New research shows that measles-mumps-rubella vaccination does not raise the risk of pervasive developmental disorders (PDDs), such as autism.

The current report is the latest of numerous studies to show no association between the MMR vaccine and autism.

As reported in this week’s issue of The Lancet medical journal, Dr. Liam Smeeth, from the London School of Hygiene and Tropical Medicine, and colleagues conducted a study using the UK General Practice Research Database to assess the possible link between MMR vaccination and PDDs.

The analysis included 1294 subjects who were born in 1973 or later and had a PDD diagnosis on record between 1987 and 2001. They were compared with a control group of 4469 subjects who were matched by age, sex and general practice.

The authors found no evidence that MMR vaccination increased the risk of PDD. In fact, such vaccination was tied to a 14 percent reduction in the risk of PDD, although this could have occurred by chance, statistically.

The absence of an association between the MMR vaccine and PDD was also seen when the analysis was limited to children with autism, those vaccinated prior to the third birthday, or to the period before the media began coverage of the hypothesis linking MMR with autism.

“We have found no convincing evidence that MMR vaccination increases the risk of autism or other PDDs,” the investigators note. “Research into the real origins of autism is urgently needed.”

SOURCE: Lancet, September 11, 2004.