During week 49 (December 3-9, 2017), influenza activity increased in the United States.
December 16th, 2017During week 49 (December 3-9, 2017), influenza activity increased in the United States.
- Viral Surveillance: The most frequently identified influenza virus type reported by public health laboratories during week 49 was influenza A. The percentage of respiratory specimens testing positive for influenza in clinical laboratories increased.
- Novel Influenza A Virus: One human infection with a novel influenza A virus was reported.
- Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was below the system-specific epidemic threshold in the National Center for Health Statistics (NCHS) Mortality Surveillance System.
- Influenza-associated Pediatric Deaths: One influenza-associated pediatric death was reported.
- Influenza-associated Hospitalizations: A cumulative rate of 4.3 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 2.7%, which is above the national baseline of 2.2%. Seven of the 10 regions reported ILI at or above region-specific baseline levels. Four states experienced high ILI activity; five states experienced moderate ILI activity; New York City, Puerto Rico, and 16 states experienced low ILI activity; 25 states experienced minimal ILI activity; and the District of Columbia had insufficient data.
- Geographic Spread of Influenza:The geographic spread of influenza in 12 states was reported as widespread; Puerto Rico and 26 states reported regional activity; 10 states reported local activity; the District of Columbia, the U.S. Virgin Islands and two states reported sporadic activity; and Guam did not report.
