SUMMARY

This paper summarizes influenza activity in the European Union/European Economic Area (EU/EEA) in 2012–2013. The influenza season 2012–2013 in Europe lasted from early December to late April. Overall the severity of the season could be described as moderate, based on the ILI/ARI consultation rates and the percentage of sentinel specimens positive for influenza compared to previous seasons. Both influenza A and B viruses circulating accounted for 47% and 53 % of positive sentinel specimens, respectively, with both A(H1) and A(H3) varying for dominance. Compared to outpatients, the proportion of laboratory-confirmed influenza hospitalized cases infected by A(H1N1)pdm09 was significantly higher in middle-aged patients (33 % vs. 17%, χ2=66·6, P<0·01). Despite a relatively good match between vaccine and circulating strains, vaccine effectiveness was estimated to be moderate. Key words: Infectious disease epidemiology, influenza (seasonal), respiratory infections, surveillance system. Influenza is an acute respiratory disease of major pub-lic health importance that has been causing epidemics and pandemics of human disease for centuries, wit