title: Estimation of the association between antibody titers and protection against confirmed influenza virus infection in children.
abstract: Antibody titers measured by hemagglutination inhibition (HAI) correlate with protection against influenza virus infection and are used to specify criteria for vaccine licensure. In a randomized, controlled trial of seasonal influenza vaccination in 773 children aged 6-17 years, we estimated that HAI titers of 1:40 against A(H1N1)pdm09 and B(Victoria lineage) were associated with 48% (95% confidence interval [CI], 30%-62%) and 55% (95% CI, 32%-70%) protection against PCR-confirmed infection with each strain. Our analysis accounted for waning in antibody titers over time, and could be particularly useful in settings where influenza activity is delayed or prolonged relative to measurement of antibody titers.
authors.affiliation: School of Public Health.
authors.forename: Sophia
authors.initials: S
authors.lastname: Ng
authors.forename: Vicky J
authors.initials: VJ
authors.lastname: Fang
authors.forename: Dennis K M
authors.initials: DK
authors.lastname: Ip
authors.forename: Kwok-Hung
authors.initials: KH
authors.lastname: Chan
authors.forename: Gabriel M
authors.initials: GM
authors.lastname: Leung
authors.forename: J S Malik
authors.initials: JS
authors.lastname: Peiris
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Cowling
mesh_terms: D000293:Adolescent; D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology*; D002648:Child; D006385:Hemagglutination Inhibition Tests / Q000379:methods; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D009981:Influenza B virus / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D007251:Influenza, Human / Q000097:blood / Q000276:immunology* / Q000517:prevention & control* / Q000821:virology; D016016:Proportional Hazards Models
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines
keywords: antibody; children; immunity; influenza; vaccine
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