Hemagglutination Inhibition Antibody Titers as a Correlate of Protection Against Seasonal A/H3N2 Influenza Disease

• Published in: Open forum infectious diseases Vol. 2; no. 2; p. ofv067
• Main Authors: Benoit, Anne, Beran, Jiri, Devaster, Jeanne-Marie, Esen, Meral, Launay, Odile, Leroux-Roels, Geert, McElhaney, Janet E., Oostvogels, Lidia, van Essen, Gerrit A., Gaglani, Manjusha, Jackson, Lisa A., Vesikari, Timo, Legrand, Catherine, Tibaldi, Fabian, Innis, Bruce L., Dewé, Walthère
• Format: Journal Article
• Language: English
• Published: United States Oxford University Press 01.04.2015
• Subjects: Influenza; Major; influenza; vaccine; modeling; serologic correlates; A/H3N2
• ISSN: 2328-8957; 2328-8957
• DOI: 10.1093/ofid/ofv067

Background.  To investigate the relationship between hemagglutinin-inhibition (HI) antibody levels to the risk of influenza disease, we conducted a correlate of protection analysis using pooled data from previously published randomized trials. Methods.  Data on the occurrence of laboratory-confirmed influenza and HI levels pre- and postvaccination were analyzed from 4 datasets: 3 datasets included subjects aged <65 years who received inactivated trivalent influenza vaccine (TIV) or placebo, and 1 dataset included subjects aged ≥65 years who received AS03-adjuvanted TIV (AS03-TIV) or TIV. A logistic model was used to evaluate the relationship between the postvaccination titer of A/H3N2 HI antibodies and occurrence of A/H3N2 disease. We then built a receiver-operating characteristic curve to ide.jpegy a potential cutoff titer between protection and no protection. Results.  The baseline odds ratio of A/H3N2 disease was higher for subjects aged ≥65 years than <65 years and higher in seasons of strong epidemic intensity than moderate or low intensity. Including age and epidemic intensity as covariates, a 4-fold increase in titer was associated with a 2-fold decrease in the risk of A/H3N2 disease. Conclusions.  The modeling exercise confirmed a relationship between A/H3N2 disease and HI responses, but it did not allow an evaluation of the predictive power of the HI response.