More than 500 children suffered serious reactions following last year's measles vaccination campaign, which some scientists believe was unnecessary.
Tom Sackville, Parliamentary Secretary at the Department of Health, said last night that one quarter of the 530 cases were of the "immediate allergic type reactions from which no serious or long-lasting effects were known to have resulted."
Three-quarters suffered "late-onset" serious reactions, such as arthritis or flu-like symptoms but none suffered any long-term damage, a spokesman for the Department said. "The Medicines Control Agency has checked them all out and found no causal link."
But parents of more than 170 children who, it is claimed, developed crippling illnesses after the immunisation, last night dismissed suggestions that no child suffered long-term damage.
They claim their children, aged between five and 16, have been left with problems ranging from partial paralysis and incontinence to seizures and brain damage, and up to 100 promised they would continue with legal action for compensation. The parents say appropriate warnings about the risks were not given.
Jackie Fletcher, founder of JABS, a parents' support group ,said: "The ministers are out of touch with what has happened if they truly believe that no child suffered long-term damage."
The campaign to vaccinate 8m school children in the UK followed public health specialists' forecasts of a measles epidemic on a scale not seen since the 1950s. Parents were told that up to 200,000 people could be infected, and there would be up to 50 deaths among children in an outbreak.
In the event, only 35 measles cases were diagnosed in the first four months of 1995, just two of them in children.
The Government says this proves the success of the campaign, but critics, led by Dr Richard Nicholson, a paediatrician and editor of the Bulletin of Medical Ethics, say evidence to support predictions of an epidemic has never been produced.
Speaking during a Commons adjournment debate last night, Mr Sackville said that, by mid-1994, measles was occurring at a higher frequency in England and Wales and an epidemic had already occurred in Scotland.
There was a total of 2,735 reactions reported from 1,202 children - a rate of one child affected for every 6,700 reactions. Most reports were of minor damage or of harm unlikely to have been caused by the vaccine. There were no deaths.