National Center for Immunization and Respiratory Diseases (U.S.). Influenza Division.

All data are preliminary and may change as more reports are received. During week 8 (February 18-24, 2018), influenza activity decreased in the United States. • Viral Surveillance: While influenza A(H3) viruses continue to be predominant this season, during week 8 the overall proportion of influenza A viruses is declining and the proportion of influenza B viruses is increasing. 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 above the system-specific epidemic threshold in the National Center for Health Statistics (NCHS) Mortality Surveillance System. • Influenza-associated Pediatric Deaths: Seventeen influenza-associated pediatric deaths were reported. • Influenza-associated Hospitalizations: A cumulative rate of 81.7 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 5.0%, which is above the national baseline of 2.2%. All 10 regions reported ILI at or above region-specific baseline levels. New York City, the District of Columbia, and 32 states experienced high ILI activity; Puerto Rico and nine states experienced moderate ILI activity; six states experienced low ILI activity; and three states experienced minimal ILI activity. • Geographic Spread of Influenza: The geographic spread of influenza in Puerto Rico and 45 states was reported as widespread; Guam and two states reported regional activity; the District of Columbia and three states reported local activity; and the U.S. Virgin Islands reported no activity.

Webpage

United States

Stephen B. Thacker CDC Library collection