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 20 ending May 21, 2016

All data are preliminary and may change as more reports are received.

Synopsis:

During week 20 (May 15-21, 2016), influenza activity decreased in the United States.

• Viral Surveillance: The most frequently identified influenza virus type reported by public health laboratories during week 20 was influenza A. 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 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 31.2 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 1.3%, which is below the national baseline of 2.1%. All 10 regions reported ILI below region-specific baseline levels. Puerto Rico experienced moderate ILI activity; three states experienced low ILI activity; New York City and 46 states experienced minimal ILI activity; and the District of Columbia and one state had insufficient data.
• Geographic Spread of Influenza: The geographic spread of influenza in Puerto Rico and one state was reported as widespread; Guam and six states reported regional activity; 14 states reported local activity; the District of Columbia, the U.S. Virgin Islands, and 28 states reported sporadic activity; and one state reported no activity.