Measuring Antibody Responses to a Live Attenuated Influenza Vaccine in Children

Autor: Iksung Cho, Julie Cordova, Keith S. Reisinger, Min-Shi Lee, Marilyn J. August, George Kemble, Lopa Adhikary, Robert E. Walker, Kutubuddin Mahmood, Paul M. Mendelman
Rok vydání: 2004
Předmět:
Zdroj: Pediatric Infectious Disease Journal. 23:852-856
ISSN: 0891-3668
Popis: Background: Hemagglutination inhibition (HAI) assay is the standard method for evaluating inactivated influenza vaccines, but no standard assay has been established for evaluating live attenuated influenza vaccines (LAIV). LAIV containing A/Beijing/262/ 95(H1N1) induced low serum HAI antibody responses to the antigenic variant, A/New Caledonia/20/99(H1N1) in a serologic study but provided protection against the A/New Caledonia-like viruses in a community study. Neutralization and HAI assays were compared by measuring H NN cross-reactive antibody responses to the LAIV in children. Methods: Sera were collected from 50 children 1-8 years of age before vaccination and 4-6 weeks after each dose of the LAIV. Antibody titers to the 3 vaccine viruses were measured by the HAI assay, whereas antibody titers against the H1N1 vaccine virus (A/Beijing/262/95) and 2 H1N1 antigenic variants (A/Shenzhen/ 227/95 and A/New Caledonia/20/99) were measured by the HAI and neutralization assays. Results: Initially seronegative participants were more likely to develop HAI seroconversion responses to the 3 vaccine viruses than the baseline seropositive participants (77% versus 14% for H1N1, 100% versus 20% for H3N2, 100% versus 19% for B, P < 0.01, Fisher's exact test). For the H1N1 cross-reactive antibody responses, seroconversion rates measured by the neutralization assay were significantly higher than those measured by the HAI assay (95% versus 78%, P = 0.0485 for A/Beijing/262/95; 75% versus 24%, P < 0.0001 for A/Shenzhen/227/95; 51% versus 5%, P < 0.0001 for A/New Caledonia/20/99). Conclusions: The neutralization assay was more sensitive than the HAI assay for measuring H1NI antibody responses after vaccination of children with the LAIV and may provide a better correlate of clinical protection provided by the LAIV.
Databáze: OpenAIRE