Concurrent and cross-season protection of inactivated influenza vaccine against A(H1N1)pdm09 illness among young children: 2012-2013 case-control evaluation of influenza vaccine effectiveness

Vaccine. 2015 Jun 9;33(25):2917-21. doi: 10.1016/j.vaccine.2015.04.063. Epub 2015 Apr 26.

Abstract

In 2012-2013, we examined 1729 laboratory-confirmed A(H1N1)pdm09 influenza cases matched 1:1 with healthy controls and estimated influenza vaccine effectiveness (VE) for trivalent inactivated influenza vaccine (IIV3) to be 67% (95% confidence interval=58-74%) for ages 8 months to 6 years old. Among children aged 8-35 months old, VE for fully vaccinated children (73%, 60-81%) was significantly higher than VE for partially vaccinated children (55%, 33-70%). Significant cross-season protection from prior IIV3 was noted, including VE of 31% (8-48%) from IIV3 received in 2010-2011 against influenza illness in 2012--2013 without subsequent boosting doses.

Keywords: A(H1N1)pdm09 influenza; Children; Influenza vaccines; Prior vaccination; Vaccine effectiveness.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Case-Control Studies
  • Child
  • Child, Preschool
  • China
  • Cross Protection*
  • Female
  • Humans
  • Infant
  • Influenza A Virus, H1N1 Subtype / immunology*
  • Influenza Vaccines / immunology*
  • Influenza, Human / prevention & control*
  • Influenza, Human / virology
  • Male
  • Seasons
  • Vaccination
  • Vaccine Potency
  • Vaccines, Inactivated / immunology

Substances

  • Influenza Vaccines
  • Vaccines, Inactivated