Influenza and influenza-like illnesses in Poland in the epidemic season 2010/2011 according to the SENTINEL influenza surveillance system.

The aim of this study was to analyze data collected by the SENTINEL influenza surveillance system in Poland in the first post-pandemic season 2010/2011. The results include weeks 35/2010-17/2011. Physicians registered weekly number of influenza-like illnesses and collected specimens. Laboratory tests were done using PCR and/or real-time PCR or immunofluorescence. Laboratories also isolated the influenza virus. Influenza-like illness incidence amounted to 2802.7/100000. Weekly incidence ranged from 11.3/100000 to 232/100000. The most affected group was children 0-4 years. Influenza-like illness peak occurred between weeks 02/2011 and 11/2011. Influenza infections were confirmed in 34.9% of specimens. More cases were caused by influenza A, including A(H1N1)pdm09 than influenza B (59.9% vs. 40.1%). The isolated strains were similar to A/California/7/2009 or B/Brisbane/60/2008. Season 2010/2011 in Poland did not differ from the rest of Europe. Further improvement is necessary, especially in the area of specimen collection at the beginning of an epidemic season and carrying out the isolation of the influenza virus.