"No link" between MMR and autism

Scientists say they have strong evidence that the MMR vaccination is not linked to a rise in autism.

Researchers looked at the incidence of autism in a Japanese city before and after the withdrawal of the measles, mumps and rubella jab in 1993.

New Scientist reports autism rates kept rising after MMR was withdrawn.

Michael Rutter of the Institute of Psychiatry who worked on the study, said it "rubbished" the link between MMR and a general rise in autism.

However, autism campaigners said they would want to see more conclusive proof from UK-based studies before being convinced the jab was safe.

Concern over a link between the two were raised after a study by Dr. Andrew Wakefield published in the Lancet in 1998 which claimed MMR might trigger autism.

However, no research has ever proved a link, and the overwhelming majority of experts believe the vaccine is safe.

Despite this, rates of MMR vaccination in England have continued to fall. In some areas, they are just over 60%.

Steady rise

This study is the first to look at rates of autism after the withdrawal of the vaccine.

Japan withdrew MMR after concerns that the strain of mumps vaccine it contained was linked to cases of meningitis, and replaced it with single vaccines.

MMR take-up had fallen steadily in the years prior to its removal.

Japan's program targeted one-year-olds. The proportion who received the jab fell from 69.8% in 1988, to 33.6% in 1990 and just 1.8% in 1992.

The researchers from the Yokohama Rehabilitation Center and the Institute of Psychiatry looked at the incidence of autism spectrum disorders among 31,426 children up to the age of seven born from 1988 to 1996.

The research, also published in the Journal of Child Psychology and Psychiatry, found that the number of cases continued to rise after the MMR vaccination programme stopped.

There were between 48 cases per 10,000 children born in 1988.The rate was steadily seen to rise to 117.2 per 10,000 for those born in 1996.

The same pattern was seen in incidence of a particular form of autism in which children appear to develop normally and then regress, which Dr. Andrew Wakefield linked to MMR.

UK research call

Professor Rutter told the BBC News Website: "If there was a true causal relationship between MMR and autism, one would have expected rates to fall after the vaccine was withdrawn.

"In fact, the rate continued to rise."

He added: "These findings are resoundingly negative in relation to the link between MMR and autism. They rubbish the claim that MMR is having a general effect on the rate of autism."

He said the research did not deal with the suggestion that there is a small group of children who are unusually vulnerable in whom MMR triggers autism - but there was no evidence that this was the case.

However, Professor Rutter said there had certainly been a rise in autism cases.

"Professionals are better at picking it up. And there has been a broadening of the definition, so it's not just children with the most severe form of autism, but all gradients within the range of autistic disorders who are diagnosed."

Jean Golding, Professor of Paediatric and Perinatal Epidemiology and is based in the Department of Clinical Medicine at the University of Bristol, is carrying out research into the causes of autism.

She said: "These findings are in line with all of the other research that's been done. I think that this is evidence that there isn't a link."

Stuart Notholt, of the National Autistic Society added: "This new research on the MMR vaccination and autism adds to the body of evidence, most of which would support the hypothesis that there is no link between the MMR vaccination and autism."

And Stephen Rooney, of Sense, the national deafblind and rubella association, said: "Since MMR was introduced, the number of congenital rubella births and the number of rubella-related terminations of pregnancy have both fallen dramatically."

The Department of Health said the research supported its belief that MMR remained the best form of protection against measles, mumps and rubella.

But Jackie Fletcher of the campaign group Jabs, said: "Instead of relying on research carried out abroad, we would like the government to actually clinically investigate the 1,700 children believed to have been affected by the MMR jab in the UK.

"We've all got the same objective of preventing infectious diseases. But we also want to prevent injury to children too."

Source: BBC News