FACT CHECK #ESWHY0CH

WHAT WE FOUND

Why this is widely believed The belief that vaccines cause autism often stems from a now-retracted 1998 study that contained falsified data [14, 17]. This misconception persisted because the timing of routine childhood vaccinations can coincide with the age when some children begin to show signs of autism spectrum disorder, leading to a perceived connection [13, 17]. The ongoing mystery surrounding the exact causes of autism also fuels a search for explanations, contributing to the spread of false narratives despite scientific consensus [15, 23]. What the evidence shows Decades of rigorous and scientifically sound research have conclusively proven that vaccines do not cause autism [1, 9, 10, 11, 20, 22]. Large-scale meta-reviews of data from over 1.2 million children and more than 50 high-quality studies have found no connection between vaccines and autism, including the MMR vaccine, thimerosal, and mercury exposure [3, 9, 18]. Despite recent misleading changes to a CDC webpage in late 2025 that were not evidence-based, leading scientific organizations reaffirmed that the overwhelming evidence remains clear: vaccines are not a cause of autism [2, 4, 5, 7, 8, 9, 11, 12]. The bigger picture It is natural to seek explanations for complex conditions like autism, but the scientific evidence unequivocally demonstrates that vaccines are not a cause. Instead, autism is understood to involve a combination of genetic and environmental factors, with brain development changes beginning before birth [16, 19, 25]. Continuing to vaccinate protects children and communities from serious diseases without increasing the risk of autism [10, 20].

SOURCES

1. 1 · aap.orgNEWS
   Fact Checked: Vaccines: Safe and Effective, No Link to Autism - AAP

   TIER C — Donate Fact Checked # Fact Checked: Vaccines: Safe and Effective, No Link to Autism Home / News Room / Fact Checked / Fact Checked: Vaccines: Safe and Effective, No Link to Autism ## The Claim in Context Some individuals wrongly assert there is a link between vaccines and autism. B

2. 2 · factcheck.orgNEWS
   Revised CDC Website About Autism and Vaccines Is Not Evidence ...

   TIER C — FactCheck.org® A Project of The Annenberg Public Policy Center FactCheck Posts › Featured Posts › SciCheck # Revised CDC Website About Autism and Vaccines Is Not Evidence-Based By Jessica McDonald and Kate Yandell Posted on This article is available in both English and Español Under Robert F.

3. 3 · autismspeaks.orgNEWS
   Do vaccines cause autism? - Autism Speaks

   TIER C — Researchers analyzed data from over 1.2 million children across five large cohort studies and five case-control studies. They found no connection between vaccines and autism, including the MMR vaccine, thimerosal and mercury exposure. This large-scale meta-review provides strong evidence that vacc

4. 4 · cdc.govNEWS
   Autism and Vaccines - CDC

   TIER C — ## Vaccines do not cause Autism\ Pursuant to the Data Quality Act (DQA), which requires federal agencies to ensure the quality, objectivity, utility, and integrity of information they disseminate to the public, this webpage has been updated because the statement "Vaccines do not cause autism" is no

5. 5 · healthychildren.orgNEWS
   Vaccine Safety: Examine the Evidence - HealthyChildren.org

   TIER C — Find a Pediatrician ##### Safety & Prevention All Around At Home At Play Immunizations RSV Quiz HPV Q&A Childhood Immunizations Quiz Measles Facts: Test Your Knowledge On The Go Image 8 Image 9 recently added misleading claims to its autism webpage. We want to be clear: decades of high-quality

6. 6 · publichealthcollaborative.orgNEWS
   Dubious “study” claims childhood vaccines cause autism

   TIER C — ## Recommendation A recent paper falsely claimed that childhood vaccines are linked to developmental disorders. Debunking messaging may explain that the paper, which was published on a blog, is not a legitimate study; wasn’t peer-reviewed; was funded, written, and “reviewed” by well-known anti-vacc

7. 7 · cnn.comNEWS
   CDC website changed to include false claims that link autism and ...

   TIER C — “No environmental factor has been better studied as a potential cause of autism than vaccines. This includes vaccine ingredients as well as the body’s response to vaccines,” the Autism Science Foundation said in a statement Thursday. child receives vaccination whooping cough Vaccines Fast Facts D

8. 8 · chop.eduNEWS
   Vaccines and autism | Children's Hospital of Philadelphia

   TIER C — Recently, officials in the federal government suggested that acetaminophen is a cause of autism. The data they relied on were from limited studies that are not considered to represent the overwhelming body of evidence. For these reasons, scientists who study autism and professional organizations rep

9. 9 · academyhealth.orgNEWS
   Scientific Evidence Is Clear. New CDC Language on Autism ...

