TWO children who claim that they were severely disabled by the triple vaccine for measles, mumps and rubella have launched a multi-million-pound test case to claim compensation from the manufacturer.

Adam Wilsher, 14, who is deaf, and Paul Sayers, 11, who suffers from acute autism, have received Legal Aid to pursue SmithKline Beecham, the manufacturer of an MMR vaccine, for negligence and breach of duty.

The cases are the first writs served against a manufacturer of the MMR injection which was administered to more than four million children. The outcome will determine whether another 500 children who claim to have experienced adverse side-effects will follow.

Other children claim to have suffered brain damage, communication problems, arthritis and immuno-deficiency diseases from MMR vaccines and can be expected to seek up to £1 million each, according to legal experts.

The writs are the culmination of a 10-year campaign by parents. Jackie Fletcher, a founding member of Jabs, a pressure group that supports the families of children claiming to have been affected by vaccines, said: "The myth of the triple vaccine being safe will finally be laid to rest if we win. This has been a long struggle and we hope that justice will be done for our children."

Mrs Fletcher's son, Robert, was three and beginning to speak when he had his injection. He subsequently suffered from autism and epilepsy. She said that at least 500 members of Jabs wanted compensation. Mrs Fletcher stressed that the parents were not calling for all vaccines to be abolished. They were asking for recognition that some children had been disabled as a result of the MMR vaccine and should be compensated.

Paul Sayers, of Beaumaris, Anglesey, suffers from severe autism - a psychiatric disorder that makes it difficult for him to communicate or make relationships - and needs to be cared for day and night. His parents followed the advice of the former chief medical officer, Sir Kenneth Calman - that it was better for children to accept the vaccine rather than run the risk of being contaminated by one of the three viral diseases.

Paul's medical problems began when he was given the MMR injection in 1988. Innys Sayers, his mother, believes that the vaccine proved too traumatic for her son. She said: "I have given up my career in publishing and moved away from London because of the effects of the vaccine. Now my life revolves around caring for my son and providing the stability he needs."

Adam Wilsher was four when his parents took him for the MMR vaccine in October 1988. They claim that he suffered violent side-effects as soon as the injection was administered, became very ill, and lost his hearing while recovering.

The combined MMR vaccination against all three viruses was introduced in Britain in October 1988 after being widely used for several years in America. In September 1992, after research linked a cluster of cases of meningitis in Nottingham to batches of the mumps strain in the vaccination, products made by two of the three manufacturers, SmithKline Beecham and Merieux, were withdrawn.

All three vaccines used weakened mumps, measles and rubella viruses, to stimulate resistance. The two withdrawn brands were Immravax, made by Merieux UK Limited, and Pluserix, made by SmithKline Beecham.

Both the Sayers and the Wilsher families claim that the Pluserix injection was defective and that the injuries were caused by the manufacturer's negligence in the research, manufacture, testing and development. SmithKline Beecham denies liability and said that its vaccine was withdrawn in 1992 as soon as the manufacturers became aware that it carried an increased risk of provoking meningitis. A spokesman for the company said: "There is no proof that the vaccine causes deafness or autism."

Since 1992 all the triple vaccines have been produced by Merck Sharpe and Dohme, with about a million babies a year being immunised in this way.

17 September