A report in the online medical journal International Paediatrics said the relative risk of autism in a child was five times higher after administration of the measles, mumps and rubella vaccine than for DTP, another combined vaccine, against diptheria, tetanus and pertussis (whooping cough).

British groups campaigning for single vaccines said that the study justified their concerns. But the findings were dismissed as flawed by the Department of Health and the government's health protection agency (HPA).

The research was conducted by Dr Mark Geier and his son, David Geier, based in Silver Springs, Maryland. They have made several studies of reported adverse reactions to vaccines.

Dr Geier, president of the Genetics Centers of America, and Mr Geier, president of MedCon, a medical-legal consultancy, examined a database set up by the centre for disease control.

According to the database, almost 25 million first doses of MMR were given to children between 1994 and 2000, compared with 63 million for DTP. Of the MMR doses, there were 133 reports of suspected neurological problems, autism, brain damage and loss of coordination. There were 29 reports of autism among boys and eight among girls - five times higher than for DTP.

The study said that improvements needed to be made to the MMR vaccine to increase its safety, but failing that, parents ought to be offered single jabs for their children.

Andrew Wakefield, the doctor who first suggested MMR's link with autism five years ago, said that the report made the current practice of refusing individual vaccines "untenable".