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Autism
& The MMR Vaccine
Peter
E. Tanguay, M.D.
In
February 1998, an article in Lancet by Wakefield and colleagues
at the Royal Free Hospital and School of Medicine in London, reported
that eight children who had received MMR (measles, mumps and rubella)
vaccine developed symptoms of "autism spectrum disorder"
between one day to two weeks after vaccination. the children also
all developed inflammatory bowel disease (IBD). They suggested
that MMR vaccination led to IBD, resulting in malabsorption, neurological
damage and "autism." An accompanying commentary in Lancet,
followed by many letters-to-the-editors, pointed out that shortcomings
in Wakefield's methods could well have led to misleading results.
MMR vaccination is given around the same time when most cases
of autism are first suspected. Wakefield's patients were not a
random sample: he and his colleagues interest in supposed MMR-induced
autism was already well known, and cases were being referred to
them on that basis. There were no control groups, no double-blinding
and no independent observers or diagnosis. Several writers argued
that chronic non-specific colitis, as described by Wakefield,
is a common form of non-infective colonic inflammation in this
age group. Wakefield replied to these letters, claiming that his
critics were misinformed or had misinterpreted his statements.
He did not directly address the methodological problems of his
study and continued to argue that MMR vaccine could cause autism.
Subsequently, Wakefield's claims were given wide coverage in the
English press.
In
March 1998, an article in the British Medical Journal recalled
a similar situation which had happened in the early 1970s, when
anecdotal reports linked pertussis vaccination with infant brain
damage. Again it was an example of a temporal link between a vaccine
and a devastating childhood condition whose natural peak onset
was at a time when most children routinely received the vaccine.
A national study eventually showed that while there was a temporal
association with encephalopathy, any risk of lasting damage from
the vaccine was so rare as to be unquantifiable. Following the
initial report, however, parental and professional anxiety had
soared, and national immunization rates fell from 80 to 30 percent.
The number of susceptible children rose, and in the twelve years
after 1976 three major pertussis epidemics occurred, resulting
in 300,000 cases and 70 deaths
In
1998 and 1999 two studies appeared (both in Lancet) which
did not support Wakefield's beliefs. Peltola and his colleagues
reported a follow-up study on MMR vaccination in Finland, involving
three million doses, in which 31 children developed mild gastrointestinal
disorders and none developed autism. In a reverse approach, Taylor
and his colleagues at the University College Medical School in
London, identified 498 cases of autism from the disability registers
of eight North Thames health districts in England. They found
no temporal association with autism within one to two years after
vaccination with MMR. They concluded that if such cases occurred,
it was so rare as not to be identifiable in this size of sample.
The Journal of Pediatrics reported Taylor's findings under
the headline, "New research demolishes the link between MMR
vaccine and autism."
Despite
the lack of scientific support for the MMR-autism link, it continues
to have its advocates. Wakefield, for one, remains convinced.
At a congressional hearing convened by Representative Dan Burton
last April [this was written in 2000], he testified that he has
now studied 150 children with "autistic entercolitis"
(Note that now it even has its own specific name) and that he
expects to publish a detailed analysis of his cases. The Internet
reverberates with accusations of cover-ups by the proponents of
MMR vaccination. It is not unlike what happened some years ago
with cold fusion. Despite the fact that cold fusion has been shown
to violate fundamental laws of physics as well as to have no evidence
in its favor, there are still small groups of physicists and other
supporters who gather annually to proclaim its truth and to argue
that if only the "right" experiments could be done,
cold fusion would be vindicated. All of us want to prevent autism,
and there is a human propensity to interpret chance association
with cause. Before we think about stopping vaccinations, we should
not forget the 70 preventable pertussis deaths in England between
1970 and 1990.
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