The most in-depth analysis to date has cleared the controversial MMR vaccine of any link to autism or bowel disease.

The researchers say their findings provide clear reassurance for patients and health professionals that the combined jab for measles, mumps and rubella is safe.

A team led by Dr Anna Donald and Dr Vivek Muthu have examined research into MMR from 180 countries around the world.

MMR is the best way to protect children against measles, mumps and rubella

Department of Health

They found no evidence that MMR or single measles vaccines are associated with autism or inflammatory bowel disease.

But they did find strong evidence that both MMR and single measles vaccination virtually eliminate risk of measles and measles complications.

Fever

The researchers also found evidence that both types of vaccine are associated with a small risk of developing a minor fever within three weeks of vaccination.

However, measles itself causes acute fever in all infected children.

Dr Anna Donald said questions had been answered

The link between MMR and autism and inflammatory bowel disorders was raised by controversial research carried out in 1998 by Dr Andrew Wakefield, then of London's Royal Free Hospital.

Dr Wakefield highlighted a possible relation between MMR and developmental disorder in 12 children with bowel symptoms.

Subsequent public concern over the safety led to a record low vaccination rate between July and September 2001 of just 84.2%, though the rate has recently risen again.

The government says that 95% of children need to be immunised to eradicate the threat of a measles epidemic.

Flaws

The latest research, published in the journal Clinical Evidence, says that Dr Wakefield's research was flawed in a number of ways.

It was small, selective in its sample, and failed to make comparisons with healthy children.

How can scientists explain to parents the coexistence of these symptoms in their children?

David Potter

The researchers conclude that the study "does not establish MMR as a cause of inflammatory bowel disease, autism, or developmental regression, and that its hypothesis has been satisfactorily tested by scientifically reliable studies."

A Department of Health spokesman said "This review confirms earlier studies that the scientific evidence finds no link between MMR and autism or inflammatory bowel disease.

"We hope that parents are encouraged by these latest conclusions on the safety of this vaccine.

"Vaccine safety is a paramount concern and we will continue to monitor all the evidence.

"MMR is the best way to protect children against measles, mumps and rubella."

Scepticism

But Dr Peter Mansfield, a GP from Louth in Lincolnshire, who was reported to the General Medical Council for offering his patients single measles jabs, said the study did not offer conclusive proof that MMR was safe.

He said Dr Wakefield's research was not the only study that provided cause for concern. Another study had found traces of the measles virus in the bowel lining of children with a form of autism, but not in other children.

Dr Mansfield told BBC News Online: "It must be wrong to say there is no evidence linking MMR to autism and bowel disorders, although it may be possible to say that evidence is counterbalanced by evidence that points to the opposite."

Dr Mansfield said he was awaiting the results of a major review of the research currently being undertaken by the Oxford-based Cochrane Collaboration, due to be published at the end of the year.

The National Autistic Society said there were a significant number of parents whose children have autism and severe gastrointestinal symptoms.

But Jackie Fletcher, of campaign group Jabs, said: "This is a review of a review of reviews."

There had been a "missed opportunity" to examine fresh evidence of children with MMR, she said, adding that personal testimonies should be taken from parents.

David Potter, head of autism policy and information at the NAS, said: "How can scientists explain to parents the coexistence of these symptoms in their children?

"There is an urgent need to study these cases to establish what physiological and pathological mechanisms are occurring in these children if parents are to be reassured."