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

Synopsis: During week 45 (November 8-14, 2015), influenza activity increased slightly in the United States.

• Viral Surveillance: The most frequently identified influenza virus type reported by public health laboratories in week 45 was influenza A viruses, with influenza A (H3) viruses predominating. The percentage of respiratory specimens testing positive for influenza in clinical laboratories is low.

• Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was below their system-specific epidemic threshold in both the NCHS Mortality Surveillance System and the 122 Cities Mortality Reporting System.

• Influenza-associated Pediatric Deaths: One influenza-associated pediatric death was reported.

• Outpatient Illness Surveillance: The proportion of outpatient visits for influenza-like illness (ILI) was 1.6%, which is below the national baseline of 2.1%. Two of 10 regions reported ILI at or above region-specific baseline levels. One state experienced moderate ILI activity; Puerto Rico and two states experienced low ILI activity; New York City and 47 states experienced minimal ILI activity; and the District of Columbia had insufficient data.

• Geographic Spread of Influenza: The geographic spread of influenza in Guam was

• reported as widespread; Puerto Rico reported regional activity; four states reported local activity; 40 states reported sporadic activity; and the District of Columbia, the U.S. Virgin Islands, and six states reported no influenza activity.

External_F1545.pdf

Stephen B. Thacker CDC Library collection

United States