Immunogenicity of an inactivated monovalent 2009 H1N1 influenza vaccine in pregnant women.

Journal Article (Journal Article)

BACKGROUND: Although pregnant women are at increased risk of severe illness following influenza infection, there is relatively little information on the immunogenicity of influenza vaccines administered during pregnancy. METHODS: We conducted a clinical trial that enrolled 120 pregnant women in which participants were randomly assigned to receive an inactivated 2009 H1N1 influenza vaccine containing either 25 μg or 49 μg of hemagglutinin (HA) in a 2-dose series with a 21-day period between administration of the first and second doses. RESULTS: Following the first vaccination, HA inhibition (HAI) titers of ≥1:40 were detected in 93% (95% confidence interval [CI], 82%-98%) of subjects who received the 25-μg dose and 97% (95% CI, 88%-100%) of subjects receiving the 49-μg dose. In cord blood samples, HAI titers of ≥1:40 were found in 87% (95% CI, 73%-96%) of samples from the 25-μg dose group and in 89% (95% CI, 76%-96%) from the 49-μg dose group. Microneutralization titers tended to be higher than HAI titers, but the patterns of response were similar. CONCLUSIONS: In pregnant women, 1 dose of an inactivated 2009 H1N1 influenza vaccine containing 25 μg of HA elicited an antibody response typically associated with protection against influenza infection. Efficient transplacental transfer of antibody was also documented.

Full Text

Duke Authors

Cited Authors

  • Jackson, LA; Patel, SM; Swamy, GK; Frey, SE; Creech, CB; Munoz, FM; Artal, R; Keitel, WA; Noah, DL; Petrie, CR; Wolff, M; Edwards, KM

Published Date

  • September 15, 2011

Published In

Volume / Issue

  • 204 / 6

Start / End Page

  • 854 - 863

PubMed ID

  • 21849282

Pubmed Central ID

  • PMC3156926

Electronic International Standard Serial Number (EISSN)

  • 1537-6613

Digital Object Identifier (DOI)

  • 10.1093/infdis/jir440


  • eng

Conference Location

  • United States