Weekly influenza surveillance overview, March 18, 2011 - Week 10

The majority of European countries reported decreasing ILI/ARI trends. Most countries reported some regional or sporadic influenza activity.
In week 10/2011, the proportion of influenza B viruses (58.9%) in sentinel specimens was higher than the percentage of influenza A viruses (41.1%).
Thirty-two (3.0%) of influenza A(H1) 2009 viruses tested for susceptibility were resistant to oseltamivir but remained sensitive for zanamivir. All the resistant viruses carried the H275Y mutation.
In week 10/2011, five countries reported 39 cases of all-cause severe acute respiratory infection (SARI) and 43 hospitalised confirmed influenza cases. The latter were mostly (68.4%) due to influenza A(H1N1)2009 virus infection.