   TIER C — For more than two decades, the science has been conclusive: the overwhelming evidence shows that vaccines do not cause autism. This is not a matter of debate. The evidence base includes more than 50 high-quality studies, multiple Cochrane reviews, and data from over 15 million children worldwide. Re

10. 10 · pmc.ncbi.nlm.nih.govNEWS
    Vaccination as a cause of autism—myths and controversies - PMC

    TIER C — Avoiding vaccination exposes the individual and the community to the risk of contracting long-forgotten diseases. The fact that the association between the MMR vaccine and autism persists in the public's mind despite plenty of scientific evidence to the contrary raises questions about what constitut

11. 11 · idsociety.orgNEWS
    Statement on CDC's vaccines and autism webpage - IDSA

    TIER C — Skip to nav Skip to content # Statement on CDC’s vaccines and autism webpage ###### Last Updated November 20, 2025 Decades of rigorous and scientifically sound research have proven that vaccines do not cause autism. CDC’s sudden decision to change language on its website reversing that finding i

12. 12 · npr.orgNEWS
    The CDC revives debunked 'link' between childhood vaccines ... - NPR

    TIER C — "The new statement shows a lack of understanding of the term 'evidence,'" the Autism Science Foundation said in a statement the organization provided to NPR, adding, "No environmental factor has been better studied as a potential cause of autism than vaccines." It's a statement that's confusing by

13. 13 · familydoctor.orgNEWS
    Vaccines: Myth Versus Fact | Family Doctor - FamilyDoctor.org

    TIER C — Timing may be behind why people believe vaccines and autism are related. Some children begin to show signs of autism spectrum disorder around the same time they receive the vaccine for measles, mumps, and rubella. ### Myth: Vaccinations aren’t safe to get while pregnant. Fact: Actually, the opposi

14. 14 · publichealthcollaborative.orgNEWS
    Vaccines Do Not Cause Autism: Messaging Guidance

    TIER C — The misconception that vaccines cause autism originated from a 1998 study that was later retracted because it contained falsified data and conclusions not based on scientific evidence. Because of this study, false narratives have been ongoing and have gown in the years following the COVID-19 pandemi

15. 15 · pmc.ncbi.nlm.nih.govNEWS
    The myth of vaccination and autism spectrum - PMC - NIH

    TIER C — The perceived unexplained rise in autism incidence and the mystery surrounding the causes of autism continues to feed the myth linking autism to immunizations schedule. A study in Italy that investigated vaccine beliefs in Italian mothers concluded that “When trying to make sense of the unpredictabl

16. 16 · aap.orgNEWS
    Fact Checked: Vaccines: Safe and Effective, No Link to Autism - AAP

    TIER C — Scientists are learning more about potential causes of autism all the time. One thing we know with certainty is that vaccines are not one of the causes. There is no single, root cause of autism. A combination of influences is likely involved. Certain genetic syndromes are associated with a higher li

17. 17 · aaaai.orgNEWS
    Vaccines: The Myths and the Facts - AAAAI

    TIER C — Myth:Vaccines cause autism and sudden infant death syndrome (SIDS). [...] during the same age range that children are receiving their routine immunizations. The 1998 study that raised concerns about a possible link between measles-mumps-rubella (MMR) vaccine and autism was retracted by the journal t

18. 18 · en.wikipedia.orgNEWS
    Vaccines and autism - Wikipedia

    TIER C — The idea that thiomersal was a cause or trigger for autism is now considered disproven, as incidence rates for autism increased steadily even after thiomersal was removed from childhood vaccines. The cause of autism and mercury poisoning being associated is improbable because the symptoms of mercury

19. 19 · immunize.orgNEWS
    [PDF] Evidence Shows Vaccines Unrelated to Autism | Immunize.org

    TIER C — language, cognition, emotion and processing of information. The types of brain cells that are affected in autism start to grow during prenatal development, adding to evidence that autism starts before birth. Just like any complex disorder, genetics together with environmental factors play a role. Sc

20. 20 · autismspeaks.orgNEWS
    Do vaccines cause autism? - Autism Speaks

    TIER C — ## Vaccines and autism Scientists have conducted extensive research all over the world over the last two decades to examine the link between childhood vaccinations and autism. The result of this research is clear: vaccines do not cause autism. Additionally, vaccination can protect children from ma

21. 21 · paho.orgNEWS
    Debunking Immunization Myths - PAHO/WHO

    TIER C — 1. Home 2. Topics 3. Immunization 4. Debunking Immunization Myths # Debunking Immunization Myths ## Resources to manage false information about vaccines Get your answers to the most common myths about immunizations and vaccines. Myth: Vaccines cause autism. Explanation There are no detailed st

22. 22 · cdn.kingcounty.govNEWS
    [PDF] Vaccines & Autism: Unraveling the Myth - King County

    TIER C — Many studies around the world, involving hundreds of thousands of children, have all found the same thing: vaccines do not cause autism. Vaccines do not cause autism. I'm wondering about autism. Are vaccines safe for my child? Vaccines & Autism: Unraveling the Myth Learn More: kingcounty.gov/immuniz

23. 23 · chop.eduNEWS
    Vaccines and autism | Children's Hospital of Philadelphia

    TIER C — # Vaccines and autism # Vaccines and autism Autism has been studied for decades, including its causes. As with other conditions, when we don’t understand their cause, many things can be considered as the cause. For many years, people have questioned things that babies are exposed to before

24. 24 · statnews.comNEWS
    Here is how we know that vaccines do not cause autism - STAT News

    TIER C — Researchers have had two responses to this allegation: First, data don’t indicate that vaccines increase the risk that children will contract other infections. Second, vaccines have become much more targeted over time, often involving fewer antigens to stimulate the immune system than earlier versio

25. 25 · mayoclinichealthsystem.orgNEWS
    Autism-vaccine link debunked - Mayo Clinic Health System

    TIER C — ### Here's what you need to know: #### Autism spectrum disorder Autism spectrum disorder is a condition related to brain development that affects how a person perceives and socializes with others. This disorder causes problems in social interaction and communication. It also includes limited and r