommend on Facebook ... influenza circulate and cause illness. More Information about Flu Viruses Types of Influenza Viruses Influenza A and ...

Detection of extensive cross-neutralization between pandemic and seasonal A/H1N1 Influenza Viruses using a pseudotype neutralization assay.

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Béatrice Labrosse

Full Text Available BACKGROUND: Cross-immunity between seasonal and pandemic A/H1N1 influenza viruses remains uncertain. In particular, the extent that previous infection or vaccination by seasonal A/H1N1 viruses can elicit protective immunity against pandemic A/H1N1 is unclear. METHODOLOGY/PRINCIPAL FINDINGS: Neutralizing titers against seasonal A/H1N1 (A/Brisbane/59/2007 and against pandemic A/H1N1 (A/California/04/2009 were measured using an HIV-1-based pseudovirus neutralization assay. Using this highly sensitive assay, we found that a large fraction of subjects who had never been exposed to pandemic A/H1N1 express high levels of pandemic A/H1N1 neutralizing titers. A significant correlation was seen between neutralization of pandemic A/H1N1 and neutralization of a standard seasonal A/H1N1 strain. Significantly higher pandemic A/H1N1 neutralizing titers were measured in subjects who had received vaccination against seasonal influenza in 2008-2009. Higher pandemic neutralizing titers were also measured in subjects over 60 years of age. CONCLUSIONS/SIGNIFICANCE: Our findings reveal that the extent of protective cross-immunity between seasonal and pandemic A/H1N1 influenza viruses may be more important than previously estimated. This cross-immunity could provide a possible explanation of the relatively mild profile of the recent influenza pandemic.

I-MOVE multicentre case-control study 2010/11 to 2014/15: Is there within-season waning of influenza type/subtype vaccine effectiveness with increasing time since vaccination?

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Kissling, Esther; Nunes, Baltazar; Robertson, Chris; Valenciano, Marta; Reuss, Annicka; Larrauri, Amparo; Cohen, Jean Marie; Oroszi, Beatrix; Rizzo, Caterina; Machado, Ausenda; Pitigoi, Daniela; Domegan, Lisa; Paradowska-Stankiewicz, Iwona; Buchholz, Udo; Gherasim, Alin; Daviaud, Isabelle; Horváth, Judit Krisztina; Bella, Antonino; Lupulescu, Emilia; O Donnell, Joan; Korczyńska, Monika; Moren, Alain

2016-04-21

Since the 2008/9 influenza season, the I-MOVE multicentre case-control study measures influenza vaccine effectiveness (VE) against medically-attended influenza-like-illness (ILI) laboratory confirmed as influenza. In 2011/12, European studies reported a decline in VE against influenza A(H3N2) within the season. Using combined I-MOVE data from 2010/11 to 2014/15 we studied the effects of time since vaccination on influenza type/subtype-specific VE. We modelled influenza type/subtype-specific VE by time since vaccination using a restricted cubic spline, controlling for potential confounders (age, sex, time of onset, chronic conditions). Over 10,000 ILI cases were included in each analysis of influenza A(H3N2), A(H1N1)pdm09 and B; with 4,759, 3,152 and 3,617 influenza positive cases respectively. VE against influenza A(H3N2) reached 50.6% (95% CI: 30.0-65.1) 38 days after vaccination, declined to 0% (95% CI: -18.1-15.2) from 111 days onwards. At day 54 VE against influenza A(H1N1)pdm09 reached 55.3% (95% CI: 37.9-67.9) and remained between this value and 50.3% (95% CI: 34.8-62.1) until season end. VE against influenza B declined from 70.7% (95% CI: 51.3-82.4) 44 days after vaccination to 21.4% (95% CI: -57.4-60.8) at season end. To assess if vaccination campaign strategies need revising more evidence on VE by time since vaccination is urgently needed.

The use of ambient humidity conditions to improve influenza forecast.

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Shaman, Jeffrey; Kandula, Sasikiran; Yang, Wan; Karspeck, Alicia

2017-11-01

Laboratory and epidemiological evidence indicate that ambient humidity modulates the survival and transmission of influenza. Here we explore whether the inclusion of humidity forcing in mathematical models describing influenza transmission improves the accuracy of forecasts generated with those models. We generate retrospective forecasts for 95 cities over 10 seasons in the United States and assess both forecast accuracy and error. Overall, we find that humidity forcing improves forecast performance (at 1-4 lead weeks, 3.8% more peak week and 4.4% more peak intensity forecasts are accurate than with no forcing) and that forecasts generated using daily climatological humidity forcing generally outperform forecasts that utilize daily observed humidity forcing (4.4% and 2.6% respectively). These findings hold for predictions of outbreak peak intensity, peak timing, and incidence over 2- and 4-week horizons. The results indicate that use of climatological humidity forcing is warranted for current operational influenza forecast.

Novel framework for assessing epidemiologic effects of influenza epidemics and pandemics.

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Reed, Carrie; Biggerstaff, Matthew; Finelli, Lyn; Koonin, Lisa M; Beauvais, Denise; Uzicanin, Amra; Plummer, Andrew; Bresee, Joe; Redd, Stephen C; Jernigan, Daniel B

2013-01-01

The effects of influenza on a population are attributable to the clinical severity of illness and the number of persons infected, which can vary greatly between seasons or pandemics. To create a systematic framework for assessing the public health effects of an emerging pandemic, we reviewed data from past influenza seasons and pandemics to characterize severity and transmissibility (based on ranges of these measures in the United States) and outlined a formal assessment of the potential effects of a novel virus. The assessment was divided into 2 periods. Because early in a pandemic, measurement of severity and transmissibility is uncertain, we used a broad dichotomous scale in the initial assessment to divide the range of historic values. In the refined assessment, as more data became available, we categorized those values more precisely. By organizing and prioritizing data collection, this approach may inform an evidence-based assessment of pandemic effects and guide decision making.

Guinea pig model for evaluating the potential public health risk of swine and avian influenza viruses.

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Sun, Yipeng; Bi, Yuhai; Pu, Juan; Hu, Yanxin; Wang, Jingjing; Gao, Huijie; Liu, Linqing; Xu, Qi; Tan, Yuanyuan; Liu, Mengda; Guo, Xin; Yang, Hanchun; Liu, Jinhua

2010-11-23

The influenza viruses circulating in animals sporadically transmit to humans and pose pandemic threats. Animal models to evaluate the potential public health risk potential of these viruses are needed. We investigated the guinea pig as a mammalian model for the study of the replication and transmission characteristics of selected swine H1N1, H1N2, H3N2 and avian H9N2 influenza viruses, compared to those of pandemic (H1N1) 2009 and seasonal human H1N1, H3N2 influenza viruses. The swine and avian influenza viruses investigated were restricted to the respiratory system of guinea pigs and shed at high titers in nasal tracts without prior adaptation, similar to human strains. None of the swine and avian influenza viruses showed transmissibility among guinea pigs; in contrast, pandemic (H1N1) 2009 virus transmitted from infected guinea pigs to all animals and seasonal human influenza viruses could also horizontally transmit in guinea pigs. The analysis of the receptor distribution in the guinea pig respiratory tissues by lectin histochemistry indicated that both SAα2,3-Gal and SAα2,6-Gal receptors widely presented in the nasal tract and the trachea, while SAα2,3-Gal receptor was the main receptor in the lung. We propose that the guinea pig could serve as a useful mammalian model to evaluate the potential public health threat of swine and avian influenza viruses.

Knowledge of influenza vaccination recommendation and early vaccination uptake during the 2015-16 season among adults aged ≥18years - United States.

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Lu, Peng-Jun; Srivastav, Anup; Santibanez, Tammy A; Christopher Stringer, M; Bostwick, Michael; Dever, Jill A; Stanley Kurtz, Marshica; Williams, Walter W

2017-08-03

Since 2010, the Advisory Committee on Immunization Practices (ACIP) has recommended that all persons aged ≥6months receive annual influenza vaccination. We analyzed data from the 2015 National Internet Flu Survey (NIFS), to assess knowledge and awareness of the influenza vaccination recommendation and early influenza vaccination coverage during the 2015-16 season among adults. Predictive marginals from a multivariable logistic regression model were used to identify factors independently associated with adults' knowledge and awareness of the vaccination recommendation and early vaccine uptake during the 2015-16 influenza season. Among the 3301 respondents aged ≥18years, 19.6% indicated knowing that influenza vaccination is recommended for all persons aged ≥6months. Of respondents, 62.3% indicated awareness that there was a recommendation for influenza vaccination, but did not indicate correct knowledge of the recommended age group. Overall, 39.9% of adults aged ≥18years reported having an influenza vaccination. Age 65years and older, being female, having a college or higher education, not being in work force, having annual household income ≥$75,000, reporting having received an influenza vaccination early in the 2015-16 season, having children aged ≤17years in the household, and having high-risk conditions were independently associated with a higher correct knowledge of the influenza vaccination recommendation. Approximately 1 in 5 had correct knowledge of the recommendation that all persons aged ≥6months should receive an influenza vaccination annually, with some socio-economic groups being even less aware. Clinic based education in combination with strategies known to increase uptake of recommended vaccines, such as patient reminder/recall systems and other healthcare system-based interventions are needed to improve vaccination, which could also improve awareness. Published by Elsevier Ltd.

Patient reported outcome data following influenza A (H1N1p vaccination in the 2009–2010 season: web-based and telephone evaluation

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Wade AG

2011-10-01

Full Text Available Alan G Wade1, Gordon M Crawford1, Neil Pumford1, Alex McConnachie21Patients Direct, 3 Todd Campus, Glasgow, UK; 2Robertson Centre for Biostatistics, University of Glasgow, Glasgow, UKBackground: There has been worldwide interest in the safety of the pandemic influenza A (H1N1p vaccines, although limited data are available from the vaccine recipients’ perspective. This evaluation was designed to collect data from people who had received an influenza vaccination during the 2009–2010 season using a web-based data collection tool supplemented by telephone reporting (PROBE.Methods: People scheduled to receive the influenza A (H1N1p or seasonal influenza vaccines were recruited through media advertising and campaigns throughout the West of Scotland. Vaccine recipients participated in the evaluation by answering demographic and side effect questions using PROBE methodology on the day of the immunization, after 3 days, 8 days, 6 weeks, 12 weeks, and 26 weeks.Results: A total of 1103 vaccine recipients including 134 young children (0–4 years participated in the evaluation; 694 (63% received H1N1p vaccine only, 135 (12% seasonal vaccine only, 224 (20% both H1N1p and seasonal vaccines, and 50 (5% received H1N1p or seasonal vaccine with a non-influenza vaccine (eg, travel or pneumococcal. Overall, 42% of recipients reported experiencing a side effect after their baseline vaccination; the most commonly reported were general and arm side effects (>20%. Injection site discomfort/pain and flu-like symptoms were reported by 57% and 24% of recipients, respectively. A significantly higher proportion of the 960 H1N1p vaccine recipients experienced a side effect (44% vs 27%, P < 0.001 or injection site discomfort/pain (61% vs 26%, P < 0.001 than those receiving seasonal influenza vaccines. Female sex and H1N1p vaccination were associated with a significantly higher risk of injection site discomfort/pain, whereas the 70+ age group was associated with a

Universal influenza vaccines, science fiction or soon reality?

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de Vries, Rory D; Altenburg, Arwen F; Rimmelzwaan, Guus F

2015-01-01

Currently used influenza vaccines are only effective when the vaccine strains match the epidemic strains antigenically. To this end, seasonal influenza vaccines must be updated almost annually. Furthermore, seasonal influenza vaccines fail to afford protection against antigenically distinct pandemic influenza viruses. Because of an ever-present threat of the next influenza pandemic and the continuous emergence of drift variants of seasonal influenza A viruses, there is a need for an universal influenza vaccine that induces protective immunity against all influenza A viruses. Here, we summarize some of the efforts that are ongoing to develop universal influenza vaccines.

Molecular characterization and phylogenetic analysis of human influenza A viruses isolated in Iran during the 2014-2015 season.

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Moasser, Elham; Behzadian, Farida; Moattari, Afagh; Fotouhi, Fatemeh; Rahimi, Amir; Zaraket, Hassan; Hosseini, Seyed Younes

2017-07-01

Influenza A viruses are an important cause of severe infectious diseases in humans and are characterized by their fast evolution rate. Global monitoring of these viruses is critical to detect newly emerging variants during annual epidemics. Here, we sought to genetically characterize influenza A/H1N1pdm09 and A/H3N2 viruses collected in Iran during the 2014-2015 influenza season. A total of 200 nasopharyngeal swabs were collected from patients with influenza-like illnesses. Swabs were screened for influenza A and B using real-time PCR. Furthermore, positive specimens with high virus load underwent virus isolation and genetic characterization of their hemagglutinin (HA) and M genes. Of the 200 specimens, 80 were influenza A-positive, including 44 A/H1N1pdm09 and 36 A/H3N2, while 18 were influenza B-positive. Phylogenetic analysis of the HA genes of the A/H1N1pdm09 viruses revealed the circulation of clade 6C, characterized by amino acid substitutions D97N, V234I and K283E. Analysis of the A/H3N2 viruses showed a genetic drift from the vaccine strain A/Texas/50/2012 with 5 mutations (T128A, R142G, N145S, P198S and S219F) belonging to the antigenic sites A, B, and D of the HA protein. The A/H3N2 viruses belonged to phylogenetic clades 3C.2 and 3C.3. The M gene trees of the Iranian A/H1N1pdm09 and A/H3N2 mirrored the clustering patterns of their corresponding HA trees. Our results reveal co-circulation of several influenza A virus strains in Iran during the 2014-2015 influenza season.

Seasonal Influenza A H1N1pdm09 Virus and Severe Outcomes: A Reason for Broader Vaccination in Non-Elderly, At-Risk People.

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Elisa Minchole

Full Text Available Recent pandemics of influenza A H1N1pdm09 virus have caused severe illness, especially in young people. Very few studies on influenza A H1N1pdm09 in post-pandemic periods exist, and there is no information on the severity of both seasonal influenza A(H1N1 and A(H3N2 from the same season, adjusting for potential confounders, including vaccine.We performed a retrospective observational study of adults hospitalized during the 2014 season with influenza A(H1N1 or A(H3N2. All patients underwent the same diagnostic and therapeutic protocol in a single hospital, including early Oseltamivir therapy. We included 234 patients: 146 (62.4% influenza A(H1N1 and 88 (37.6% A(H3N2. A(H1N1 patients were younger (p<0.01, developed more pneumonia (p<0.01, respiratory complications (p = 0.015, ARDS (p = 0.047, and septic shock (p = 0.049, were more frequently admitted to the ICU (p = 0.022, required IMV (p = 0.049, and were less frequently vaccinated (p = 0.008. After adjusting for age, comorbidities, time from onset of illness, and vaccine status, influenza A(H1N1 (OR, 2.525, coinfection (OR, 2.821, and no vaccination (OR, 3.086 were independent risk factors for severe disease.Hospitalized patients with influenza A(H1N1 were more than twice as likely to have severe influenza. They were younger and most had not received the vaccine. Our findings suggest that seasonal influenza A(H1N1 maintains some features of pandemic viruses, and recommend wider use of vaccination in younger adult high-risk patients.

The role of influenza in the epidemiology of pneumonia

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Shrestha, Sourya; Foxman, Betsy; Berus, Joshua; van Panhuis, Willem G.; Steiner, Claudia; Viboud, Cécile; Rohani, Pejman

2015-01-01

Interactions arising from sequential viral and bacterial infections play important roles in the epidemiological outcome of many respiratory pathogens. Influenza virus has been implicated in the pathogenesis of several respiratory bacterial pathogens commonly associated with pneumonia. Though clinical evidence supporting this interaction is unambiguous, its population-level effects—magnitude, epidemiological impact and variation during pandemic and seasonal outbreaks—remain unclear. To address these unknowns, we used longitudinal influenza and pneumonia incidence data, at different spatial resolutions and across different epidemiological periods, to infer the nature, timing and the intensity of influenza-pneumonia interaction. We used a mechanistic transmission model within a likelihood-based inference framework to carry out formal hypothesis testing. Irrespective of the source of data examined, we found that influenza infection increases the risk of pneumonia by ~100-fold. We found no support for enhanced transmission or severity impact of the interaction. For model-validation, we challenged our fitted model to make out-of-sample pneumonia predictions during pandemic and non-pandemic periods. The consistency in our inference tests carried out on several distinct datasets, and the predictive skill of our model increase confidence in our overall conclusion that influenza infection substantially enhances the risk of pneumonia, though only for a short period. PMID:26486591

Determinants of seasonal influenza vaccination in pregnant women in Valencia, Spain

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R. Vila-Candel

2016-11-01

Full Text Available Abstract Background In most countries the coverage of seasonal influenza vaccination in pregnant women is low. We investigated the acceptance, reasons for rejection and professional involvement related to vaccine information in pregnant women in Valencia, Spain. Methods Observational retrospective study in 200 pregnant women, 100 vaccinated and 100 unvaccinated, were interviewed during the 2014/2015 vaccination campaign. Electronic medical records, immunization registry and telephone interviews were used to determine reasons for vaccination and immunization rejection. Results 40.5% of pregnant women in the health department were vaccinated. The midwife was identified as source of information for 89% of women. The vaccine was rejected due to low perceptions of risk of influenza infection (23%, lack of information (19%, considering the vaccine as superfluous (16%, close proximity of delivery date (13% and fear of side effects (12%. Conclusion Pregnant women in Spain declined to be vaccinated due to under-estimation of the risk of contracting or being harmed by influenza, and lack of information. Interventions aiming to optimize vaccination coverage should include information addressing the safety and effectiveness of the current vaccine together with improved professional training and motivation.

Comparative analyses of pandemic H1N1 and seasonal H1N1, H3N2, and influenza B infections depict distinct clinical pictures in ferrets.

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Stephen S H Huang

Full Text Available Influenza A and B infections are a worldwide health concern to both humans and animals. High genetic evolution rates of the influenza virus allow the constant emergence of new strains and cause illness variation. Since human influenza infections are often complicated by secondary factors such as age and underlying medical conditions, strain or subtype specific clinical features are difficult to assess. Here we infected ferrets with 13 currently circulating influenza strains (including strains of pandemic 2009 H1N1 [H1N1pdm] and seasonal A/H1N1, A/H3N2, and B viruses. The clinical parameters were measured daily for 14 days in stable environmental conditions to compare clinical characteristics. We found that H1N1pdm strains had a more severe physiological impact than all season strains where pandemic A/California/07/2009 was the most clinically pathogenic pandemic strain. The most serious illness among seasonal A/H1N1 and A/H3N2 groups was caused by A/Solomon Islands/03/2006 and A/Perth/16/2009, respectively. Among the 13 studied strains, B/Hubei-Wujiagang/158/2009 presented the mildest clinical symptoms. We have also discovered that disease severity (by clinical illness and histopathology correlated with influenza specific antibody response but not viral replication in the upper respiratory tract. H1N1pdm induced the highest and most rapid antibody response followed by seasonal A/H3N2, seasonal A/H1N1 and seasonal influenza B (with B/Hubei-Wujiagang/158/2009 inducing the weakest response. Our study is the first to compare the clinical features of multiple circulating influenza strains in ferrets. These findings will help to characterize the clinical pictures of specific influenza strains as well as give insights into the development and administration of appropriate influenza therapeutics.

Seasonal influenza vaccine coverage among high-risk populations in Thailand, 2010-2012.

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Owusu, Jocelynn T; Prapasiri, Prabda; Ditsungnoen, Darunee; Leetongin, Grit; Yoocharoen, Pornsak; Rattanayot, Jarowee; Olsen, Sonja J; Muangchana, Charung

2015-01-29

The Advisory Committee on Immunization Practice of Thailand prioritizes seasonal influenza vaccinations for populations who are at highest risk for serious complications (pregnant women, children 6 months-2 years, persons ≥65 years, persons with chronic diseases, obese persons), and healthcare personnel and poultry cullers. The Thailand government purchases seasonal influenza vaccine for these groups. We assessed vaccination coverage among high-risk groups in Thailand from 2010 to 2012. National records on persons who received publicly purchased vaccines from 2010 to 2012 were analyzed by high-risk category. Denominator data from multiple sources were compared to calculate coverage. Vaccine coverage was defined as the proportion of individuals in each category who received the vaccine. Vaccine wastage was defined as the proportion of publicly purchased vaccines that were not used. From 2010 to 2012, 8.18 million influenza vaccines were publicly purchased (range, 2.37-3.29 million doses/year), and vaccine purchases increased 39% over these years. Vaccine wastage was 9.5%. Approximately 5.7 million (77%) vaccine doses were administered to persons ≥65 years and persons with chronic diseases, 1.4 million (19%) to healthcare personnel/poultry cullers, 82,570 (1.1%) to children 6 months-2 years, 78,885 (1.1%) to obese persons, 26,481 (0.4%) to mentally disabled persons, and 17,787 (0.2%) to pregnant women. Between 2010 and 2012, coverage increased among persons with chronic diseases (8.6% versus 14%; pThailand. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

The use of ambient humidity conditions to improve influenza forecast.

