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 17, ending April 29, flu activity decreased. While the 2016-2017 flu season has peaked, 4 states (AZ, CO, LA, and SC) continue to report low flu activity.

Learn More

2016-2017 Influenza Season Week 17 ending April 29, 2017

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

Synopsis:

During week 17 (April 23-29, 2017), influenza activity decreased in the United States.

Viral Surveillance: The most frequently identified influenza virus type reported by public health laboratories during week 17 was influenza B. The percentage of respiratory specimens testing positive for influenza in clinical laboratories decreased.
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:Ten influenza-associated pediatric deaths were reported, seven that occurred during the 2016-2017 season and three that occurred during the 2015-2016 season.
Influenza-associated Hospitalizations:A cumulative rate for the season of 63.8 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 1.4%, which is below the national baseline of 2.2%. All ten regions reported ILI below their region-specific baseline levels. Four states experienced low ILI activity; New York City, Puerto Rico, and 46 states experienced minimal ILI activity; and the District of Columbia had insufficient data.
Geographic Spread of Influenza: The geographic spread of influenza in three states was reported as widespread; Guam and eight states reported regional activity; the District of Columbia, Puerto Rico, and 20 states reported local activity; 19 states reported sporadic activity; and the U.S. Virgin Islands reported no activity.