Separate doses of measles, mumps and rubella vaccines are not a safe alternative to the combined MMR jab, which some parents have shunned because of scares over alleged links to autism and bowel disease, government and independent scientists said yesterday.
The heads of the independent Joint Committee on Immunisation and Vaccination (JCVI) and the Committee on the Safety of Medicines, as well as the government's head of immunisation, came together to warn that obtaining individual vaccinations for the three diseases involves delay, which exposes children to the real and increasing risk of infection. Last week the government said that low rates of immunisation could shortly lead to a fatal measles outbreak, as it did last year in Ireland, where there were two deaths, and the Netherlands, where there were three.
Michael Langman, head of the JCVI, said there were also worries about some of the individual vaccines available in other European countries. Some parents in Britain have gone abroad for supplies of separate vaccines because of the MMR scare.
"The mumps vaccine in France is the Urabe vaccine, which is one we have abandoned in the UK because of a distinct, though small, risk of meningitis," he said. He added that there were doubts about the efficacy of the measles vaccine used in Switzerland and that high potency measles vaccines used in the past had been withdrawn by the World Health Organisation. The main measles vaccine used in Europe is, however, the same one used in the MMR jab.
The government has banned individual vaccines from the NHS, but some private clinics have imported supplies.
The scientists cited Japan as proof that single vaccinations do not protect the population as well as the combined MMR. In Japan, which has single measles and rubella injections, there were 79 deaths from measles between 1992 and 1997. There have been no deaths in Britain since 1990.
The two committees had again reviewed the safety data for the MMR vaccination, the scientists said, and concluded that the combined jab was the safest way to protect children.
They cited a 14-year follow-up study of children immunised with MMR in Finland, released last month, which found only 173 potentially serious reactions in 1.8m children vaccinated. Nearly half those reactions were probably caused by other things. The most serious were cases of encephalitis, of which there were three.
The authors of the study say they found "no cases of inflammatory bowel disease or autism" linked to MMR.
"This finding is important because were there an association with MMR vaccination after such a short interval as suggested, this prospective study design would undoubtedly have disclosed at least some cases," they write in the Paediatric Infectious Diseases Journal.
The scientists were mounting a pre-emptive strike ahead of a further study to be published by Andrew Wakefield of the Royal Free hospital in London. Dr Wakefield first suggested a link between MMR, bowel disease and autism in a paper which caused uproar when it was published in the Lancet in February 1998.
Dr Wakefield's next paper is expected to question the clinical trials that were carried out to ensure the safety and efficacy of the combined MMR before it was licensed in 1972. He is expected to claim that the trials were inadequate, the follow-up data was collected over too short a period and that the vaccines can interact.
Alasdair Breckenridge, chairman of the Committee on the Safety of Medicines, insisted there was sufficient evidence of MMR's safety available in 1972, and that there was far more evidence now that more than 500m doses have been given to children worldwide.
David Salisbury, head of immunisation at the Department of Health, said officials were concerned about further scare stories. "This would be a really unfortunate time to have coverage go down when we really need to be working our hardest to get coverage up," he said.
