title: Injection site and risk of medically attended local reactions to acellular pertussis vaccine.
abstract: OBJECTIVE
  To assess whether the risk of medically attended local reactions to the fifth dose of the diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccine varies according to injection site (arm versus thigh).
  
  
  METHODS
  We conducted a retrospective cohort study of children aged 4 through 6 years in the Vaccine Safety Datalink population who received a DTaP vaccination during the period from 2002 through 2006. Medically attended local reactions to the DTaP vaccine were presumptively identified from administrative data and were confirmed by medical record review.
  
  
  RESULTS
  Among the 233,616 children in the study population, 1017 (0.4%) had a confirmed medically attended local reaction to the fifth dose of the DTaP vaccine. The rate of those reactions was significantly higher with vaccinations given in the arm (47.4 per 10,000 vaccinations) compared with vaccinations given in the thigh (32.1 per 10,000 vaccinations) (P < .001). In a multivariable analysis adjusted for age, gender, and study site, children vaccinated in the arm had a 78% higher risk of a local reaction (relative risk: 1.78 [95% confidence interval: 1.43-2.21]).
  
  
  CONCLUSIONS
  Local reactions to the fifth dose of the DTaP vaccine that require medical evaluation are uncommon, but the risk of those reactions is significantly higher when the vaccine is injected in the arm. These findings suggest that the thigh should be considered as an acceptable site of injection for this vaccination.
authors.affiliation: Group Health Research Institute, 1730 Minor Ave, Suite 1600, Seattle, WA 98101, USA. jackson.l@ghc.org
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Jackson
authors.forename: Onchee
authors.initials: O
authors.lastname: Yu
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Nelson
authors.forename: Clara
authors.initials: C
authors.lastname: Dominguez
authors.forename: Do
authors.initials: D
authors.lastname: Peterson
authors.forename: Roger
authors.initials: R
authors.lastname: Baxter
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Hambidge
authors.forename: Allison L
authors.initials: AL
authors.lastname: Naleway
authors.forename: Edward A
authors.initials: EA
authors.lastname: Belongia
authors.forename: James D
authors.initials: JD
authors.lastname: Nordin
authors.forename: James
authors.initials: J
authors.lastname: Baggs
mesh_terms: D001132:Arm; D002648:Child; D002675:Child, Preschool; D022681:Diphtheria-Tetanus-acellular Pertussis Vaccines / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D015994:Incidence; D007273:Injections, Intramuscular; D008297:Male; D012189:Retrospective Studies; D012867:Skin / Q000187:drug effects* / Q000473:pathology; D013848:Thigh; D014481:United States / Q000453:epidemiology; D014917:Whooping Cough / Q000517:prevention & control*
chemical_list: D022681:Diphtheria-Tetanus-acellular Pertussis Vaccines