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: