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

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

2015-2016 Influenza Season Week 9 ending March 5, 2016

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Synopsis:

During week 9 (February 28-March 5, 2016), influenza activity remained elevated in the United States.

• Viral Surveillance: The most frequently identified influenza virus type reported by public health laboratories during week 9 was influenza A, with influenza A (H1N1)pdm09 viruses predominating. The percentage of respiratory specimens testing positive for influenza in clinical laboratories increased.
• Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was below their system-specific epidemic threshold in both the NCHS Mortality Surveillance System and the 122 Cities Mortality Reporting System.
• Influenza-associated Pediatric Deaths: Two influenza-associated pediatric deaths were reported.
• Influenza-associated Hospitalizations: A cumulative rate for the season of 10.4 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 3.5%, which is above the national baseline of 2.1%. All 10 regions reported ILI at or above region-specific baseline levels. Puerto Rico and 10 states experienced high ILI activity; New York City and 13 states experienced moderate ILI activity; 12 states experienced low ILI activity; 15 states experienced minimal ILI activity; and the District of Columbia had insufficient data.
• Geographic Spread of Influenza: The geographic spread of influenza in Puerto Rico and 37 states was reported as widespread; Guam and 13 states reported regional activity; the District of Columbia reported local activity; and the U.S. Virgin Islands reported sporadic activity.