MMR report 'not denial of autism link'. Crucial child study missed many cases, claim US experts
Jamie Doward, social affairs editor
Sunday October 10, 2004
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.
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.
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.
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
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
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.'
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.'
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.