Which vaccine is associated with causing autism spectrum disorder (ASD)?

No Vaccines Cause Autism

There is no scientific evidence that any vaccine causes autism spectrum disorder (ASD). 1 Multiple high-quality scientific studies and guidelines have thoroughly investigated and refuted any causal relationship between vaccines and autism.

Scientific Evidence Against Vaccine-Autism Link

The American Academy of Pediatrics (AAP) has clearly stated that there is no evidence linking vaccines to autism:

• A large body of scientific evidence demonstrates that thimerosal-containing vaccines are not associated with increased risk of autism spectrum disorders in children 1
• The preponderance of available data has not supported hypotheses that the measles-mumps-rubella (MMR) vaccine or thimerosal (a mercury-containing preservative formerly used in some vaccines) causes autism 1
• Concerns about vaccines causing autism have been extensively studied and repeatedly disproven 1

The Origin of the Vaccine-Autism Myth

The vaccine-autism controversy originated from a now-retracted 1998 paper published in The Lancet that suggested a possible link between the MMR vaccine and autism. This paper has been thoroughly discredited:

• The paper described only 12 cases and was later found to have significant methodological flaws 2
• In 2010, the General Medical Council published a report against Dr. Wakefield (the lead author), revealing that the children's hospital records did not contain the evidence claimed in the paper 2
• The Lancet fully retracted the 1998 paper 2, 3
• It was later revealed that Dr. Wakefield had been approached by lawyers representing an anti-vaccine lobby who supported his research, suggesting significant conflicts of interest 2

Comprehensive Scientific Consensus

Multiple authoritative medical organizations and extensive research have confirmed that vaccines do not cause autism:

• The Institute of Medicine concluded that the evidence favors rejection of a causal relationship between MMR vaccine and autism spectrum disorder 4
• Studies published since the Institute of Medicine report have continued to find no increased risk of autism associated with MMR or other vaccines 4, 3
• Epidemiological studies have consistently found no association between MMR vaccination and autism, even among high-risk children whose older siblings had autism 3

Understanding Autism's True Origins

Current scientific understanding of autism points to different causes:

• Autism is a neurodevelopmental condition with a strong genetic component 1, 3
• The neurological differences in autism likely occur early in embryonic development, before vaccines are administered 5
• Autism has approximately 4 times higher prevalence in males than females 1
• Various abnormalities have been identified in postmortem studies, particularly within the limbic system 1

Public Health Implications

The unfounded concerns about vaccines and autism have had serious public health consequences:

• Decreasing acceptance of vaccination has led to outbreaks or resurgence of preventable diseases like measles 3
• Despite overwhelming evidence of vaccine safety, some parents remain hesitant to vaccinate their children due to persistent myths 6
• The timing of autism diagnosis (typically after routine childhood immunizations) contributes to the misconception of a causal relationship 6

Conclusion

The scientific evidence is clear and consistent: vaccines do not cause autism. The original study suggesting this link has been thoroughly discredited, and numerous subsequent studies have found no association between vaccines and autism spectrum disorders. Parents should be reassured that vaccinating their children according to recommended schedules is both safe and essential for protecting against serious preventable diseases.