Weekly influenza surveillance overview, April 27 2012 - Week 16
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; 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 drawing to a close all across Europe.
The 2011–2012 influenza season started late and has been without any clear geographic progression. During week 16/2012, low intensity was reported in all countries except Slovakia, which reported medium intensity. Decreasing or stable trends were reported by all countries except the UK (Northern Ireland) which reported increasing trends.
Virological surveillance for week 16/2012 shows that of 315 sentinel specimens tested, 76 (24.1%) were positive for influenza virus, thus continuing the downward trend in percentage since week 8. As expected towards the end of the season, the proportion of B viruses in comparison with A viruses has increased substantially. The percentage of influenza-positive specimens and the epidemiological trends show that influenza viruses are still circulating in a number of EU countries.
For latest information on genetic and antigenic influenza virus characterisation in this European season from ECDC-affiliated countries, see the March 2012 report of the Community Network of Reference Laboratories for Human Influenza in Europe.
