Autism Biomedical Information Network

MMR Vaccine Surveillance for Adverse Effects

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Despite the administration of millions of doses of combined measles, mumps, and rubella (MMR) vaccine, as well as other vaccines, and the unquestioned impact on disease prevention, with only extremely rare adverse events, there is still a widespread belief that MMR is, in some unaccountable way, linked to the development of autism. This perception has not been borne out by extensive monitoring of vaccination programs. A recent paper from Finland adds to the literature on vaccine surveillance (see abstract below). Between 1982 and 1996 almost 3 million doses of vaccine were given to 1.8 million individuals in Finland. There were reports of 173 potentially serious reactions, including one death which remained unexplained after post mortem study. Febrile seizures were the most commonly reported adverse event. However, on further analysis 45% were attributable to other circumstances, including concurrent illness. The association with MMR, based on a temporal relation, was simply one of coincidence in most instances. The incidence of serious adverse events, possibly related to MMR, is rare (5.3 per 100,000 vacinees or 3.2 per 100,000 vaccine doses). The authors conclude, "Clearly, post hoc non est propter hoc, a sequence does not prove consequence."

The vaccination program reduced by one-third all cases of encephalitis and eliminated congenital rubella as well as community-acquired measles, mumps, and rubella.

There was not a single report of autism or inflammatory bowel disease during the 14 years of surveillance.


Title: Serious adverse events after measles-mumps-rubella vaccination during a fourteen-year prospective follow-up.

Authors: Patja A, Davidkin I, Kurki T, Kallio MJT, Valle M, Peltola H

Publication: Pediatr Infect Dis J 2000;19(12):1127-34

Background: Several disorders have been attributed to measles-mumps-rubella (MMR) vaccination during the past decade. The aim of this prospective study was to identify serious adverse events causally related to MMR vaccination.

Methods: When the MMR vaccination program was launched in Finland in 1982, a countrywide surveillance system was set up to detect serious adverse events associated with MMR. To obtain detailed case histories vaccinees' clinical charts were reviewed. Serum samples were analyzed to trace concurrent infections.

Setting: All hospitals and health centers in Finland from 1982 through 1996.

Results: Immunization of 1.8 million individuals and consumption of almost 3 million vaccine doses by the end of 1996 gave rise to 173 potentially serious reactions claimed to have been caused by MMR vaccination. In all, 77 neurologic, 73 allergic and 22 miscellaneous reactions and 1 death were reported, febrile seizure being the most common event. However, 45% of these events proved to be probably caused or contributed by some other factor, giving an incidence of serious adverse events with possible or indeterminate causal relation with MMR vaccination of 5.3 per 100,000 vaccinees or 3.2 per 100,000 vaccine doses.

Conclusions: Causality between immunization and a subsequent untoward event cannot be estimated solely on the basis of a temporal relation. Comprehensive analysis of the reported adverse reactions established that serious events causally related to MMR vaccine are rare and greatly outweighed by the risks of natural MMR diseases.

Abstract Copyright ©2000 by Lippincott Williams & Wilkins, Inc.

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