The Government tried to bolster faltering public confidence in the MMR (measles, mumps and rubella) vaccine yesterday by issuing results from the biggest study to date on its safety.

The Government tried to bolster faltering public confidence in the MMR (measles, mumps and rubella) vaccine yesterday by issuing results from the biggest study to date on its safety.

Experts fear a public health disaster if unfounded fears about the vaccine leave large numbers of children unprotected against diseases which can cause permanent damage and death. Outbreaks of measles in Ireland and Holland in the past year have infected 3,500 children, put scores in hospital and left five dead.

Finnish researchers who followed up 1.8 million children given three million doses of MMR vaccine between 1982 and 1996 found no cases of autism or bowel disease linked with the vaccine. There were 173 adverse reactions but 45 per cent were "probably caused or contributed" by a factor other than the vaccine.

Government scientists yesterday cited the study, in the December issue of The Pediatric Infectious Disease Journal, in the growing body of evidence showing the vaccine is safe. More than 500 million doses of MMR have been given worldwide and continuous monitoring has not revealed a significant risk.

There has been a sharp fall in uptake of the vaccine since publication of a study in 1998 by a team from the Royal Free Hospital, London, suggesting a link with autism and bowel disease. In the UK, four studies examining the suggested link have failed to confirm it. But national vaccination rates with MMR have fallen from 93 per cent to 88 per cent and in some areas, mainly in London, they have fallen to 74 per cent, increasing risk of a measles outbreak.

Loss of confidence in MMR has led to rising demand for the three component vaccines to be given separately. At a Health Department press conference yesterday, the heads of the Committee on Safety of Medicines (CSM) and the Joint Committee on Immunisation and Vaccination (JCIV) rejected this, saying it would increase the risk to children.

David Salisbury, head of the Health Department's immunisation programme, said giving the three vaccines separately, with a period of weeks or months between each, would mean children were left partially unprotected until they had all three vaccines.

"They will get measles, some of them will die. They will get rubella and they will infect their pregnant mothers and they will have children who will be severely damaged."

Professor Michael Langman, chairman of the JCIV, which decides vaccine policy, said if four months were left between each single vaccine and measles was the last to be given, it would mean 650,000 children aged one to two would be exposed to the risk of measles for that period. "Measles does kill," he said. "Denying children the [MMR] vaccine is actually dangerous. That is all there is to it."

Japan was the only country in the world that recommended single measles and rubella vaccines but it suffered periodic outbreaks of measles because children were vulnerable between jabs. Between 1992 and 1997 there were 79 deaths from measles in Japan. There have been no deaths from measles in the UK since 1990.

Professor Alasdair Breckenridge, chairman of the CSM, said evidence for the safety of MMR was better than that for single vaccines because MMR had been used more widely, for longer and with extensive reviews. No such safety review had been conducted of the single measles vaccine which is not licensed in the UK.

"The overriding message is that there is an extremely large body of evidence, including modern, large, long-term studies, which supports the safety of MMR," he said.

Dr Liam Fox, Tory health spokesman, said he accepted MMR vaccine was safe but separate vaccines should be made available until public confidence was restored.