Altered response to A(H1N1)pnd09 vaccination in pregnant women: a single blinded randomized controlled trial

PLoS One. 2013 Apr 18;8(4):e56700. doi: 10.1371/journal.pone.0056700. Print 2013.

Abstract

Background: Pregnant women were suspected to be at particular risk when H1N1pnd09 influenza became pandemic in 2009. Our primary objective was to compare the immune responses conferred by MF59®-adjuvanted vaccine (Focetria®) in H1N1pnd09-naïve pregnant and non-pregnant women. The secondary aims were to compare influences of dose and adjuvant on the immune response.

Methods: The study was nested in the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC2010) pregnancy cohort in 2009-2010 and conducted as a single-blinded block-randomised [1∶1∶1] controlled clinical trial in pregnant women after gestational week 20: (1) 7.5 µg H1N1pnd09 antigen with MF59-adjuvant (Pa7.5 µg); (2) 3.75 µg antigen half MF59-adjuvanted (Pa3.75 µg); (3) 15 µg antigen unadjuvanted (P15 µg); and in non-pregnant women receiving (4) 7.5 µg antigen full adjuvanted (NPa7.5 µg). Blood samples were collected at baseline, 3 weeks, 3 and 10 months after vaccination, adverse events were recorded prospectively.

Results: 58 pregnant women were allocated to Pa7.5 µg and 149 non-pregnant women were recruited to NPa7.5 µg. The sero-conversion rate was significantly increased in non-pregnant (NPa7.5 µg) compared with pregnant (Pa7.5 µg) women (OR = 2.48 [1.03-5.95], p = 0.04) and geometric mean titers trended towards being higher, but this difference was not statistically significant (ratio 1.27 [0.85-1.93], p = 0.23). The significant titer increase rate showed no difference between pregnant (Pa7.5 µg) and non-pregnant (NPa7.5 µg) groups (OR = 0.49 [0.13-1.85], p = 0.29).

Conclusion: Our study suggests the immune response to the 7.5 µg MF59-adjuvanted Focetria® H1N1pnd09 vaccine in pregnant women may be diminished compared with non-pregnant women.

Trial registration: ClinicalTrials.gov NCT01012557.

Publication types

  • Clinical Trial, Phase IV
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic
  • Adult
  • Female
  • Humans
  • Influenza A Virus, H1N1 Subtype / immunology*
  • Influenza Vaccines / administration & dosage*
  • Influenza Vaccines / adverse effects
  • Influenza Vaccines / immunology
  • Influenza, Human / prevention & control*
  • Polysorbates
  • Pregnancy
  • Pregnancy Complications, Infectious / prevention & control*
  • Prospective Studies
  • Seroepidemiologic Studies
  • Squalene
  • Vaccination

Substances

  • Adjuvants, Immunologic
  • Influenza Vaccines
  • MF59 oil emulsion
  • Polysorbates
  • focetria
  • Squalene

Associated data

  • ClinicalTrials.gov/NCT01012557

Grants and funding

The nested vaccine study is funded by Novartis Vaccines and Diagnostics GmbH, Marburg, Germany, who provided vaccines and funding as an unrestricted institutional grant. The Copenhagen Prospective Study on Asthma in Childhood is funded by private and public research funds (see www.copsac.com). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.