Weekly influenza surveillance overview, 21 – 27 Nov 2011 (week 47)

During week 47/2011, low influenza activity was notified by all 28 countries reporting.
Of 561 sentinel specimens tested during week 47/2011, six (1.1%) were positive for influenza virus. Of the 43 influenza virus detections in sentinel specimens since week 40/2011, 69.8% were type A and 30.2% were type B viruses. Of 22 influenza A viruses subtyped, 13.6% were A(H1)pdm09 and 86.4% were A(H3) viruses.
Since week 40/2011, 38 SARI cases have been reported by four countries. Twelve of these patients were confirmed as influenza positive.
Eight weeks after the beginning of the surveillance season for influenza in the Northern Hemisphere, there has been no evidence of sustained transmission in EU/EAA countries, but more influenza viruses are being detected.