Influenza resources for health professionals

Influenza activity summary, Week 6

• During Week 6, there was sporadic influenza activity across most of Alberta. 31 influenza A (H3) isolates, 1 influenza (H1N1) isolate, and 2 influenza B isolates were lab-confirmed during Week 6. There were no influenza outbreaks reported. Influenza activity so far this season remains low compared to previous seasons. View map 
• ILI was diagnosed in 0.30% of patients seen by sentinel physicians, which is higher than the previous week (0.14%) and below the seasonal average (1.02%).
• The number of influenza cases clinically diagnosed in physician offices increased slightly from the previous week and numbers remain below those seen in previous seasons. The number of cases diagnosed by emergency departments was similar to the previous week, and remains similar to the 2008/09 season.
• The percent positive rate for influenza in respiratory virus specimens was 7.5% which is lower than the previous week. Respiratory syncytial virus (RSV) and rhino/enterovirus made up the majority of respiratory virus detections this week. The number of influenza detections is lower than seen in previous seasons for Week 6. View graph 
• The 2011/12 influenza vaccine protects against H3N2 (A/Perth/16/2009), H1N1 (A/California/7/2009), and influenza B (B/Brisbane/60/2008, Victoria lineage). To date all influenza A H3N2 and H1N1 strains characterized by the National Microbiology Laboratory are covered by the vaccine. Approximately 58% of the influenza B strains characterized are covered by the vaccine, while 42% are not (B/Wisconsin/01/2010, Yagamata lineage).
• Since September 1, 2011, 242 influenza isolates have been tested for antiviral resistance. None exhibited resistance to oseltamivir or zanamivir. Nearly all strains tested were resistant to amantadine. This is similar to the previous season, where oseltamivir and zanamivir resistance rates remained low and amantadine resistance rates remained very high. View graph 
• View the weekly surveillance report