Fact Or Fiction


FACT: Vaccines do not cause autism.”

Autism can be a challenging and complex diagnosis for parents and doctors. Autism spectrum disorder (ASD) is characterized by challenges with social interaction, speech, and behavior.

Over the last 20 years, the rate at which children are diagnosed with ASD has increased. Throughout this period, however, the diagnostic criteria for ASD has expanded; individuals who would not have been diagnosed with ASD in the past might now fall on the spectrum.

After an autism diagnosis, parents may wonder what caused the disorder in their child. Because the age when children receive the MMR (measles-mumps-rubella) vaccine (around 12-15 months) is the same age when children begin to show diagnosable signs of autism, parents might worry that the vaccine contributed to their child’s autism diagnosis.

The increased frequency of autism diagnoses and concern from parents has prompted researchers to explore the causes of autism. Current theories suggest that it is a genetically-based disorder. For instance, studies of twins found that if one identical twin is diagnosed with autism, it is up to 90% more likely that their twin will also be diagnosed. Researchers continue to search for other potential contributing factors and possible treatments.

Fortunately, the question of whether vaccines or vaccine components cause autism has been answered by science, and the results are clear: vaccines do not cause autism. 

Many concerns about a link between vaccines and autism stem from a now-retracted study of twelve children published in the British Medical Journal’s (BMJ) Lancet by Andrew Wakefield. His study found that the children began to experience the first signs developmental delay shortly after receiving the MMR vaccine. Even though he was unable to find a clear scientific link between MMR and autism, Wakefield stated that the MMR vaccine should not be used.

In 2010, The Lancet fully retracted Wakefield’s study after discovering that Wakefield acted unethically while performing his study. He took blood samples from children at his son’s birthday party and failed to disclose that he received funding from parents who already had concerns about the MMR vaccine. The British Medical Council barred Wakefield from practicing medicine and revoked his license, finding him guilty on 30 charges of professional misconduct.

This single fraudulent study has led some parents to distrust the MMR vaccine, to vaccine refusal and, ultimately, to the resurgence of measles. In response to the study, public and medical concern over a possible link between vaccines and autism led researchers to produce more than 25 studies across the world.

None of these studies has been able to recreate Wakefield’s findings or find any connections between the MMR vaccine and autism.

This is also true for thimerosal, a mercury-containing preservative that has been used for decades in multi-dose vaccines and medicines to prevent bacterial growth. Thimerosal has not been used in childhood vaccines since 2001, except in some doses of influenza vaccine. Numerous studies have shown that there is no link between thimerosal in vaccines and autism.

After a decade of research, we can confidently say vaccines do not cause autism.

This means that as a parent you can be confident in choosing to immunize your children. It also means that we can focus our attention on researching the causes of autism and providing better services for those affected by it.

Additional resources:

Autism Science Foundation 

"Secrets of the MMR Scare"

Healthy Children – Vaccine Safety

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