RISK OF ANAPHYLAXIS AFTER VACCINATION OF CHILDREN AND ADOLESCENTS

Bohlke K, Davis RL, Marcy SM, et al. Pediatrics. 2003;112:815–820Anaphylaxis is a risk of vaccination. This study retrospectively quantified the risk in a population of pediatric patients.Children and adolescents enrolled in 4 West Coast health maintenance organizations that participated in the Vaccine Safety Data Link Project between 1991 and 1997 were studied.A total of 7 644 049 vaccine doses were administered to 2 226 907 children between the ages of 0 and 17 years at 3 sites and between 0 and 6 years at a fourth site. Potential cases of anaphylaxis were identified by using International Classification of Diseases, 9th revision, codes suggesting anaphylaxis. A total of 657 cases were reviewed, of 664 cases of interest. Missing chart information excluded 7 cases. Criteria including organ systems involved in reactions, timing of reactions after vaccination, and treatments were reviewed, to identify possible or probable cases of anaphylaxis. Two analyses were performed. One included all sites, and 1 included a single site for which more detailed data on outpatient diagnoses were available.Six possible cases of anaphylaxis were identified. After a more detailed chart review, 2 cases were considered unlikely to be anaphylaxis, 1 case was unlikely to be secondary to vaccination, and 1 case of anaphylaxis predated and was not attributable to vaccination. The final risk of anaphylaxis was calculated as 0.26 case per 1 000 000 doses (2 cases per 7 644 049 doses). At the single site with more complete data on outpatient diagnoses, a risk of 1.53 cases per 1 000 000 doses was calculated. Rates for individual vaccines ranged from 0 to 14.4 cases per 1 000 000 doses. Most reactions were seen with diphtheria- and tetanus-containing vaccines, hepatitis B vaccine, measles-mumps-rubella vaccine, and oral polio vaccine. These vaccines were also more commonly administered. No reactions were seen with diphtheria-tetanus-acellular pertussis vaccine, influenza vaccine, inactivated polio vaccine, adult diphtheria-tetanus vaccine, hepatitis A vaccine, or varicella vaccine. However, these vaccines were less commonly administered. No deaths resulted from the anaphylactic episodes. No association was made with atopic status.The frequency of vaccine-associated anaphylaxis is very low. Nonetheless, providers should be prepared to provide immediate treatment should it occur.Vaccination remains one of the most effective preventative treatments provided for children. Some advocates for better access to vaccination lobby for administration of vaccines at locations where acute health care is absent (eg, pharmacies). Although the risk of anaphylaxis is extremely low, it is not negligible. Providers of vaccines must be prepared to provide immediate treatment if anaphylaxis should occur, and society must determine when the need for vaccine access outweighs this risk.