Weekly influenza surveillance overview, 2 - 8 January 2012 - Week 1

During week 1/2012, low influenza activity was notified by all 26 of the 27 countries reporting (Malta reported medium activity) with five countries (Italy, Netherlands, Norway, Spain and Sweden) now indicating local or regional spread.
Of 625 sentinel specimens collected and tested during week 1/2012, 81 (13%) were positive for influenza viruses. Though less than the percentage reported in week 52 (which will have been affected by the Christmas/New Year holiday), it shows an upward progression since last month.
Of 632 influenza A viruses sub-typed from sentinel and non-sentinel sources since week 40/2011, 588 (93%) were of the H3 subtype. No antiviral resistance has been detected as yet.
Since week 40/2011, 157 severe acute respiratory infection (SARI) cases have been reported by six countries. Fifty-five of them were confirmed influenza-positive cases and of those typed or sub-typed 14 were A(H1N1)pdm09, 17 were A(H3) and four were influenza B viruses.
Influenza transmission is showing some progression in Europe this season and is currently dominated by A(H3N2) viruses.