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

Synopsis: During week 48 (November 25-December 1), influenza activity increased in the U.S.

o Viral Surveillance: Of 5,511 specimens tested and reported by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories during week 48, 1,139 (20.7%) were positive for influenza.

o Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was below the epidemic threshold.

o Influenza-associated Pediatric Deaths: Three influenza-associated pediatric deaths were reported. One of these deaths was associated with an influenza B virus and two were associated with influenza A viruses for which the subtype was not determined.

o Outpatient Illness Surveillance: The proportion of outpatient visits for influenza-like illness (ILI) was 1.9%, which is below the national baseline of 2.2%. Three regions reported ILI above region-specific baseline levels. Four states experienced high ILI activity, three states experienced moderate ILI activity; 6 states experienced low ILI activity; New York City and 37 states experienced minimal ILI activity, and the District of Columbia had insufficient data.

o Geographic Spread of Influenza: The geographic spread of influenza in 8 states was reported as widespread; 15 states reported regional activity; 15 states reported local activity; the District of Columbia, Guam, and 12 states reported sporadic activity, and Puerto Rico and the U.S. Virgin Islands did not report.

Date from document properties.

Stephen B. Thacker CDC Library collection

United States