Low vaccine effectiveness against influenza A(H3N2) virus among elderly people in Denmark in 2012/13--a rapid epidemiological and virological assessment

Euro Surveill. 2013 Feb 7;18(6):20397.

Abstract

In Denmark, the 2012/13 influenza season has been dominated by influenza A(H3N2). We estimated the vaccine effectiveness (VE) of the trivalent influenza vaccine by linking national registers in a test-negative case-control study of patients tested for influenza aged ≥65 years. The adjusted VE against laboratory-confirmed influenza A and B was -11% (95% CI: -41 to 14) and 69% (95% CI: 26 to 87), respectively. Genetic characterisation of the influenza A(H3N2) viruses indicated genetic drift, with seven substitutions at key antigenic sites.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Case-Control Studies
  • Denmark / epidemiology
  • Female
  • Hemagglutination Inhibition Tests
  • Humans
  • Influenza A Virus, H3N2 Subtype / genetics*
  • Influenza A Virus, H3N2 Subtype / immunology
  • Influenza A Virus, H3N2 Subtype / isolation & purification*
  • Influenza Vaccines / administration & dosage
  • Influenza Vaccines / immunology*
  • Influenza, Human / diagnosis
  • Influenza, Human / epidemiology
  • Influenza, Human / virology*
  • Male
  • Outcome Assessment, Health Care*
  • Population Surveillance
  • RNA, Viral / genetics
  • Real-Time Polymerase Chain Reaction
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Analysis, DNA
  • Sex Distribution

Substances

  • Influenza Vaccines
  • RNA, Viral