Weekly U.S. Influenza Surveillance Report | Seasonal Influenza (Flu) | CDC

Weekly U.S. Influenza Surveillance Report | Seasonal Influenza (Flu) | CDC





Full report also available as PDF

Synopsis:

During week 12 (March 20-26, 2016), influenza activity decreased slightly, but remained elevated in the United States.

• Viral Surveillance: The most frequently identified influenza virus type reported by public health laboratories during week 12 was influenza A, with influenza A (H1N1)pdm09 viruses predominating. The percentage of respiratory specimens testing positive for influenza in clinical laboratories decreased.
• Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was below the system-specific epidemic threshold in the NCHS Mortality Surveillance System and above the system-specific epidemic threshold in the 122 Cities Mortality Reporting System.
• Influenza-associated Pediatric Deaths: Three influenza-associated pediatric deaths were reported.
• Influenza-associated Hospitalizations: A cumulative rate for the season of 21.4 laboratory-confirmed influenza-associated hospitalizations per 100,000 population was reported.
• Outpatient Illness Surveillance: The proportion of outpatient visits for influenza-like illness (ILI) was 2.9%, which is above the national baseline of 2.1%. Nine of 10 regions reported ILI at or above region-specific baseline levels. Puerto Rico and two states experienced high ILI activity; New York City and seven states experienced moderate ILI activity; 15 states experienced low ILI activity; 26 states experienced minimal ILI activity; and the District of Columbia had insufficient data.
• Geographic Spread of Influenza: The geographic spread of influenza in Guam, Puerto Rico and 29 states was reported as widespread; 18 states reported regional activity; the District of Columbia and two states reported local activity; one state reported sporadic activity; and the U.S. Virgin Islands did not report.