Estimating age‐specific cumulative incidence for the 2009 influenza pandemic: a meta‐analysis of A(H1N1)pdm09 serological studies from 19 countries

Influenza and Other Respiratory Viruses

Maria D. Van Kerkhove¹  Siddhivinayak Hirve¹  Artemis Koukounari²  Anthony W. Mounts¹ 

[1] Global Influenza Programme, WHO, Geneva, Switzerland;MRC Centre for Outbreak Analysis and Modelling, Imperial College London, London, UK

关键词: A(H1N1)pdm09;    cross‐reactive antibodies;    cumulative incidence;    H1N1pdm;    seroprevalence;   

DOI  :  10.1111/irv.12074

来源: Wiley

【 摘 要 】

Abstract

Background

The global impact of the 2009 influenza A(H1N1) pandemic (H1N1pdm) is not well understood.

Objectives

We estimate overall and age-specific prevalence of cross-reactive antibodies to H1N1pdm virus and rates of H1N1pdm infection during the first year of the pandemic using data from published and unpublished H1N1pdm seroepidemiological studies.

Methods

Primary aggregate H1N1pdm serologic data from each study were stratified in standardized age groups and evaluated based on when sera were collected in relation to national or subnational peak H1N1pdm activity. Seropositivity was assessed using well-described and standardized hemagglutination inhibition (HI titers ≥32 or ≥40) and microneutralization (MN ≥ 40) laboratory assays. The prevalence of cross-reactive antibodies to the H1N1pdm virus was estimated for studies using sera collected prior to the start of the pandemic (between 2004 and April 2009); H1N1pdm cumulative incidence was estimated for studies in which collected both pre- and post-pandemic sera; and H1N1pdm seropositivity was calculated from studies with post-pandemic sera only (collected between December 2009–June 2010).

Results

Data from 27 published/unpublished studies from 19 countries/administrative regions – Australia, Canada, China, Finland, France, Germany, Hong Kong SAR, India, Iran, Italy, Japan, Netherlands, New Zealand, Norway, Reunion Island, Singapore, United Kingdom, United States, and Vietnam – were eligible for inclusion. The overall age-standardized pre-pandemic prevalence of cross-reactive antibodies was 5% (95%CI 3–7%) and varied significantly by age with the highest rates among persons ≥65 years old (14% 95%CI 8–24%). Overall age-standardized H1N1pdm cumulative incidence was 24% (95%CI 20–27%) and varied significantly by age with the highest in children 5–19 (47% 95%CI 39–55%) and 0–4 years old (36% 95%CI 30–43%).

Conclusions

Our results offer unique insight into the global impact of the H1N1 pandemic and highlight the need for standardization of seroepidemiological studies and for their inclusion in pre-pandemic preparedness plans. Our results taken together with recent global pandemic respiratory-associated mortality estimates suggest that the case fatality ratio of the pandemic virus was approximately 0·02%.

【 授权许可】

Unknown   
© 2013 John Wiley & Sons Ltd