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Jeffrey Shaman

2017-11-01

Full Text Available Laboratory and epidemiological evidence indicate that ambient humidity modulates the survival and transmission of influenza. Here we explore whether the inclusion of humidity forcing in mathematical models describing influenza transmission improves the accuracy of forecasts generated with those models. We generate retrospective forecasts for 95 cities over 10 seasons in the United States and assess both forecast accuracy and error. Overall, we find that humidity forcing improves forecast performance (at 1-4 lead weeks, 3.8% more peak week and 4.4% more peak intensity forecasts are accurate than with no forcing and that forecasts generated using daily climatological humidity forcing generally outperform forecasts that utilize daily observed humidity forcing (4.4% and 2.6% respectively. These findings hold for predictions of outbreak peak intensity, peak timing, and incidence over 2- and 4-week horizons. The results indicate that use of climatological humidity forcing is warranted for current operational influenza forecast.

Inefficient Transmission of H5N1 Influenza Viruses in a Ferret Contact Model▿

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Yen, Hui-Ling; Lipatov, Aleksandr S.; Ilyushina, Natalia A.; Govorkova, Elena A.; Franks, John; Yilmaz, Neziha; Douglas, Alan; Hay, Alan; Krauss, Scott; Rehg, Jerold E.; Hoffmann, Erich; Webster, Robert G.

2007-01-01

The abilities to infect and transmit efficiently among humans are essential for a novel influenza A virus to cause a pandemic. To evaluate the pandemic potential of widely disseminated H5N1 influenza viruses, a ferret contact model using experimental groups comprised of one inoculated ferret and two contact ferrets was used to study the transmissibility of four human H5N1 viruses isolated from 2003 to 2006. The effects of viral pathogenicity and receptor binding specificity (affinity to synth...

Statistical estimates of absenteeism attributable to seasonal and pandemic influenza from the Canadian Labour Force Survey

OpenAIRE

Zheng Hui; Schanzer Dena L; Gilmore Jason

2011-01-01

Abstract Background As many respiratory viruses are responsible for influenza like symptoms, accurate measures of the disease burden are not available and estimates are generally based on statistical methods. The objective of this study was to estimate absenteeism rates and hours lost due to seasonal influenza and compare these estimates with estimates of absenteeism attributable to the two H1N1 pandemic waves that occurred in 2009. Methods Key absenteeism variables were extracted from Statis...

Multiple estimates of transmissibility for the 2009 influenza pandemic based on influenza-like-illness data from small US military populations.

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Pete Riley

Full Text Available Rapidly characterizing the amplitude and variability in transmissibility of novel human influenza strains as they emerge is a key public health priority. However, comparison of early estimates of the basic reproduction number during the 2009 pandemic were challenging because of inconsistent data sources and methods. Here, we define and analyze influenza-like-illness (ILI case data from 2009-2010 for the 50 largest spatially distinct US military installations (military population defined by zip code, MPZ. We used publicly available data from non-military sources to show that patterns of ILI incidence in many of these MPZs closely followed the pattern of their enclosing civilian population. After characterizing the broad patterns of incidence (e.g. single-peak, double-peak, we defined a parsimonious SIR-like model with two possible values for intrinsic transmissibility across three epochs. We fitted the parameters of this model to data from all 50 MPZs, finding them to be reasonably well clustered with a median (mean value of 1.39 (1.57 and standard deviation of 0.41. An increasing temporal trend in transmissibility ([Formula: see text], p-value: 0.013 during the period of our study was robust to the removal of high transmissibility outliers and to the removal of the smaller 20 MPZs. Our results demonstrate the utility of rapidly available - and consistent - data from multiple populations.

Influenza A Subtyping

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Kaul, Karen L.; Mangold, Kathy A.; Du, Hongyan; Pesavento, Kristen M.; Nawrocki, John; Nowak, Jan A.

2010-01-01

Influenza virus subtyping has emerged as a critical tool in the diagnosis of influenza. Antiviral resistance is present in the majority of seasonal H1N1 influenza A infections, with association of viral strain type and antiviral resistance. Influenza A virus subtypes can be reliably distinguished by examining conserved sequences in the matrix protein gene. We describe our experience with an assay for influenza A subtyping based on matrix gene sequences. Viral RNA was prepared from nasopharyngeal swab samples, and real-time RT-PCR detection of influenza A and B was performed using a laboratory developed analyte-specific reagent-based assay that targets a conserved region of the influenza A matrix protein gene. FluA-positive samples were analyzed using a second RT-PCR assay targeting the matrix protein gene to distinguish seasonal influenza subtypes based on differential melting of fluorescence resonance energy transfer probes. The novel H1N1 influenza strain responsible for the 2009 pandemic showed a melting profile distinct from that of seasonal H1N1 or H3N2 and compatible with the predicted melting temperature based on the published novel H1N1 matrix gene sequence. Validation by comparison with the Centers for Disease Control and Prevention real-time RT-PCR for swine influenza A (novel H1N1) test showed this assay to be both rapid and reliable (>99% sensitive and specific) in the identification of the novel H1N1 influenza A virus strain. PMID:20595627

Seasonal influenza vaccine and protection against pandemic (H1N1 2009-associated illness among US military personnel.

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Matthew C Johns

Full Text Available INTRODUCTION: A novel A/H1N1 virus is the cause of the present influenza pandemic; vaccination is a key countermeasure, however, few data assessing prior seasonal vaccine effectiveness (VE against the pandemic strain of H1N1 (pH1N1 virus are available. MATERIALS AND METHODS: Surveillance of influenza-related medical encounter data of active duty military service members stationed in the United States during the period of April-October 2009 with comparison of pH1N1-confirmed cases and location and date-matched controls. Crude odds ratios (OR and VE estimates for immunized versus non-immunized were calculated as well as adjusted OR (AOR controlling for sex, age group, and history of prior influenza vaccination. Separate stratified VE analyses by vaccine type (trivalent inactivated [TIV] or live attenuated [LAIV], age groups and hospitalization status were also performed. For the period of April 20 to October 15, 2009, a total of 1,205 cases of pH1N1-confirmed cases were reported, 966 (80% among males and over one-half (58% under 25 years of age. Overall VE for service members was found to be 45% (95% CI, 33 to 55%. Immunization with prior season's TIV (VE = 44%, 95% CI, 32 to 54% as well as LAIV (VE = 24%, 95% CI, 6 to 38% were both found to be associated with protection. Of significance, VE against a severe disease outcome was higher (VE = 62%, 95% CI, 14 to 84% than against milder outcomes (VE = 42%, 95% CI, 29 to 53%. CONCLUSION: A moderate association with protection against clinically apparent, laboratory-confirmed Pandemic (H1N1 2009-associated illness was found for immunization with either TIV or LAIV 2008-09 seasonal influenza vaccines. This association with protection was found to be especially apparent for severe disease as compared to milder outcome, as well as in the youngest and older populations. Prior vaccination with seasonal influenza vaccines in 2004-08 was also independently associated with protection.

Risks of avian influenza transmission in areas of intensive free-ranging duck production with wild waterfowl

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Cappelle, Julien; Zhao, Delong; Gilbert, Marius; Newman, Scott H.; Takekawa, John Y.; Gaidet, Nicolas; Prosser, Diann J.; Liu, Ying; Li, Peng; Shu, Yuelong; Xiao, Xiangming

2014-01-01

For decades, southern China has been considered to be an important source for emerging influenza viruses since key hosts live together in high densities in areas with intensive agriculture. However, the underlying conditions of emergence and spread of avian influenza viruses (AIV) have not been studied in detail, particularly the complex spatiotemporal interplay of viral transmission between wild and domestic ducks, two major actors of AIV epidemiology. In this synthesis, we examine the risks of avian influenza spread in Poyang Lake, an area of intensive free-ranging duck production and large numbers of wild waterfowl. Our synthesis shows that farming of free-grazing domestic ducks is intensive in this area and synchronized with wild duck migration. The presence of juvenile domestic ducks in harvested paddy fields prior to the arrival and departure of migrant ducks in the same fields may amplify the risk of AIV circulation and facilitate the transmission between wild and domestic populations. We provide evidence associating wild ducks migration with the spread of H5N1 in the spring of 2008 from southern China to South Korea, Russia, and Japan, supported by documented wild duck movements and phylogenetic analyses of highly pathogenic avian influenza H5N1 sequences. We suggest that prevention measures based on a modification of agricultural practices may be implemented in these areas to reduce the intensity of AIV transmission between wild and domestic ducks. This would require involving all local stakeholders to discuss feasible and acceptable solutions.

Human Phase 1 trial of low-dose inactivated seasonal influenza vaccine formulated with Advax™ delta inulin adjuvant.

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Gordon, David L; Sajkov, Dimitar; Honda-Okubo, Yoshikazu; Wilks, Samuel H; Aban, Malet; Barr, Ian G; Petrovsky, Nikolai

2016-07-19

Influenza vaccines are usually non-adjuvanted but addition of adjuvant may improve immunogenicity and permit dose-sparing, critical for vaccine supply in the event of an influenza pandemic. The aim of this first-in-man study was to determine the effect of delta inulin adjuvant on the safety and immunogenicity of a reduced dose seasonal influenza vaccine. Healthy male and female adults aged 18-65years were recruited to participate in a randomized controlled study to compare the safety, tolerability and immunogenicity of a reduced-dose 2007 Southern Hemisphere trivalent inactivated influenza vaccine formulated with Advax™ delta inulin adjuvant (LTIV+Adj) when compared to a full-dose of the standard TIV vaccine which does not contain an adjuvant. LTIV+Adj provided equivalent immunogenicity to standard TIV vaccine as assessed by hemagglutination inhibition (HI) assays against each vaccine strain as well as against a number of heterosubtypic strains. HI responses were sustained at 3months post-immunisation in both groups. Antibody landscapes against a large panel of H3N2 influenza viruses showed distinct age effects whereby subjects over 40years old had a bimodal baseline HI distribution pattern, with the highest HI titers against the very oldest H3N2 isolates and with a second HI peak against influenza isolates from the last 5-10years. By contrast, subjects >40years had a unimodal baseline HI distribution with peak recognition of H3N2 isolates from approximately 20years ago. The reduced dose TIV vaccine containing Advax adjuvant was well tolerated and no safety issues were identified. Hence, delta inulin may be a useful adjuvant for use in seasonal or pandemic influenza vaccines. Australia New Zealand Clinical Trial Registry: ACTRN12607000599471. Copyright © 2016 Elsevier Ltd. All rights reserved.

Multi-colored immunochromatography using nanobeads for rapid and sensitive typing of seasonal influenza viruses.

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Sakurai, Akira; Takayama, Katsuyoshi; Nomura, Namiko; Yamamoto, Naoki; Sakoda, Yoshihiro; Kobayashi, Yukuharu; Kida, Hiroshi; Shibasaki, Futoshi

2014-12-01

Immunochromatography (IC) is an antigen-detection assay that plays an important role in the rapid diagnosis of influenza viruses because of its rapid turnaround and ease of use. Despite the usefulness of IC, the limit of detection of common IC kits is as high as 10(3)-10(4) plaque forming units (pfu) per reaction, resulting in their limited sensitivities. Early diagnosis within 24h would provide more appropriate timing of treatment. In this study, a multi-colored NanoAct™ bead IC was established to detect seasonal influenza viruses. This method has approximately 10-fold higher sensitivity than that of colloidal gold or colored latex bead IC assays, and does not require specific instruments. More notably, NanoAct™ bead IC can distinguish influenza A and B viruses from clinical samples with a straightforward readout composed of colored lines. Our results will provide new strategies for the diagnosis, treatment, and a chance to survey of influenza viruses in developing countries and in the field research. Copyright © 2014 Elsevier B.V. All rights reserved.

A Single-Amino-Acid Substitution at Position 225 in Hemagglutinin Alters the Transmissibility of Eurasian Avian-Like H1N1 Swine Influenza Virus in Guinea Pigs.

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Wang, Zeng; Yang, Huanliang; Chen, Yan; Tao, Shiyu; Liu, Liling; Kong, Huihui; Ma, Shujie; Meng, Fei; Suzuki, Yasuo; Qiao, Chuanling; Chen, Hualan

2017-11-01

Efficient transmission from human to human is the prerequisite for an influenza virus to cause a pandemic; however, the molecular determinants of influenza virus transmission are still largely unknown. In this study, we explored the molecular basis for transmission of Eurasian avian-like H1N1 (EAH1N1) swine influenza viruses by comparing two viruses that are genetically similar but differ in their transmissibility in guinea pigs: the A/swine/Guangxi/18/2011 virus (GX/18) is highly transmissible by respiratory droplet in guinea pigs, whereas the A/swine/Heilongjiang/27/2012 virus (HLJ/27) does not transmit in this animal model. We used reverse genetics to generate a series of reassortants and mutants in the GX/18 background and tested their transmissibility in guinea pigs. We found that a single-amino-acid substitution of glycine (G) for glutamic acid (E) at position 225 (E225G) in the HA1 protein completely abolished the respiratory droplet transmission of GX/18, whereas the substitution of E for G at the same position (G225E) in HA1 enabled HLJ/27 to transmit in guinea pigs. We investigated the underlying mechanism and found that viruses bearing 225E in HA1 replicated more rapidly than viruses bearing 225G due to differences in assembly and budding efficiencies. Our study indicates that the amino acid 225E in HA1 plays a key role in EAH1N1 swine influenza virus transmission and provides important information for evaluating the pandemic potential of field influenza virus strains. IMPORTANCE Efficient transmission among humans is a prerequisite for a novel influenza virus to cause a human pandemic. Transmissibility of influenza viruses is a polygenic trait, and understanding the genetic determinants for transmissibility will provide useful insights for evaluating the pandemic potential of influenza viruses in the field. Several amino acids in the hemagglutinin (HA) protein of influenza viruses have been shown to be important for transmissibility, usually by

Guinea pig model for evaluating the potential public health risk of swine and avian influenza viruses.

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Yipeng Sun

Full Text Available BACKGROUND: The influenza viruses circulating in animals sporadically transmit to humans and pose pandemic threats. Animal models to evaluate the potential public health risk potential of these viruses are needed. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the guinea pig as a mammalian model for the study of the replication and transmission characteristics of selected swine H1N1, H1N2, H3N2 and avian H9N2 influenza viruses, compared to those of pandemic (H1N1 2009 and seasonal human H1N1, H3N2 influenza viruses. The swine and avian influenza viruses investigated were restricted to the respiratory system of guinea pigs and shed at high titers in nasal tracts without prior adaptation, similar to human strains. None of the swine and avian influenza viruses showed transmissibility among guinea pigs; in contrast, pandemic (H1N1 2009 virus transmitted from infected guinea pigs to all animals and seasonal human influenza viruses could also horizontally transmit in guinea pigs. The analysis of the receptor distribution in the guinea pig respiratory tissues by lectin histochemistry indicated that both SAα2,3-Gal and SAα2,6-Gal receptors widely presented in the nasal tract and the trachea, while SAα2,3-Gal receptor was the main receptor in the lung. CONCLUSIONS/SIGNIFICANCE: We propose that the guinea pig could serve as a useful mammalian model to evaluate the potential public health threat of swine and avian influenza viruses.

The use of nonhuman primates in research on seasonal, pandemic and avian influenza, 1893-2014.

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Davis, A Sally; Taubenberger, Jeffery K; Bray, Mike

2015-05-01

Attempts to reproduce the features of human influenza in laboratory animals date from the early 1890s, when Richard Pfeiffer inoculated apes with bacteria recovered from influenza patients and produced a mild respiratory illness. Numerous studies employing nonhuman primates (NHPs) were performed during the 1918 pandemic and the following decade. Most used bacterial preparations to infect animals, but some sought a filterable agent for the disease. Since the viral etiology of influenza was established in the early 1930s, studies in NHPs have been supplemented by a much larger number of experiments in mice, ferrets and human volunteers. However, the emergence of a novel swine-origin H1N1 influenza virus in 1976 and the highly pathogenic H5N1 avian influenza virus in 1997 stimulated an increase in NHP research, because these agents are difficult to study in naturally infected patients and cannot be administered to human volunteers. In this paper, we review the published literature on the use of NHPs in influenza research from 1893 through the end of 2014. The first section summarizes observational studies of naturally occurring influenza-like syndromes in wild and captive primates, including serologic investigations. The second provides a chronological account of experimental infections of NHPs, beginning with Pfeiffer's study and covering all published research on seasonal and pandemic influenza viruses, including vaccine and antiviral drug testing. The third section reviews experimental infections of NHPs with avian influenza viruses that have caused disease in humans since 1997. The paper concludes with suggestions for further studies to more clearly define and optimize the role of NHPs as experimental animals for influenza research. Published by Elsevier B.V.

Southward autumn migration of waterfowl facilitates cross-continental transmission of the highly pathogenic avian influenza H5N1 virus

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Xu, Yanjie; Gong, Peng; Wielstra, Ben; Si, Yali

2016-08-01

The highly pathogenic avian influenza subtype H5N1 (HPAI H5N1) is a worldwide zoonotic infectious disease, threatening humans, poultry and wild birds. The role of wild birds in the spread of HPAI H5N1 has previously been investigated by comparing disease spread patterns with bird migration routes. However, the different roles that the southward autumn and northward spring migration might play in virus transmission have hardly been explored. Using direction analysis, we analyze HPAI H5N1 transmission directions and angular concentration of currently circulating viral clades, and compare these with waterfowl seasonal migration directions along major waterfowl flyways. Out of 22 HPAI H5N1 transmission directions, 18 had both a southward direction and a relatively high concentration. Differences between disease transmission and waterfowl migration directions were significantly smaller for autumn than for spring migration. The four northward transmission directions were found along Asian flyways, where the initial epicenter of the virus was located. We suggest waterfowl first picked up the virus from East Asia, then brought it to the north via spring migration, and then spread it to other parts of world mainly by autumn migration. We emphasize waterfowl autumn migration plays a relatively important role in HPAI H5N1 transmission compared to spring migration.

US school/academic institution disaster and pandemic preparedness and seasonal influenza vaccination among school nurses.

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Rebmann, Terri; Elliott, Michael B; Reddick, Dave; D Swick, Zachary

2012-09-01

School pandemic preparedness is essential, but has not been evaluated. An online survey was sent to school nurses (from state school nurse associations and/or state departments of education) between May and July 2011. Overall school pandemic preparedness scores were calculated by assigning 1 point for each item in the school's pandemic plan; the maximum score was 11. Linear regression was used to describe factors associated with higher school pandemic preparedness scores. Nurse influenza vaccine uptake was assessed as well. A total of 1,997 nurses from 26 states completed the survey. Almost three-quarters (73.7%; n = 1,472) reported receiving the seasonal influenza vaccine during the 2010-11 season. Very few (2.2%; n = 43) reported that their school/district had a mandatory influenza vaccination policy. Pandemic preparedness scores ranged from 0 to 10 points, with an average score of 4.3. Determinants of school pandemic preparedness were as follows: planning to be a point of dispensing during a future pandemic (P nurse complete the survey (P school nurse study participant be a member of the school disaster planning committee (P schools must continue to address gaps in pandemic planning. Copyright © 2012 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Transmission Bottleneck Size Estimation from Pathogen Deep-Sequencing Data, with an Application to Human Influenza A Virus.

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Sobel Leonard, Ashley; Weissman, Daniel B; Greenbaum, Benjamin; Ghedin, Elodie; Koelle, Katia

2017-07-15

The bottleneck governing infectious disease transmission describes the size of the pathogen population transferred from the donor to the recipient host. Accurate quantification of the bottleneck size is particularly important for rapidly evolving pathogens such as influenza virus, as narrow bottlenecks reduce the amount of transferred viral genetic diversity and, thus, may decrease the rate of viral adaptation. Previous studies have estimated bottleneck sizes governing viral transmission by using statistical analyses of variants identified in pathogen sequencing data. These analyses, however, did not account for variant calling thresholds and stochastic viral replication dynamics within recipient hosts. Because these factors can skew bottleneck size estimates, we introduce a new method for inferring bottleneck sizes that accounts for these factors. Through the use of a simulated data set, we first show that our method, based on beta-binomial sampling, accurately recovers transmission bottleneck sizes, whereas other methods fail to do so. We then apply our method to a data set of influenza A virus (IAV) infections for which viral deep-sequencing data from transmission pairs are available. We find that the IAV transmission bottleneck size estimates in this study are highly variable across transmission pairs, while the mean bottleneck size of 196 virions is consistent with a previous estimate for this data set. Furthermore, regression analysis shows a positive association between estimated bottleneck size and donor infection severity, as measured by temperature. These results support findings from experimental transmission studies showing that bottleneck sizes across transmission events can be variable and influenced in part by epidemiological factors. IMPORTANCE The transmission bottleneck size describes the size of the pathogen population transferred from the donor to the recipient host and may affect the rate of pathogen adaptation within host populations. Recent

Seasonal influenza vaccination coverage and its determinants among nursing homes personnel in western France

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Christelle Elias

2017-07-01

Full Text Available Abstract Background Influenza-associated deaths is an important risk for the elderly in nursing homes (NHs worldwide. Vaccination coverage among residents is high but poorly effective due to immunosenescence. Hence, vaccination of personnel is an efficient way to protect residents. Our objective was to quantify the seasonal influenza vaccination (IV coverage among NH for elderly workers and identify its determinants in France. Methods We conducted a cross-sectional study in March 2016 in a randomized sample of NHs of the Ille-et-Vilaine department of Brittany, in western France. A standardized questionnaire was administered to a randomized sample of NH workers for face-to-face interviews. General data about the establishment was also collected. Results Among the 33 NHs surveyed, IV coverage for the 2015–2016 season among permanent workers was estimated at 20% (95% Confidence Interval (CI 15.3%–26.4% ranging from 0% to 69% depending on the establishments surveyed. Moreover, IV was associated with having previously experienced a “severe” influenza episode in the past (Prevalence Ratio 1.48, 95% CI 1.01–2.17, and varied by professional categories (p < 0.004 with better coverage among administrative staff. Better knowledge about influenza prevention tools was also correlated (p < 0.001 with a higher IV coverage. Individual perceptions of vaccination benefits had a significant influence on the IV coverage (p < 0.001. Although IV coverage did not reach a high rate, our study showed that personnel considered themselves sufficiently informed about IV. Conclusions IV coverage remains low in the NH worker population in Ille-et-Vilaine and also possibly in France. Strong variations of IV coverage among NHs suggest that management and working environment play an important role. To overcome vaccine “hesitancy”, specific communication tools may be required to be adapted to the various NH professionals to improve influenza prevention.

