Weekly influenza surveillance overview, 6-12 February 2012 - Week 6
Medium influenza activity was reported by 13 countries and increasing trends by 17 countries.
Among 1 718 sentinel specimens, the positivity percentage for influenza was 46%, which is around the same as in week 5. This was the first week this season without a clear increase (apart from the Christmas period). There were significant differences across countries (with more than 30 sentinel specimens analysed) ranging from 16–84%.
Of the 2 025 influenza viruses detected from sentinel and non-sentinel sources during week 6/2012, 96% were type A and 4% were type B. Of the 1 015 influenza A viruses subtyped, 99% were A(H3) and 1% were A(H1)pdm09.
Since the start of the season, 493 SARI cases have been reported by six countries, 300 of which were related to influenza. Of the cases with influenza typing/subtyping results available, 85% were associated with A(H3), 9% with A(H1)pdm09 and 6% with B viruses.
No resistance to the neuraminidase inhibitors (oseltamivir and zanamivir) has been reported so far this season.
Influenza activity continued to increase in week 6, though with significant variation in timing across Europe and no clear geographic progression this season. The dominant virus remains A(H3).
Executive summary
Influenza activity continued to increase in week 6, though with significant variation in timing across Europe and no clear geographic progression this season. The dominant virus remains A(H3). Main surveillance data is now available in ECDC’s Weekly Influenza Surveillance Overview.
Thirteen countries reported medium activity, with an increasing trend in 17 countries. Type A is still dominating the season with 96% of the 2 025 influenza viruses detected from sentinel and non-sentinel sources during week 6/2012, while the remaining 4% were type B. Of the 1 015 influenza A viruses subtyped, 99% were A(H3) and 1% were A(H1)pdm09. So far no resistance to the neuraminidase inhibitors (oseltamivir and zanamivir) has been reported.
Apart from the Christmas and New Year holiday period, this was the first week this season without a clear increase in sentinel specimens (1718). The positivity percentage for influenza was 46%, which is around the same as in week 5. There were significant differences across countries (with more than 30 sentinel specimens analysed) ranging from 16–84%.
Since the start of the season, 493 severe influenza (SARI) cases have been reported by six countries, 300 of which were related to influenza. Of the cases with influenza typing/subtyping results available, 85% were associated with A(H3), 9% with A(H1)pdm09 and 6% with B viruses.
