Influenza vaccine effectiveness in adults 65 years and older, Denmark, 2015/16 - a rapid epidemiological and virological assessment

Euro Surveill. 2016;21(14). doi: 10.2807/1560-7917.ES.2016.21.14.30189.

Abstract

In Denmark, both influenza A(H1N1)pdm09 and influenza B co-circulated in the 2015/16 season. We estimated the vaccine effectiveness (VE) of the trivalent influenza vaccine in patients 65 years and older using the test-negative case-control design. The adjusted VE against influenza A(H1N1)pdm09 was 35.0% (95% confidence interval (CI): 11.1-52.4) and against influenza B 4.1% (95% CI: -22.0 to 24.7). The majority of influenza A(H1N1)pdm09 circulating in 2015/16 belonged to the new genetic subgroup subclade 6B.1.

Keywords: antigenic characterization; genetic drift; phylogeny; seasonal influenza; vaccine effectiveness.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Case-Control Studies
  • Denmark / epidemiology
  • Female
  • Humans
  • Influenza A Virus, H1N1 Subtype / genetics
  • Influenza A Virus, H1N1 Subtype / immunology*
  • Influenza A Virus, H1N1 Subtype / isolation & purification
  • Influenza Vaccines / administration & dosage*
  • Influenza, Human / epidemiology
  • Influenza, Human / immunology
  • Influenza, Human / prevention & control*
  • Influenza, Human / virology
  • Male
  • Outcome Assessment, Health Care
  • Pandemics / prevention & control*
  • Seasons
  • Sentinel Surveillance
  • Vaccination / statistics & numerical data*
  • Vaccine Potency*

Substances

  • Influenza Vaccines