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Title
Diphtheria-tetanus-pertussis vaccine and serious neurologic illness: an updated review of the
epidemiologic evidence.
AuthorWentz KR; Marcuse EK
AddressDepartment of Epidemiology, University of Washington School of Medicine, Seattle.
Source
Pediatrics,
87:
3, 1991 Mar,
287-97
AbstractA widespread impression that DTP vaccine does cause brain damage has been based first on historical
precedent--smallpox and rabies vaccines were recognized as sometimes causing devastating neurologic illness;
analogy to pertussis--the disease can cause encephalopathy; and more recently on anecdotal evidence,
particularly case series. A noncausal relationship--coincidence--could explain the temporal relation
between DTP vaccine and neurologic illness, inasmuch as DTP vaccine is given at the age of emergence
of idiopathic neurologic disease. The relationship between DTP vaccine and neurologic illness lacks
specificity. Case series have had an impact on both physicians' and the lay public's impression of the
safety of pertussis vaccine greatly out of proportion to their scientific importance. Case series
can be useful for generating hypotheses but cannot provide evidence that pertussis vaccine is causally
related to acute neurologic illness or brain damage. Observational studies using cohort and ecologic
designs did not find an association between DTP vaccine and serious neurologic illness, but they were
not powerful enough to detect an association as rare as that observed by the NCES investigators. The
case-control design offers the best chance of providing causal evidence regarding DTP vaccine and serious
neurologic illness. The NCES is the only published case-control study of this issue. This study
found a rare association between DTP vaccine and some types of acute neurologic illness. Bias and chance
are unlikely to account entirely for the association demonstrated by the NCES. However, the association
has not yet been replicated by other case-control studies. The NCES does not demonstrate that DTP vaccine
causes permanent brain damage.