title: Failure of inactivated influenza A vaccine to protect healthy children aged 6-24 months.
abstract: BACKGROUND
  The efficacy of inactivated influenza vaccine in healthy infants and children younger than 24 months has not been confirmed. The aim of the present study was to determine the prophylactic effect of inactivated influenza vaccine against influenza A in healthy children aged 6-24 months.
  
  
  METHODS
  Healthy infants and young children (6-24 months old) were immunized by subcutaneous injection of inactivated influenza vaccine before influenza seasons. Age matched children were randomly assigned as the control. These children were followed up from January to April in each year (2000, 2001 and 2002). The attack rates of influenza A infection was compared and statistically assessed.
  
  
  RESULTS
  The attack rate of influenza A virus infection in the vaccine group and the control group were 14.8% (n = 27) vs 12.5% (n = 32) in 2000 (P = 0.526); 2.8% (n = 72) vs 7.2% (n = 69) in 2001 (P = 0.203); and 3.4% (n = 52) vs 8.9% (n = 56) in 2002 (P = 0.205). The attack rates of influenza A between the two groups were not significantly different.
  
  
  CONCLUSIONS
  Inactivated influenza vaccine did not reduce the attack rate of influenza A infection in 6-24 month old children.
authors.affiliation: Department of Pediatrics, Public Shisou General Hospital, Shisou, Japan. magotaro@kcc.zaq.ne.jp
authors.forename: Taro
authors.initials: T
authors.lastname: Maeda
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Shintani
authors.forename: Kanako
authors.initials: K
authors.lastname: Nakano
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Terashima
authors.forename: Yoshiyasu
authors.initials: Y
authors.lastname: Yamada
mesh_terms: D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D009980:Influenza A virus; D007252:Influenza Vaccines / Q000627:therapeutic use*; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D017211:Treatment Failure; D015164:Vaccines, Inactivated / Q000627:therapeutic use
chemical_list: D007252:Influenza Vaccines; D015164:Vaccines, Inactivated