Search

Please cite this paper as: Vega et al. (2012) Influenza surveillance in Europe: establishing epidemic thresholds by the moving epidemic method. Influenza and Other Respiratory Viruses 7(4), 546-558. Background Timely influenza surveillance is important to monitor influenza epidemics. Objectives (i) To calculate the epidemic threshold for influenza-like illness (ILI) and acute respiratory infections (ARI) in 19 countries, as well as the thresholds for different levels of intensity. (ii) To evaluate the performance of these thresholds. Methods The moving epidemic method (MEM) has been developed to determine the baseline influenza activity and an epidemic threshold. False alerts, detection lags and timeliness of the detection of epidemics were calculated. The performance was evaluated using a cross-validation procedure. Results The overall sensitivity of the MEM threshold was 71·8% and the specificity was 95·5%. The median of the timeliness was 1 week (range: 0-4·5). Conclusions The method produced a robust and specific signal to detect influenza epidemics. The good balance between the sensitivity and specificity of the epidemic threshold to detect seasonal epidemics and avoid false alerts has advantages for public health purposes. This method may serve as standard to define the start of the annual influenza epidemic in countries in Europe. [ABSTRACT FROM AUTHOR]

Please cite this paper as: van Gageldonk-Lafeber et al. (2011) The relative clinical impact of 2009 pandemic influenza A (H1N1) in the community compared to seasonal influenza in the Netherlands was most marked among 5-14 year olds. Influenza and Other Respiratory Viruses 5(6), e513-e520. Background So far, most pandemic influenza reports were based on case studies focusing on severe disease. For public health policy, it is essential to consider the overall impact of the pandemic, including mild diseases. Objectives The aim of our study is to gain insight into the epidemiology of 2009 pandemic influenza in the community and to estimate the relative impact of pandemic compared to seasonal influenza. Methods The relative impact of pandemic influenza in the general population was assessed as the influenza-like illness (ILI) incidence during the pandemic season compared with that during regular seasons. Influenza-like illness incidences and virus diagnostics were derived from continuous sentinel surveillance systems. The incidence of hospital admissions, based on the mandatory notification of pandemic influenza, was used to relate the impact of severe disease to that in the community. Results The overall incidence of general practitioners-attended ILI was 96 consultations per 10 000 persons. Highest incidences were reported in children and lowest in persons aged ≥65 years. For 5-14 year olds, the incidence during the pandemic was higher than during all preceding seasons. Samples originating from 5 to 19 year olds were statistically significant more often positive for pandemic influenza A (H1N1) 2009 virus as compared with samples from 0 to 4 year olds. Moreover, the incidence of hospital admission owing to pandemic influenza was highest in the youngest children. Conclusions Our study showed that while the absolute incidences of 2009 pandemic influenza were highest in children aged 0-4 years, the relative clinical impact in the community compared to seasonal influenza in previous years was most noticeable in healthy children 5-14 years of age. [ABSTRACT FROM AUTHOR]

Please cite this paper as: Moghadas et al. (2011) Canada in the face of the 2009 H1N1 pandemic. Influenza and Other Respiratory Viruses 5(2), 83-88. Initial public health responses to the 2009 influenza H1N1 pandemic were based on difficult decisions in the face of substantial uncertainty. Policy effectiveness depends critically on such decisions, and future planning for maximum protection of community health requires understanding of the impact of public health responses in observed scenarios. In alignment with the objectives of the Pandemic Influenza Outbreak Research Modelling Team (Pan-InfORM) and the Centre for Disease Modelling (CDM), a focused workshop was organized to: (i) evaluate Canada's response to the spring and autumn waves of the novel H1N1 pandemic; (ii) learn lessons from public health responses, and identify challenges that await public health planners and decision-makers; and (iii) understand how best to integrate resources to overcome these challenges. We report on key presentations and discussions that took place to achieve the objectives of the workshop. Future emerging infectious diseases are likely to bring far greater challenges than those imposed by the 2009 H1N1 pandemic. Canada must address these challenges and enhance its capacity for emergency responses by integrating modelling, surveillance, planning, and decision-making. [ABSTRACT FROM AUTHOR]

Please cite this paper as: Yavarian et al. (2012). Epidemiological aspects of pandemic influenza A(H1N1) virus from 2009 to 2011 in Iran. Influenza and Other Respiratory Viruses 6(601), e74-e76. [ABSTRACT FROM AUTHOR]