How close are countries of the WHO European Region to achieving the goal of vaccinating 75% of key risk groups against influenza? Results from national surveys on seasonal influenza vaccination programmes, 2008/2009 to 2014/2015.

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Jorgensen, Pernille; Mereckiene, Jolita; Cotter, Suzanne; Johansen, Kari; Tsolova, Svetla; Brown, Caroline

2018-01-25

Influenza vaccination is recommended especially for persons at risk of complications. In 2003, the World Health Assembly urged Member States (MS) to increase vaccination coverage to 75% among older persons by 2010. To assess progress towards the 2010 vaccination goal and describe seasonal influenza vaccination recommendations in the World Health Organization (WHO) European Region. Data on seasonal influenza vaccine recommendations, dose distribution, and target group coverage were obtained from two sources: European Union and European Economic Area MS data were extracted from influenza vaccination surveys covering seven seasons (2008/2009-2014/2015) published by the Vaccine European New Integrated Collaboration Effort and European Centre for Disease Prevention and Control. For the remaining WHO European MS, a separate survey on policies and uptake for all seasons (2008/2009-2014/2015) was distributed to national immunization programmes in 2015. Data was available from 49 of 53 MS. All but two had a national influenza vaccination policy. High-income countries distributed considerably higher number of vaccines per capita (median; 139.2 per 1000 population) compared to lower-middle-income countries (median; 6.1 per 1000 population). Most countries recommended vaccination for older persons, individuals with chronic disease, healthcare workers, and pregnant women. Children were included in < 50% of national policies. Only one country reached 75% coverage in older persons (2014/2015), while a number of countries reported declining vaccination uptake. Coverage of target groups was overall low, but with large variations between countries. Vaccination coverage was not monitored for several groups. Despite policy recommendations, influenza vaccination uptake remains suboptimal. Low levels of vaccination is not only a missed opportunity for preventing influenza in vulnerable groups, but could negatively affect pandemic preparedness. Improved understanding of barriers to

Influenza A virus infection of healthy piglets in an abattoir in Brazil: animal-human interface and risk for interspecies transmission

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Ariane Ribeiro Amorim

2013-08-01

Full Text Available Asymptomatic influenza virus infections in pigs are frequent and the lack of measures for controlling viral spread facilitates the circulation of different virus strains between pigs. The goal of this study was to demonstrate the circulation of influenza A virus strains among asymptomatic piglets in an abattoir in Brazil and discuss the potential public health impacts. Tracheal samples (n = 330 were collected from asymptomatic animals by a veterinarian that also performed visual lung tissue examinations. No slaughtered animals presented with any noticeable macroscopic signs of influenza infection following examination of lung tissues. Samples were then analysed by reverse transcription-polymerase chain reaction that resulted in the identification of 30 (9% influenza A positive samples. The presence of asymptomatic pig infections suggested that these animals could facilitate virus dissemination and act as a source of infection for the herd, thereby enabling the emergence of influenza outbreaks associated with significant economic losses. Furthermore, the continuous exposure of the farm and abattoir workers to the virus increases the risk for interspecies transmission. Monitoring measures of swine influenza virus infections and vaccination and monitoring of employees for influenza infection should also be considered. In addition regulatory agencies should consider the public health ramifications regarding the potential zoonotic viral transmission between humans and pigs.

Phylogenetic analysis of influenza A viruses (H3N2 circulating in Zhytomyr region during 2013–2014 epidemic season

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Boyalska O. G.

2015-06-01

Full Text Available Aim. To perform phylogenetic analysis of the hemagglutinin (HA and neuraminidase (NA genes of influenza A(H3N2 viruses circulating in the Zhytomyr region during 2013–2014 epidemic season. To make comparison of the HA and NA genes sequences of the Zhytomyr region isolates with the HA and NA genes sequences of influenza viruses circulating in the world. Methods. Laboratory diagnosis was conducted by real-time polymerase chain reaction (RT-PCR. In this study the sequencing and phylogenetic analysis were carried out. Results. For the first time the genes of influenza A(H3N2 viruses isolated in the Zhytomyr region during 2013–2014 epidemic season, coding hemagglutinin and neuraminidase were compared with their orthologs. According to the results of this comparison the phylogenetic tree was constructed. Additionally, the amino acid substitutions of the influenza viruses circulating in Ukraine and worldwide were analyzed. Conclusions. The nucleotide sequences of the influenza A(H3N2 viruses genes HA and NA isolated in the Zhytomyr region were identified. Based on the nucleotide sequences of HA and NA we constructed the influenza virus phylogenetic tree demonstrating that the virus isolated in the Zhytomyr region was closely related to the Ukrainian isolate from Kharkov and in the world to the isolates from Germany, Romania, Italy.

Intercontinental circulation of human influenza A(H1N2) reassortant viruses during the 2001-2002 influenza season.

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Xu, Xiyan; Smith, Catherine B; Mungall, Bruce A; Lindstrom, Stephen E; Hall, Henrietta E; Subbarao, Kanta; Cox, Nancy J; Klimov, Alexander

2002-11-15

Reassortant influenza A viruses bearing the H1 subtype of hemagglutinin (HA) and the N2 subtype of neuraminidase (NA) were isolated from humans in the United States, Canada, Singapore, Malaysia, India, Oman, Egypt, and several countries in Europe during the 2001-2002 influenza season. The HAs of these H1N2 viruses were similar to that of the A/New Caledonia/20/99(H1N1) vaccine strain both antigenically and genetically, and the NAs were antigenically and genetically related to those of recent human H3N2 reference strains, such as A/Moscow/10/99(H3N2). All 6 internal genes of the H1N2 reassortants examined originated from an H3N2 virus. This article documents the first widespread circulation of H1N2 reassortants on 4 continents. The current influenza vaccine is expected to provide good protection against H1N2 viruses, because it contains the A/New Caledonia/20/99(H1N1) and A/Moscow/10/99(H3N2)-like viruses, which have H1 and N2 antigens that are similar to those of recent H1N2 viruses.

The avian-origin PB1 gene segment facilitated replication and transmissibility of the H3N2/1968 pandemic influenza virus.

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Wendel, Isabel; Rubbenstroth, Dennis; Doedt, Jennifer; Kochs, Georg; Wilhelm, Jochen; Staeheli, Peter; Klenk, Hans-Dieter; Matrosovich, Mikhail

2015-04-01

The H2N2/1957 and H3N2/1968 pandemic influenza viruses emerged via the exchange of genomic RNA segments between human and avian viruses. The avian hemagglutinin (HA) allowed the hybrid viruses to escape preexisting immunity in the human population. Both pandemic viruses further received the PB1 gene segment from the avian parent (Y. Kawaoka, S. Krauss, and R. G. Webster, J Virol 63:4603-4608, 1989), but the biological significance of this observation was not understood. To assess whether the avian-origin PB1 segment provided pandemic viruses with some selective advantage, either on its own or via cooperation with the homologous HA segment, we modeled by reverse genetics the reassortment event that led to the emergence of the H3N2/1968 pandemic virus. Using seasonal H2N2 virus A/California/1/66 (Cal) as a surrogate precursor human virus and pandemic virus A/Hong Kong/1/68 (H3N2) (HK) as a source of avian-derived PB1 and HA gene segments, we generated four reassortant recombinant viruses and compared pairs of viruses which differed solely by the origin of PB1. Replacement of the PB1 segment of Cal by PB1 of HK facilitated viral polymerase activity, replication efficiency in human cells, and contact transmission in guinea pigs. A combination of PB1 and HA segments of HK did not enhance replicative fitness of the reassortant virus compared with the single-gene PB1 reassortant. Our data suggest that the avian PB1 segment of the 1968 pandemic virus served to enhance viral growth and transmissibility, likely by enhancing activity of the viral polymerase complex. Despite the high impact of influenza pandemics on human health, some mechanisms underlying the emergence of pandemic influenza viruses still are poorly understood. Thus, it was unclear why both H2N2/1957 and H3N2/1968 reassortant pandemic viruses contained, in addition to the avian HA, the PB1 gene segment of the avian parent. Here, we addressed this long-standing question by modeling the emergence of the H3N2

Prospective surveillance and molecular characterization of seasonal influenza in a university cohort in Singapore.

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Virk, Ramandeep Kaur; Tambyah, Paul Anantharajah; Inoue, Masafumi; Lim, Elizabeth Ai-Sim; Chan, Ka-Wei; Chua, Catherine; Tan, Boon-Huan

2014-01-01

Southeast Asia is believed to be a potential locus for the emergence of novel influenza strains, and therefore accurate sentinel surveillance in the region is critical. Limited information exists on sentinel surveillance of influenza-like illness (ILI) in young adults in Singapore in a University campus setting. The objective of the present study was to determine the proportion of ILI caused by influenza A and B viruses in a university cohort in Singapore. We conducted a prospective surveillance study from May through October 2007, at the National University of Singapore (NUS). Basic demographic information and nasopharyngeal swabs were collected from students and staff with ILI. Reverse-transcriptase PCR (RT-PCR) and viral isolation were employed to detect influenza viruses. Sequencing of hemagglutinin (HA) and neuraminidase (NA) genes of some representative isolates was also performed. Overall proportions of influenza A and B virus infections were 47/266 (18%) and 9/266 (3%) respectively. The predominant subtype was A/H3N2 (55%) and the rest were A/H1N1 (45%). The overall sensitivity difference for detection of influenza A viruses using RT-PCR and viral isolation was 53%. Phylogenetic analyses of HA and NA gene sequences of Singapore strains showed identities higher than 98% within both the genes. The strains were more similar to strains included in the WHO vaccine recommendation for the following year (2008). Genetic markers of oseltamivir resistance were not detected in any of the sequenced Singapore isolates. HA and NA gene sequences of Singapore strains were similar to vaccine strains for the upcoming influenza season. No drug resistance was found. Sentinel surveillance on university campuses should make use of molecular methods to better detect emerging and re-emerging influenza viral threats.

Prospective surveillance and molecular characterization of seasonal influenza in a university cohort in Singapore.

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Ramandeep Kaur Virk

Full Text Available BACKGROUND: Southeast Asia is believed to be a potential locus for the emergence of novel influenza strains, and therefore accurate sentinel surveillance in the region is critical. Limited information exists on sentinel surveillance of influenza-like illness (ILI in young adults in Singapore in a University campus setting. The objective of the present study was to determine the proportion of ILI caused by influenza A and B viruses in a university cohort in Singapore. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a prospective surveillance study from May through October 2007, at the National University of Singapore (NUS. Basic demographic information and nasopharyngeal swabs were collected from students and staff with ILI. Reverse-transcriptase PCR (RT-PCR and viral isolation were employed to detect influenza viruses. Sequencing of hemagglutinin (HA and neuraminidase (NA genes of some representative isolates was also performed. Overall proportions of influenza A and B virus infections were 47/266 (18% and 9/266 (3% respectively. The predominant subtype was A/H3N2 (55% and the rest were A/H1N1 (45%. The overall sensitivity difference for detection of influenza A viruses using RT-PCR and viral isolation was 53%. Phylogenetic analyses of HA and NA gene sequences of Singapore strains showed identities higher than 98% within both the genes. The strains were more similar to strains included in the WHO vaccine recommendation for the following year (2008. Genetic markers of oseltamivir resistance were not detected in any of the sequenced Singapore isolates. CONCLUSIONS/SIGNIFICANCE: HA and NA gene sequences of Singapore strains were similar to vaccine strains for the upcoming influenza season. No drug resistance was found. Sentinel surveillance on university campuses should make use of molecular methods to better detect emerging and re-emerging influenza viral threats.

Reviewing the History of Pandemic Influenza: Understanding Patterns of Emergence and Transmission

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Saunders-Hastings, Patrick R.; Krewski, Daniel

2016-01-01

For centuries, novel strains of influenza have emerged to produce human pandemics, causing widespread illness, death, and disruption. There have been four influenza pandemics in the past hundred years. During this time, globalization processes, alongside advances in medicine and epidemiology, have altered the way these pandemics are experienced. Drawing on international case studies, this paper provides a review of the impact of past influenza pandemics, while examining the evolution of our understanding of, and response to, these viruses. This review argues that pandemic influenza is in part a consequence of human development, and highlights the importance of considering outbreaks within the context of shifting global landscapes. While progress in infectious disease prevention, control, and treatment has improved our ability to respond to such outbreaks, globalization processes relating to human behaviour, demographics, and mobility have increased the threat of pandemic emergence and accelerated global disease transmission. Preparedness planning must continue to evolve to keep pace with this heightened risk. Herein, we look to the past for insights on the pandemic experience, underlining both progress and persisting challenges. However, given the uncertain timing and severity of future pandemics, we emphasize the need for flexible policies capable of responding to change as such emergencies develop. PMID:27929449

Influenza Vaccination in Young Children Reduces Influenza-Associated Hospitalizations in Older Adults, 2002–2006

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Cohen, Steven A.; Chui, Kenneth K.H.; Naumova, Elena N.

2011-01-01

OBJECTIVES To assess how influenza vaccination coverage in children is related to pneumonia and influenza (P&I) in US seniors and if these associations are modified by sociodemographic factors. DESIGN We abstracted approximately 5 million hospitalization records from the Centers for Medicare and Medicaid Services for four influenza years, 2002–2006. We estimated a single year age distribution of rates of P&I hospitalization by state for each influenza season and observed an exponential acceleration in the P&I rates with age for each influenza season. State-and season-specific P&I rate accelerations were regressed against the percentage of vaccinated children, seniors, or both using mixed effects models. SETTING United States population, 2002–2006 PARTICIPANTS US population aged 65 and above MEASUREMENTS State-level influenza annual vaccination coverage data in children and seniors were obtained from the National Immunization Survey and the Behavioral Risk Factor Surveillance System, respectively. RESULTS Child influenza vaccination coverage was negatively associated with age acceleration in P&I, whereas influenza vaccination in the seniors themselves was not significantly associated with P&I in seniors. CONCLUSION Vaccination of children against influenza may induce herd immunity against influenza for seniors and has the potential to be more beneficial to seniors than the existing policy to prevent influenza by vaccinating seniors themselves. PMID:21275932

Changes in genetically drifted H3N2 influenza A viruses and vaccine effectiveness in adults 65 years and older during the 2016/17 season in Denmark

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Trebbien, Ramona; Fischer, Thea K; Krause, Tyra Grove

2017-01-01

BACKGROUND: In Denmark, influenza A virus of the subtype H3N2 has been dominating the 2016/17 season, as in most countries of the Northern Hemisphere. OBJECTIVES: This study was conducted as part of the Danish seasonal influenza surveillance programme to genetically characterize circulating H3N2...

Effect of influenza and pneumococcal vaccines in elderly persons in years of low influenza activity.

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Christenson, Brith; Pauksen, Karlis; Sylvan, Staffan P E

2008-04-28

The present prospective study was conducted from 2003-2005, among all individuals 65 years and older in Uppsala County, a region with 300 000 inhabitants situated close to the Stockholm urban area.The objective of this study was to assess the preventive effect of influenza and pneumococcal vaccination in reducing hospitalisation and length of hospital stay (LOHS) even during periods of low influenza activity. The specificity of the apparent vaccine associations were evaluated in relation to the influenza seasons. In 2003, the total study population was 41,059, of which 12,907 (31%) received influenza vaccine of these, 4,447 (11%) were administered the pneumococcal vaccine. In 2004, 14,799 (34%) individuals received the influenza vaccine and 8,843 (21%) the pneumococcal vaccine and in 2005 16,926 (39%) individuals were given the influenza vaccine and 12,340 (28%) the pneumococcal vaccine.Our findings indicated that 35% of the vaccinated cohort belonged to a medical risk category (mainly those persons that received the pneumococcal vaccine). Data on hospitalisation and mortality during the 3-year period were obtained from the administrative database of the Uppsala county council. During the influenza seasons, reduction of hospital admissions and significantly shorter in-hospital stay for influenza was observed in the vaccinated cohort (below 80 years of age). For individuals who also had received the pneumococcal vaccine, a significant reduction of hospital admissions and of in-hospital stay was observed for invasive pneumococcal disease and for pneumococcal pneumonia. Effectiveness was observed for cardiac failure even in persons that also had received the pneumococcal vaccine, despite that the pneumococcal vaccinated mainly belonged to a medical risk category. Reduction of death from all causes was observed during the influenza season of 2004, in the 75-84-year old age group and in all age-groups during the influenza season 2005. The present study confirmed the

Effect of receptor binding domain mutations on receptor binding and transmissibility of avian influenza H5N1 viruses

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Maines, Taronna R; Chen, Li-Mei; Van Hoeven, Neal

2011-01-01

Although H5N1 influenza viruses have been responsible for hundreds of human infections, these avian influenza viruses have not fully adapted to the human host. The lack of sustained transmission in humans may be due, in part, to their avian-like receptor preference. Here, we have introduced recep...

Contact heterogeneity, rather than transmission efficiency, limits the emergence and spread of canine influenza virus.

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Benjamin D Dalziel

2014-10-01

Full Text Available Host-range shifts in influenza virus are a major risk factor for pandemics. A key question in the study of emerging zoonoses is how the evolution of transmission efficiency interacts with heterogeneity in contact patterns in the new host species, as this interplay influences disease dynamics and prospects for control. Here we use a synergistic mixture of models and data to tease apart the evolutionary and demographic processes controlling a host-range shift in equine H3N8-derived canine influenza virus (CIV. CIV has experienced 15 years of continuous transfer among dogs in the United States, but maintains a patchy distribution, characterized by sporadic short-lived outbreaks coupled with endemic hotspots in large animal shelters. We show that CIV has a high reproductive potential in these facilities (mean R(0 = 3.9 and that these hotspots act as refugia from the sparsely connected majority of the dog population. Intriguingly, CIV has evolved a transmission efficiency that closely matches the minimum required to persist in these refugia, leaving it poised on the extinction/invasion threshold of the host contact network. Corresponding phylogenetic analyses show strong geographic clustering in three US regions, and that the effective reproductive number of the virus (R(e in the general dog population is close to 1.0. Our results highlight the critical role of host contact structure in CIV dynamics, and show how host contact networks could shape the evolution of pathogen transmission efficiency. Importantly, efficient control measures could eradicate the virus, in turn minimizing the risk of future sustained transmission among companion dogs that could represent a potential new axis to the human-animal interface for influenza.

The use of nonhuman primates in research on seasonal, pandemic and avian influenza, 1893–2014

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Davis, A. Sally; Taubenberger, Jeffery K.; Bray, Mike

2015-01-01

Attempts to reproduce the features of human influenza in laboratory animals date from the early 1890s, when Richard Pfeiffer inoculated apes with bacteria recovered from influenza patients and produced a mild respiratory illness. Numerous studies employing nonhuman primates (NHPs) were performed during the 1918 pandemic and the following decade. Most used bacterial preparations to infect animals, but some sought a filterable agent for the disease. Since the viral etiology of influenza was established in the early 1930s, studies in NHPs have been supplemented by a much larger number of experiments in mice, ferrets and human volunteers. However, the emergence of a novel swine-origin H1N1 influenza virus in 1976 and the highly pathogenic H5N1 avian influenza virus in 1997 stimulated an increase in NHP research, because these agents are difficult to study in naturally infected patients and cannot be administered to human volunteers. In this paper, we review the published literature on the use of NHPs in influenza research from 1893 through the end of 2014. The first section summarizes observational studies of naturally occurring influenza-like syndromes in wild and captive primates, including serologic investigations. The second provides a chronological account of experimental infections of NHPs, beginning with Pfeiffer’s study and covering all published research on seasonal and pandemic influenza viruses, including vaccine and antiviral drug testing. The third section reviews experimental infections of NHPs with avian influenza viruses that have caused disease in humans since 1997. The paper concludes with suggestions for further studies to more clearly define and optimize the role of NHPs as experimental animals for influenza research. PMID:25746173

Mandatory influenza vaccination for all healthcare personnel: a review on justification, implementation and effectiveness.

