The community impact of the 2009 influenza pandemic in the WHO European region: a comparison with historical seasonal data from 28 countries.

Background The world has recently experienced the first influenza pandemic of the 21st century that lasted 14 months from June 2009 to August 2010. This study aimed to compare the timing, geographic spread and community impact during the winter wave of influenza pandemic A (H1N1) 2009 to historical influenza seasons in countries of the WHO European region.