title: Pre- and postpandemic estimates of 2009 pandemic influenza A(H1N1) seroprotection to inform surveillance-based incidence, by age, during the 2013-2014 epidemic in Canada.
abstract: To understand the epidemic resurgence of influenza due to the 2009 pandemic influenza A(H1N1) strain (A[H1N1]pdm09) during the 2013-2014 influenza season, we compared age-related cross-sectional estimates of seroprotection before the pandemic (during 2009) and after the pandemic (during 2010 and 2013) to subsequent surveillance-based, laboratory-confirmed incidence of influenza due to A(H1N1)pdm09 in British Columbia, Canada. Prepandemic seroprotection was negligible except for very old adults (defined as adults aged ≥ 80 years), among whom 80% had seroprotection. Conversely, postpandemic seroprotection followed a U-shaped distribution, with detection in approximately 35%-45% of working-aged adults but in ≥ 70% of very old adults and young children, excluding children aged <5 years in 2013, among whom seroprotection again decreased to <20%. The incidence was 5-fold higher during 2013-2014, compared with 2010-2011, and was highest among children aged <5 years and working-aged adults, reflecting a mirror image of the age-based seroprotection data.
authors: British Columbia Centre for Disease Control University of British Columbia, Vancouver.
authors: Danuta M
authors: DM
authors: Skowronski
authors: British Columbia Centre for Disease Control.
authors: Catharine
authors: C
authors: Chambers
authors: British Columbia Centre for Disease Control University of British Columbia, Vancouver.
authors: Suzana
authors: S
authors: Sabaiduc
authors: British Columbia Centre for Disease Control University of British Columbia, Vancouver.
authors: Naveed Z
authors: NZ
authors: Janjua
authors: British Columbia Centre for Disease Control.
authors: Guiyun
authors: G
authors: Li
authors: British Columbia Centre for Disease Control University of British Columbia, Vancouver.
authors: Martin
authors: M
authors: Petric
authors: British Columbia Centre for Disease Control University of British Columbia, Vancouver.
authors: Mel
authors: M
authors: Krajden
authors: BC Biomedical Laboratories, Surrey.
authors: Dale
authors: D
authors: Purych
authors: National Microbiology Laboratory, Public Health Agency of Canada University of Manitoba, Winnipeg.
authors: Yan
authors: Y
authors: Li
authors: Institut National de Santé Publique du Québec Laval University, Quebec, Canada.
authors: Gaston
authors: G
authors: De Serres
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000276:immunology; D001955:British Columbia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D058872:Epidemics; D005260:Female; D006385:Hemagglutination Inhibition Tests / Q000379:methods; D006801:Humans; D015994:Incidence; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D012621:Seasons; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral
keywords: A(H1N1)pdm09; hemagglutination inhibition; incidence; influenza; seroprotection; serosurvey; surveillance