Weekly influenza surveillance overview, week 4 2014

​For week 4/2014:
• Influenza activity continued to increase in most reporting countries throughout the EU/EEA region. ILI rates were similar or higher than those for 2013 in Bulgaria, Greece, Portugal and Spain.
• Proportions of sentinel A(H1)pdm09 and A(H3) viruses varied substantially between countries. Very few influenza B viruses were detected.
• In five reporting countries, 87% of hospitalised laboratory-confirmed influenza cases were related to infection with A(H1)pdm09 virus.

Influenza activity has continued to increase in almost all EU/EEA countries, with varying proportions of A(H1)pdm09 and A(H3) among countries.