7 Feb 2013

Low vaccine effectiveness against influenza A(H3N2) virus among elderly people in Denmark in 2012/13 – a rapid epidemiological and virological assessment (Euro Surveill., abstract, edited)

[Source: Eurosurveillance, full text: (LINK). Abstract, edited.]

Eurosurveillance, Volume 18, Issue 6, 07 February 2013

Rapid communications

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

K Bragstad1,2, H D Emborg2,3, T Kølsen Fischer1, M Voldstedlund3, S Gubbels 3, B Andersen1, K Mølbak3, T G Krause ()3

  1. National Influenza Centre, Department of Microbiological Diagnostics and Virology, Statens Serum Institut, Copenhagen
  2. These authors contributed equally to the work and share first authorship
  3. Department of Infectious Disease Epidemiology, Statens Serum Institut, Copenhagen

Citation style for this article: Bragstad K, Emborg HD, Kølsen Fischer T, Voldstedlund M, Gubbels S, Andersen B, Mølbak K, Krause TG. 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;18(6):pii=20397. Available online: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=20397
Date of submission: 29 January 2013


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.

-

------