allergy documented by a positive reaction to skin patch testing with 20 percent neomycin sulfate.

Controlled Observational Studies

None.

Controlled Clinical Trials

None.

Causality Argument

Evidence from individual reports in VAERS and the literature is consistent with a causal relation between measles vaccine and MMR and anaphylaxis. The most compelling evidence consists of the cases reported by Herman and colleagues (1983) and by Thurston (1987). All four patients received MMR. In most cases of MMR-associated anaphylaxis, the precise component of the vaccine responsible for the severe reaction was not identified. In addition to the measles and mumps antigens, egg proteins, antibiotics, and other contaminants have been implicated. Reported cases of anaphylaxis following administration of these vaccines are extremely rare, and several reports suggest that anaphylaxis to measles vaccine is overreported and that not all of the cases are substantiated (Fescharek et al., 1990; McEwen, 1983; Pollock and Morris, 1983; Sokhey, 1991; Taranger and Wiholm, 1987; Thurston, 1987; Van Asperen et al., 1981). In 1983, Pollock and Morris estimated that anaphylaxis or collapse within 24 hours of vaccination occurred with a frequency of about 9 cases per 170,000 doses of measles vaccine administered in a large region of England over 7 years. In children with a history of anaphylactic reactions to egg, only five cases of immediate allergic reaction had been reported after distribution of more than 174 million doses of measles vaccine in the United States (American Academy of Pediatrics, Committee on Infectious Diseases, 1991).

Conclusion

The evidence establishes a causal relation between MMR and anaphylaxis.

The evidence favors acceptance of a causal relation between measles vaccine and anaphylaxis.

Because these conclusions are not based on controlled studies, the criteria for the diagnosis of anaphylaxis are variable, and pharmacologic intervention complicates the diagnosis, no reliable estimate of incidence or rela-



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