A hypothesis linking childhood vaccines with autism has been the subject of an intense debate for almost a decade. On one side are the parents and families of autistic children, many of whom are convinced that the link between autism and vaccines is real. On the other side are researchers who have conducted numerous medical studies, some involving thousands of children, that have found no evidence that autism is linked to vaccines.

As the debate rages on, parents of autistic children are accused of looking for someone to blame, and possibly to sue. Other people believe that the medical community and pharmaceutical companies know there’s a connection between autism and vaccines and are conspiring to keep this information from the public.

The Case for Autism Linked to Vaccines

The argument that childhood vaccines and autism are related is based on both scientific and anecdotal evidence. In fact, the average age of autism onset corresponds closely with the age at which children receive the Measles, Mumps, and Rubella (MMR) vaccine.

Over the last 20 years, supporters of the argument claiming an autism and vaccine link note that incidence rates of autism have increased from one in 10,000 to one in 150. Such an enormous increase must, they argue, have a common cause. And the one event that most children share is childhood vaccinations.

The ‘autism linked to vaccines’ side of the argument does have a smoking gun to point to: the preservative thimerosal. Thimerosal was a common ingredient in childhood vaccines until 1999, when pharmaceutical companies bowed to public pressure and began removing it from vaccines.

Thimerosal became a prime suspect in the search for a link between childhood vaccines and autism because it contains high amounts of mercury. For the most part, thimerosal is no longer used in childhood vaccines, but some pharmaceutical companies still have it listed on their vaccine labels.

The more extreme members of the autism and vaccines camp argue that this is because if the companies removed thimerosal all at once, autism rates would plummet, leaving the companies open to damaging lawsuits.

The Case against Autism and Vaccine Connections

On the other side of the “do vaccines cause autism?” question are organizations such as the Institute of Medicine, the Centers for Disease Control and the Food and Drug Administration.

The argument against the link between childhood vaccines and autism relies on multiple studies involving hundreds of thousands of children, none of which have found any link between autism and vaccines.

Opponents of these studies sometimes suggest that the results are influenced more by politics than facts, implying the government and pharmaceutical companies influence the published results. Similar extensive studies done in Canada and Europe, however, agree with the American research results.

The MMR vaccine receives the most study, mostly because of the apparent link between the three in one vaccine and the onset of many children’s autistic symptoms. This apparent link may be nothing more than coincidence: the average age of autism onset (approximately three to four years of age) may simply coincide with the MMR vaccination.

Are We Asking the Right Questions?

People on both sides of the autism and vaccines debate want a clear answer to the question. Many insist that the real issue is not who’s to blame, but how to solve the dilemma.

Some suggest that medical studies may not be asking the right questions. A 2007 parent phone survey by Generation Rescue compared rates of autism and other neurological disorders in vaccinated children with unvaccinated children. According to survey results of 9,000 boys aged four to 17, vaccinated boys were 61 percent more likely to have autism.

Previous studies have not compared vaccinated and unvaccinated children. While this study certainly breaks new ground, it is only one study, and further research is needed to confirm or refute its findings. In other words, this debate isn’t likely to end soon.

Balancing the Risks

Do vaccines cause autism? The jury is still out on the question. If thimerosal is indeed the culprit, we will see a dramatic drop in autism in the next few years.

Even if a link exists between autism and childhood vaccines, parents must balance the risk of autism against the risk of the diseases the vaccines prevent. In the Western world, for instance, we easily forget that measles remains a killer in third world countries. The debate then turns to which is worse: autism or the diseases vaccinations prevent?

Hopefully, further research on vaccines and autism will either establish the link between the two and end the crisis or refute the link and allow researchers to pursue the investigation of other possible causes.


Fackler, A. (2005). Autism and childhood vaccines. Retrieved July 5, 2007, from the Yahoo Health Web site: health.yahoo.com/ency/healthwise/ue4907.

Olmsted, D. (2007).The age of autism: Study sees vaccine risk. Retrieved July 5, 2007, from the Science Daily Web site: www.sciencedaily.com/upi/index.php?feed=Science

 Posted on : June 14, 2014