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Wang, Tiffany L; Jing, Ling; Bocchini, Joseph A

2017-10-01

As healthcare-associated influenza is a serious public health concern, this review examines legal and ethical arguments supporting mandatory influenza vaccination policies for healthcare personnel, implementation issues and evidence of effectiveness. Spread of influenza from healthcare personnel to patients can result in severe harm or death. Although most healthcare personnel believe that they should be vaccinated against seasonal influenza, the Centers for Disease Control and Prevention (CDC) report that only 79% of personnel were vaccinated during the 2015-2016 season. Vaccination rates were as low as 44.9% in institutions that did not promote or offer the vaccine, compared with rates of more than 90% in institutions with mandatory vaccination policies. Policies that mandate influenza vaccination for healthcare personnel have legal and ethical justifications. Implementing such policies require multipronged approaches that include education efforts, easy access to vaccines, vaccine promotion, leadership support and consistent communication emphasizing patient safety. Mandatory influenza vaccination for healthcare personnel is a necessary step in protecting patients. Patients who interact with healthcare personnel are often at an elevated risk of complications from influenza. Vaccination is the best available strategy for protecting against influenza and evidence shows that institutional policies and state laws can effectively increase healthcare personnel vaccination rates, decreasing the risk of transmission in healthcare settings. There are legal and ethical precedents for institutional mandatory influenza policies and state laws, although successful implementation requires addressing both administrative and attitudinal barriers.

Spanish flu, Asian flu, Hong Kong flu, and seasonal influenza in Japan under social and demographic influence: review and analysis using the two-population model.

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Yoshikura, Hiroshi

2014-01-01

When cumulative numbers of patients (X) and deaths (Y) associated with an influenza epidemic are plotted using the log-log scale, the plots fall on an ascending straight line generally expressed as logY = k(logX - logN0). For the 2009 H1N1 influenza pandemic, the slope k was ～0.6 for Mexico and ～2 for other countries. The two-population model was proposed to explain this phenomenon (Yoshikura H. Jpn J Infect Dis. 2012;65:279-88; Yoshikura H. Jpn J Infect Dis. 2009;62:411-2; and Yoshikura H. Jpn J Infect Dis. 2009;62:482-4). The current article reviews and analyzes previous influenza epidemics in Japan to examine whether the two-population model is applicable to them. The slope k was found to be ～2 for the Spanish flu during 1918-1920 and the Asian flu during 1957-1958, and ～1 for the Hong Kong flu and seasonal influenza prior to 1960-1961; however, k was ～0.6 for seasonal influenza after 1960-1961. This transition of the slope k of seasonal influenza plots from ～1 to ～0.6 corresponded to the shift in influenza mortality toward the older age groups and a drastic reduction in infant mortality rates due to improvements in the standard of living during the 1950s and 1960s. All the above observations could be well explained by reconstitution of the influenza epidemic based on the two-population model.

Assessment of seasonal influenza vaccine effectiveness in patients from a central Italy reference hospital: pitfalls and intricacies from a pilot case-control study

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Katleen de Gaetano Donati

2014-07-01

Full Text Available Objectives: Influenza vaccination protects high-risk populations from severe outcomes. We assessed the feasibility of testing influenza vaccine effectiveness against hospitalization with laboratory-confirmed influenza.Methods: All hospitalized patients with influenza-like illness within 14 days, were swabbed. Cases were positive at RT-PCR for influenza A/B. Results: AtRome “GemelliHospital” (Season 2011-2012 104 patients were contacted and 62 recruited. Considering total sample and target group (n= 47, 76%, only 29% and 38% had been vaccinated. Eighteen patients were laboratory-confirmed for influenza.Conclusions: RecruitedILI patients and prevalence of vaccinated subjects were less than expected. Larger numbers are warranted to study vaccine effectiveness against severe influenza outcomes.  

Novel H7N9 influenza virus shows low infectious dose, high growth rate, and efficient contact transmission in the guinea pig model.

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Gabbard, Jon D; Dlugolenski, Daniel; Van Riel, Debby; Marshall, Nicolle; Galloway, Summer E; Howerth, Elizabeth W; Campbell, Patricia J; Jones, Cheryl; Johnson, Scott; Byrd-Leotis, Lauren; Steinhauer, David A; Kuiken, Thijs; Tompkins, S Mark; Tripp, Ralph; Lowen, Anice C; Steel, John

2014-02-01

The zoonotic outbreak of H7N9 subtype avian influenza virus that occurred in eastern China in the spring of 2013 resulted in 135 confirmed human cases, 44 of which were lethal. Sequencing of the viral genome revealed a number of molecular signatures associated with virulence or transmission in mammals. We report here that, in the guinea pig model, a human isolate of novel H7N9 influenza virus, A/Anhui/1/2013 (An/13), is highly dissimilar to an H7N1 avian isolate and instead behaves similarly to a human seasonal strain in several respects. An/13 was found to have a low 50% infectious dose, grow to high titers in the upper respiratory tract, and transmit efficiently among cocaged guinea pigs. The pH of fusion of the hemagglutinin (HA) and the binding of virus to fixed guinea pig tissues were also examined. The An/13 HA displayed a relatively elevated pH of fusion characteristic of many avian strains, and An/13 resembled avian viruses in terms of attachment to tissues. One important difference was seen between An/13 and both the H3N2 human and the H7N1 avian viruses: when inoculated intranasally at a high dose, only the An/13 virus led to productive infection of the lower respiratory tract of guinea pigs. In sum, An/13 was found to retain fusion and attachment properties of an avian influenza virus but displayed robust growth and contact transmission in the guinea pig model atypical of avian strains and indicative of mammalian adaptation.

Novel H7N9 Influenza Virus Shows Low Infectious Dose, High Growth Rate, and Efficient Contact Transmission in the Guinea Pig Model

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Gabbard, Jon D.; Dlugolenski, Daniel; Van Riel, Debby; Marshall, Nicolle; Galloway, Summer E.; Howerth, Elizabeth W.; Campbell, Patricia J.; Jones, Cheryl; Johnson, Scott; Byrd-Leotis, Lauren; Steinhauer, David A.; Kuiken, Thijs; Tompkins, S. Mark; Tripp, Ralph; Lowen, Anice C.

2014-01-01

The zoonotic outbreak of H7N9 subtype avian influenza virus that occurred in eastern China in the spring of 2013 resulted in 135 confirmed human cases, 44 of which were lethal. Sequencing of the viral genome revealed a number of molecular signatures associated with virulence or transmission in mammals. We report here that, in the guinea pig model, a human isolate of novel H7N9 influenza virus, A/Anhui/1/2013 (An/13), is highly dissimilar to an H7N1 avian isolate and instead behaves similarly to a human seasonal strain in several respects. An/13 was found to have a low 50% infectious dose, grow to high titers in the upper respiratory tract, and transmit efficiently among cocaged guinea pigs. The pH of fusion of the hemagglutinin (HA) and the binding of virus to fixed guinea pig tissues were also examined. The An/13 HA displayed a relatively elevated pH of fusion characteristic of many avian strains, and An/13 resembled avian viruses in terms of attachment to tissues. One important difference was seen between An/13 and both the H3N2 human and the H7N1 avian viruses: when inoculated intranasally at a high dose, only the An/13 virus led to productive infection of the lower respiratory tract of guinea pigs. In sum, An/13 was found to retain fusion and attachment properties of an avian influenza virus but displayed robust growth and contact transmission in the guinea pig model atypical of avian strains and indicative of mammalian adaptation. PMID:24227867

Avian influenza: a review.

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Thomas, Jennifer K; Noppenberger, Jennifer

2007-01-15

A review of the avian influenza A/H5N1 virus, including human cases, viral transmission, clinical features, vaccines and antivirals, surveillance plans, infection control, and emergency response plans, is presented. The World Health Organization (WHO) considers the avian influenza A/H5N1 virus a public health risk with pandemic potential. The next human influenza pandemic, if caused by the avian influenza A/H5N1 virus, is estimated to have a potential mortality rate of more than a hundred million. Outbreaks in poultry have been associated with human transmission. WHO has documented 258 confirmed human infections with a mortality rate greater than 50%. Bird-to-human transmission of the avian influenza virus is likely by the oral-fecal route. The most effective defense against an influenza pandemic would be a directed vaccine to elicit a specific immune response toward the strain or strains of the influenza virus. However, until there is an influenza pandemic, there is no evidence that vaccines or antivirals used in the treatment or prevention of such an outbreak would decrease morbidity or mortality. Surveillance of the bird and human populations for the highly pathogenic H5N1 is being conducted. Infection-control measures and an emergency response plan are discussed. Avian influenza virus A/H5N1 is a public health threat that has the potential to cause serious illness and death in humans. Understanding its pathology, transmission, clinical features, and pharmacologic treatments and preparing for the prevention and management of its outbreak will help avoid its potentially devastating consequences.

Seasonal influenza vaccination for children in Thailand: a cost-effectiveness analysis.

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Meeyai, Aronrag; Praditsitthikorn, Naiyana; Kotirum, Surachai; Kulpeng, Wantanee; Putthasri, Weerasak; Cooper, Ben S; Teerawattananon, Yot

2015-05-01

Seasonal influenza is a major cause of mortality worldwide. Routine immunization of children has the potential to reduce this mortality through both direct and indirect protection, but has not been adopted by any low- or middle-income countries. We developed a framework to evaluate the cost-effectiveness of influenza vaccination policies in developing countries and used it to consider annual vaccination of school- and preschool-aged children with either trivalent inactivated influenza vaccine (TIV) or trivalent live-attenuated influenza vaccine (LAIV) in Thailand. We also compared these approaches with a policy of expanding TIV coverage in the elderly. We developed an age-structured model to evaluate the cost-effectiveness of eight vaccination policies parameterized using country-level data from Thailand. For policies using LAIV, we considered five different age groups of children to vaccinate. We adopted a Bayesian evidence-synthesis framework, expressing uncertainty in parameters through probability distributions derived by fitting the model to prospectively collected laboratory-confirmed influenza data from 2005-2009, by meta-analysis of clinical trial data, and by using prior probability distributions derived from literature review and elicitation of expert opinion. We performed sensitivity analyses using alternative assumptions about prior immunity, contact patterns between age groups, the proportion of infections that are symptomatic, cost per unit vaccine, and vaccine effectiveness. Vaccination of children with LAIV was found to be highly cost-effective, with incremental cost-effectiveness ratios between about 2,000 and 5,000 international dollars per disability-adjusted life year averted, and was consistently preferred to TIV-based policies. These findings were robust to extensive sensitivity analyses. The optimal age group to vaccinate with LAIV, however, was sensitive both to the willingness to pay for health benefits and to assumptions about contact

Genetics, receptor binding property, and transmissibility in mammals of naturally isolated H9N2 Avian Influenza viruses.

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Xuyong Li

2014-11-01

Full Text Available H9N2 subtype influenza viruses have been detected in different species of wild birds and domestic poultry in many countries for several decades. Because these viruses are of low pathogenicity in poultry, their eradication is not a priority for animal disease control in many countries, which has allowed them to continue to evolve and spread. Here, we characterized the genetic variation, receptor-binding specificity, replication capability, and transmission in mammals of a series of H9N2 influenza viruses that were detected in live poultry markets in southern China between 2009 and 2013. Thirty-five viruses represented 17 genotypes on the basis of genomic diversity, and one specific "internal-gene-combination" predominated among the H9N2 viruses. This gene combination was also present in the H7N9 and H10N8 viruses that have infected humans in China. All of the 35 viruses preferentially bound to the human-like receptor, although two also retained the ability to bind to the avian-like receptor. Six of nine viruses tested were transmissible in ferrets by respiratory droplet; two were highly transmissible. Some H9N2 viruses readily acquired the 627K or 701N mutation in their PB2 gene upon infection of ferrets, further enhancing their virulence and transmission in mammals. Our study indicates that the widespread dissemination of H9N2 viruses poses a threat to human health not only because of the potential of these viruses to cause an influenza pandemic, but also because they can function as "vehicles" to deliver different subtypes of influenza viruses from avian species to humans.

Characterization of influenza virus among influenza like illness cases in Mumbai, India.

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Roy, Soumen; Dahake, Ritwik; Patil, Deepak; Tawde, Shweta; Mukherjee, Sandeepan; Athlekar, Shrikant; Chowdhary, Abhay; Deshmukh, Ranjana

2014-01-01

The present study was carried out to monitor influenza viruses by identifying the virus and studying the seasonal variation during 2007-2009 in Mumbai. A total of 193 clinical respiratory samples (nasal and throat swab) were collected from patients having influenza like illness in Mumbai region. One-step real-time reverse-transcriptase PCR (rRTPCR) was used to detect Influenza type A (H1 and H3) and Influenza type B virus. Isolation of the virus was carried out using in vitro system which was further confirmed and typed by hemagglutination assay and hemagglutination inhibition assay. Out of 193 samples 24 (12.4 3%) samples tested positive for influenza virus, of which 13 (6.73 %) were influenza type A virus and 10 (5.18 %) were influenza type B virus, while 1 sample (0.51 %) was positive for both. By culture methods, 3 (1.55 %) viral isolates were obtained. All the three isolates were found to be Influenza type B/Malaysia (Victoria lineage) by Hemagglutination Inhibition Assay. The data generated from the present study reveals that both Influenza type A and B are prevalent in Mumbai with considerable activity. The peak activity was observed during monsoon season.

Effects of influenza vaccination and influenza illness on exacerbations in multiple sclerosis

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De Keyser, J; Zwanikken, C

1998-01-01

Despite reports that influenza vaccination appears to be safe in multiple sclerosis there is uncertainty which patients may benefit from it. By using a questionnaire we compared the effects of influenza illness (1995-1996 season) and influenza vaccination (autumn of 1996) on neurologic symptoms in

Attitudes, believes, determinants and organisational barriers behind the low seasonal influenza vaccination uptake in healthcare workers - A cross-sectional survey.

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Boey, Lise; Bral, Charlotte; Roelants, Mathieu; De Schryver, Antoon; Godderis, Lode; Hoppenbrouwers, Karel; Vandermeulen, Corinne

2018-04-28

Seasonal influenza threatens hospitalised patients and residents of nursing homes annually. Due to age and chronic disease their protection following immunisation is diminished. Additional immunisation of direct contacts and in particular healthcare workers (HCWs) has proven added value. As vaccination coverage in HCWs remains low, we aimed to gain insight in the factors behind the demotivation for influenza vaccination. Attitudes and believes towards influenza vaccination and socio-demographic and professional determinants were surveyed in 5141 Belgian HCWs from 13 hospitals and 14 nursing homes. Additionally, influenza campaign coordinators of the participating healthcare institutions were interviewed about the factors of success/failure in their campaigns. The mean vaccination coverage registered by the participating healthcare institutions was 40.4% in the hospitals and 45.3% in the nursing homes. Overall, up to 90% of HCWs found it important not to infect their patients. However, only 20% of non-vaccinated HCWs considered influenza vaccination a duty to not harm their patients. Up to 40% of unvaccinated staff believed they could get influenza after vaccination and that vaccination weakens their immune system. Also, only about 20% of unvaccinated staff thought to have a high chance of getting influenza. Reasons for unvaccinated staff to get vaccinated in the future are self-protection and protection of family members. Factors that positively influenced vaccination coverage are encouragement by supervisors (OR, hospitals: 7.1, p < 0.001; nursing homes: 7.5, p < 0.001) and well-organized vaccination campaigns with on-site vaccination. Factors that negatively affected vaccination coverage are misconceptions about influenza and its vaccine (OR, range 0.1-0.7, p < 0.001 for most misconceptions) and underestimation of the risk of contracting influenza by patients or HCWs (OR of perceived susceptibility, range 2.1-5.1, p < 0.001 for most factors

Modeling seasonal behavior changes and disease transmission with application to chronic wasting disease.

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Oraby, Tamer; Vasilyeva, Olga; Krewski, Daniel; Lutscher, Frithjof

2014-01-07

Behavior and habitat of wildlife animals change seasonally according to environmental conditions. Mathematical models need to represent this seasonality to be able to make realistic predictions about the future of a population and the effectiveness of human interventions. Managing and modeling disease in wild animal populations requires particular care in that disease transmission dynamics is a critical consideration in the etiology of both human and animal diseases, with different transmission paradigms requiring different disease risk management strategies. Since transmission of infectious diseases among wildlife depends strongly on social behavior, mechanisms of disease transmission could also change seasonally. A specific consideration in this regard confronted by modellers is whether the contact rate between individuals is density-dependent or frequency-dependent. We argue that seasonal behavior changes could lead to a seasonal shift between density and frequency dependence. This hypothesis is explored in the case of chronic wasting disease (CWD), a fatal disease that affects deer, elk and moose in many areas of North America. Specifically, we introduce a strategic CWD risk model based on direct disease transmission that accounts for the seasonal change in the transmission dynamics and habitats occupied, guided by information derived from cervid ecology. The model is composed of summer and winter susceptible-infected (SI) equations, with frequency-dependent and density-dependent transmission dynamics, respectively. The model includes impulsive birth events with density-dependent birth rate. We determine the basic reproduction number as a weighted average of two seasonal reproduction numbers. We parameterize the model from data derived from the scientific literature on CWD and deer ecology, and conduct global and local sensitivity analyses of the basic reproduction number. We explore the effectiveness of different culling strategies for the management of CWD

Influenza vaccine coverage, influenza-associated morbidity and all-cause mortality in Catalonia (Spain).

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Muñoz, M Pilar; Soldevila, Núria; Martínez, Anna; Carmona, Glòria; Batalla, Joan; Acosta, Lesly M; Domínguez, Angela

2011-07-12

The objective of this work was to study the behaviour of influenza with respect to morbidity and all-cause mortality in Catalonia, and their association with influenza vaccination coverage. The study was carried out over 13 influenza seasons, from epidemiological week 40 of 1994 to week 20 of 2007, and included confirmed cases of influenza and all-cause mortality. Two generalized linear models were fitted: influenza-associated morbidity was modelled by Poisson regression and all-cause mortality by negative binomial regression. The seasonal component was modelled with the periodic function formed by the sum of the sinus and cosines. Expected influenza mortality during periods of influenza virus circulation was estimated by Poisson regression and its confidence intervals using the Bootstrap approach. Vaccination coverage was associated with a reduction in influenza-associated morbidity (pcase of influenza-associated morbidity, an increase of 5% in vaccination coverage represented a reduction of 3% in the incidence rate of influenza. There was a positive association between influenza-associated morbidity and all-cause mortality. Excess mortality attributable to influenza epidemics was estimated as 34.4 (95% CI: 28.4-40.8) weekly deaths. In conclusion, all-cause mortality is a good indicator of influenza surveillance and vaccination coverage is associated with a reduction in influenza-associated morbidity but not with all-cause mortality. Copyright © 2011 Elsevier Ltd. All rights reserved.

Protection against H5N1 by multiple immunizations with seasonal influenza vaccine in mice is correlated with H5 cross-reactive antibodies

NARCIS (Netherlands)

Roos, Anna; Roozendaal, Ramon; Theeuwsen, Jessica; Riahi, Sarra; Vaneman, Joost; Tolboom, Jeroen; Dekking, Liesbeth; Koudstaal, Wouter; Goudsmit, Jaap; Radošević, Katarina

2015-01-01

Background: Current seasonal influenza vaccines are believed to confer protection against a narrow range of virus strains. However, their protective ability is commonly estimated based on an in vitro correlate of protection that only considers a subset of anti-influenza antibodies that are typically

Influenza A (H3N2) virus in swine at agricultural fairs and transmission to humans, Michigan and Ohio, USA, 2016

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An 18 case outbreak of variant H3N2 influenza A occurred during 2016 after exposure to influenza-infected swine at seven agricultural fairs. Sixteen cases were infected with a reassortant between 2010-2011 human seasonal H3N2 strains and viruses endemic in North American swine, a viral lineage incre...

Genetic analysis of influenza B viruses isolated in Uganda during the 2009–2010 seasons

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Byarugaba Denis K

2013-01-01

Full Text Available Abstract Background Influenza B viruses can cause morbidity and mortality in humans but due to the lack of an animal reservoir are not associated with pandemics. Because of this, there is relatively limited genetic sequences available for influenza B viruses, especially from developing countries. Complete genome analysis of one influenza B virus and several gene segments of other influenza B viruses isolated from Uganda from May 2009 through December 2010 was therefore undertaken in this study. Methods Samples were collected from patients showing influenza like illness and screened for influenza A and B by PCR. Influenza B viruses were isolated on Madin-Darby Canine Kidney cells and selected isolates were subsequently sequenced and analyzed phylogenetically. Findings Of the 2,089 samples collected during the period, 292 were positive by PCR for influenza A or B; 12.3% of the PCR positives were influenza B. Thirty influenza B viruses were recovered and of these 25 that grew well consistently on subculture were subjected to further analysis. All the isolates belonged to the B/Victoria-lineage as identified by hemagglutination inhibition assay and genetic analysis except one isolate that grouped with the B-Yamagata-lineage. The Ugandan B/Victoria-lineage isolates grouped in clade 1 which was defined by the N75K, N165K and S172P substitutions in hemagglutinin (HA protein clustered together with the B/Brisbane/60/2008 vaccine strain. The Yamagata-like Ugandan strain, B/Uganda/MUWRP-053/2009, clustered with clade 3 Yamagata viruses such as B/Bangladesh/3333/2007 which is characterized by S150I and N166Y substitutions in HA. Conclusion In general there was limited variation among the Ugandan isolates but they were interestingly closer to viruses from West and North Africa than from neighboring Kenya. Our isolates closely matched the World Health Organization recommended vaccines for the seasons.

