title: Surveillance for influenza during the 2009 influenza A (H1N1) pandemic-United States, April 2009-March 2010.
abstract: The emergence in April 2009 and subsequent spread of the 2009 pandemic influenza A (H1N1) virus resulted in the first pandemic of the 21st century. This historic event was associated with unusual patterns of influenza activity in terms of the timing and persons affected in the United States throughout the summer and fall months of 2009 and the winter of 2010. The US Influenza Surveillance System identified 2 distinct waves of pandemic influenza H1N1 activity--the first peaking in June 2009, followed by a second peak in October 2009. All influenza surveillance components showed levels of influenza activity above that typically seen during late summer and early fall. During this period, influenza activity reached its highest level during the week ending 24 October 2009. This report summarizes US influenza surveillance data from 12 April 2009 through 27 March 2010.
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. lsb1@cdc.gov
authors.forename: Lynnette
authors.initials: L
authors.lastname: Brammer
authors.forename: Lenee
authors.initials: L
authors.lastname: Blanton
authors.forename: Scott
authors.initials: S
authors.lastname: Epperson
authors.forename: Desiree
authors.initials: D
authors.lastname: Mustaquim
authors.forename: Amber
authors.initials: A
authors.lastname: Bishop
authors.forename: Krista
authors.initials: K
authors.lastname: Kniss
authors.forename: Rosaline
authors.initials: R
authors.lastname: Dhara
authors.forename: Mackenzie
authors.initials: M
authors.lastname: Nowell
authors.forename: Laurie
authors.initials: L
authors.lastname: Kamimoto
authors.forename: Lyn
authors.initials: L
authors.lastname: Finelli
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology*; D008297:Male; D008875:Middle Aged; D058873:Pandemics; D011159:Population Surveillance; D012621:Seasons; D014481:United States / Q000453:epidemiology; D055815:Young Adult