2009-2010 Influenza Season Week 43 ending October 31, 2009

During week 43 (October 25-31, 2009), influenza activity remained elevated in the U.S.

  • 5,258 (37.2%) specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division were positive for influenza.
  • Over 99% of all subtyped influenza A viruses being reported to CDC were 2009 influenza A (H1N1) viruses.
  • The proportion of deaths attributed to pneumonia and influenza (P&I) was above the epidemic threshold.
  • Eighteen influenza-associated pediatric deaths were reported. Fifteen of these deaths were associated with 2009 influenza A (H1N1) virus infection and three were associated with an influenza A virus for which the subtype was undetermined.
  • The proportion of outpatient visits for influenza-like illness (ILI) was above the national baseline. All 10 regions reported ILI above region-specific baseline levels.
  • Forty-eight states reported geographically widespread influenza activity, two states reported regional influenza activity, the District of Columbia reported local influenza activity; Puerto Rico and Guam reported sporadic influenza activity, and the U.S. Virgin Islands did not report.