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New research says MMR vaccine does not cause autism

A new study published on Tuesday dealt a fresh blow to accusations that a triple vaccine against measles, mumps and rubella (MMR) is linked to autism.

The study, which appears in the Archives of Disease in Childhood published by the British Medical Association (BMA), found no evidence of any abnormal biological response from the shot that could point to a link between the vaccine and autism.

The investigation by British doctors comes nearly 10 years to the day since a paper, appearing in The Lancet, unleashed a health scare that prompted many parents to refuse the MMR jab for their children.

That paper has since been debunked by several other studies and was finally retracted by 10 of its 13 authors in 2004.

"This [new] study really supports the view these are safe vaccines," said David Brown, a researcher at Britain's Health Protection Agency who worked on the study. "The evidence is now so solid there really isn't a need for further studies here."

In 1998, Dr Andrew Wakefield of Royal Free Hospital in London and colleagues sparked a fierce worldwide debate among scientists and a health scare by suggesting the MMR jab caused autism. Outbreaks of all three diseases followed.

The new study is based on antibody tests on blood samples taken from 240 children aged between 10 and 12 in southern England. It looked at 98 children with autism, and two comparison groups -- 52 children with special educational needs but no autism, and 90 children who were developing normally.

All of the children had been given the MMR vaccination, but not all had been given the two scheduled doses.

The researchers looked at three paths that have been shuggested as the various links between MMR vaccine and autism: evidence of persistent measles infection; an abnormal immune response; and an inflammatory bowel disorder called enterocolitis.

They found no association at all.

Other investigations into the MMR scare have similarly found no evidence to support a link.

Two of them have been large-scale population studies -- one among 31,000 children in Japan and 28,000 children in Canada -- while one probe was conducted into a mercury-based chemical, thimerosal, used as a preservative in MMR vaccines but dropped in 1999.

Autism is a neuropsychiatric disorder that impairs a child's ability to communicate and interact with others.

The disorder appears to have been rising massively in developed countries for the past two decades, but experts are divided as to why this should be so.

Some say there may be an environmental cause. Others say that cases of autism are more likely to be detected and reported because the taboo surrounding this condition is receding.

The MMR scare was mainly centered on Britain, but also affected other countries to a lesser degree. In some parts of Britain, the proportion of children getting the vaccination slumped to 60 percent, triggering outbreaks of measles that placed infants' lives at risk.
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