The parents fear the vaccine could cause autism or other disorders following controversial research disputed by the government.

Family doctors in the Swansea area are calling for a local campaign to encourage take-up of the MMR jab.

In some parts of the city, so many parents are refusing the jab that immunisation rates are down to just 72%, while twice as many teenagers are contracting mumps.

Roland Salman of the Communicable Diseases Centre

Yvonne Davies was so worried about the triple vaccine that she paid £200 so that her grand-daughter Nia could have three, single injections administered privately.

But she worries that the decision over what kind of vaccine to use is being made more difficult by a government determined the triple dose is safe.

"Before long, people will say:' I'm not having the MMR - but unfortunately I can't have an alternative, even privately, and there will be epidemics'."

Rubella fears

Doctors suspect measles cases are on the rise too, as some children fail to return for a booster vaccination.

They are also concerned at the prospect of a return of rubella, said Dr Roland Salman, Director of the Communicable Diseases Centre.

"In the future, when these girls become women of child-bearing age, they will be susceptible to getting German measles when they are pregnant.

"The worry would be that we will see an upswing of handicapped children," he said.

The controversy over MMR began in 1998, following research by Dr Andrew Wakefield, then a reader in experimental gastroenterology at London's Royal Free Hospital.

This is a genuinely new syndrome and urgent further research is needed:   Dr Andrew Wakefield: 1998

In February, he suggested that the MMR vaccine might be linked to an increased risk of autism and bowel disorders.

Dr Wakefield said he had evidence that children's behaviour changed drastically, shortly after they received the MMR jab.

He said: "This is a genuinely new syndrome and urgent further research is needed to determine whether MMR may give rise to this complication in a small number of people."

Dr Wakefield put forward a theory that the combination of the three virus strains contained in MMR may overload the body's immune system and cause the bowel disorder to develop.

Controversy continues

But the UK Government has always rebutted his theories and, in March 1998, a panel of experts set up by the Medical Research Council said there was "no evidence to indicate any link" between the MMR jab and bowel disease or autism in children.

Since then, the government has continued to cite ongoing studies to support its views that MMR is safe.

Dr Wakefield has continued to maintain his concerns about its safety.