Age-Dependent Patterns of Infection and Severity Explaining the Low Impact of 2009 Influenza A (H1N1): Evidence From Serial Serologic Surveys in the Netherlands
Open Access
- 24 October 2011
- journal article
- research article
- Published by Oxford University Press (OUP) in American Journal of Epidemiology
- Vol. 174 (11), 1307-1315
- https://doi.org/10.1093/aje/kwr245
Abstract
Despite considerable research efforts in specific subpopulations, reliable estimates of the infection attack rates and severity of 2009 influenza A (H1N1) in the general population remain scarce. Such estimates are essential to the tailoring of future control strategies. Therefore, 2 serial population-based serologic surveys were conducted, before and after the 2009 influenza A (H1N1) epidemic, in the Netherlands. Random age-stratified samples were obtained using a 2-stage cluster design. Participants donated blood and completed a questionnaire. Data on sentinel general practitioner-attended influenza-like illness and nationwide hospitalization and mortality were used to assess the severity of infection. The estimated infection attack rates were low in the general population (7.6%, 95% confidence interval: 3.6, 11) but high in children aged 5–19 years (35%, 95% confidence interval: 25, 45). The estimated hospitalization and mortality rates per infection increased significantly with age (5–19 years: 0.042% and 0.00094%, respectively; 20–39 years: 0.12% and 0.0025%; 40–59 years: 0.68% and 0.032%; 60–75 years: >0.81% and >0.068%). The high infection attack rate in children and the very low attack rate in older adults, together with the low severity of illness per infection in children but substantial severity in older adults, produced an epidemic with a low overall impact.Keywords
This publication has 34 references indexed in Scilit:
- The Infection Attack Rate and Severity of 2009 Pandemic H1N1 Influenza in Hong KongClinical Infectious Diseases, 2010
- Reflections on Pandemic (H1N1) 2009 and the International ResponsePLoS Medicine, 2010
- Seroepidemiology of pandemic influenza A (H1N1) 2009 virus infections in Pune, IndiaBMC Infectious Diseases, 2010
- Studies Needed to Address Public Health Challenges of the 2009 H1N1 Influenza Pandemic: Insights from ModelingPLoS Medicine, 2010
- Optimizing infectious disease interventions during an emerging epidemicProceedings of the National Academy of Sciences of the United States of America, 2009
- The Severity of Pandemic H1N1 Influenza in the United States, from April to July 2009: A Bayesian AnalysisPLoS Medicine, 2009
- Cross-Reactive Antibody Responses to the 2009 Pandemic H1N1 Influenza VirusNew England Journal of Medicine, 2009
- Pathogenesis and Transmission of Swine-Origin 2009 A(H1N1) Influenza Virus in FerretsScience, 2009
- In vitro and in vivo characterization of new swine-origin H1N1 influenza virusesNature, 2009
- Pandemic Potential of a Strain of Influenza A (H1N1): Early FindingsScience, 2009