While the levels of influenza-like-activity have begun to drop across much of North America, some areas of the Northern Hemisphere have yet to see their seasonal peak.
Some excerpts from the week 5 report:
Weekly reporting on influenza surveillance in Europe for the 2012–13 season started in week 40/2012 and active influenza transmission began around week 49/2012, approximately six weeks earlier than in the 2011/2012 season.
- In week 5/2013, 19 countries reported concomitantly high/medium-intensity transmission and wide geographic spread. Twenty-two countries reported increasing trends in influenza activity.
- In week 5/2013, the proportion of influenza-positive sentinel specimens continued to increase, reaching 55%.
- Since week 40/2012, the proportions of influenza A and B viruses have remained similar (51% vs. 49%), but among type A viruses, the percentage of A(H1)pdm09 has continued to increase (64%), compared to 52% in week 2/2012.
- For week 5/2013, of 71 hospitalised laboratory-confirmed influenza cases reported by six countries, 33 (46%) tested positive for influenza A viruses and 38 (54%) for type B viruses.
On 8 February, ECDC published its annual risk assessment for seasonal influenza 2012–2013, based on data up to week 3/2013. The risk assessment is available here.
Influenza activity continued to rise across Europe in week 5/2013. In a few countries, the epidemics seemed to have passed their peaks, although some countries experienced a resurgence of ILI rates.
The ECDC is now producing a weekly Infographic that provides a quick review of the flu season in Europe.
Unlike North America, which this year has seen a flu season dominated by H3N2 Influenza A virus, in Europe the flu this season is nearly equally divided between influenza A & B.
And among the influenza A strains identified, 64% have been the 2009 H1N1 strain, and 36% H3N2. This year, In North America, H1N1 has been a relatively minor player.
Elsewhere around the world, we are seeing flu on the rise in Hong Kong as well.