Seasonal influenza vaccination rates and reasons for non-vaccination in children with gastrointestinal disorders.

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Peleg, Noam; Zevit, Noam; Shamir, Raanan; Chodick, Gabriel; Levy, Itzhak

2015-01-01

Despite advances in the treatment and prevention of influenza, it is still considered an important cause of morbidity and mortality worldwide. Annual vaccination is the safest and most effective mean of prevention. Our study aims were to explore the uptake of influenza vaccination among children with gastrointestinal disorders, and to characterize non-adherent patients. The present cross-sectional study included parents of pediatric patients attending the Gastroenterology Institute at Schneider Children's Medical Center of Israel between September and October 2011. Parents were asked to complete a questionnaire concerning demographic and clinical parameters, influenza vaccination of the child, and reasons for not vaccinating the child, when appropriate. The study population included 273 patients (50% female), with a median age of 10 years (range, 2-18 years). Overall, the rate of seasonal influenza vaccination was 30.8%. Higher rates were found among immunosuppressed patients (46.1%), and in patients with inflammatory bowel disease (50%). There was no significant effect of patient age, gender, ethnic origin or parental level of education on the vaccination rate. Vaccination rates were significantly associated with parents' information and knowledge of, as well as their personal beliefs regarding the vaccine (Pvaccination rates are relatively low in the pediatric population attending gastroenterology clinics, in both high- and low-risk groups. The importance of parental knowledge in compliance with influenza vaccination of children should prompt general pediatricians and gastroenterologists to discuss and address the common misconceptions regarding the vaccine. Copyright © 2014 Elsevier Ltd. All rights reserved.

Avian Influenza A Virus Infections in Humans

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... people has ranged from mild to severe. Avian Influenza Transmission Avian Influenza Transmission Infographic [555 KB, 2 pages] Spanish [ ... important for public health. Signs and Symptoms of Avian Influenza A Virus Infections in Humans The reported signs ...

Microdroplet sandwich real-time rt-PCR for detection of pandemic and seasonal influenza subtypes.

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Stephanie L Angione

Full Text Available As demonstrated by the recent 2012/2013 flu epidemic, the continual emergence of new viral strains highlights the need for accurate medical diagnostics in multiple community settings. If rapid, robust, and sensitive diagnostics for influenza subtyping were available, it would help identify epidemics, facilitate appropriate antiviral usage, decrease inappropriate antibiotic usage, and eliminate the extra cost of unnecessary laboratory testing and treatment. Here, we describe a droplet sandwich platform that can detect influenza subtypes using real-time reverse-transcription polymerase chain reaction (rtRT-PCR. Using clinical samples collected during the 2010/11 season, we effectively differentiate between H1N1p (swine pandemic, H1N1s (seasonal, and H3N2 with an overall assay sensitivity was 96%, with 100% specificity for each subtype. Additionally, we demonstrate the ability to detect viral loads as low as 10(4 copies/mL, which is two orders of magnitude lower than viral loads in typical infected patients. This platform performs diagnostics in a miniaturized format without sacrificing any sensitivity, and can thus be easily developed into devices which are ideal for small clinics and pharmacies.

Bird Flu (Avian Influenza)

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Bird flu (avian influenza) Overview Bird flu is caused by a type of influenza virus that rarely infects humans. More than a ... for Disease Control and Prevention estimates that seasonal influenza is responsible for ... heat destroys avian viruses, cooked poultry isn't a health threat. ...

Effect of influenza and pneumococcal vaccines in elderly persons in years of low influenza activity

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Sylvan Staffan PE

2008-04-01

Full Text Available Abstract Background The present prospective study was conducted from 2003–2005, among all individuals 65 years and older in Uppsala County, a region with 300 000 inhabitants situated close to the Stockholm urban area. The objective of this study was to assess the preventive effect of influenza and pneumococcal vaccination in reducing hospitalisation and length of hospital stay (LOHS even during periods of low influenza activity. The specificity of the apparent vaccine associations were evaluated in relation to the influenza seasons. Results In 2003, the total study population was 41,059, of which 12,907 (31% received influenza vaccine of these, 4,447 (11% were administered the pneumococcal vaccine. In 2004, 14,799 (34% individuals received the influenza vaccine and 8,843 (21% the pneumococcal vaccine and in 2005 16,926 (39% individuals were given the influenza vaccine and 12,340 (28% the pneumococcal vaccine. Our findings indicated that 35% of the vaccinated cohort belonged to a medical risk category (mainly those persons that received the pneumococcal vaccine. Data on hospitalisation and mortality during the 3-year period were obtained from the administrative database of the Uppsala county council. During the influenza seasons, reduction of hospital admissions and significantly shorter in-hospital stay for influenza was observed in the vaccinated cohort (below 80 years of age. For individuals who also had received the pneumococcal vaccine, a significant reduction of hospital admissions and of in-hospital stay was observed for invasive pneumococcal disease and for pneumococcal pneumonia. Effectiveness was observed for cardiac failure even in persons that also had received the pneumococcal vaccine, despite that the pneumococcal vaccinated mainly belonged to a medical risk category. Reduction of death from all causes was observed during the influenza season of 2004, in the 75–84-year old age group and in all age-groups during the influenza

Influenza activity in Europe during eight seasons (1999–2007: an evaluation of the indicators used to measure activity and an assessment of the timing, length and course of peak activity (spread across Europe

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Meijer Adam

2007-11-01

Full Text Available Abstract Background The European Influenza Surveillance Scheme (EISS has collected clinical and virological data on influenza since 1996 in an increasing number of countries. The EISS dataset was used to characterise important epidemiological features of influenza activity in Europe during eight winters (1999–2007. The following questions were addressed: 1 are the sentinel clinical reports a good measure of influenza activity? 2 how long is a typical influenza season in Europe? 3 is there a west-east and/or south-north course of peak activity ('spread' of influenza in Europe? Methods Influenza activity was measured by collecting data from sentinel general practitioners (GPs and reports by national reference laboratories. The sentinel reports were first evaluated by comparing them to the laboratory reports and were then used to assess the timing and spread of influenza activity across Europe during eight seasons. Results We found a good match between the clinical sentinel data and laboratory reports of influenza collected by sentinel physicians (overall match of 72% for +/- 1 week difference. We also found a moderate to good match between the clinical sentinel data and laboratory reports of influenza from non-sentinel sources (overall match of 60% for +/- 1 week. There were no statistically significant differences between countries using ILI (influenza-like illness or ARI (acute respiratory disease as case definition. When looking at the peak-weeks of clinical activity, the average length of an influenza season in Europe was 15.6 weeks (median 15 weeks; range 12–19 weeks. Plotting the peak weeks of clinical influenza activity reported by sentinel GPs against the longitude or latitude of each country indicated that there was a west-east spread of peak activity (spread of influenza across Europe in four winters (2001–2002, 2002–2003, 2003–2004 and 2004–2005 and a south-north spread in three winters (2001–2002, 2004–2005 and 2006�

FluTE, a publicly available stochastic influenza epidemic simulation model.

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Dennis L Chao

2010-01-01

Full Text Available Mathematical and computer models of epidemics have contributed to our understanding of the spread of infectious disease and the measures needed to contain or mitigate them. To help prepare for future influenza seasonal epidemics or pandemics, we developed a new stochastic model of the spread of influenza across a large population. Individuals in this model have realistic social contact networks, and transmission and infections are based on the current state of knowledge of the natural history of influenza. The model has been calibrated so that outcomes are consistent with the 1957/1958 Asian A(H2N2 and 2009 pandemic A(H1N1 influenza viruses. We present examples of how this model can be used to study the dynamics of influenza epidemics in the United States and simulate how to mitigate or delay them using pharmaceutical interventions and social distancing measures. Computer simulation models play an essential role in informing public policy and evaluating pandemic preparedness plans. We have made the source code of this model publicly available to encourage its use and further development.

FluTE, a publicly available stochastic influenza epidemic simulation model.

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Chao, Dennis L; Halloran, M Elizabeth; Obenchain, Valerie J; Longini, Ira M

2010-01-29

Mathematical and computer models of epidemics have contributed to our understanding of the spread of infectious disease and the measures needed to contain or mitigate them. To help prepare for future influenza seasonal epidemics or pandemics, we developed a new stochastic model of the spread of influenza across a large population. Individuals in this model have realistic social contact networks, and transmission and infections are based on the current state of knowledge of the natural history of influenza. The model has been calibrated so that outcomes are consistent with the 1957/1958 Asian A(H2N2) and 2009 pandemic A(H1N1) influenza viruses. We present examples of how this model can be used to study the dynamics of influenza epidemics in the United States and simulate how to mitigate or delay them using pharmaceutical interventions and social distancing measures. Computer simulation models play an essential role in informing public policy and evaluating pandemic preparedness plans. We have made the source code of this model publicly available to encourage its use and further development.

Age groups and spread of influenza: implications for vaccination strategy

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Hsieh Ying-Hen

2010-04-01

Full Text Available Abstract Background The unpredictable nature of the potentially devastating impact of 2009 pH1N1 influenza pandemic highlights the need for pandemic preparedness planning, where modeling studies could be most useful for simulations of possible future scenarios. Methods A compartmental model with pre-symptomatic and asymptomatic influenza infections is proposed which incorporates age groups as well as intervention measures such as age-specific vaccination, in order to study spread of influenza in a community. Results We derive the basic reproduction number and other effective reproduction numbers under various intervention measures. For illustration, we make use of the Pneumonia and Influenza (P&I mortality data and vaccination data of the very young (age 0-2 and the very old (age >64 during 2004-2005 Taiwan winter influenza season to fit our model and to compute the relevant reproduction numbers. The reproduction number for this winter flu season is estimated to be slightly above one (~1.0001. Conclusions Comparatively large errors in fitting the P&I mortality data of the elderly (>64 were observed shortly after winter school closings in January, which may indicate the impact of younger, more active age groups transmitting influenza to other age groups outside of the school settings; in particular, to the elderly in the households. Pre-symptomatic infections seemed to have little effect on the model fit, while asymptomatic infection by asymptomatic infectives has a more pronounced impact on the model fit for the elderly mortality, perhaps indicating a larger role in disease transmission by asymptomatic infection. Simulations indicate that the impact of vaccination on the disease incidence might not be fully revealed in the change (or the lack thereof in the effective reproduction number with interventions, but could still be substantial. The estimated per contact transmission probability for susceptible elderly is significantly higher than that

[Laboratory diagnosis of pandemic influenza at the Department of Medical Microbiology of the Regional Authority of Public Health based in Banská Bystrica in the season 2009-2010].

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Kissová, R; Mad'arová, L; Klement, C

2011-02-01

The Department of Medical Microbiology of the Regional Authority of Public Health (RAPH) in Banská Bystrica serves as a catchment laboratory of virology for the Central Slovakia Region, and in the influenza season 2009/10, it also served as such for the East Slovakia Region. Specimens (nasopharyngeal swabs and post-mortem specimens) from patients with suspected influenza were obtained from both sentinel and non-sentinel physicians. The specimens were analyzed by a rapid test, followed by real-time PCR (RT-PCR) for influenza A or B diagnosis. RT-PCR subtyping for pandemic influenza A/H1N1 was performed. From May 2009 to June 2010, 2497 specimens were analyzed for the presence of influenza A and B viruses and in particular for the presence of pandemic influenza A/H1N1 virus. As many as 537 of 589 influenza A-positive specimens, i.e. 21.5% of all specimens analyzed and 91.2% of influenza A-positive specimens, were subtyped as pandemic influenza A/H1N1. In the influenza season 2009/10, the new pandemic influenza A/H1N1 clearly predominated in Central and Eastern Slovakia. PCR tests have played a key role in diagnosing patients with suspected pandemic influenza in the laboratory participating in the surveillance of influenza and influenza-like illness in the Slovak Republic.

US healthcare costs attributable to type A and type B influenza.

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Yan, Songkai; Weycker, Derek; Sokolowski, Stefania

2017-09-02

While the overall healthcare burden of seasonal influenza in the United States (US) has been well characterized, the proportion of influenza burden attributable to type A and type B illness warrants further elucidation. The aim of this study was to estimate numbers of healthcare encounters and healthcare costs attributable to influenza viral strains A and B in the US during the 2001/2002 - 2008/2009 seasons. Healthcare encounters and costs in the US during the 2001/2002 - 2008/2009 seasons for influenza type A and influenza type B were estimated separately and collectively, by season and age group, based on data from published literature and secondary sources for: rates of influenza-related encounters requiring formal healthcare, unit costs of influenza-related healthcare encounters, and estimates of population size. Across 8 seasons, projected annual numbers of influenza-related healthcare encounters ranged from 11.3-25.6 million, and healthcare costs, from $2.0-$5.8 billion. While the majority of influenza illness was attributable to type A strains, type B strains accounted for 37% of healthcare costs across all seasons, and as much as 66% in a single season. The outpatient burden of type B disease was considerable among persons aged 18-64 y while the hospital cost burden was highest in young children. Influenza viral strain B was associated with considerable health system burden each year during the period of interest. Increasing influenza vaccine coverage, especially with the recently approved quadrivalent products including an additional type B strain, could potentially reduce overall annual influenza burden in the US.

The process by which perceived autonomy support predicts motivation, intention, and behavior for seasonal influenza prevention in Hong Kong older adults.

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Chung, Pak-Kwong; Zhang, Chun-Qing; Liu, Jing-Dong; Chan, Derwin King-Chung; Si, Gangyan; Hagger, Martin S

2017-07-28

This study examined the effectiveness of a theoretical framework that integrates self-determination theory (SDT) and the theory of planned behavior (TPB) in explaining the use of facemasks to prevent seasonal influenza among Hong Kong older adults. Data were collected at two time points in the winter in Hong Kong, during which influenza is most prevalent. At Time 1, older adults (N = 141) completed self-report measures of SDT (perceived autonomy support from senior center staff, autonomous motivation for influenza prevention) and TPB (attitude, subjective norm, perceived behavioral control, and intention for influenza prevention) constructs with respect to facemask used to prevent infection. Two weeks later, at Time 2, participants' acceptance of a facemask to prevent influenza in the presence of an experimenter with flu-like symptoms was recorded. Path analysis found that perceived autonomy support of senior center staff was positively and significantly linked to autonomous motivation for facemask use, which, in turn, was positively related to intentions to wear facemasks through the mediation of attitude, subjective norm, and perceived behavioral control. However, the effect of intention on facemask use was not significant. Results generally support the proposed framework and the findings of previous studies with respect to intention, but the non-significant intention-behavior relationship may warrant future research to examine the reasons for older adults not to wear facemasks to prevent seasonal influenza despite having positive intentions to do so.

The process by which perceived autonomy support predicts motivation, intention, and behavior for seasonal influenza prevention in Hong Kong older adults

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Pak-Kwong Chung

2017-07-01

Full Text Available Abstract Background This study examined the effectiveness of a theoretical framework that integrates self-determination theory (SDT and the theory of planned behavior (TPB in explaining the use of facemasks to prevent seasonal influenza among Hong Kong older adults. Methods Data were collected at two time points in the winter in Hong Kong, during which influenza is most prevalent. At Time 1, older adults (N = 141 completed self-report measures of SDT (perceived autonomy support from senior center staff, autonomous motivation for influenza prevention and TPB (attitude, subjective norm, perceived behavioral control, and intention for influenza prevention constructs with respect to facemask used to prevent infection. Two weeks later, at Time 2, participants’ acceptance of a facemask to prevent influenza in the presence of an experimenter with flu-like symptoms was recorded. Results Path analysis found that perceived autonomy support of senior center staff was positively and significantly linked to autonomous motivation for facemask use, which, in turn, was positively related to intentions to wear facemasks through the mediation of attitude, subjective norm, and perceived behavioral control. However, the effect of intention on facemask use was not significant. Conclusions Results generally support the proposed framework and the findings of previous studies with respect to intention, but the non-significant intention-behavior relationship may warrant future research to examine the reasons for older adults not to wear facemasks to prevent seasonal influenza despite having positive intentions to do so.

Effectiveness of 2010/2011 seasonal influenza vaccine in Ireland.

LENUS (Irish Health Repository)

Barret, A S

2012-02-01

We conducted a case-control study to estimate the 2010\\/2011 trivalent influenza vaccine effectiveness (TIVE) using the Irish general practitioners\\' influenza sentinel surveillance scheme. Cases were influenza-like illness (ILI) patients with laboratory-confirmed influenza. Controls were ILI patients who tested negative for influenza. Participating sentinel general practitioners (GP) collected swabs from patients presenting with ILI along with their vaccination history and other individual characteristics. The TIVE was computed as (1 - odds ratiofor vaccination) x100%. Of 60 sentinel GP practices, 22 expressed interest in participating in the study and 17 (28%) recruited at least one ILI patient. In the analysis, we included 106 cases and 85 controls. Seven controls (8.2%) and one influenza case (0.9%) had been vaccinated in 2010\\/2011. The estimated TIVE against any influenza subtype was 89.4% [95% CI: 13.8; 99.8%], suggesting a protective effect against GP-attended laboratory confirmed influenza. This study design could be used to monitor influenza vaccine effectiveness annually but sample size and vaccination coverage should be increased to obtain precise and adjusted estimates.

Avian Influenza (Bird Flu)

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Assessment of validation of health-economics decision models in intervention studies of seasonal influenza and breast cancer

NARCIS (Netherlands)

De Boer, P.T.; Frederix, G.W.; Al, M.J.; Feenstra, T.F.; Vemer, P.

2015-01-01

Objectives: We aimed to review recently published health-economic (HE) decision models to assess the reporting of validation efforts. An infectious disease (seasonal influenza, SI) and a chronic disease (breast cancer, BC) were used as examples, giving a preliminary insight in the reporting of

The seasonal influence of climate and environment on yellow fever transmission across Africa.

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Hamlet, Arran; Jean, Kévin; Perea, William; Yactayo, Sergio; Biey, Joseph; Van Kerkhove, Maria; Ferguson, Neil; Garske, Tini

2018-03-01

Yellow fever virus (YFV) is a vector-borne flavivirus endemic to Africa and Latin America. Ninety per cent of the global burden occurs in Africa where it is primarily transmitted by Aedes spp, with Aedes aegypti the main vector for urban yellow fever (YF). Mosquito life cycle and viral replication in the mosquito are heavily dependent on climate, particularly temperature and rainfall. We aimed to assess whether seasonal variations in climatic factors are associated with the seasonality of YF reports. We constructed a temperature suitability index for YFV transmission, capturing the temperature dependence of mosquito behaviour and viral replication within the mosquito. We then fitted a series of multilevel logistic regression models to a dataset of YF reports across Africa, considering location and seasonality of occurrence for seasonal models, against the temperature suitability index, rainfall and the Enhanced Vegetation Index (EVI) as covariates alongside further demographic indicators. Model fit was assessed by the Area Under the Curve (AUC), and models were ranked by Akaike's Information Criterion which was used to weight model outputs to create combined model predictions. The seasonal model accurately captured both the geographic and temporal heterogeneities in YF transmission (AUC = 0.81), and did not perform significantly worse than the annual model which only captured the geographic distribution. The interaction between temperature suitability and rainfall accounted for much of the occurrence of YF, which offers a statistical explanation for the spatio-temporal variability in transmission. The description of seasonality offers an explanation for heterogeneities in the West-East YF burden across Africa. Annual climatic variables may indicate a transmission suitability not always reflected in seasonal interactions. This finding, in conjunction with forecasted data, could highlight areas of increased transmission and provide insights into the occurrence of

Underutilization of Influenza Vaccine

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Marshall K. Cheney

2013-04-01

Full Text Available Yearly influenza vaccination continues to be underutilized by those who would most benefit from it. The Health Belief Model was used to explain differences in beliefs about influenza vaccination among at-risk individuals resistant to influenza vaccination. Survey data were collected from 74 members of at-risk groups who were not vaccinated for influenza during the previous flu season. Accepting individuals were more likely to perceive flu as a threat to health and perceive access barriers, and cues to action were the most important influence on whether they plan to get vaccinated. In comparison, resistant individuals did not feel threatened by the flu, access barriers were not a problem, and they did not respond favorably to cues to action. Perceived threat, perceived access barriers, and cues to action were significantly associated with plans to be vaccinated for influenza in the next flu season. Participants who saw influenza as a threat to their health had 5.4 times the odds of planning to be vaccinated than those who did not. Participants reporting barriers to accessing influenza vaccination had 7.5 times the odds of reporting plans to be vaccinated. Those responding positively to cues to action had 12.2 times the odds of planning to be vaccinated in the next flu season than those who did not. Accepting and resistant individuals have significant differences in their beliefs, which require different intervention strategies to increase vaccination rates. These findings provide important information to researchers and practitioners working to increase influenza vaccination rates.

