Summary, week 1/2013

Levels of influenza activity in countries in the WHO European Region are heterogeneous, with widespread activity mainly in the western and northern parts of the Region and no or sporadic activity in the eastern part, but a gradual increase overall. Influenza A(H1N1)pdm09, A(H3N2) and type B viruses continue to co-circulate, but the proportion of A(H1N1)pdm09 relative to A(H3N2) is increasing. The number of reported hospitalizations due to severe acute respiratory infection (SARI) remains stable, with 8% of cases being associated with influenza detection.