Synopsis: During week 13 (March 29-April 4, 2015), influenza activity continued to decrease in the United States. o ViralSurveillance:Of10,684specimenstestedandreportedbyU.S.WorldHealth Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories during week 13, 1,138 (10.7%) were positive for influenza. o PneumoniaandInfluenzaMortality:Theproportionofdeathsattributedtopneumoniaand influenza (P&I) was below the epidemic threshold. o Influenza-associatedPediatricDeaths:Twoinfluenza-associatedpediatricdeathswere reported. o Influenza-associatedHospitalizations:Acumulativeratefortheseasonof61.1 laboratory-confirmed influenza-associated hospitalizations per 100,000 population was reported. o OutpatientIllnessSurveillance:Theproportionofoutpatientvisitsforinfluenza-likeillness (ILI) was 1.8%, which is below the national baseline of 2.0%. Five regions reported ILI at or above region-specific baseline levels. Puerto Rico experienced moderate ILI activity; seven states experienced low ILI activity; New York City and 43 states experienced minimal ILI activity; and the District of Columbia had insufficient data. o GeographicSpreadofInfluenza:Thegeographicspreadofinfluenzainfourstateswas reported as widespread; 17 states reported regional activity; the District of Columbia, Guam, and 22 states reported local activity; and Puerto Rico, the U.S. Virgin Islands, and seven states reported sporadic activity.

Stephen B. Thacker CDC Library collection