title: Children with asthma hospitalized with seasonal or pandemic influenza, 2003-2009.
abstract: OBJECTIVE
  To describe the characteristics and clinical courses of asthmatic children hospitalized with seasonal or 2009 pandemic H1N1 influenza and compare complications by influenza type.
  
  
  METHODS
  During the 2003-2009 influenza seasons and the 2009 pandemic, we conducted surveillance of 5.3 million children aged 17 years or younger for hospitalization with laboratory-confirmed influenza and identified those with asthma (defined as those aged 2-17 years with a history of asthma in their medical record or a discharge code for acute asthma exacerbation or status asthmaticus). We collected data from medical records on medical history and clinical course; data on asthma severity and control were not routinely collected.
  
  
  RESULTS
  During the 2003-2009 influenza seasons, 701 (32%) of 2165 children hospitalized with influenza had asthma; during the 2009 pandemic, 733 (44%) of 1660 children had asthma. The median age of the asthmatic children was 7 years, and 73% had no additional medical conditions. Compared with asthmatic children with seasonal influenza, a higher proportion with 2009 pandemic H1N1 influenza required intensive care (16% vs 22%; P=.01) and were diagnosed with pneumonia (40% vs 46%; P=.04), whereas equal proportions had respiratory failure (5% vs 5%; P=.8) and died (1% vs 1%; P=.4). More asthmatic children with influenza A (seasonal or pandemic) had diagnoses of asthma exacerbations compared with those with influenza B (51% vs 29%; P<.01).
  
  
  CONCLUSIONS
  The majority of asthmatic children hospitalized with influenza have no additional medical conditions. Complications such as pneumonia and need for intensive care occur in a substantial proportion, highlighting the importance of influenza prevention through vaccination among asthmatic children.
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention, 1600 Clifton Rd, MS A-32, Atlanta, GA 30333, USA. fdawood@cdc.gov
authors.forename: Fatimah S
authors.initials: FS
authors.lastname: Dawood
authors.forename: Laurie
authors.initials: L
authors.lastname: Kamimoto
authors.forename: Tiffany A
authors.initials: TA
authors.lastname: D'Mello
authors.forename: Arthur
authors.initials: A
authors.lastname: Reingold
authors.forename: Ken
authors.initials: K
authors.lastname: Gershman
authors.forename: James
authors.initials: J
authors.lastname: Meek
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Arnold
authors.forename: Monica
authors.initials: M
authors.lastname: Farley
authors.forename: Patricia
authors.initials: P
authors.lastname: Ryan
authors.forename: Ruth
authors.initials: R
authors.lastname: Lynfield
authors.forename: Craig
authors.initials: C
authors.lastname: Morin
authors.forename: Joan
authors.initials: J
authors.lastname: Baumbach
authors.forename: Shelley
authors.initials: S
authors.lastname: Zansky
authors.forename: Nancy
authors.initials: N
authors.lastname: Bennett
authors.forename: Ann
authors.initials: A
authors.lastname: Thomas
authors.forename: William
authors.initials: W
authors.lastname: Schaffner
authors.forename: David
authors.initials: D
authors.lastname: Kirschke
authors.forename: Lyn
authors.initials: L
authors.lastname: Finelli
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000150:complications* / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D005260:Female; D006760:Hospitalization; D006801:Humans; D007251:Influenza, Human / Q000150:complications* / Q000453:epidemiology / Q000628:therapy; D008297:Male; D058873:Pandemics; D012621:Seasons; D013997:Time Factors