Epidemiological and virological situation update of the 2010/2011 influenza season in the WHO European Region (Week 40/2010 to Week 03/2011)

NARCIS (Netherlands)

Mott, J.A.; Pereyaslov, D.; Jorgensen, P.; Brown, C.S.; Martirosyan, L.; Meerhoff, T.

2011-01-01

This overview of influenza data from the WHO European Region from weeks 40/2010 through week 3/2011 has been submitted for consideration during the WHO Northern Hemisphere Vaccine Strain Selection Meeting, to be held on 14-17 February, 2011, in Geneva. The 2010/2011 influenza season arrived 8-10

Modeling seasonal measles transmission in China

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Bai, Zhenguo; Liu, Dan

2015-08-01

A discrete-time deterministic measles model with periodic transmission rate is formulated and studied. The basic reproduction number R0 is defined and used as the threshold parameter in determining the dynamics of the model. It is shown that the disease will die out if R0 1 . Parameters in the model are estimated on the basis of demographic and epidemiological data. Numerical simulations are presented to describe the seasonal fluctuation of measles infection in China.

Seasonality of absolute humidity explains seasonality of influenza-like illness in Vietnam

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Pham Quang Thai

2015-12-01

Conclusions: Our results identify a role for AH in driving the epidemiology of ILI in a tropical setting. However, in contrast to temperate regions, high rather than low AH is associated with increased ILI activity. Fluctuation in AH may be the climate factor that underlies and unifies the seasonality of ILI in both temperate and tropical regions. Alternatively, the mechanism of action of AH on disease transmission may be different in cold-dry versus hot-humid settings.

Pathogenesis and transmission of avian influenza A (H7N9) virus in ferrets and mice.

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Belser, Jessica A; Gustin, Kortney M; Pearce, Melissa B; Maines, Taronna R; Zeng, Hui; Pappas, Claudia; Sun, Xiangjie; Carney, Paul J; Villanueva, Julie M; Stevens, James; Katz, Jacqueline M; Tumpey, Terrence M

2013-09-26

On 29 March 2013, the Chinese Center for Disease Control and Prevention confirmed the first reported case of human infection with an avian influenza A(H7N9) virus. The recent human infections with H7N9 virus, totalling over 130 cases with 39 fatalities to date, have been characterized by severe pulmonary disease and acute respiratory distress syndrome (ARDS). This is concerning because H7 viruses have typically been associated with ocular disease in humans, rather than severe respiratory disease. This recent outbreak underscores the need to better understand the pathogenesis and transmission of these viruses in mammals. Here we assess the ability of A/Anhui/1/2013 and A/Shanghai/1/2013 (H7N9) viruses, isolated from fatal human cases, to cause disease in mice and ferrets and to transmit to naive animals. Both H7N9 viruses replicated to higher titre in human airway epithelial cells and in the respiratory tract of ferrets compared to a seasonal H3N2 virus. Moreover, the H7N9 viruses showed greater infectivity and lethality in mice compared to genetically related H7N9 and H9N2 viruses. The H7N9 viruses were readily transmitted to naive ferrets through direct contact but, unlike the seasonal H3N2 virus, did not transmit readily by respiratory droplets. The lack of efficient respiratory droplet transmission was corroborated by low receptor-binding specificity for human-like α2,6-linked sialosides. Our results indicate that H7N9 viruses have the capacity for efficient replication in mammals and human airway cells and highlight the need for continued public health surveillance of this emerging virus.

Protecting Healthcare Personnel in Outpatient Settings: The Influence of Mandatory Versus Nonmandatory Influenza Vaccination Policies on Workplace Absenteeism During Multiple Respiratory Virus Seasons.

Science.gov (United States)

Frederick, John; Brown, Alexandria C; Cummings, Derek A; Gaydos, Charlotte A; Gibert, Cynthia L; Gorse, Geoffrey J; Los, Jenna G; Nyquist, Ann-Christine; Perl, Trish M; Price, Connie S; Radonovich, Lewis J; Reich, Nicholas G; Rodriguez-Barradas, Maria C; Bessesen, Mary T; Simberkoff, Michael S

2018-04-01

OBJECTIVE To determine the effect of mandatory and nonmandatory influenza vaccination policies on vaccination rates and symptomatic absenteeism among healthcare personnel (HCP). DESIGN Retrospective observational cohort study. SETTING This study took place at 3 university medical centers with mandatory influenza vaccination policies and 4 Veterans Affairs (VA) healthcare systems with nonmandatory influenza vaccination policies. PARTICIPANTS The study included 2,304 outpatient HCP at mandatory vaccination sites and 1,759 outpatient HCP at nonmandatory vaccination sites. METHODS To determine the incidence and duration of absenteeism in outpatient settings, HCP participating in the Respiratory Protection Effectiveness Clinical Trial at both mandatory and nonmandatory vaccination sites over 3 viral respiratory illness (VRI) seasons (2012-2015) reported their influenza vaccination status and symptomatic days absent from work weekly throughout a 12-week period during the peak VRI season each year. The adjusted effects of vaccination and other modulating factors on absenteeism rates were estimated using multivariable regression models. RESULTS The proportion of participants who received influenza vaccination was lower each year at nonmandatory than at mandatory vaccination sites (odds ratio [OR], 0.09; 95% confidence interval [CI], 0.07-0.11). Among HCP who reported at least 1 sick day, vaccinated HCP had lower symptomatic days absent compared to unvaccinated HCP (OR for 2012-2013 and 2013-2014, 0.82; 95% CI, 0.72-0.93; OR for 2014-2015, 0.81; 95% CI, 0.69-0.95). CONCLUSIONS These data suggest that mandatory HCP influenza vaccination policies increase influenza vaccination rates and that HCP symptomatic absenteeism diminishes as rates of influenza vaccination increase. These findings should be considered in formulating HCP influenza vaccination policies. Infect Control Hosp Epidemiol 2018;39:452-461.

Measuring Cellular Immunity to Influenza: Methods of Detection, Applications and Challenges

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Lynda Coughlan

2015-04-01

Full Text Available Influenza A virus is a respiratory pathogen which causes both seasonal epidemics and occasional pandemics; infection continues to be a significant cause of mortality worldwide. Current influenza vaccines principally stimulate humoral immune responses that are largely directed towards the variant surface antigens of influenza. Vaccination can result in an effective, albeit strain-specific antibody response and there is a need for vaccines that can provide superior, long-lasting immunity to influenza. Vaccination approaches targeting conserved viral antigens have the potential to provide broadly cross-reactive, heterosubtypic immunity to diverse influenza viruses. However, the field lacks consensus on the correlates of protection for cellular immunity in reducing severe influenza infection, transmission or disease outcome. Furthermore, unlike serological methods such as the standardized haemagglutination inhibition assay, there remains a large degree of variation in both the types of assays and method of reporting cellular outputs. T-cell directed immunity has long been known to play a role in ameliorating the severity and/or duration of influenza infection, but the precise phenotype, magnitude and longevity of the requisite protective response is unclear. In order to progress the development of universal influenza vaccines, it is critical to standardize assays across sites to facilitate direct comparisons between clinical trials.

Estimation of transmission parameters of H5N1 avian influenza virus in chickens.

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Annemarie Bouma

2009-01-01

Full Text Available Despite considerable research efforts, little is yet known about key epidemiological parameters of H5N1 highly pathogenic influenza viruses in their avian hosts. Here we show how these parameters can be estimated using a limited number of birds in experimental transmission studies. Our quantitative estimates, based on Bayesian methods of inference, reveal that (i the period of latency of H5N1 influenza virus in unvaccinated chickens is short (mean: 0.24 days; 95% credible interval: 0.099-0.48 days; (ii the infectious period of H5N1 virus in unvaccinated chickens is approximately 2 days (mean: 2.1 days; 95%CI: 1.8-2.3 days; (iii the reproduction number of H5N1 virus in unvaccinated chickens need not be high (mean: 1.6; 95%CI: 0.90-2.5, although the virus is expected to spread rapidly because it has a short generation interval in unvaccinated chickens (mean: 1.3 days; 95%CI: 1.0-1.5 days; and (iv vaccination with genetically and antigenically distant H5N2 vaccines can effectively halt transmission. Simulations based on the estimated parameters indicate that herd immunity may be obtained if at least 80% of chickens in a flock are vaccinated. We discuss the implications for the control of H5N1 avian influenza virus in areas where it is endemic.

Low Pathogenic Avian Influenza (H7N1) Transmission Between Wild Ducks and Domestic Ducks

DEFF Research Database (Denmark)

Therkildsen, O. R.; Jensen, Trine Hammer; Handberg, Kurt

2011-01-01

This article describes a virological investigation in a mixed flock of ducks and geese following detection of avian influenza virus antibodies in domestic geese. Low pathogenic H7N1 was found in both domestic and wild birds, indicating that transmission of virus was likely to have taken place...

Associating sex-biased and seasonal behaviour with contact patterns and transmission risk in Gopherus agassizii

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Aiello, Christina M.; Esque, Todd; Nussear, K. E.; Emblidge, P. G.; Hudson, P. J.

2018-01-01

Interactions between wildlife hosts act as transmission routes for directly transmitted pathogens and vary in ways that affect transmission efficiency. Identifying drivers of contact variation can allow both contact inference and estimation of transmission dynamics despite limited data. In desert tortoises, mating strategy, burrow use and seasonal change influence numerous behaviours and likely shape contact patterns. In this study, we ask to what extent tortoise contact behaviour varies between sexes and seasons, and whether space or burrow-use data can be used to infer contact characteristics consistent with those recorded by proximity loggers. We identified sex and season-biased contact behaviour in both wild and captive populations indicative of female-female avoidance and seasonal male mate-seeking behaviour. Space and burrow-use patterns were informative, but did not always predict the extent of sex or seasonal biases on contact. We discuss the implications these findings have for transmission patterns and disease mitigation in tortoise populations.

What's new with the flu? Reflections regarding the management and prevention of influenza from the 2nd New Zealand Influenza Symposium, November 2015.

Science.gov (United States)

Charania, Nadia A; Mansoor, Osman D; Murfitt, Diana; Turner, Nikki M

2016-09-09

Influenza is a common respiratory viral infection. Seasonal outbreaks of influenza cause substantial morbidity and mortality that burdens healthcare services every year. The influenza virus constantly evolves by antigenic drift and occasionally by antigenic shift, making this disease particularly challenging to manage and prevent. As influenza viruses cause seasonal outbreaks and also have the ability to cause pandemics leading to widespread social and economic losses, focused discussions on improving management and prevention efforts is warranted. The Immunisation Advisory Centre (IMAC) hosted the 2nd New Zealand Influenza Symposium (NZiS) in November 2015. International and national participants discussed current issues in influenza management and prevention. Experts in the field presented data from recent studies and discussed the ecology of influenza viruses, epidemiology of influenza, methods of prevention and minimisation, and experiences from the 2015 seasonal influenza immunisation campaign. The symposium concluded that although much progress in this field has been made, many areas for future research remain.

Avian influenza H5N1 transmission in households, Indonesia.

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Tjandra Y Aditama

Full Text Available BACKGROUND: Disease transmission patterns are needed to inform public health interventions, but remain largely unknown for avian influenza H5N1 virus infections. A recent study on the 139 outbreaks detected in Indonesia between 2005 and 2009 found that the type of exposure to sources of H5N1 virus for both the index case and their household members impacted the risk of additional cases in the household. This study describes the disease transmission patterns in those outbreak households. METHODOLOGY/PRINCIPAL FINDINGS: We compared cases (n = 177 and contacts (n = 496 in the 113 sporadic and 26 cluster outbreaks detected between July 2005 and July 2009 to estimate attack rates and disease intervals. We used final size household models to fit transmission parameters to data on household size, cases and blood-related household contacts to assess the relative contribution of zoonotic and human-to-human transmission of the virus, as well as the reproduction number for human virus transmission. The overall household attack rate was 18.3% and secondary attack rate was 5.5%. Secondary attack rate remained stable as household size increased. The mean interval between onset of subsequent cases in outbreaks was 5.6 days. The transmission model found that human transmission was very rare, with a reproduction number between 0.1 and 0.25, and the upper confidence bounds below 0.4. Transmission model fit was best when the denominator population was restricted to blood-related household contacts of index cases. CONCLUSIONS/SIGNIFICANCE: The study only found strong support for human transmission of the virus when a single large cluster was included in the transmission model. The reproduction number was well below the threshold for sustained transmission. This study provides baseline information on the transmission dynamics for the current zoonotic virus and can be used to detect and define signatures of a virus with increasing capacity for human

Assessing evidence for avian-to-human transmission of influenza A/H9N2 virus in rural farming communities in northern Vietnam.

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Hoa, Le Nguyen Minh; Tuan, Nguyen Anh; My, Pham Ha; Huong, Tran Thi Kieu; Chi, Nguyen Thi Yen; Hau Thu, Trang Thi; Carrique-Mas, Juan; Duong, Mai Thuy; Tho, Nguyen Dang; Hoang, Nguyen Dang; Thanh, To Long; Diep, Nguyen Thi; Duong, Nguyen van; Toan, Tran Khanh; Tung, Trinh Son; Mai, Le Quynh; Iqbal, Munir; Wertheim, Heiman; van Doorn, H Rogier; Bryant, Juliet E; The Vizions Consortium

2017-08-01

Rural farming communities in northern Vietnam do not routinely practice vaccination for influenza A viruses (IAV) for either humans or poultry, which enables us to study transmission intensity via seroepidemiology. Using samples from a longitudinal cohort of farming households, we determined the number of symptomatic and asymptomatic human infections for seasonal IAV and avian A/H9 over 2 years. As expected, we detected virologically confirmed acute cases of seasonal IAV in humans, as well as large numbers of subclinical seroconversions to A/H1pdm [55/265 (21 %)], A/H3 [95/265 (36 %)] and A/H9 [24/265 (9 %)]. Five of the A/H9 human seroconverters likely represented true infections rather than heterosubtypic immunity, because the individuals seroconverted solely to A/H9. Among co-located poultry, we found significantly higher seroprevalance for A/H5 compared to A/H9 in both chickens and ducks [for northern study sites overall, 337/1105 (30.5 %) seropositive for A/H5 and 123/1105 (11.1 %) seropositive for A/H9].

Preliminary findings of a randomized trial of non-pharmaceutical interventions to prevent influenza transmission in households.

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Benjamin J Cowling

2008-05-01

Full Text Available There are sparse data on whether non-pharmaceutical interventions can reduce the spread of influenza. We implemented a study of the feasibility and efficacy of face masks and hand hygiene to reduce influenza transmission among Hong Kong household members.We conducted a cluster randomized controlled trial of households (composed of at least 3 members where an index subject presented with influenza-like-illness of <48 hours duration. After influenza was confirmed in an index case by the QuickVue Influenza A+B rapid test, the household of the index subject was randomized to 1 control or 2 surgical face masks or 3 hand hygiene. Households were visited within 36 hours, and 3, 6 and 9 days later. Nose and throat swabs were collected from index subjects and all household contacts at each home visit and tested by viral culture. The primary outcome measure was laboratory culture confirmed influenza in a household contact; the secondary outcome was clinically diagnosed influenza (by self-reported symptoms. We randomized 198 households and completed follow up home visits in 128; the index cases in 122 of those households had laboratory-confirmed influenza. There were 21 household contacts with laboratory confirmed influenza corresponding to a secondary attack ratio of 6%. Clinical secondary attack ratios varied from 5% to 18% depending on case definitions. The laboratory-based or clinical secondary attack ratios did not significantly differ across the intervention arms. Adherence to interventions was variable.The secondary attack ratios were lower than anticipated, and lower than reported in other countries, perhaps due to differing patterns of susceptibility, lack of significant antigenic drift in circulating influenza virus strains recently, and/or issues related to the symptomatic recruitment design. Lessons learnt from this pilot have informed changes for the main study in 2008.ClinicalTrials.gov NCT00425893 HKClinicalTrials.com HKCTR-365.

Response to 2009 pandemic and seasonal influenza vaccines co-administered to HIV-infected and HIV-uninfected former drug users living in a rehabilitation community in Italy.

Science.gov (United States)

Pariani, Elena; Boschini, Antonio; Amendola, Antonella; Poletti, Raffaella; Anselmi, Giovanni; Begnini, Marco; Ranghiero, Alberto; Cecconi, Gianluca; Zanetti, Alessandro R

2011-11-15

2009 A(H1N1) pandemic influenza vaccination was recommended as a priority to essential workers and high-risk individuals, including HIV-infected patients and people living in communities. HIV-infected and HIV-uninfected former drug-users (18-60 years old) living in a rehabilitation community (San Patrignano, Italy) received one dose of a MF59-adjuvanted 2009 pandemic influenza vaccine and one dose of a 2009-2010 seasonal trivalent inactivated influenza vaccine (containing A/Brisbane/59/2007(H1N1), A/Brisbane/10/2007(H3N2), B/Brisbane/60/2008) simultaneously. Antibodies against each vaccine antigen were determined at the time of vaccination and one and six months post-vaccination by hemagglutination-inhibition test. 49 HIV-infected and 60 HIV-uninfected subjects completed the study. Most (98%) HIV-infected participants were on antiretroviral treatment, the median CD4+ cell count was 350 (IQR 300)cells/μl and viremia was suppressed in 91.8% of cases. One month post-vaccination, no significant changes in immune-virological parameters were observed. One month post-vaccination, the immune responses to both pandemic and seasonal vaccine met the EMA-CPMP criteria for immunogenicity of influenza vaccines in both HIV-infected and HIV-uninfected subjects. No difference in vaccine responses was observed between the two groups. Six months after vaccination, the percentages of vaccinees with antibody titres ≥1:40 and antibody geometric mean titres significantly decreased in both groups. However, they were significantly lower in HIV-infected than in HIV-uninfected vaccinees. In subjects who had been primed to seasonal influenza the year before (through either vaccination or natural infection), levels of antibodies against 2009 A(H1N1) were higher than those measured in unprimed subjects, both one month and six months post-vaccination. The co-administration of a single dose of 2009 pandemic MF59-adjuvanted influenza vaccine with a seasonal vaccine provided a protective immune

Prevalence of antibodies and humoral response after seasonal trivalent vaccination against influenza B lineages in an elderly population of Spain.

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Muñoz, Ivan Sanz; Rello, Silvia Rojo; Lejarazu, Raúl Ortiz de

2017-11-24

The aim of this study was to analyze the presence of antibodies against both Yamagata and Victoria influenza B lineages and to check the response after seasonal trivalent vaccination. Haemagglutination inhibition assays were performed with pre-and post-vaccination serum samples from 174 individuals ≥65 years of age vaccinated with seasonal trivalent influenza vaccines during the 2006-2007, 2008-2009, 2009-2010 and 2010-2011 vaccine campaigns. 33.9% of individuals showed pre-vaccine protective antibodies (≥1/40) against B/Yamagata lineage and 41.4% against B/Victoria lineage. The annual trivalent vaccine induced significant homologous seroconversion in 14-35.6% of individuals in each vaccine campaign. The population ≥65 years has low-moderate seroprotection against B influenza lineages. Trivalent vaccination induced a slight increase of seroprotection. The trivalent vaccine should be administered to all individuals ≥65 years in all vaccine campaigns. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

The impacts of email reminder/recall on adolescent influenza vaccination.

Science.gov (United States)

Dombkowski, Kevin J; Cowan, Anne E; Reeves, Sarah L; Foley, Matthew R; Dempsey, Amanda F

2017-05-25

We sought to: (1) explore the feasibility of using email for seasonal influenza vaccination reminders to parents of adolescents and (2) assess influenza vaccination rates among adolescents whose parents were randomized to either receive or not receive email reminders. Email addresses were obtained for parents of patients 10-18years from 4 practices in Michigan. Addresses were randomized to either receive email reminders, or not. Reminder messages were sent during October 2012-March 2013 (Season 1) and October 2013-March 2014 (Season 2). Vaccination status was determined 60days following the last email reminder for each season using the statewide Michigan Care Improvement Registry (MCIR); per protocol bivariate and multivariate logistic regression analyses were conducted to evaluate reminder notification. After email cleaning, testing, and matching with MCIR, approximately half of email addresses (2348 of 5312 in Season 1; 3457 of 6549 in Season 2) were randomized. Bivariate analyses found that influenza vaccination within 60days after notification date was similar among those notified (34%) versus not notified (29%) in both Season 1 (p=0.06) and Season 2 (39% vs. 37%, p=0.20). However, multivariate models adjusted for season, site, and receipt of notification in two seasons found a higher likelihood of influenza vaccination among children that received notification (aOR=1.28, 95% CI=1.09, 1.51); in addition, differences in influenza vaccination were also observed between practice sites (range: p=0.15 to pemail influenza vaccine reminders to parents of adolescents are feasible, but not without complications. Our study demonstrates that email reminders from practices can yield increases in influenza vaccination rates among adolescents. Practices should consider email as an option for influenza reminders and establish business practices for collecting and maintaining patient email addresses. This study is registered at www.ClinicalTrials.gov id #NCT01732315. Copyright

Analysis and Modeling of Influenza Outbreaks as Driven by Weather

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Thrastarson, H. T.; Teixeira, J.; Serman, E. A.; Parekh, A.; Yeo, E.

