Format

Send to

Choose Destination
Pediatr Infect Dis J. 2004 Sep;23(9):852-6.

Measuring antibody responses to a live attenuated influenza vaccine in children.

Author information

1
MedImmune Vaccines, Mountain View, CA, USA.

Abstract

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 H1N1 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 H1N1 antibody responses after vaccination of children with the LAIV and may provide a better correlate of clinical protection provided by the LAIV.

PMID:
15361726
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Wolters Kluwer
Loading ...
Support Center