Scientists rule out vaccine health risk
11 June 1999
The theory that autism and bowel diseases could be caused by childhood vaccinations against measles, mumps and rubella was officially demolished yesterday with the publication of two studies commissioned by the department of health.
Parents were urged to accept the finality of the latest research and have their children immunised against three diseases which can be damaging or even fatal. The numbers having the jab have dropped because of the scare - from 90% to 75% at 16 months old - and public health officials fear an epidemic if coverage does not go back up. The last measles epidemic, in 1988, was one of the smallest, but 17 children died.
Jeremy Metters, deputy chief medical officer, admitted that it was never possible to prove conclusively that something did not have an adverse effect. But "these studies confirm that there is no evidence of a link".
One of the studies was by a working party of the committee on the safety of medicines. It looked at all the medical records of children whose parents had gone to solicitors looking to take legal action over the alleged link between autism or bowel disease and the MMR jab.
Mike Langman, professor of medicine at Birmingham university, who chaired the working party, said it reviewed 92 cases of autism and 15 of Crohn's disease. Medical reports indicated that in 36 cases there was evidence of autism before the vaccination and in another 28 there were family histories. Only eight autistic children and four with Crohn's appeared to develop symptoms after having the vaccination, but there was no reason to suspect MMR was the cause. None of the autistic children had Crohn's disease.
Rates of autism are rising, but not, the scientists stated, because of the MMR jab which was introduced in 1988.
The other study, published today in the Lancet medical journal, looked at 498 children with autism born since 1979 in the north Thames region. It was carried out by a team from the Royal Free Hospital medical school - where Andrew Wakefield and colleagues, who published the research, are also based.
Brent Taylor, professor of community child health, who wrote the Lancet report with Elizabeth Miller, of the public health laboratory service, and others, looked at the age when autism showed itself in each child. They took three measures - the age at diagnosis, the age at which parents first became concerned, and the age when the child's development seems to go into reverse and words are lost and behaviour deteriorates, which is common in autism. They compared these with the age at which the child had any vaccination for measles, with or without mumps and rubella.
They found the introduction of the MMR jab had no connection with the steep rise in cases of autism. "It is important to recognise that the rise occurred before the introduction of the MMR and there has been no change in the trend since," said Dr Miller.
The children with autism did not have more vaccinations, or at different ages, than other children. The age at which children were diagnosed with autism was the same whether or not they had the jab, and there was no cluster of cases or parental anxieties in the six weeks after vaccination.
Professor Taylor said: "I do hope our results will be able to reassure parents and others. A very large number of children are presently at risk of these very seriously damaging and occasionally fatal diseases."
No other studies, including a review of the evidence by the medical research council last year, have supported the theories of Dr Wakefield, Roy Pounder and their colleagues. Arie Zuckerman, dean of the Royal Free Hospital medical school, said the scientists had not provided any virological evidence for their claims.
In two publications recently - in the Journal of Medical Virology in August 1988 and in Gastroenterology this year - they had admitted they could not substantiate the link between measles virus and either Crohn's or autism.