2017-12-01

Seasonal influenza outbreaks are a major source of illness, mortality and economic burden worldwide. Attributing what drives the seasonality of the outbreaks is still an unsettled problem. But in temperate regions absolute humidity conditions are a strong candidate (Shaman et al., 2010) and some studies have associated temperature conditions with influenza outbreaks. We use humidity and temperature data from NASA's AIRS (Atmospheric Infra-Red Sounder) instrument as well as data for influenza incidence in the US and South Africa to explore the connection between weather and influenza seasonality at different spatial scales. We also incorporate influenza surveillance data, satellite data and humidity forecasts into a numerical epidemiological prediction system. Our results give support for the role of local weather conditions as drivers of the seasonality of influenza in temperate regions. This can have implications for public health efforts where forecasting of the timing and intensity of influenza outbreaks has a great potential role (e.g., aiding management and organization of vaccines, drugs and other resources).

Influence of birth rates and transmission rates on the global seasonality of rotavirus incidence.

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Pitzer, Virginia E; Viboud, Cécile; Lopman, Ben A; Patel, Manish M; Parashar, Umesh D; Grenfell, Bryan T

2011-11-07

Rotavirus is a major cause of mortality in developing countries, and yet the dynamics of rotavirus in such settings are poorly understood. Rotavirus is typically less seasonal in the tropics, although recent observational studies have challenged the universality of this pattern. While numerous studies have examined the association between environmental factors and rotavirus incidence, here we explore the role of intrinsic factors. By fitting a mathematical model of rotavirus transmission dynamics to published age distributions of cases from 15 countries, we obtain estimates of local transmission rates. Model-predicted patterns of seasonal incidence based solely on differences in birth rates and transmission rates are significantly correlated with those observed (Spearman's ρ = 0.65, p birth rates and transmission rates and explore how vaccination may impact these patterns. Our results suggest that the relative lack of rotavirus seasonality observed in many tropical countries may be due to the high birth rates and transmission rates typical of developing countries rather than being driven primarily by environmental conditions. While vaccination is expected to decrease the overall burden of disease, it may increase the degree of seasonal variation in the incidence of rotavirus in some settings.

Laboratory surveillance of influenza-like illness in seven teaching hospitals, South Korea: 2011-2012 season.

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Ji Yun Noh

Full Text Available BACKGROUND: A well-constructed and properly operating influenza surveillance scheme is essential for public health. This study was conducted to evaluate the distribution of respiratory viruses in patients with influenza-like illness (ILI through the first teaching hospital-based surveillance scheme for ILI in South Korea. METHODS: Respiratory specimens were obtained from adult patients (≥18 years who visited the emergency department (ED with ILI from week 40, 2011 to week 22, 2012. Multiplex PCR was performed to detect respiratory viruses: influenza virus, adenovirus, coronavirus, respiratory syncytial virus, rhinovirus, human metapneumovirus, parainfluenza virus, bocavirus, and enterovirus. RESULTS: Among 1,983 patients who visited the ED with ILI, 811 (40.9% were male. The median age of patients was 43 years. Influenza vaccination rate was 21.7% (430/1,983 during the 2011-2012 season. At least one comorbidity was found in 18% of patients. The positive rate of respiratory viruses was 52.1% (1,033/1,983 and the total number of detected viruses was 1,100. Influenza A virus was the dominant agent (677, 61.5% in all age groups. The prevalence of human metapneumovirus was higher in patients more than 50 years old, while adenovirus was detected only in younger adults. In 58 (5.6% cases, two or more respiratory viruses were detected. The co-incidence case was identified more frequently in patients with hematologic malignancy or organ transplantation recipients, however it was not related to clinical outcomes. CONCLUSION: This study is valuable as the first extensive laboratory surveillance of the epidemiology of respiratory viruses in ILI patients through a teaching hospital-based influenza surveillance system in South Korea.

An innovative influenza vaccination policy: targeting last season's patients.

Science.gov (United States)

Yamin, Dan; Gavious, Arieh; Solnik, Eyal; Davidovitch, Nadav; Balicer, Ran D; Galvani, Alison P; Pliskin, Joseph S

2014-05-01

Influenza vaccination is the primary approach to prevent influenza annually. WHO/CDC recommendations prioritize vaccinations mainly on the basis of age and co-morbidities, but have never considered influenza infection history of individuals for vaccination targeting. We evaluated such influenza vaccination policies through small-world contact networks simulations. Further, to verify our findings we analyzed, independently, large-scale empirical data of influenza diagnosis from the two largest Health Maintenance Organizations in Israel, together covering more than 74% of the Israeli population. These longitudinal individual-level data include about nine million cases of influenza diagnosed over a decade. Through contact network epidemiology simulations, we found that individuals previously infected with influenza have a disproportionate probability of being highly connected within networks and transmitting to others. Therefore, we showed that prioritizing those previously infected for vaccination would be more effective than a random vaccination policy in reducing infection. The effectiveness of such a policy is robust over a range of epidemiological assumptions, including cross-reactivity between influenza strains conferring partial protection as high as 55%. Empirically, our analysis of the medical records confirms that in every age group, case definition for influenza, clinical diagnosis, and year tested, patients infected in the year prior had a substantially higher risk of becoming infected in the subsequent year. Accordingly, considering individual infection history in targeting and promoting influenza vaccination is predicted to be a highly effective supplement to the current policy. Our approach can also be generalized for other infectious disease, computer viruses, or ecological networks.

An innovative influenza vaccination policy: targeting last season's patients.

Directory of Open Access Journals (Sweden)

Dan Yamin

2014-05-01

Full Text Available Influenza vaccination is the primary approach to prevent influenza annually. WHO/CDC recommendations prioritize vaccinations mainly on the basis of age and co-morbidities, but have never considered influenza infection history of individuals for vaccination targeting. We evaluated such influenza vaccination policies through small-world contact networks simulations. Further, to verify our findings we analyzed, independently, large-scale empirical data of influenza diagnosis from the two largest Health Maintenance Organizations in Israel, together covering more than 74% of the Israeli population. These longitudinal individual-level data include about nine million cases of influenza diagnosed over a decade. Through contact network epidemiology simulations, we found that individuals previously infected with influenza have a disproportionate probability of being highly connected within networks and transmitting to others. Therefore, we showed that prioritizing those previously infected for vaccination would be more effective than a random vaccination policy in reducing infection. The effectiveness of such a policy is robust over a range of epidemiological assumptions, including cross-reactivity between influenza strains conferring partial protection as high as 55%. Empirically, our analysis of the medical records confirms that in every age group, case definition for influenza, clinical diagnosis, and year tested, patients infected in the year prior had a substantially higher risk of becoming infected in the subsequent year. Accordingly, considering individual infection history in targeting and promoting influenza vaccination is predicted to be a highly effective supplement to the current policy. Our approach can also be generalized for other infectious disease, computer viruses, or ecological networks.

REASONS WHY THE ELDER PEOPLE DID NOT VACCINATE AGAINST INFLUENZA SEASONAL

Directory of Open Access Journals (Sweden)

Ludmila Mourão Xavier-Gomes

2012-08-01

Full Text Available OBJETIVO: Compreender os motivos que levaram os idosos a não se vacinarem contra a Influenza seasonal. MÉTODOS: Estudo descritivo e qualitativo, fundamento na Teoria das Representações Sociais. A coleta de dados foi mediante entrevista semiestruturada gravada com 10 idosos que não se vacinaram contra a Influenza. RESULTADOS: Os idosos demonstraram medo da agulha e desconhecimento acerca dos eventos adversos da vacinação, evidenciados através da preocupação com as reações provocadas pela vacina. Os idosos apresentam a ‘crença do idoso saudável’ que, está associada à recusa ao tabu de que apenas aqueles que estão doentes é que precisam da vacina. À vacina é atribuído o aspecto curativo, desconsiderando assim os benefícios preventivos. CONCLUSÃO: Os motivos que levaram os idosos a não se vacinarem contra a gripe estão associados a crenças, mitos e a falta de informação, orientação. Portanto torna-se necessário a orientação e incentivo dos profissionais de saúde.

Mapping of the US Domestic Influenza Virologic Surveillance Landscape.

Science.gov (United States)

Jester, Barbara; Schwerzmann, Joy; Mustaquim, Desiree; Aden, Tricia; Brammer, Lynnette; Humes, Rosemary; Shult, Pete; Shahangian, Shahram; Gubareva, Larisa; Xu, Xiyan; Miller, Joseph; Jernigan, Daniel

2018-07-17

Influenza virologic surveillance is critical each season for tracking influenza circulation, following trends in antiviral drug resistance, detecting novel influenza infections in humans, and selecting viruses for use in annual seasonal vaccine production. We developed a framework and process map for characterizing the landscape of US influenza virologic surveillance into 5 tiers of influenza testing: outpatient settings (tier 1), inpatient settings and commercial laboratories (tier 2), state public health laboratories (tier 3), National Influenza Reference Center laboratories (tier 4), and Centers for Disease Control and Prevention laboratories (tier 5). During the 2015-16 season, the numbers of influenza tests directly contributing to virologic surveillance were 804,000 in tiers 1 and 2; 78,000 in tier 3; 2,800 in tier 4; and 3,400 in tier 5. With the release of the 2017 US Pandemic Influenza Plan, the proposed framework will support public health officials in modeling, surveillance, and pandemic planning and response.

Matrix-M Adjuvated Seasonal Virosomal Influenza Vaccine Induces Partial Protection in Mice and Ferrets against Avian H5 and H7 Challenge.

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Freek Cox

Full Text Available There is a constant threat of zoonotic influenza viruses causing a pandemic outbreak in humans. It is virtually impossible to predict which virus strain will cause the next pandemic and it takes a considerable amount of time before a safe and effective vaccine will be available once a pandemic occurs. In addition, development of pandemic vaccines is hampered by the generally poor immunogenicity of avian influenza viruses in humans. An effective pre-pandemic vaccine is therefore required as a first line of defense. Broadening of the protective efficacy of current seasonal vaccines by adding an adjuvant may be a way to provide such first line of defense. Here we evaluate whether a seasonal trivalent virosomal vaccine (TVV adjuvated with the saponin-based adjuvant Matrix-M (MM can confer protection against avian influenza H5 and H7 virus strains in mice and ferrets. We demonstrate that mice were protected from death against challenges with H5N1 and H7N7, but that the protection was not complete as evidenced by severe clinical signs. In ferrets, protection against H7N9 was not observed. In contrast, reduced upper and lower respiratory tract viral loads and reduced lung pathology, was achieved in H5N1 challenged ferrets. Together these results suggest that, at least to some extent, Matrix-M adjuvated seasonal virosomal influenza vaccine can serve as an interim measure to decrease morbidity and mortality associated with a pandemic outbreak.

Molecular epidemiology of influenza A/H3N2 viruses circulating in Uganda.

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Denis K Byarugaba

Full Text Available The increasing availability of complete influenza virus genomes is deepening our understanding of influenza evolutionary dynamics and facilitating the selection of vaccine strains. However, only one complete African influenza virus sequence is available in the public domain. Here we present a complete genome analysis of 59 influenza A/H3N2 viruses isolated from humans in Uganda during the 2008 and 2009 season. Isolates were recovered from hospital-based sentinel surveillance for influenza-like illnesses and their whole genome sequenced. The viruses circulating during these two seasons clearly differed from each other phylogenetically. They showed a slow evolution away from the 2009/10 recommended vaccine strain (A/Brisbane/10/07, instead clustering with the 2010/11 recommended vaccine strain (A/Perth/16/09 in the A/Victoria/208/09 clade, as observed in other global regions. All of the isolates carried the adamantane resistance marker S31N in the M2 gene and carried several markers of enhanced transmission; as expected, none carried any marker of neuraminidase inhibitor resistance. The hemagglutinin gene of the 2009 isolates differed from that of the 2008 isolates in antigenic sites A, B, D, and to a lesser extent, C and E indicating evidence of an early phylogenetic shift from the 2008 to 2009 viruses. The internal genes of the 2009 isolates were similar to those of one 2008 isolate, A/Uganda/MUWRP-050/2008. Another 2008 isolate had a truncated PB1-F2 protein. Whole genome sequencing can enhance surveillance of future seasonal changes in the viral genome which is crucial to ensure that selected vaccine strains are protective against the strains circulating in Eastern Africa. This data provides an important baseline for this surveillance. Overall the influenza virus activity in Uganda appears to mirror that observed in other regions of the southern hemisphere.

Airborne transmission of a highly pathogenic avian influenza strain H5N1 between groups of chickens quantified in an experimental setting.

NARCIS (Netherlands)

Spekreijse, D.; Bouma, A.; Koch, G.; Stegeman, J.A.

2011-01-01

Highly pathogenic avian influenza (HPAI) is a devastating viral disease of poultry and quick control of outbreaks is vital. Airborne transmission has often been suggested as a route of transmission between flocks, but knowledge of the rate of transmission via this route is sparse. In the current

Codon usage bias and the evolution of influenza A viruses. Codon Usage Biases of Influenza Virus

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Wong Emily HM

2010-08-01

Full Text Available Abstract Background The influenza A virus is an important infectious cause of morbidity and mortality in humans and was responsible for 3 pandemics in the 20th century. As the replication of the influenza virus is based on its host's machinery, codon usage of its viral genes might be subject to host selection pressures, especially after interspecies transmission. A better understanding of viral evolution and host adaptive responses might help control this disease. Results Relative Synonymous Codon Usage (RSCU values of the genes from segment 1 to segment 6 of avian and human influenza viruses, including pandemic H1N1, were studied via Correspondence Analysis (CA. The codon usage patterns of seasonal human influenza viruses were distinct among their subtypes and different from those of avian viruses. Newly isolated viruses could be added to the CA results, creating a tool to investigate the host origin and evolution of viral genes. It was found that the 1918 pandemic H1N1 virus contained genes with mammalian-like viral codon usage patterns, indicating that the introduction of this virus to humans was not through in toto transfer of an avian influenza virus. Many human viral genes had directional changes in codon usage over time of viral isolation, indicating the effect of host selection pressures. These changes reduced the overall GC content and the usage of G at the third codon position in the viral genome. Limited evidence of translational selection pressure was found in a few viral genes. Conclusions Codon usage patterns from CA allowed identification of host origin and evolutionary trends in influenza viruses, providing an alternative method and a tool to understand the evolution of influenza viruses. Human influenza viruses are subject to selection pressure on codon usage which might assist in understanding the characteristics of newly emerging viruses.

Seasonal patterns in human A (H5N1 virus infection: analysis of global cases.

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Maya B Mathur

Full Text Available Human cases of highly pathogenic avian influenza (HPAI A (H5N1 have high mortality. Despite abundant data on seasonal patterns in influenza epidemics, it is unknown whether similar patterns exist for human HPAI H5N1 cases worldwide. Such knowledge could help decrease avian-to-human transmission through increased prevention and control activities during peak periods.We performed a systematic search of published human HPAI H5N1 cases to date, collecting month, year, country, season, hemisphere, and climate data. We used negative binomial regression to predict changes in case incidence as a function of season. To investigate hemisphere as a potential moderator, we used AIC and the likelihood-ratio test to compare the season-only model to nested models including a main effect or interaction with hemisphere. Finally, we visually assessed replication of seasonal patterns across climate groups based on the Köppen-Geiger climate classification.We identified 617 human cases (611 with complete seasonal data occurring in 15 countries in Southeast Asia, Africa, and the Middle East. Case occurrence was much higher in winter (n = 285, p = 0.03 than summer (n = 64, and the winter peak occurred across diverse climate groups. There was no significant interaction between hemisphere and season.Across diverse climates, HPAI H5N1 virus infection in humans increases significantly in winter. This is consistent with increased poultry outbreaks and HPAI H5N1 virus transmission during cold and dry conditions. Prioritizing prevention and control activities among poultry and focusing public health messaging to reduce poultry exposures during winter months may help to reduce zoonotic transmission of HPAI H5N1 virus in resource-limited settings.

Seroprevalence of Antibodies against Plasmodium falciparum Sporozoite Antigens as Predictive Disease Transmission Markers in an Area of Ghana with Seasonal Malaria Transmission.

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Kwadwo A Kusi

Full Text Available As an increasing number of malaria-endemic countries approach the disease elimination phase, sustenance of control efforts and effective monitoring are necessary to ensure success. Mathematical models that estimate anti-parasite antibody seroconversion rates are gaining relevance as more sensitive transmission intensity estimation tools. Models however estimate yearly seroconversion and seroreversion rates and usually predict long term changes in transmission, occurring years before the time of sampling. Another challenge is the identification of appropriate antigen targets since specific antibody levels must directly reflect changes in transmission patterns. We therefore investigated the potential of antibodies to sporozoite and blood stage antigens for detecting short term differences in malaria transmission in two communities in Northern Ghana with marked, seasonal transmission.Cross-sectional surveys were conducted during the rainy and dry seasons in two communities, one in close proximity to an irrigation dam and the other at least 20 Km away from the dam. Antibodies against the sporozoite-specific antigens circumsporozoite protein (CSP and Cell traversal for ookinetes and sporozoites (CelTOS and the classical blood stage antigen apical membrane antigen 1 (AMA1 were measured by indirect ELISA. Antibody levels and seroprevalence were compared between surveys and between study communities. Antibody seroprevalence data were fitted to a modified reversible catalytic model to estimate the seroconversion and seroreversion rates.Changes in sporozoite-specific antibody levels and seroprevalence directly reflected differences in parasite prevalence between the rainy and dry seasons and hence the extent of malaria transmission. Seroconversion rate estimates from modelled seroprevalence data did not however support the above observation.The data confirms the potential utility of sporozoite-specific antigens as useful markers for monitoring short term/seasonal

The Relationship of Avian Influenza and Waterbirds in Creating Genetic Diversity and the Role of Waterbirds as Reservoir for Avian Influenza

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Dyah Ayu Hewajuli

2012-03-01

Full Text Available Outbreaks of Avian Influenza (AI has enormous implications for poultry and human health.These outbreaks are caused by influenza A virus that belongS to the family of Orthomyxoviridae. These viruses are RNA viruses, negative polarity, and the envelope has segmented genom. Generally, Avian Influenza is a disease which originally occurred in birds with complex ecology including reassortment and transmission among different species of birds and mammals. The gene of AI virus can be transmitted among human and avian species as shown by the virus reasortantment that caused pandemic human influenza in 1957 and 1968. Pandemi in 1957 and 1968 were different from previously human viruses because the substitution of several genes are derived from avian viruses. Wild waterfowls especially Anseriformes (duck, muscovy duck and geese and Charadriiformes (gulls, seabirds, wild birds are the natural reservoirs for influenza type A viruses and play important role on the ecology and propagation of the virus. From this reservoir, influenza type A virus usually can be transmitted to other birds, mammals (including human and caused outbreak of lethal diseases. Waterfowl that is infected with influenza A virus usually does not show any clinical symptoms. However, several reports stated that HPAI viruses can cause severe disease with neurogical disorders led to death in waterfowl. Migration of birds including waterfowls have active role in transmitting and spreading the disease. Movement of wild birds and inappropriate poultry trade transportation play a greater role as vector in spreading HPAI to humans. Ecological change of environment has also a great effect in spreading AI viruses. The spreading pattern of AI viruses is usually influenced by seasons, where the prevalence of AI was reported to be in the fall, winter and rainy seasons. Finally, the effective control strategies against the spreading of AI viruses is required. Programs of monitoring, surveilence and

65 Years of influenza surveillance by a WHO-coordinated global network.

Science.gov (United States)

Ziegler, Thedi; Mamahit, Awandha; Cox, Nancy J

2018-05-04

The 1918 devastating influenza pandemic left a lasting impact on influenza experts and the public, and the importance of global influenza surveillance was soon recognized. The WHO Global Influenza Surveillance Network (GISN) was founded in 1952 and renamed to Global Influenza Surveillance and Response System in 2011 upon the adoption by the World Health Assembly, of the Pandemic Influenza Preparedness Framework for the Sharing of Influenza Viruses and Access to Vaccines and Other Benefits ("PIP Framework"). The importance of influenza surveillance had been recognized and promoted by experts prior to the years leading up to the establishment of WHO. In the 65 years of its existence, the Network has grown to comprise 143 National Influenza Centers recognized by WHO, 6 WHO Collaborating Centers, 4 Essential Regulatory Laboratories, and 13 H5 Reference Laboratories. The Network has proven its excellence throughout these 65 years, providing detailed information on circulating seasonal influenza viruses, as well as immediate response to the influenza pandemics in 1957, 1968, and 2009, and to threats caused by animal influenza viruses and by zoonotic transmission of coronaviruses. For its central role in global public health, the Network has been highly recognized by its many partners and by international bodies. Several generations of world renown influenza scientists have brought the Network to where it is now and they will take it forward to the future, as influenza will remain a pre-eminent threat to humans and to animals. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Influenza Pandemic Infrastructure Response in Thailand

Centers for Disease Control (CDC) Podcasts

Influenza viruses change antigenic properties, or drift, every year and they create seasonal outbreaks. Occasionally, influenza viruses change in a major way, called a “shift." If an influenza virus shifts, the entire human population is susceptible to the new influenza virus, creating the potential for a pandemic. On this podcast, CDC's Dr. Scott Dowell discusses responding to an influenza pandemic.