Please cite this paper as: Castilla et al. (2013) Risk factors and effectiveness of preventive measures against influenza in the community. Influenza and Other Respiratory Viruses 7(2) 177-183. Background The role of different risk exposures and preventive measures against influenza has not been well established. Objective The aim of this study was to evaluate risk factors and measures to prevent influenza infection in the community. Methods We conducted a multicenter case-control study. Cases were 481 outpatients aged 18 years or older with laboratory-confirmed influenza A(H1N1)09 in the 2009-2010 season in Spain. A control was selected for each case from outpatients from the same area matched by age and date of consultation. Information on risk situations, preventive measures and other variables was obtained by interview and review of the medical record. Results In the multivariate conditional logistic regression analysis, the risk of a diagnosis of influenza increased with the number of cohabitants (compared with <3 cohabitants, three cohabitants had an OR = 1·80, 95% CI 1·12-2·89, and ≥5 cohabitants had an OR = 2·66, 95% CI 1·31-5·41) and for health care workers (OR = 2·94, 95% CI 1·53-5·66). The use of metropolitan public transport was associated with a lower frequency of a diagnosis of influenza (OR = 0·45, 95% CI 0·30-0·68) but not the use of taxis or long-distance transport. The influenza A(H1N1)09 vaccine had a protective effect (OR = 0·13, 95% CI 0·04-0·48), unlike hand washing after touching contaminated surfaces or the use of alcohol-based hand sanitizers. Conclusion The home environment appears to play an important role in the spread of influenza in adults, but not the use of public transport. Health care workers have a higher risk of contracting influenza. Vaccination was the most effective preventive measure. [ABSTRACT FROM AUTHOR]

Background: The importance of influenza viruses in respiratory infections in sub‐Saharan Africa has been historically overlooked, including in Burkina Faso. Objectives: This study therefore aimed at evaluating the prevalence and seasonal occurrence of influenza viruses in children under 5 years old, at risk of influenza‐related complications, presenting with influenza‐like illness (ILI) or severe acute respiratory infection (SARI). The study also aimed at identifying the periods with increased influenza transmission for vaccination recommendations in Burkina Faso. Methods: From January 2014 to December 2015, ILI and SARI (2015 only) patients were recruited in six healthcare centers in Burkina Faso. Influenza A and B molecular detection and subtyping were performed. Clade clustering of a subset of A(H1N1)pdm09 and A(H3N2) strains was deduced by performing phylogenetic analyses on hemagglutinin gene sequences. Weekly surveillance data from FluNet (2011‐2013; 2016) and this study (2014‐2015) were used to identify periods of increased influenza activity. Results: Influenza A and B viruses were detected in 15.1% (112 of 743) of ILI and 6.6% (12 of 181) of SARI patients. Overall, influenza A viruses were largely predominant (81 of 124, 65.3%), with 69.1% of A(H3N2) and 30.9% of A(H1N1)pdm09 strains. Four waves of increased transmission were identified in 2014‐2015, each dominated by different influenza subtypes and clades. Between 2011 and 2016, periods of increased influenza activity varied in their frequency, duration, and timing. Conclusion: Influenza A and B viruses were detected in a substantial number of ILI and SARI cases in Burkina Faso. Vaccination in September‐October would likely protect the highest number of patients. [ABSTRACT FROM AUTHOR]

The 2009 influenza A(H1N1)pdm09 pandemic highlighted the need for improved scientific knowledge to support better pandemic preparedness and seasonal influenza control. The Southern Hemisphere Influenza and Vaccine Effectiveness Research and Surveillance ( SHIVERS) project, a 5-year (2012-2016) multiagency and multidisciplinary collaboration, aimed to measure disease burden, epidemiology, aetiology, risk factors, immunology, effectiveness of vaccination and other prevention strategies for influenza and other respiratory infectious diseases of public health importance. Two active, prospective, population-based surveillance systems were established for monitoring influenza and other respiratory pathogens among those hospitalized patients with acute respiratory illness and those enrolled patients seeking consultations at sentinel general practices. In 2015, a sero-epidemiological study will use a sample of patients from the same practices. These data will provide a full picture of the disease burden and risk factors from asymptomatic infections to severe hospitalized disease and deaths and related economic burden. The results during the first 2 years (2012-2013) provided scientific evidence to (a) support a change to NZ's vaccination policy for young children due to high influenza hospitalizations in these children; (b) contribute to the revision of the World Health Organization's case definition for severe acute respiratory illness for global influenza surveillance; and (c) contribute in part to vaccine strain selection using vaccine effectiveness assessment in the prevention of influenza-related consultations and hospitalizations. In summary, SHIVERS provides valuable international platforms for supporting seasonal influenza control and pandemic preparedness, and responding to other emerging/endemic respiratory-related infections. [ABSTRACT FROM AUTHOR]

