Study shows decreased vaccine effectiveness of the seasonal influenza vaccine; ECDC Director urges to develop more effective vaccinesArchived


Preliminary results of European vaccine effectiveness study show decreased protective effect of the seasonal influenza vaccine in 2011/2012 season. ECDC Director Marc Sprenger calls for action.

On 12 April 2012, the Eurosurveillance journal published early estimates of the effectiveness of the 2011/2012 influenza vaccine, showing a rather low protective effect of the vaccine of around 43% in a study across eight European countries. This is about ten percentage points lower than what was found using the same methodology last season (2010/2011).

Authors of the study conclude that the low to moderate vaccine effectiveness observed in the study may be explained by a limited match between the circulating influenza A(H3) virus strains and the vaccine strain. The WHO has issued a recommendation for the next winter season (2012/2013) to change the A(H3N2) component to one that fits better with the viruses that have been circulating this season. Also, since protection from immunisation declines over time, a contributing factor in the decrease of vaccine effectiveness could be the late onset of the influenza season in 2012.  

These preliminary results come from the Influenza Monitoring Vaccine Effectiveness in Europe (I-MOVE). I-MOVE is a network funded by ECDC and coordinated by EpiConcept to monitor seasonal and pandemic influenza vaccine effectiveness. Final publication of the whole series of I-MOVE studies will provide full data on vaccine effectiveness of the seasonal influenza vaccine for the 2011/2012 season. 

“With vaccination remaining the single most effective protective measure against the flu, it is crucial for researchers and vaccine manufacturers to develop more effective vaccines,” urges ECDC Director Marc Sprenger. “As a watchdog, ECDC will continue to monitor vaccine effectiveness.”

See all updates on influenza vaccine effectiveness

Peer-Reviewed Publication

Effectiveness of influenza vaccine against influenza A in Europe in seasons of different A(H1N1)pdm09 and the same A(H3N2) vaccine components (2016–17 and 2017–18)

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