Weekly U.S. Influenza Surveillance Report
January 31st, 2016During week 3 (January 17-23, 2016), influenza activity increased slightly in the United States.
- Viral Surveillance: The most frequently identified influenza virus type reported by public health laboratories during week 3 was influenza A, with influenza A (H1N1)pdm09 viruses predominating. The percentage of respiratory specimens testing positive for influenza in clinical laboratories increased.
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- Novel Influenza A Virus: One human infection with a novel influenza A virus was reported.
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- 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: No influenza-associated pediatric deaths were reported.
- Influenza-associated Hospitalizations: A cumulative rate for the season of 2.1 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 2.2%, which is above the national baseline of 2.1%. Six of 10 regions reported ILI at or above region-specific baseline levels. Puerto Rico experienced high ILI activity; three states experienced moderate ILI activity; five states experienced low ILI activity; New York City and 42 states experienced minimal ILI activity; and the District of Columbia had insufficient data.
- Geographic Spread of Influenza: The geographic spread of influenza in four states was reported as widespread; Puerto Rico and 14 states reported regional activity; Guam and 12 states reported local activity; and the District of Columbia, the U.S. Virgin Islands and 20 states reported sporadic activity.