The World Health Organization's declaration of an imminent swine-origin influenza A pandemic in April 2009 triggered the global launch of national pandemic preparedness plans. An integral component of pandemic preparedness in many countries was the targeted use of antiviral therapy for containment, disease mitigation, and treatment. The 2009 pandemic marked the first pandemic during which influenza antivirals were available for global use. Although most national pandemic plans included provisions for antiviral treatment, these pre-determined protocols required frequent updating as more information became available about the virus, and its susceptibility to antiviral agents, the epidemiology of infection, and the population groups that were most susceptible to severe disease. National public health agencies in countries with both plans for use of antivirals and pre-existing stockpiles, including those in Japan, the United Kingdom, and the United States, operated distinctly different antiviral distribution and treatment programs from one another. In the 3 years following the pandemic, there is still little comparison of the diversity of national antiviral treatment policies and drug distribution mechanisms that were implemented, whether they had any mitigating effects and which might be most efficient. The purpose of this study is to outline roles of antiviral medicines in a pandemic period, provide insights into the diversity of antiviral treatment and distribution policies applied by selected countries between April 2009- July 2010, and to stimulate discussion on whether these policies remain appropriate for implementation in future pandemics. [ABSTRACT FROM AUTHOR]

The 2009 H1 N1 pandemic had considerable impact on risk perceptions, vaccination campaigns, and global health governance. In this context, risk communication issues have been probably the most puzzling and the least understood in retrospect. This article reviews the current knowledge on the following issues: risk and pandemic perceptions; vaccination perceptions and practices; rumors and rumor propagation; and health risk communication. It also highlights the research gaps in these areas that remain to be further explored in the future. [ABSTRACT FROM AUTHOR]

The World Health Organization has identified studies of the role of host genetics on susceptibility to severe influenza as a priority. A systematic review was conducted in June 2011 to summarise the evidence on the role of host genetics in susceptibility to influenza, and this report updates that previously published review. Animal studies suggest that genetic control of susceptibility to severe influenza in mice is complex and not controlled by a single locus, but there is encouraging evidence that some of the host genetic determinants of susceptibility to severe disease may be common across influenza subtypes. Although a number of studies on genetic susceptibility to influenza in humans have been published recently, all are underpowered and unreplicated, so do not provide robust statistical evidence of an association between the identified genetic loci and susceptibility. One study does however present convincing functional evidence for an important role for IFITM3 in susceptibility to severe influenza in mice, and some evidence that this may also be important in human A/H1N1/pdm2009 infection. [ABSTRACT FROM AUTHOR]

Background The United States was the second country to have a major outbreak of novel influenza A/H1N1 in what has become a new pandemic. Appropriate public health responses to this pandemic depend in part on early estimates of key epidemiological parameters of the virus in defined populations. Methods We use a likelihood-based method to estimate the basic reproductive number ( R0) and serial interval using individual level U.S. data from the Centers for Disease Control and Prevention (CDC). We adjust for missing dates of illness and changes in case ascertainment. Using prior estimates for the serial interval we also estimate the reproductive number only. Results Using the raw CDC data, we estimate the reproductive number to be between 2·2 and 2·3 and the mean of the serial interval (μ) between 2·5 and 2·6 days. After adjustment for increased case ascertainment our estimates change to 1·7 to 1·8 for R0 and 2·2 to 2·3 days for μ. In a sensitivity analysis making use of previous estimates of the mean of the serial interval, both for this epidemic (μ = 1·91 days) and for seasonal influenza (μ = 3·6 days), we estimate the reproductive number at 1·5 to 3·1. Conclusions With adjustments for data imperfections we obtain useful estimates of key epidemiological parameters for the current influenza H1N1 outbreak in the United States. Estimates that adjust for suspected increases in reporting suggest that substantial reductions in the spread of this epidemic may be achievable with aggressive control measures, while sensitivity analyses suggest the possibility that even such measures would have limited effect in reducing total attack rates. [ABSTRACT FROM AUTHOR]

Background Given the enormity of challenges involved in pandemic preparedness, design and implementation of effective and cost-effective public health policies is a major task that requires an integrated approach through engagement of scientific, administrative, and political communities across disciplines. There is ample evidence to suggest that modeling may be a viable approach to accomplish this task. Methods To demonstrate the importance of synergism between modelers, public health experts, and policymakers, the University of Winnipeg organized an interdisciplinary workshop on the role of models in pandemic preparedness in September 2008. The workshop provided an excellent opportunity to present outcomes of recent scientific investigations that thoroughly evaluate the merits of preventive, therapeutic, and social distancing mechanisms, where community structures, priority groups, healthcare providers, and responders to emergency situations are given specific consideration. Results This interactive workshop was clearly successful in strengthening ties between various disciplines and creating venues for modelers to effectively communicate with policymakers. The importance of modeling in pandemic planning was highlighted, and key parameters that affect policy decision-making were identified. Core assumptions and important activities in Canadian pandemic plans at the provincial and national levels were also discussed. Conclusions There will be little time for thoughtful and rapid reflection once an influenza pandemic strikes, and therefore preparedness is an unavoidable priority. Modeling and simulations are key resources in pandemic planning to map out interdependencies and support complex decision-making. Models are most effective in formulating strategies for managing public health crises when there are synergies between modelers, planners, and policymakers. [ABSTRACT FROM AUTHOR]