Overall the evidence base for the efficacy and effectiveness of newer and enhanced influenza vaccines appears limited at present, with a number of potentially relevant studies identified as ongoing.

This extended report aims to provide a broad overview of the epidemiology and virology of the 2009 pandemic in the European Union and European Economic Area countries. The main trends and information are derived from the analysis and interpretation of the epidemiological and virological data and other analyses provided to the European Centre for Disease Prevention and Control’s European Surveillance system through the European Influenza Surveillance Network.