The 2011-2012 influenza season started later than in recent seasons and has been without any clear
geographic progression. Noteworthy this week:
• Like last week, medium or high intensity was reported by 17 countries; 13 countries reported increasing
trends. Bulgaria and Italy have reported decreasing trends for three weeks in a row and thus are the
first two countries that have peaked in Europe this season.
• Of 1 712 sentinel specimens tested, 884 (51.6%) were positive for influenza virus, a similar percentage
as in the two previous weeks. Of these sentinel viruses, 88.9% were type A and 11.1% were type B.
This is the highest percentage for B this season.