Study: Vaccines Don't Cause Autism
MMR, Thimerosal-Exposure Not Linked to Incidence
The Search for Answers
So if vaccines are not contributing to the rise in reported autismautism cases, what is? Fombonne says the increase can be explained by a broadening of what is considered autism and related disorders, increased awareness of these disorders, and a greater emphasis on early diagnosis.
American Academy of Pediatrics spokesman Joseph Bocchini, MD, tells WebMD that while it is clear that these are important contributors to the increase in diagnosed cases, other unidentified contributors may also be playing a role.
Bocchini is chief of pediatric infectious diseases at Louisiana State University Health Sciences Center in Shreveport.
"We don't know if there is an actual increase in incidence, but we are working to find that out," he says.
He adds that the Canadian study supports a "large body of data" showing no association between MMR vaccines or thimerosal exposure and pervasive developmental disorders like autism.
"It is understandable that parents of children with these disorders would want to find something that they can point to as a cause, and it is also understandable that they would look at vaccines. But when you look at the evidence in an objective way there is simply nothing to link vaccines with these disorders."