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Comparative Study
. 2012;7(3):e33048.
doi: 10.1371/journal.pone.0033048. Epub 2012 Mar 22.

Pandemic influenza A H1N1 2009 infection versus vaccination: a cohort study comparing immune responses in pregnancy

Barbra M Fisher  1 , Janice Van Bockern, Jan Hart, Anne M Lynch, Virginia D Winn, Ronald S Gibbs, Adriana Weinberg
Affiliations
Comparative Study

Pandemic influenza A H1N1 2009 infection versus vaccination: a cohort study comparing immune responses in pregnancy

Barbra M Fisher et al. PLoS One. 2012.

Abstract

Background: With the emergence of H1N1 pandemic (pH1N1) influenza, the CDC recommended that pregnant women be one of five initial target groups to receive the 2009 monovalent H1N1 vaccine, regardless of prior infection with this influenza strain. We sought to compare the immune response of pregnant women to H1N1 infection versus vaccination and to determine the extent of passive immunity conferred to the newborn.

Methods/findings: During the 2009-2010 influenza season, we enrolled a cohort of women who either had confirmed pH1N1 infection during pregnancy, did not have pH1N1 during pregnancy but were vaccinated against pH1N1, or did not have illness or vaccination. Maternal and umbilical cord venous blood samples were collected at delivery. Hemagglutination inhibition assays (HAI) for pH1N1 were performed. Data were analyzed using linear regression analyses. HAIs were performed for matched maternal/cord blood pairs for 16 women with confirmed pH1N1 infection, 14 women vaccinated against pH1N1, and 10 women without infection or vaccination. We found that pH1N1 vaccination and wild-type infection during pregnancy did not differ with respect to (1) HAI titers at delivery, (2) HAI antibody decay slopes over time, and (3) HAI titers in the cord blood.

Conclusions: Vaccination against pH1N1 confers a similar HAI antibody response as compared to pH1N1 infection during pregnancy, both in quantity and quality. Illness or vaccination during pregnancy confers passive immunity to the newborn.

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Conflict of interest statement

Competing Interests: RG is a consultant for pharmacosurveillance (effect of H1N1 vaccine on pregnancy outcomes) for Novartis Diagnostics and Therapeutics. All other authors have declared that no competing interests exist. This does not alter the authors' adherence to all the PLoS ONE policies on sharing data and materials.

Figures

Figure 1
Figure 1. Geometric mean titers for the cohort.
Figure 2
Figure 2. Persistence of maternal antibodies to pandemic H1N1 influenza following wild-type infection or vaccination.
Figure 3
Figure 3. Transplacental transfer of antibodies to pandemic H1N1 influenza following wild-type infection or vaccination.
See this image and copyright information in PMC

Comment in

References

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