Planning for the next influenza H1N1 season: a modelling study

BMC Infectious Diseases

Research Article

Daniel Levy-Bruhl¹  Isabelle Bonmarin¹  Nathanael Lapidus²  Camille Pelat²  Fabrice Carrat³ 

[1] Département des maladies infectieuses, Institut de Veille Sanitaire, 94415, Saint-Maurice, France;Université Pierre et Marie Curie - Paris 6, UMR-S 707F-75012, Paris, France;Inserm U707, F-75012, Paris, France;Université Pierre et Marie Curie - Paris 6, UMR-S 707F-75012, Paris, France;Inserm U707, F-75012, Paris, France;Assistance Publique Hôpitaux de Paris, Hôpital Saint Antoine, F-75012, Paris, France;F Carrat, UMR-S 707, Faculté de médecine Saint Antoine, 27 rue Chaligny, 75571CEDEX 12, PARIS, France;

关键词: Influenza;    Influenza Vaccination;    H1N1 Virus;    Medical Visit;    H1N1 Infection;   

DOI  :  10.1186/1471-2334-10-301

 received in 2010-06-04, accepted in 2010-10-21,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundThe level of herd immunity before and after the first 2009 pandemic season is not precisely known, and predicting the shape of the next pandemic H1N1 season is a difficult challenge.MethodsThis was a modelling study based on data on medical visits for influenza-like illness collected by the French General Practitioner Sentinel network, as well as pandemic H1N1 vaccination coverage rates, and an individual-centred model devoted to influenza. We estimated infection attack rates during the first 2009 pandemic H1N1 season in France, and the rates of pre- and post-exposure immunity. We then simulated various scenarios in which a pandemic influenza H1N1 virus would be reintroduced into a population with varying levels of protective cross-immunity, and considered the impact of extending influenza vaccination.ResultsDuring the first pandemic season in France, the proportion of infected persons was 18.1% overall, 38.3% among children, 14.8% among younger adults and 1.6% among the elderly. The rates of pre-exposure immunity required to fit data collected during the first pandemic season were 36% in younger adults and 85% in the elderly. We estimated that the rate of post-exposure immunity was 57.3% (95% Confidence Interval (95%CI) 49.6%-65.0%) overall, 44.6% (95%CI 35.5%-53.6%) in children, 53.8% (95%CI 44.5%-63.1%) in younger adults, and 87.4% (95%CI 82.0%-92.8%) in the elderly.The shape of a second season would depend on the degree of persistent protective cross-immunity to descendants of the 2009 H1N1 viruses. A cross-protection rate of 70% would imply that only a small proportion of the population would be affected. With a cross-protection rate of 50%, the second season would have a disease burden similar to the first, while vaccination of 50% of the entire population, in addition to the population vaccinated during the first pandemic season, would halve this burden. With a cross-protection rate of 30%, the second season could be more substantial, and vaccination would not provide a significant benefit.ConclusionsThese model-based findings should help to prepare for a second pandemic season, and highlight the need for studies of the different components of immune protection.

【 授权许可】

CC BY   
© Carrat et al; licensee BioMed Central Ltd. 2010