WHO : Influenza update - 17 December 2010 (Update 123)

Influenza update from WHO, excerpt :

" 17 December 2010 - Summary:

Since the last update, increasing influenza activity has been observed across parts of Europe, most notably in the United Kingdom, indicating the start of wintertime influenza epidemics in several countries. Influenza activity is also increasing in other temperate regions of the Northern Hemisphere, including East Asia and North America where there is evidence of the beginnings of the local winter influenza season. Worldwide, influenza A(H3N2), B, and H1N1 (2009) viruses are co-circulating with significant regional heterogeneity in the predominant circulating influenza viruses.

Countries in the temperate zone of the Northern Hemisphere

In the United Kingdom, the winter influenza epidemic is under way, particularly across England. Since mid to late November 2010 there have reports of increasing numbers of community outbreaks of influenza (due to both influenza H1N1 (2009) and B viruses), increasing proportions of sentinel respiratory specimens testing positive for influenza (56% in England during the second week of December; of which 67% were H1N1 (2009) and 33% were influenza B viruses), and increasing numbers of severe influenza cases requiring intensive care.

Available data indicate that the currently circulating strain of the H1N1 (2009) virus in the UK is epidemiologically and virologically similar to that observed last year during the influenza H1N1 2009 pandemic. All influenza viruses characterized to date have been found to be similar to the strains currently included in the seasonal influenza trivalent vaccine. (see below in Virologic Surveillance for details on the characterization of the virus) It is too early to tell what the overall impact of the current epidemic will be in the UK in comparison to the 2009 season."