Interim influenza vaccine effectiveness: A good proxy for final estimates in Spain in the seasons 2010-2014

Vaccine. 2015 Jun 26;33(29):3276-80. doi: 10.1016/j.vaccine.2015.03.051. Epub 2015 Apr 11.

Abstract

Introduction: The agreement between interim and final influenza vaccine effectiveness (VE) estimates would support the use of interim assessments as a proxy for final VE results to guide health authorities in influenza prevention. We aimed to compare interim/final VE estimates in Spain.

Methods: We used a test-negative case-control study (cycEVA) for 2010/11-2013/14 seasons. Sensitivity analyses were carried out by type/subtype of influenza virus and by target groups for vaccination.

Results: In general, interim estimates were higher compared to end-season estimates. Interim and final VE differences were higher for the target groups compared to all population. Subtype-specific interim/final VE estimates showed greater concordance (3-13%) than for any virus (7-24%).

Conclusion: In Spain, interim influenza VE estimates over 2010-2014 were a good proxy of the final protection of the vaccine. Interim and final estimates showed greater concordance for all population and if performed subtype-specific.

Keywords: Case-control studies; Influenza; Interim analysis; Sentinel networks; Vaccine effectiveness.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Case-Control Studies
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Influenza Vaccines / administration & dosage
  • Influenza Vaccines / immunology*
  • Influenza, Human / epidemiology*
  • Influenza, Human / prevention & control*
  • Male
  • Middle Aged
  • Sentinel Surveillance
  • Spain / epidemiology
  • Treatment Outcome
  • Vaccination / methods*
  • Young Adult

Substances

  • Influenza Vaccines