Medical Institute Set to Determine if Vaccines Really Cause Autism
The diagnosis of autism often occurs around age 2, when the MMR vaccine is administered. There also has been an apparent increase in the incidence of autism since the introduction of the MMR vaccine. These associations spurred some researchers to look for a possible link.
Chief among those is British researcher Andrew Wakefield, MD, an expert in bowel diseases at the Royal Free Hospital School of Medicine in London. In 1998, Wakefield sparked the debate by publishing a paper outlining the time-based association and hypothesizing that the MMR vaccine may trigger autism by causing bowel damage.
A damaged bowel would fail to properly filter dietary products in the gut and, in effect, allow toxic materials to be distributed in the brain, Wakefield explained.
Since then, his theory has inspired other researchers to pursue the link between MMR and autism. Among that group is Vijendra Singh, PhD, a research professor at Utah State University in Logan, Utah.
"Based upon my research, there is a good possibility that the MMR vaccine might be the culprit," Singh tells WebMD.
His research shows that up to 80% of autistic children have antibodies triggered by the measles virus that also appear to attack a particular protein in the brain, Singh explains. Therefore, it is conceivable that the MMR vaccine may be responsible because it exposes the child to the virus, Singh says. It also is not inconceivable that those children with bowel damage would be more susceptible because their brains would be exposed to a higher level of that virus, he says.
"I cannot conclusively say that I have found a fundamental cause," Singh tells WebMD. "But this is good science. It should not be ignored."
Still, the majority of experts disagree. They say the time-based association is coincidental and that autism is a genetic disease that is triggered by some other environmental factor during the first three months of pregnancy.
In fact, there is absolute proof that the MMR vaccine is not a cause of autism, says Paul Offit, MD, a pediatrician and chief of infectious disease at the University of Pennsylvania School of Medicine. The incidence of autism is really no greater whether children receive the vaccine or not, he explains. And although the diagnosis is often made around age 2, trained experts frequently can identify autistic children at a much earlier age, he tells WebMD.
As for the increase in the number of reported cases, Offit points out that U.S. and U.K. recently adopted a broader definition of autism that seems to be capturing a larger number of cases.
And as for Wakefield's bowel theory, Offit observes that Wakefield failed to study the children who got the vaccine but didn't develop autism when he developed his theory -- even though those children often exhibit the same bowel symptoms.