Thirty leading paediatricians and childhood vaccination experts have warned that continued doubts about the safety of MMR will cost lives.
MMR protects against measles, mumps and rubella
In an open letter, they plead for the media and health professionals to stop raising doubts about a vaccine they say science has shown to be safe.
The measles, mumps and rubella vaccine was linked to autism in a Lancet paper.
The 1998 paper has since been discredited, but immunisation rates have dropped in recent years.
To provide protection for the whole community the rate must be 95%. However, last year it was 83% for the UK.
This has led to fears that children in the UK are vulnerable to a mass outbreak of measles.
Cases of the disease, which can be fatal, have increased sharply. The Health Protection Agency has reported 449 cases so far this year - more than the total of 438 for the whole of 2003.
The lead author of the original paper, Dr Andrew Wakefield, is the subject of a General Medical Council investigation.
Conflict of interest
And the editor of The Lancet has admitted he would not have published the paper if he had been aware at the time of what he called a "fatal conflict of interest".
It said Dr Wakefield was funded to see if there was any evidence to support possible legal action by a group of parents who claimed their children were damaged by the vaccine. Some children were involved in both studies.
Dr Wakefield denies receiving any direct payment, and said funds were given instead to the hospital at which he worked, London's Royal Free.
A raft of major studies has found no evidence that the triple vaccine - which protects against rubella and mumps as well as measles - is unsafe.
However, leading doctors are concerned about the way a recent US study which found evidence of the measles virus in the guts of children with autism was reported.
They say the research was small-scale, inconclusive, preliminary and riddled with supposition - but this was not reflected in by the media.
And they warn it would be tragic if confidence in MMR, which had begun to return, was undermined as a result.
In their letter, they say: "We are now faced with a potentially serious situation.
"Years of low uptake mean large numbers of unprotected children are now entering school.
"Unless this is rectified urgently, and children are immunised, there will be further outbreaks and we will see more unnecessary deaths.
"It is not too late to avert this predictable tragedy. It is time that due weight is given to the overwhelming body of scientific evidence in favour of the vaccine.
"Misguided concepts of 'balance' have confused and dangerously misled parents. We all, media, politicians and health professionals, have a responsibility to protect the health of our children."
A Department of Health spokesperson welcomed the doctors' intervention.
"It is extremely important that parents protect their children from these preventable diseases. MMR is the safest and most effective vaccine.
"We strongly recommend that any parent who wants to make sure their child is up to date with their vaccinations contact their local surgery."
But Jackie Fletcher, of the lay campaigning group Jabs, said the fact that measles virus had been found in the intestines of some children with autism had still not been explained.
She said the doubts over MMR would not "go away at the stroke of a pen".