Weekly influenza surveillance overview, 11 May 2012 - week 18

Surveillance report
The weekly/bi-weekly influenza surveillance overview is a collection of timely and relevant information regarding influenza activity in Europe. It provides key statistical data on a variety of issues including the following: sentinel surveillance of influenza-like illness and acute respiratory illness; virological surveillance; hospital surveillance of severe acute respiratory infection (SARI); mortality surveillance and qualitative reporting. An up-to-date report is available on Fridays.

Executive Summary

The reported national influenza trends indicate that influenza season is coming to its end in Europe.

The 2011–2012 influenza season started late and has been without any clear geographic progression. During week 18/2012, all countries except Slovakia reported low intensity.

Virological surveillance for week 18/2012 shows that of 154 sentinel specimens tested, 23 (14.9%) were positive for influenza virus. This proportion has been continuously decreasing over the past 10 weeks.

The A(H3N2) influenza viruses examined at the WHO Collaborating Centre in London show increasing evidence of an imperfect match between the circulating viruses and the current vaccine antigen. There has also been a significant rise in the proportion of B/Yamagata viruses among the B viruses detected this season. This supports the WHO and EMA recommendation to modify two components in the trivalent vaccines for the 2012/2013 Northern Hemisphere season.

Publication file

120511-SUR-WISO.pdf

English (2.75 MB - PDF)

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