Synopsis: During week 9 (February 24 – March 2, 2013), influenza activity remained elevated in the United States, but decreased in most areas.

o Viral Surveillance: Of 6,259 specimens tested and reported by collaborating laboratories, 1,074 (17.2%) were positive for influenza.

o Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and

influenza (P&I) was above the epidemic threshold.

o Influenza-Associated Pediatric Deaths: Six pediatric deaths were reported.

o Influenza-Associated Hospitalizations: A cumulative rate for the season of 38.5

laboratory-confirmed influenza-associated hospitalizations per 100,000 population was

reported. Of reported hospitalizations, over 51% were among adults 65 years and older.

o Outpatient Illness Surveillance: The proportion of outpatient visits for influenza-like illness (ILI) was 2.3%. This is above the national baseline of 2.2%. Seven of 10 regions reported ILI at or above region-specific baseline levels. Four states experienced moderate activity; 13 states and New York City experienced low activity; 33 states experienced minimal activity, and the District of Columbia had insufficient data.

o Geographic Spread of Influenza: Nine states reported widespread influenza activity;

Puerto Rico and 24 states reported regional influenza activity; the District of Columbia and 13 states reported local influenza activity; 4 states reported sporadic influenza activity; Guam reported no influenza activity, and the U.S. Virgin Islands did not report.

Stephen B. Thacker CDC Library collection

United States