title: Childhood influenza: number needed to vaccinate to prevent 1 hospitalization or outpatient visit.
abstract: OBJECTIVE
  The goal was to assess the potential benefits of the influenza vaccine recommendations for children 6 to 59 months of age by estimating the number of children needed to be vaccinated to prevent 1 hospitalization or 1 outpatient visit attributable to influenza.
  
  
  METHODS
  The influenza burden was obtained from published studies in which rates for children 6 to 23 months and 24 to 59 months of age could be ascertained. We assumed a range of influenza vaccine efficacies of 25% to 75%, consistent with the literature. We estimated the number of children who needed to be vaccinated to prevent 1 influenza-attributable hospitalization or 1 outpatient visit for each age group.
  
  
  RESULTS
  As both vaccine efficacy and severity of the influenza season increased, the number of children who needed to be vaccinated to prevent 1 hospitalization or 1 outpatient visit decreased. The numbers of children who needed to be vaccinated to prevent 1 hospitalization in a year with 50% vaccine efficacy ranged from 1031 to 3050 for children 6 to 23 months of age and from 4255 to 6897 for children 24 to 59 months of age. For every 12 to 42 children 6 to 59 months of age vaccinated in a year with 50% vaccine efficacy, we estimated that 1 influenza-attributable outpatient visit would be prevented.
  
  
  CONCLUSIONS
  With 1 outpatient visit being prevented through vaccination of <50 children, influenza vaccination can reduce influenza-attributable medical visits in children significantly, even in years with modest vaccine efficacy.
authors.affiliation: Vanderbilt University Medical School, Nashville, Tennessee, USA.
authors.forename: Elizabeth N
authors.initials: EN
authors.lastname: Lewis
authors.forename: Marie R
authors.initials: MR
authors.lastname: Griffin
authors.forename: Peter G
authors.initials: PG
authors.lastname: Szilagyi
authors.forename: Yuwei
authors.initials: Y
authors.lastname: Zhu
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Edwards
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Poehling
mesh_terms: D017677:Age Distribution; D000554:Ambulatory Care Facilities / Q000706:statistics & numerical data*; D002675:Child, Preschool; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000517:prevention & control*; D014481:United States
chemical_list: D007252:Influenza Vaccines