A Decade of Research Shows No Link between Vaccines and Autism

by Guy McKhann, M.D.

March 12, 2009

For 10 years, a possible relationship between autism and the measles, mumps and rubella (or MMR) vaccine, commonly administered worldwide to children as young as one year, has concerned parents and the general public despite little scientific evidence of any link. The Sunday Times story “MMR Doctor Andrew Wakefield Fixed Data on Autism” outlines some of the issues that continue to plague this area of research.

The controversy began in 1998, when Andrew Wakefield published a research paper in the journal Lancet. In the article, Wakefield and 12 colleagues describe a study of 12 children, eight of whom developed a brain disorder after MMR vaccination. An important part of the original paper was the description of an inflammatory bowel condition that Wakefield later named “autistic enterocolitis.” Though the initial report was cautious, further comments by some authors, the media and parent groups emphasized the MMR vaccine as a cause of autism.

The appearance of a disabling neurological deficit such as autism in a child is a horrible thing for parents to experience. They often respond predictably, first with incredulity and non-acceptance, followed by a search for answers. This second phase is often one of anger—anger at the physician, anger at the heath system, anger at the lack of an explanation. “How could this have happened?” a parent will ask. “There must be a reason.”

Such frustration fueled the acceptance of vaccination as a cause of autism—a disease with no clear-cut explanation. The impact of this association was enormous. Increasing numbers of parents began to decline vaccination for their children. In 1998, 92 percent of children in England and Wales were vaccinated. By 2002, that figure had fallen to 84 percent—60 percent in some cities. The results of this unfortunate human experiment have confirmed the efficacy of vaccines. In 1998, only 56 cases of measles were reported in England and Wales. In 2006, there were more than 1,000. For mumps the situation is even direr: a low rate of infection in 1998 has expanded to more than 70,000 cases between 2004 and 2007. These childhood diseases used to be common, and their effects, such as encephalitis, or inflammation of the brain, which sometimes occurs with measles, were devastating. Vaccination virtually eliminated encephalitis as a complication.

We in the medical profession would dearly love to have an explanation for autism. A number of grants funded by the Dana Foundation are directed exactly at that research question. Thus, the suggestion that the MMR vaccine might be the culprit was not ignored. No other issue of autism research has received as much attention over the last 10 years. Careful studies have been carried out comparing rates of autism in vaccinated and non-vaccinated children, and in those receiving different kinds of vaccines, in this country and others. Thousands of children receiving the MMR vaccine have been analyzed. U.S. organizations such as the Centers for Disease Control and Prevention (CDC) and the Institute of Medicine of the National Academy of Sciences, as well as the U.K. National Health Service and the Canadian Pediatric Society, have all concluded that there is no evidence of a link between the MMR vaccine and autism, and that the benefits of eradicating measles far outweighs any presumed side effects. Children should get their MMR vaccinations!

What about Wakefield and his colleagues? In 2004, ten of the original authors retracted the original paper from Lancet, stating “We wish to make it clear that in this paper no causal link was established between MMR vaccine and autism as the data was insufficient.” Wakefield, who did not participate in that retraction, has had his own problems as outlined in the Times article. He is currently being reviewed by the British group that monitors medical practice, the General Medical Council (GMC).

You would think that the issue would have since died off, but it hasn’t. The legal profession has helped to perpetuate it. There are over 5,000 related law cases currently in the courts. A major step in accepting the scientific conclusions occurred recently when a special federal “vaccine” court considering three cases found that the evidence did not prove a link between autism and early childhood vaccines.

Prevention is a goal of public health policy. There is no greater prevention then what has been achieved with vaccination. In my own medical lifetime I have witnessed the eradication of polio, measles, mumps and the effects of rubella during pregnancy. There is now a vaccine for cervical cancer. As discussed in previous columns, vaccines are being tried as therapies for Alzheimer’s disease. And scientists are desperately trying to develop vaccines against two current worldwide killers: HIV and malaria. The evaluation of the safety and efficacy of vaccines should be a scientific—not political—issue.