- Serious questions were raised last night over the scientific
evidence used by the government to reject claims of a link between the
MMR vaccine and regressive autism in children.
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- A US paediatrician, Dr F Edward Yazbak, told The Observer
that a study of more than 500,000 Danish children, regarded as the definitive
analysis of the vaccine, should not be interpreted as ruling out a link
between the jab and an increase in autism in Denmark.
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- UK government health officials have consistently referred
to the 2002 study, sponsored by the US Centers for Disease Control and
Prevention, to attack claims of a link between autism and the three-in-one
vaccine for measles, mumps and rubella.
-
- But Yazbak said his examination of the Danish data showed
it could not be used to reject a link.
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- The study investigated 537,304 children born between
1991 and 1998. In Denmark, autism is normally diagnosed in children aged
five or older. Many of those born after 1994 would not have been diagnosed
by the time the study had concluded, Yazbak said.
-
- 'The most important age group to look at comprises children
aged from five to nine. The number with autism increased from 8.38 per
100,000 before the MMR jab was introduced in 1987, to 77.43 in 2000.' Writing
in the latest edition of the Journal of American Physicians and Surgeons,
Yazbak and Dr Gary Goldman, concluded: 'The systematic error of missing
a large number of autism diagnoses in the later years was a major shortcoming.
-
- 'Children with Asperger's syndrome and high-functioning
autism, who have minimal speech and behaviour impairments and are thus
not diagnosed as early as more profoundly affected children, are especially
likely to be undercounted in this study.'
-
- Dr Richard Horton, editor of the Lancet and author of
a new book MMR, science & fiction said neither Yazbal's work or the
Danish study could be used to prove or reject a link. 'There is a real
danger of taking single studies in isolation and drawing conclusions one
way or the other,' Horton said.
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- British doctor Andrew Wakefield first raised concerns
about MMR in 1998 when he published a study based on just 12 children who
had been referred to the Royal Free Hospital in Hampstead, north London,
for gastrointestinal problems.
-
- Wakefield's findings prompted him to consider whether
there was a link between the MMR vaccine and autism and bowel disease,
but the study was widely rejected by scientists.
-
- Health campaigners blame the controversy for a decline
in the number of children receiving the jab. Experts said there was a need
to look at other explanations for the apparent rise in autism. Richard
Mills, director of services of the National Autistic Society, said: 'There
is an argument that rates of autism have not increased significantly but
the diagnostic techniques and definitions have become more sophisticated.
More research needs to be done.'
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- Yazbak pointed to newly published figures from the US
that show 140,920 children aged six to 21 were diagnosed with autism last
year, compared with 12,222 in 1993. 'You cannot keep saying the diagnostic
criterion has changed when the diagnostic criterion was changed in the
US in 1994, and we are in 2004.'
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- Yazbak denied his research proved a link between MMR
and autism. But he said that, until further clinical research had been
conducted, governments should offer a choice between single vaccines and
the triple jab. A smaller study, published in the Lancet earlier this month,
corroborated the Denmark findings. It looked at the vaccination records
of 1,294 children diagnosed with autism and other disorders. The report
also based its analysis on four other research projects and found no link.
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- Guardian Unlimited © Guardian Newspapers Limited
2004 http://www.guardian.co.uk/medicine/story/0,11381,1324083,00.html
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