A team of Irish scientists say they have found a possible link between the measles virus and a new form of bowel disease in autistic children, writes Paul Cullen
Their research will add fuel to the debate on the controversial MMR vaccine, though the authors stress their research did not examine this issue.
The study by scientists from the Coombe Women's Hospital and Trinity College, Dublin found the measles virus in gut samples from 75 children out of 91 with bowel disease and autism. Only five out of 70 healthy children in a control group were found to have the virus.
Prof John O'Leary, a molecular pathologist at the Coombe hospital, says the research raises many questions about whether the measles virus has a role in bowel inflammation in autistic children. The study suggests the virus may act as an "immunological trigger".
However, he says, "the research did not set out to investigate the role of MMR in the development of either bowel disease or developmental disorder, and no conclusions about such a role could or should be drawn from our findings".
The research will be published in the journal, Molecular Pathology, in April but is already available on the journal's website, www.molpath.com.
The take-up of the MMR (measles, mumps and rubella) jab has fallen to record low levels in Ireland, largely due to public fears about a possible link between the vaccine and autism.
While medical authorities insist these fears are groundless, the take-up has dropped to less than 60 per cent in the Eastern Region Health Authority area, and about 70 per cent nationally. Public health experts have warned this could lead to a measles epidemic similar to that threatening Britain.
There were 1,595 case of measles in Ireland in 2000, the last year for which figures were available. Two children died in that year. Although the overall number of cases dropped last year, the risk of a measles epidemic is very real, according to the National Disease Surveillance Centre.
Prof O'Leary and his colleagues used samples supplied by a British research team which published the original research into the measles virus and a form of bowel disease, and suggested a further link to autism.
A commentary accompanying the published research also stresses that Prof O'Leary's work was not concerned with MMR.
"It would be entirely wrong to jump to the conclusion that the measles component of MMR 'causes' the colitis (bowel disease) or the development disorder in these particular (or any other) children," write Dr Alan Morris and Dr David Aldulaimi of Warwick University.
"Causation is rarely simple and never pure: most if not all diseases are multi-factorial in nature and the data here could equally well be interpreted as indicating that the colitis or the developmental disorder 'cause' the persistence of measles.
"In no way can the data presented here be used to support the generalisation that MMR causes all autism and/or inflammatory diseases of the bowel."
Dr Morris and Dr Aldulaimi say "reliable epidemiologists" are content that there is no significant association between MMR and either autism or bowel inflammatory conditions.
"However, epidemiology is a pretty blunt tool and the studies done do not rule out the possibility that there may be 'at risk' groups where a real link between MMR and autism/bowel inflammatory conditions exists."