Mid-Season Influenza Vaccine Effectiveness Estimates for the 2016-2017 Influenza Season (Open Access Publisher’s Version)

Science.gov (United States)

2017-08-01

VE) and findings are shared annually at the Food and Drug Administration’s advisory committee meet- ing on U.S. influenza vaccine strain selec- tion...Aeromedical Services Information Manage - ment System) and self-report from patient questionnaires. Individuals were consid- ered vaccinated if they received...surveillance are used to estimate midseason influenza vaccine effectiveness (VE) and findings are shared annually at the Food and Drug

Characteristics of seasonal influenza A and B in Latin America: influenza surveillance data from ten countries.

NARCIS (Netherlands)

Caini, S.; Alonso, W.J.; Balmaseda, A.; Bruno, A.; Busto, P.; Castillo, L.; Lozano, C. de; Mora, D. de; Fasce, R. A.; Ferreira de Almeida, W.A.; Kusznierz, G.F.; Lara, J.; Matute, M.L.; Moreno, B.; Pessanha Henriques, C.M.; Rudi, J.M.; El-Guerche Séblain, C.; Schellevis, F.; Paget, J.

2017-01-01

Introduction: The increased availability of influenza surveillance data in recent years justifies an actual and more complete overview of influenza epidemiology in Latin America. We compared the influenza surveillance systems and assessed the epidemiology of influenza A and B, including the

Characteristics of seasonal influenza A and B in Latin America: Influenza surveillance data from ten countries

NARCIS (Netherlands)

Caini, S.; Alonso, W.J.; Balmaseda, A.; Bruno, A.; Bustos, P.; Castillo, L.; Lozano, C.; Mora, D. De; Fasce, R.A.; Ferreira de Almeida, W.A.; Kusznierz, G.F.; Lara, J.; Matute, M.L.; Moreno, B.; Henriques, C.M.; Rudi, J.M.; El-Guerche Seblain, C.; Schellevis, F.; Paget, J.

2017-01-01

INTRODUCTION: The increased availability of influenza surveillance data in recent years justifies an actual and more complete overview of influenza epidemiology in Latin America. We compared the influenza surveillance systems and assessed the epidemiology of influenza A and B, including the

[Primary health care professionals attitudes towards influenza immunzation in Catalonia].

Science.gov (United States)

Torner, Nuria; Godoy, Pere; Soldevila, Núria; Toledo, Diana; Rius, Cristina; Domínguez, Angela

2016-03-01

Health personnel are at risk of acquiring influenza infection and of nosocomial influenza transmission. The objective of this study was to assess the relationship between the knowledge and attitudes of primary care health personnel in Catalonia as regards influenza vaccine and the factors related to the uptake of this vaccine. A cross-sectional study using a web survey. Primary care health personnel of the Catalan Health Institute. A total of 1212 primary health care personnel were included in the survey. Those who had medical reasons for being or not being vaccinated were excluded. A total of 423 replies were valid, with a 46.6% overall vaccination coverage. Vaccination rate was higher among 45 to 54 year-olds, paediatricians, those vaccinated in preceding seasons, and those living with chronic patients. There was an association between having received the vaccine and considering vaccination the best preventive action, advocating vaccination to at risk population, concern about acquiring influenza, and considering health personnel vaccination important. Actions taken to increase vaccination rate among health personnel should aim at correcting lack of knowledge and misconceptions about influenza vaccination of health personnel. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

Respiratory transmission of an avian H3N8 influenza virus isolated from a harbour seal

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Karlsson, Erik A.; Ip, Hon S.; Hall, Jeffrey S.; Yoon, Sun W.; Johnson, Jordan; Beck, Melinda A.; Webby, Richard J.; Schultz-Cherry, Stacey

2014-01-01

The ongoing human H7N9 influenza infections highlight the threat of emerging avian influenza viruses. In 2011, an avian H3N8 influenza virus isolated from moribund New England harbour seals was shown to have naturally acquired mutations known to increase the transmissibility of highly pathogenic H5N1 influenza viruses. To elucidate the potential human health threat, here we evaluate a panel of avian H3N8 viruses and find that the harbour seal virus displays increased affinity for mammalian receptors, transmits via respiratory droplets in ferrets and replicates in human lung cells. Analysis of a panel of human sera for H3N8 neutralizing antibodies suggests that there is no population-wide immunity to these viruses. The prevalence of H3N8 viruses in birds and multiple mammalian species including recent isolations from pigs and evidence that it was a past human pandemic virus make the need for surveillance and risk analysis of these viruses of public health importance.

Evaluation of a Multiplex Real-Time Reverse Transcriptase PCR Assay for Detection and Differentiation of Influenza Viruses A and B during the 2001-2002 Influenza Season in Israel

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Hindiyeh, Musa; Levy, Virginia; Azar, Roberto; Varsano, Noemi; Regev, Liora; Shalev, Yael; Grossman, Zehava; Mendelson, Ella

2005-01-01

The ability to rapidly diagnose influenza virus infections is of the utmost importance in the evaluation of patients with upper respiratory tract infections. It is also important for the influenza surveillance activities performed by national influenza centers. In the present study we modified a multiplex real-time reverse transcriptase PCR (RT-PCR) assay (which uses TaqMan chemistry) and evaluated it for its ability to detect and concomitantly differentiate influenza viruses A and B in 370 patient samples collected during the 2001-2002 influenza season in Israel. The performance of the TaqMan assay was compared to those of a multiplex one-step RT-PCR with gel detection, a shell vial immunofluorescence assay, and virus isolation in tissue culture. The TaqMan assay had an excellent sensitivity for the detection of influenza viruses compared to that of tissue culture. The overall sensitivity and specificity of the TaqMan assay compared to the results of culture were 98.4 and 85.5%, respectively. The sensitivity and specificity of the TaqMan assay for the detection of influenza virus A alone were 100 and 91.1%, respectively. On the other hand, the sensitivity and specificity for the detection of influenza virus B alone were 95.7 and 98.7%, respectively. The rapid turnaround time for the performance of the TaqMan assay (4.5 h) and the relatively low direct cost encourage the routine use of this assay in place of tissue culture. We conclude that the multiplex TaqMan assay is highly suitable for the rapid diagnosis of influenza virus infections both in well-established molecular biology laboratories and in reference clinical laboratories. PMID:15695650

Memory B cells and CD8⁺ lymphocytes do not control seasonal influenza A virus replication after homologous re-challenge of rhesus macaques.

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Timothy D Carroll

Full Text Available This study sought to define the role of memory lymphocytes in the protection from homologous influenza A virus re-challenge in rhesus macaques. Depleting monoclonal antibodies (mAb were administered to the animals prior to their second experimental inoculation with a human seasonal influenza A virus strain. Treatment with either anti-CD8α or anti-CD20 mAbs prior to re-challenge had minimal effect on influenza A virus replication. Thus, in non-human primates with pre-existing anti-influenza A antibodies, memory B cells and CD8α⁺ T cells do not contribute to the control of virus replication after re-challenge with a homologous strain of influenza A virus.

Genetic Reassortment Among the Influenza Viruses (Avian Influenza, Human Influenza and Swine Influenza in Pigs

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Dyah Ayu Hewajuli

2012-12-01

Full Text Available Influenza A virus is a hazardous virus and harm to respiratory tract. The virus infect birds, pigs, horses, dogs, mammals and humans. Pigs are important hosts in ecology of the influenza virus because they have two receptors, namely NeuAc 2,3Gal and NeuAc 2,6Gal which make the pigs are sensitive to infection of influenza virus from birds and humans and genetic reassortment can be occurred. Classical swine influenza H1N1 viruses had been circulated in pigs in North America and other countries for 80 years. In 1998, triple reassortant H3N2 swine influenza viruses that contains genes of human influenza A virus (H3N2, swine influenza virus (H1N1 and avian influenza are reported as cause an outbreaks in pigs in North America. Furthermore, the circulation of triple reassortant H3N2 swine influenza virus resulting reassortant H1N1 swine influenza and reassortant H1N2 swine influenza viruses cause infection in humans. Humans who were infected by triple reassortant swine influenza A virus (H1N1 usually made direct contact with pigs. Although without any clinical symptoms, pigs that are infected by triple reassortant swine influenza A (H1N1 can transmit infection to the humans around them. In June 2009, WHO declared that pandemic influenza of reassortant H1N1 influenza A virus (novel H1N1 has reached phase 6. In Indonesia until 2009, there were 1005 people were infected by H1N1 influenza A and 5 of them died. Novel H1N1 and H5N1 viruses have been circulated in humans and pigs in Indonesia. H5N1 reassortant and H1N1 viruses or the seasonal flu may could arise because of genetic reassortment between avian influenza and humans influenza viruses that infect pigs together.

Abbreviated Pandemic Influenza Planning Template for Primary Care Offices

Energy Technology Data Exchange (ETDEWEB)

HCTT CHE

2010-01-01

The Abbreviated Pandemic Influenza Plan Template for Primary Care Provider Offices is intended to assist primary care providers and office managers with preparing their offices for quickly putting a plan in place to handle an increase in patient calls and visits, whether during the 2009-2010 influenza season or future influenza seasons.

Association between the 2008-09 seasonal influenza vaccine and pandemic H1N1 illness during Spring-Summer 2009: four observational studies from Canada.

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Danuta M Skowronski

2010-04-01

Full Text Available In late spring 2009, concern was raised in Canada that prior vaccination with the 2008-09 trivalent inactivated influenza vaccine (TIV was associated with increased risk of pandemic influenza A (H1N1 (pH1N1 illness. Several epidemiologic investigations were conducted through the summer to assess this putative association.(1 test-negative case-control design based on Canada's sentinel vaccine effectiveness monitoring system in British Columbia, Alberta, Ontario, and Quebec; (2 conventional case-control design using population controls in Quebec; (3 test-negative case-control design in Ontario; and (4 prospective household transmission (cohort study in Quebec. Logistic regression was used to estimate odds ratios for TIV effect on community- or hospital-based laboratory-confirmed seasonal or pH1N1 influenza cases compared to controls with restriction, stratification, and adjustment for covariates including combinations of age, sex, comorbidity, timeliness of medical visit, prior physician visits, and/or health care worker (HCW status. For the prospective study risk ratios were computed. Based on the sentinel study of 672 cases and 857 controls, 2008-09 TIV was associated with statistically significant protection against seasonal influenza (odds ratio 0.44, 95% CI 0.33-0.59. In contrast, estimates from the sentinel and three other observational studies, involving a total of 1,226 laboratory-confirmed pH1N1 cases and 1,505 controls, indicated that prior receipt of 2008-09 TIV was associated with increased risk of medically attended pH1N1 illness during the spring-summer 2009, with estimated risk or odds ratios ranging from 1.4 to 2.5. Risk of pH1N1 hospitalization was not further increased among vaccinated people when comparing hospitalized to community cases.Prior receipt of 2008-09 TIV was associated with increased risk of medically attended pH1N1 illness during the spring-summer 2009 in Canada. The occurrence of bias (selection, information or

Influenza-associated encephalopathy: no evidence for neuroinvasion by influenza virus nor for reactivation of human herpesvirus 6 or 7.

NARCIS (Netherlands)

van Zeijl, J.H.; Bakkers, J.; Wilbrink, B.; Melchers, W.J.; Mullaart, R.A.; Galama, J.M.

2005-01-01

During 2 consecutive influenza seasons we investigated the presence of influenza virus, human herpesvirus (HHV) type 6, and HHV-7 in cerebrospinal fluid samples from 9 white children suffering from influenza-associated encephalopathy. We conclude that it is unlikely that neuroinvasion by influenza

Influenza | Florida Department of Health

Science.gov (United States)

Health Women's Health WIC Program Community Health Minority Health & Health Equity People with influenza A viruses since early March. * This late-season circulation of influenza B is expected. View the

European seasonal mortality and influenza incidence due to winter temperature variability

Science.gov (United States)

Rodó, X.; Ballester, J.; Robine, J. M.; Herrmann, F. R.

2017-12-01

Recent studies have vividly emphasized the lack of consensus on the degree of vulnerability (sensu IPCC) of European societies to current and future winter temperatures. Here we consider several climate factors, influenza incidence and daily numbers of deaths to characterize the relationship between winter temperature and mortality in a very large ensemble of European regions representing more than 400 million people. Analyses highlight the strong association between the year-to-year fluctuations in winter mean temperature and mortality, with higher seasonal cases during harsh winters, in all of the countries except the United Kingdom, the Netherlands and Belgium. This spatial distribution contrasts with the well-documented latitudinal orientation of the dependency between daily temperature and mortality within the season. A theoretical framework is proposed to reconcile the apparent contradictions between recent studies, offering an interpretation to regional differences in the vulnerability to daily, seasonal and long-term winter temperature variability. Despite the lack of a strong year-to-year association between winter mean values in some countries, it can be concluded that warmer winters will contribute to the decrease in winter mortality everywhere in Europe. More information in Ballester J, et al. (2016) Nature Climate Change 6, 927-930, doi:10.1038/NCLIMATE3070.

Airborne Transmission of Highly Pathogenic Influenza Virus during Processing of Infected Poultry.

Science.gov (United States)

Bertran, Kateri; Balzli, Charles; Kwon, Yong-Kuk; Tumpey, Terrence M; Clark, Andrew; Swayne, David E

2017-11-01

Exposure to infected poultry is a suspected cause of avian influenza (H5N1) virus infections in humans. We detected infectious droplets and aerosols during laboratory-simulated processing of asymptomatic chickens infected with human- (clades 1 and 2.2.1) and avian- (clades 1.1, 2.2, and 2.1) origin H5N1 viruses. We detected fewer airborne infectious particles in simulated processing of infected ducks. Influenza virus-naive chickens and ferrets exposed to the air space in which virus-infected chickens were processed became infected and died, suggesting that the slaughter of infected chickens is an efficient source of airborne virus that can infect birds and mammals. We did not detect consistent infections in ducks and ferrets exposed to the air space in which virus-infected ducks were processed. Our results support the hypothesis that airborne transmission of HPAI viruses can occur among poultry and from poultry to humans during home or live-poultry market slaughter of infected poultry.

Analytical detection of influenza A(H3N2)v and other A variant viruses from the USA by rapid influenza diagnostic tests.

Science.gov (United States)

Balish, Amanda; Garten, Rebecca; Klimov, Alexander; Villanueva, Julie

2013-07-01

The performance of rapid influenza diagnostic tests (RIDTs) that detect influenza viral nucleoprotein (NP) antigen has been reported to be variable. Recent human infections with variant influenza A viruses that are circulating in pigs prompted the investigation of the analytical reactivity of RIDTs with these variant viruses. To determine analytical reactivity of seven FDA-cleared RIDTs with influenza A variant viruses in comparison with the reactivity with recently circulating seasonal influenza A viruses. Tenfold serial dilutions of cell culture-grown seasonal and variant influenza A viruses were prepared and tested in duplicate with seven RIDTs. All RIDTs evaluated in this study detected the seasonal influenza A(H3N2) virus, although detection limits varied among assays. All but one examined RIDT identified the influenza A(H1N1)pdm09 virus. However, only four of seven RIDTs detected all influenza A(H3N2)v, A(H1N2)v, and A(H1N1)v viruses. Reduced sensitivity of RIDTs to variant influenza viruses may be due to amino acid differences between the NP proteins of seasonal viruses and the NP proteins from viruses circulating in pigs. Clinicians should be aware of the limitations of RIDTs to detect influenza A variant viruses. Specimens from patients with influenza-like illness in whom H3N2v is suspected should be sent to public health laboratories for additional diagnostic testing. Published 2012. This article is a US Government work and is in the public domain in the USA.

Sentinel surveillance for influenza in Senegal, 1996-2009.

Science.gov (United States)

Niang, Mbayame Ndiaye; Dosseh, Annick; Ndiaye, Kader; Sagna, Monique; Gregory, Victoria; Goudiaby, Deborah; Hay, Alan; Diop, Ousmane M

2012-12-15

Data on influenza in tropical and resource-limited countries are scarce. In this study we present results from 14 years of influenza surveillance in Senegal, one of the few tropical countries in Africa from which longitudinal data are available. From 1996 to 2009, we collected respiratory specimens from outpatients presenting with influenza-like illness at 13 facilities in order to investigate the epidemiology of seasonal influenza and the characteristics of the circulating influenza viruses. Specimens were tested for influenza using viral isolation and/or reverse-transcription polymerase chain reaction (RT-PCR). From 1996 to 2009, specimens were obtained from 9176 patients; 1233 (13%) were influenza-positive by virus isolation and/or RT-PCR. Among positive samples, 958 (77%) were influenza A, 268 (22%) influenza B, and 7 (1%) influenza type C; of influenza A viruses, 619 (65%) were A(H3) and 339 (35%) A(H1), of which 13 (1%) were identified as H1N2. The proportion positive was similar for children 55 years (9%). Although influenza A(H1), A(H3), and B all circulated during most years, influenza A(H3N2) predominated during 9 of the 14 years. Influenza activity consistently peaked during the rainy season (July-September). Phylogenetic analysis showed that viruses circulating in Senegal were similar to contemporary viruses circulating elsewhere in the world. Our data confirm that influenza is prevalent in Senegal, occurs in seasonal epidemics, and contributes to the burden of respiratory diseases in all age groups.

Twitter Influenza Surveillance: Quantifying Seasonal Misdiagnosis Patterns and their Impact on Surveillance Estimates.

Science.gov (United States)

Mowery, Jared

2016-01-01

Influenza (flu) surveillance using Twitter data can potentially save lives and increase efficiency by providing governments and healthcare organizations with greater situational awareness. However, research is needed to determine the impact of Twitter users' misdiagnoses on surveillance estimates. This study establishes the importance of Twitter users' misdiagnoses by showing that Twitter flu surveillance in the United States failed during the 2011-2012 flu season, estimates the extent of misdiagnoses, and tests several methods for reducing the adverse effects of misdiagnoses. Metrics representing flu prevalence, seasonal misdiagnosis patterns, diagnosis uncertainty, flu symptoms, and noise were produced using Twitter data in conjunction with OpenSextant for geo-inferencing, and a maximum entropy classifier for identifying tweets related to illness. These metrics were tested for correlations with World Health Organization (WHO) positive specimen counts of flu from 2011 to 2014. Twitter flu surveillance erroneously indicated a typical flu season during 2011-2012, even though the flu season peaked three months late, and erroneously indicated plateaus of flu tweets before the 2012-2013 and 2013-2014 flu seasons. Enhancements based on estimates of misdiagnoses removed the erroneous plateaus and increased the Pearson correlation coefficients by .04 and .23, but failed to correct the 2011-2012 flu season estimate. A rough estimate indicates that approximately 40% of flu tweets reflected misdiagnoses. Further research into factors affecting Twitter users' misdiagnoses, in conjunction with data from additional atypical flu seasons, is needed to enable Twitter flu surveillance systems to produce reliable estimates during atypical flu seasons.

Socioeconomic burden of influenza in the Republic of Korea, 2007-2010.

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Mina Suh

Full Text Available BACKGROUND: Although the socioeconomic burden of 2009 pandemic influenza A (H1N1 was considerable, no reliable estimates have been reported. Our aim was to compared medical costs and socioeconomic burden resulting from pandemic influenza A (H1N1 2009 with that of previous seasonal influenza. METHODS: We estimated the medical costs and socioeconomic burden of influenza from May 2007 to April 2010. We used representative national data sources(data from the Health Insurance Review Agency, the National Health Insurance Corporation, the Korea Centers for Disease Control and Prevention, and the Korean National Statistics Office including medical utilization, prescription of antivirals, and vaccination. Uncertainty of data was explored through sensitivity analysis using Monte Carlo simulation. RESULTS: Compared with the seasonal influenza, total medical costs (US$291.7 million associated with pandemic (H1N1 2009 increased more than 37-fold. Compared with the 2007-2008 season, outpatient diagnostic costs (US$135.3 million were 773 times higher in the 2009-2010 season, and the mean diagnostic cost per outpatient visit was 58.8 times higher. Total socioeconomic burden of pandemic (H1N1 2009 was estimated at US$1581.3 million (10%-90%: US$1436.0-1808.3 million and those of seasonal influenza was estimated at US$44.7 million (10%-90%: US$32.4-57.9 million in 2007-2008 season and US$42.3 million (10%-90%: US$31.5-53.8 million in 2008-2009 season. Indirect costs accounted for 56.0% of total costs in pandemic (H1N1 2009, and 66.48-68.09% in seasonal influenza. The largest contributors to total burden were productivity losses of caregiver in pandemic (H1N1 2009, and productivity losses due to morbidity of outpatient in seasonal influenza. CONCLUSIONS: In the Republic of Korea, socioeconomic burden of pandemic (H1N1 2009 were considerably higher than burden of the previous two influenza seasons, primarily because of high diagnostic costs and longer sick leave.