Risk of anaphylaxis after vaccination of children and adolescents

Pediatrics. 2003 Oct;112(4):815-20. doi: 10.1542/peds.112.4.815.


Objective: To quantify the risk of anaphylaxis after vaccination of children and adolescents.

Methods: The study population consisted of children and adolescents who were enrolled at 4 health maintenance organizations that participated in the Vaccine Safety Datalink Project. For the period 1991-1997, we identified potential cases by searching for occurrences of International Classification of Diseases, Ninth Revision (ICD-9) code 995.0 (anaphylactic shock), E948.0 through E948.9 (adverse reaction from bacterial vaccines), and E949.0 through E949.9 (adverse reaction from other vaccines and biological substances). At 1 study site, we also included a range of other allergy codes. We restricted to diagnoses on days 0 to 2 after vaccination (ICD-9 995.0) or day 0 (all other ICD-9 codes). We then reviewed the medical record to confirm the diagnosis.

Results: We identified 5 cases of potentially vaccine-associated anaphylaxis after administration of 7 644 049 vaccine doses, for a risk of 0.65 cases/million doses (95% confidence interval: 0.21-1.53). None of the episodes resulted in death. Vaccines that were administered before the anaphylactic episodes were generally given in combination and included measles-mumps-rubella, hepatitis B, diphtheria-tetanus, diphtheria-tetanus-pertussis, Haemophilus influenzae type b, and oral polio vaccine. One case of anaphylaxis followed measles-mumps-rubella vaccine alone. At the site at which we reviewed additional allergy codes, we identified 1 case after 653 990 vaccine doses, for a risk of 1.53 cases/million doses (95% confidence interval: 0.04-8.52).

Conclusions: Patients and health care providers can be reassured that vaccine-associated anaphylaxis is a rare event. Nevertheless, providers should be prepared to provide immediate medical treatment should it occur.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adverse Drug Reaction Reporting Systems / statistics & numerical data
  • Anaphylaxis / epidemiology*
  • Anaphylaxis / etiology
  • California / epidemiology
  • Child
  • Child, Preschool
  • Cohort Studies
  • Female
  • Health Maintenance Organizations / statistics & numerical data
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Oregon / epidemiology
  • Risk
  • Vaccination / adverse effects*
  • Vaccines / adverse effects*
  • Washington / epidemiology


  • Vaccines