Influenza vaccine effectiveness
Vaccine effectiveness is an estimate of the likelihood that a vaccine prevents influenza infection when used in everyday practice. To establish how well influenza vaccines work each season, influenza vaccine effectiveness is measured in observational studies.
In EU/EEA, the ECDC founded network I-MOVE (Influenza - Monitoring Vaccine Effectiveness) is responsible for measuring the vaccine effectiveness.
The studies provide country-specific and pooled effectiveness results for influenza vaccines authorised and used in EU/EEA Member States. The results are presented by age group and by different influenza vaccine strain. Since the influenza season 2012/13 results from observational studies assessing LAIV (Live attenuated influenza vaccine) used in children are available.
In general, a vaccine effectiveness of ~30-60% has been estimated for the three different influenza A (H1N1, H3N2) and B strains (Victoria or Yamagata lineages).
In Europe influenza vaccine effectiveness studies were initiated by ECDC and have been followed systematically since the influenza season 2008/2009.
Table: Overview of articles on effectiveness of inactivated seasonal influenza vaccines estimated in multi-center studies conducted by the I-MOVE network in Europe
The live attenuated influenza vaccines used in paediatric programmes in Finland, Germany and United Kingdom have also been evaluated:
ECDC Study protocols for influenza vaccine effectiveness studies
Protocols for case-control studies to measure influenza vaccine effectiveness in the EU and EEA Member States
Protocols for cohort database studies to measure influenza vaccine effectiveness in the EU and EEA Member States
See all updates on vaccine defectiveness
Co-circulation of influenza a(H1N1)pdm09 and influenza a(H3N2) viruses, world health organization (WHO) european region, october 2018 to february 2019