Effectiveness of A(H1N1)pdm09 influenza vaccine in adults recommended for annual influenza vaccination

PLoS One. 2013 Jun 20;8(6):e66125. doi: 10.1371/journal.pone.0066125. Print 2013.

Abstract

Introduction: Because of variability in published A(H1N1)pdm09 influenza vaccine effectiveness estimates, we conducted a study in the adults belonging to the risk groups to assess the A(H1N1)pdm09 MF59-adjuvanted influenza vaccine effectiveness.

Methods: VE against influenza and/or pneumonia was assessed in the cohort study (n>25000), and vaccine effectiveness against laboratory-confirmed A(H1N1)pdm09 influenza was assessed in a matched case-control study (16 pairs). Odds ratios (OR) and their 95% confidence intervals (95% CI) were calculated by using multivariate logistic regression; vaccine effectiveness was estimated as (1-odds ratio)*100%.

Results: Vaccine effectiveness against laboratory-confirmed A(H1N1)pdm09 influenza and influenza and/or pneumonia was 98% (84-100%) and 33% (2-54%) respectively. The vaccine did not prevent influenza and/or pneumonia in 18-59 years old subjects, and was 49% (16-69%) effective in 60 years and older subjects.

Conclusions: Even though we cannot entirely rule out that selection bias, residual confounding and/or cross-protection has played a role, the present results indicate that the MF59-adjuvanted A(H1N1)pdm09 influenza vaccine has been effective in preventing laboratory-confirmed A(H1N1)pdm09 influenza and influenza and/or pneumonia, the latter notably in 60 years and older subjects.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic / administration & dosage
  • Adolescent
  • Adult
  • Case-Control Studies
  • Female
  • Humans
  • Influenza A Virus, H1N1 Subtype / immunology*
  • Influenza Vaccines / administration & dosage
  • Influenza Vaccines / immunology*
  • Influenza, Human / immunology
  • Influenza, Human / prevention & control*
  • Influenza, Human / virology
  • Male
  • Middle Aged
  • Netherlands
  • Polysorbates / administration & dosage
  • Retrospective Studies
  • Squalene / administration & dosage
  • Vaccination*
  • Young Adult

Substances

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

Grant support

The work was supported by the University of Groningen, University Medical Center Groningen, the Netherlands. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.