Biphasic Waning of Hemagglutination Inhibition Antibody Titers After Influenza Vaccination in Children

Abstract We explored the potential for a biphasic pattern in waning of antibody titers after influenza vaccination. We collected blood samples in a randomized controlled trial of influenza vaccination in children and tested them with hemagglutination inhibition assays for influenza A(H3N2) and influenza B/Victoria lineage. Using piecewise log-linear mixed-effects models, we found evidence for a faster initial waning of antibody titers for the first 1–2 years after vaccination and then slower longer-term declines. Children with higher postvaccination titers had faster antibody decay. We explored the biphasic waning of hemagglutination inhibition antibody titers after influenza vaccination in children. We found evidence for a faster waning for the first 1–2 years and then slower longer-term declines. Children with higher postvaccination titers had faster antibody decay.