title: Trivalent inactivated influenza vaccine is not associated with sickle cell crises in children.
abstract: OBJECTIVE
  Children with sickle cell disease are considered at high risk for complications from influenza infection and are recommended to receive annual influenza vaccination. However, data on the safety of influenza vaccination in children with sickle cell anemia are sparse.
  
  
  METHODS
  Using a retrospective cohort of children aged 6 months to 17 years in 8 managed care organizations that comprise the Vaccine Safety Datalink and who had a diagnosis of sickle cell anemia from 1999 to 2006, we conducted matched case-control and self-controlled case series studies to examine the association of trivalent inactivated influenza vaccination with hospitalization for sickle cell crisis in the 2 weeks after vaccination.
  
  
  RESULTS
  From an original pool of 1085 pediatric subjects with a diagnosis of sickle cell anemia, we identified 179 children with at least 1 sickle cell crisis during any influenza season (October 1-March 31). In the matched case-control study (matching on age category, gender, Vaccine Safety Datalink site, and season), the odds ratio of hospitalization for a crisis in vaccinated compared with unvaccinated children was not significant: 1.3 (95% confidence interval 0.8-2.2). In the self-controlled case series study of hospitalized cases, the incident rate ratio for hospitalization with sickle cell crisis in the 2 weeks after trivalent inactivated influenza vaccination was also not significant: 1.2 (95% confidence interval 0.75-1.95).
  
  
  CONCLUSIONS
  This large cohort study did not find an association of influenza vaccination and hospitalization for sickle cell crises in children with sickle cell anemia.
authors.affiliation: Institute for Health Research, Kaiser Permanente Colorado, Denver, Colorado, USA. simon.hambidge@dhha.org
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Hambidge
authors.forename: Colleen
authors.initials: C
authors.lastname: Ross
authors.forename: Jason
authors.initials: J
authors.lastname: Glanz
authors.forename: David
authors.initials: D
authors.lastname: McClure
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Daley
authors.forename: Stan
authors.initials: S
authors.lastname: Xu
authors.forename: Jo Ann
authors.initials: JA
authors.lastname: Shoup
authors.forename: Komal
authors.initials: K
authors.lastname: Narwaney
authors.forename: James
authors.initials: J
authors.lastname: Baggs
authors.forename: Eric
authors.initials: E
authors.lastname: Weintraub
mesh_terms: D000293:Adolescent; D000755:Anemia, Sickle Cell / Q000150:complications* / Q000276:immunology / Q000628:therapy; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006760:Hospitalization; D006801:Humans; D007223:Infant; D007252:Influenza Vaccines / Q000009:adverse effects*; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male
chemical_list: D007252:Influenza Vaccines