Weekly influenza surveillance overview, 19 April 2013 - Week 15

Weekly reporting on influenza surveillance in Europe for the 2012–13 season started in week 40/2012 and will finish after week 20/2013. Active influenza transmission began around week 49/2012 with ILI/ARI rates peaking in almost all countries between weeks 52/2012 and 8/2013.• Twenty-five of 28 reporting countries indicated low-intensity transmission.• Decreasing or stable trends were reported by all reporting countries.• The proportion of influenza-positive sentinel specimens (34%) has continued to decrease since the peak observed in week 5/2013 (61%), in line with the lower numbers of specimens being tested. • Since week 40/2012, 47% of sentinel surveillance specimens testing positive for influenza virus have been type A and 53% type B. Of the influenza A viruses subtyped, the proportion of A(H1)pdm09 viruses was 64%.• Forty-four hospitalised, laboratory-confirmed influenza cases were reported by three countries.In all reporting countries, influenza activity continued to decline or had already returned to baseline levels. After more than three months of active transmission, a long period compared to other years, the 2012–13 influenza season is waning and moving towards its end.