Weekly U.S. Influenza Surveillance Report
The CDC Influenza Division collects, compiles, and analyzes information on Influenza activity year-round in the US and produces FluView, a weekly influenza surveillance report. During week 12, ending March 25, influenza activity decreased in the United States, but widespread influenza activity was still reported by 10 states (AL, AR, GA, KY, MN, NC, OK, SC, TN, & VA).
Full report also available as PDF
2016-2017 Influenza Season Week 12 ending March 25, 2017
All data are preliminary and may change as more reports are received.
During week 12 (March 19-25, 2017), influenza activity remained elevated in the United States.
- Viral Surveillance: The most frequently identified influenza virus subtype reported by public health laboratories during week 12 was influenza A (H3). The percentage of respiratory specimens testing positive for influenza in clinical laboratories increased slightly.
- Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was above the system-specific epidemic threshold in the National Center for Health Statistics (NCHS) Mortality Surveillance System.
- Influenza-associated Pediatric Deaths: Six influenza-associated pediatric deaths were reported.
- Influenza-associated Hospitalizations: A cumulative rate for the season of 54.1 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 3.2%, which is above the national baseline of 2.2%. Eight of ten regions reported ILI at or above their region-specific baseline levels. 10 states experienced high ILI activity; eight states experienced moderate ILI activity; eight states experienced low ILI activity; New York City, Puerto Rico, and 24 states experienced minimal ILI activity; and the District of Columbia had insufficient data.
- Geographic Spread of Influenza: The geographic spread of influenza in 31 states was reported as widespread; Guam, Puerto Rico and 12 states reported regional activity; the District of Columbia and five states reported local activity; two states reported sporadic activity; and the U.S. Virgin Islands reported no activity.