2017-2018 Influenza Season Week 18 ending May 5, 2018
During week 18 (April 29-May 5, 2018), influenza activity decreased in the United States.
- Viral Surveillance:Overall, influenza A(H3) viruses have predominated this season. Since early March, influenza B viruses have been more frequently reported than influenza A viruses. 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 the National Center for Health Statistics (NCHS) Mortality Surveillance System.
- Influenza-associated Pediatric Deaths: Two influenza-associated pediatric deaths were reported.
- Influenza-associated Hospitalizations: A cumulative rate of 106.5 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 1.5%, which is below the national baseline of 2.2%. One of 10 regions reported ILI at or above their region-specific baseline level. Puerto Rico and one state experienced low ILI activity; and New York City, the District of Columbia, and 49 states experienced minimal ILI activity.
- Geographic Spread of Influenza: The geographic spread of influenza in three states was reported as widespread; Guam, Puerto Rico and four states reported regional activity; 16 states reported local activity; the District of Columbia, and 25 states reported sporadic activity; and the U.S. Virgin Islands and two states reported no influenza activity.
Weekly U.S. Influenza Surveillance Report
CDC's Influenza Division produces a weekly influenza surveillance report, FluView. According to this week's report (April 29 - May 5), seasonal influenza activity remained at levels below baseline in the United States. Arizona and Puerto Rico experienced low Influenza Like Illness (ILI) activity levels.