The disease, marked by an unusual inflammation of the gut, is associated with autism and could provide a clue to the origins of the devastating disorder which results in social withdrawal and difficulties in communication.
Researchers at the Royal Free Hospital in north-west London, who have studied 12 children with the syndrome, say that in eight the symptoms appeared soon after vaccination with MMR which is given at age 12 to 15 months to protect against measles, mumps and rubella. They claim to be the first in the world to identify the syndrome which they say has emerged since the start of the vaccination programme in 1988.
However, at a press conference called by the hospital yesterday to publicise the findings, published in the Lancet, doctors were divided about the implications. Most of those involved in the study say MMR vaccination should continue, but Dr Andrew Wakefield, leader of the team, said that it should be divided into its three component parts and given separately.
The hypothesis is that the combined vaccine delivers a jolt to the child's developing immune system which could be reduced if it were divided. Dr Wakefield said: "Vaccination should continue, but it will put children at no further risk if it is dissociated into three."
A commentary in the journal, which is sceptical about the study, says the link with MMR has not been proved and warns of a "social tragedy" if the public shuns immunisation. The first symptoms of autism commonly appear in the second year of life, about the time MMR is given, leading to the possibility of a false association. Before immunisation against measles was introduced, the disease killed around 90 children a year.
Dr Simon Murch, paediatrician and co-author of the paper said there was insufficient evidence to justify a switch to single vaccines. "The link is unproven and measles is a killing infection. If this precipitates a scare and immunisation rates go down then, as night follows day, measles will return and children will die."
Dr Wakefield, reader in experimental gastro-enterology, said he had studied a further 48 children, 46 of whom had the syndrome, and had 700 referrals awaiting investigation.
An earlier study by the team had suggested that the measles virus was implicated in Crohn's disease and that the rise in cases of that disease could be linked with measles vaccination. However, other investigators have failed to replicate the findings and remain sceptical about the link, according to the Lancet.
Dr Wakefield said: "After that study appeared I received a number of calls from parents whose children had lost acquired skills and speech shortly after MMR vaccination. They also had bowel problems. They all told precisely the same story. I thought I should investigate."
Tests revealed they all had the same, previously unseen, gut disorder which the researchers have called ileal-lymphoid-nodular hyperplasia, which is similar to Crohn's disease. Professor Arie Zuckerman, dean of the Royal Free Medical School, said: "I think caution is essential. Until robust virological evidence is available [to implicate MMR] this remains a hypothesis."