Synopsis: During week 9 (February 23-March 1, 2014), influenza activity continued to decrease in the United States.

o ViralSurveillance:Of6,748specimenstestedandreportedduringweek9byU.S.World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories, 587 (8.7%) were positive for influenza.

o PneumoniaandInfluenzaMortality:Theproportionofdeathsattributedtopneumoniaand influenza (P&I) was above the epidemic threshold.

o Influenza-associatedPediatricDeaths:Fourinfluenza-associatedpediatricdeathswere reported.

o Influenza-associatedHospitalizations:Aseason-cumulativerateof28.5laboratory- confirmed influenza-associated hospitalizations per 100,000 population was reported.

o OutpatientIllnessSurveillance:Theproportionofoutpatientvisitsforinfluenza-likeillness (ILI) was 2.0%, which is at the national baseline. Five of 10 regions reported ILI at or above region-specific baseline levels. One state experienced high ILI activity; one state experienced moderate ILI activity; six states experienced low ILI activity; 42 states and New York City experienced minimal ILI activity, and the District of Columbia had insufficient data.

o GeographicSpreadofInfluenza:Thegeographicspreadofinfluenzaineightstateswas reported as widespread; 12 states reported regional influenza activity; the District of Columbia, Guam, and 26 states reported local influenza activity; Puerto Rico and four states reported sporadic influenza activity, and the U.S. Virgin Islands reported no influenza activity.

Stephen B. Thacker CDC Library collection

United States