Risk of anaphylaxis after vaccination of children and adolescents.
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.
Bohlke
Kari
K
Center for Health Studies, Group Health Cooperative, Seattle, Washington 98101-1448, USA. bohlke.k@ghc.org
Davis
Robert L
RL
Marcy
S M
SM
Braun
M M
MM
DeStefano
Frank
F
Black
Steven B
SB
Mullooly
John P
JP
Thompson
Robert S
RS
D000293:Adolescent; D016907:Adverse Drug Reaction Reporting Systems / Q000706:statistics & numerical data; D000707:Anaphylaxis / Q000453:epidemiology* / Q000209:etiology; D002140:California / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006279:Health Maintenance Organizations / Q000706:statistics & numerical data; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009922:Oregon / Q000453:epidemiology; D012306:Risk; D014611:Vaccination / Q000009:adverse effects*; D014612:Vaccines / Q000009:adverse effects*; D014861:Washington / Q000453:epidemiology
D014612:Vaccines