The following HTML text is provided to enhance online
readability. Many aspects of typography translate only awkwardly to HTML.
Please use the page image
as the authoritative form to ensure accuracy.
Adverse Events Associated with Childhood Vaccines: Evidence Bearing on Causality
and 16 were left with neurologic residua. The authors calculated rates of "encephalitis" of 1.16 cases per 1 million doses of vaccine distributed.
Among the recipients of more than 3 million doses of measles vaccine (various strains, but mostly the Schwarz strain) in the United Kingdom between 1968 and 1974, there were 47 cases of "encephalitis" (Beale, 1974). The report does not discuss the criteria used for the diagnosis. Data on the occurrence of encephalitis in temporal relation to administration of measles vaccine for the years 1965-1976 in Canada showed a rate of 1.79 cases of encephalitis per 1 million doses of vaccine distributed (White, 1983). These data are based on hospital admissions associated with International Classification of Diseases codes for "viral encephalitis unspecified" and "acute viral encephalitis.''
In a report from the former East Germany (Dietzsch and Kiehl, 1976), there were 7 central nervous system (CNS) complications out of 174,725 immunizations with an unstated vaccine, but it was probably one of the strains from the former Soviet Union. Two febrile seizures, four cases of encephalopathy, and one case of encephalitis (there was pleocytosis in the CSF) were reported. Few clinical details were reported. Two of the patients with encephalopathy and the patient with encephalitis recovered completely, one patient with encephalopathy was left with a residual paralysis, and another died of leukemia.
A report from the former Soviet Union (Ozeretskovskii and Gurvich, 1991) referred to cases of encephalitis and encephalitic reaction caused by a measles vaccine (probably the Smorodintsev strain), but offered no primary data. The authors quote three rates per 100,000 vaccinees: 0.1, 0.02, and 190 cases. The rate of 0.02 is far below the acknowledged background rate of encephalitis and the rate of 190 is far above any rates quoted anywhere for encephalitis/encephalopathy after receipt of measles vaccine. Considering the imprecision of the definition of "encephalitis" and "encephalitic reaction" and the discrepancy of the rates, it is impossible to interpret that report.
A report of adverse events associated with measles vaccine in Japan from 1978 to 1983 cited 12 cases of "encephalitis" or "encephalopathy," without describing them, and derived a rate of 3.7 cases of "encephalitis'' per 1 million vaccinees administered the Schwarz vaccine and 2.9 cases per 1 million vaccinees administered the Biken-CAM vaccine (Hirayama, 1983). A follow-up to that report published 5 years later (Isomura, 1988) mentioned 16 cases of "encephalitis" (4 more cases than the earlier report), but provided no details. The incidence rate for "encephalopathy" and "encephalitis" following measles vaccination appeared to be lower than the observed incidence of encephalitis from all causes among age-matched controls (Hirayama, 1983; Isomura, 1988). This comparison was not derived from a controlled cohort study, however.