AN OFFICIAL study used by the Department of Health to claim that there is no link between mercury used in National Health Service vaccines and autism in children is flawed, the author has admitted.
The research, by the American government's Centres for Disease Control and Prevention (CDC), has been repeatedly cited by the department and the Public Health Laboratory Service (PHLS) as evidence that mercury in vaccines is not a cause of autism. The fact that the research does not stand up to scrutiny will cause them acute embarrassment.
The CDC study cited by British officials examined whether there was any link between disorders in brain development, including autism, and a preservative called thiomersal, which is almost 50% mercury and is used in some childhood vaccines. It found no link with autism.
But confidential minutes of a secret meeting at which the research findings were presented reveal an admission by the author that many children in the survey were too young for autism to have been diagnosed.
Extracts from the minutes, obtained through America's freedom of information act by Elizabeth Birt, a lawyer and mother of an autistic child, were read out at a public meeting organised by the Institute of Medicine in Cambridge, Massachusetts, last week.
The author of the study, Dr Thomas Verstraeten, from the CDC's national immunisation programme, is quoted as saying: "One thing is for sure, there is certainly under-ascertainment of all these [conditions] because some of the children are just not old enough to be diagnosed."
A professor who has reviewed the research has also admitted that there were too few children in the study to pick up all cases of autism.
Regulators in both America and Europe recommended in July 1999 that mercury should be phased out of childhood vaccines and last month it emerged that the PHLS is to conduct a study into the possible adverse effects of mercury in vaccines, including autism.
There has been a rise in autism that coincides with the availability of more vaccines containing mercury, a lowering of the age at which they are given to babies and the introduction of the combined MMR vaccine, which does not contain mercury.