CDC Updates Web Page––No Evidence to Support “Vaccines Do Not Cause Autism” Claims

On November 19, 2025, the CDC updated its page regarding autism and vaccines, stating, “The claim ‘vaccines do not cause autism’ is not an evidence-based claim because studies have not ruled out the possibility that infant vaccines cause autism.” This statement appears under the key points section alongside the claim that “studies supporting a link have been ignored by health authorities.” The section also notes that the US Department of Health and Human Services has launched a comprehensive assessment into the causes of autism.¹

The page retains a subhead stating that vaccines do not cause autism; however, at the bottom of the page, the CDC notes that the header has not been removed due to an agreement with the chair of the US Senate Health, Education, Labor, and Pensions Committee that it would remain.¹

“It’s grossly misleading intentionally,” Morgan McSweeney, PhD, a scientist and social media health influencer known as Dr Noc, said in an interview. “It's very hard to prove a negative, and so what we do know is that over decades, in millions and millions of children, dozens and dozens of studies have all failed to show any link between [children] who get vaccines [and] having [an] increased risk of autism. And so to say that there's no evidence that vaccines don't cause autism when the reality is that there is no evidence that vaccines do cause autism—unfortunately, that's the way that science works.”

The CDC reviewed evidence from 4 studies ranging from 1991 to 2021, none of which found conclusive evidence to accept or reject a causal relationship between vaccines and autism.¹

In the 1991 study, the investigators concluded that there were no data indicating a causal relationship between the diphtheria, tetanus, and pertussis (DTaP) vaccine or the pertussis component of the vaccine and autism. The committee stated that there was a lack of reported cases of autism within 28 days of immunization.² However, they noted that a diagnosis of autism before the age of 3 is difficult.

The 2012 study did not show any clinical, diagnostic, or experimental evidence of autism after vaccination with the DTaP vaccine. The committee members added that the “evidence is inadequate to accept or reject a causal relationship between diphtheria toxoid–, tetanus toxoid–, or acellular pertussis–containing vaccines and autism.”³

In the 2014 study, the CDC stated that the key finding was that there was no evidence to accept or reject a causal relationship between the DTaP vaccine and autism. In the study abstract, the investigators stated that there was a lack of evidence for an association between the MMR (measles-mumps-rubella) vaccine and autism.⁴ For the study from 2021, the key finding showed that the evidence for an association between autism and the DTaP vaccines was unchanged, with no new studies identified.¹

“The other big thing that I think is often intentionally misrepresented is [that] in a lot of those studies, one thing you see a lot in social media clips,. . .they look at totally raw, unadjusted data,” McSweeney said. “And in some data sets, you do legitimately see that before adjusting for any other variables, among children who had more vaccines, there [are] increased rates of diagnoses of autism.”

McSweeney added that it is essential to control for other variables in research, as failing to do so can result in data that only show correlations without demonstrating causality. Furthermore, he added that another variable that needs to be corrected is health care–seeking bias. Children who receive vaccines also tend to see their pediatrician more often than children who do not receive as many vaccines. Without seeing a clinician, a child cannot receive an autism diagnosis. With unadjusted data, a link appears; however, when adjusted for whether the patient is seeing their pediatrician, the effect disappears.

“Unfortunately, there is usually an element of truth you can point to [in] that unadjusted data and say, ‘See, look, there is this relationship between vaccines and autism,’” McSweeney said. “But if it's lacking the context of those other important variables that got controlled for, you're misrepresenting the actual clinical and scientific reality and confusing people in the process and scaring people away from interventions that could otherwise help protect their children.”

READ MORE: Immunization Resource Center

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REFERENCES

1. Autism and vaccines. CDC. November 19, 2025. Accessed November 20, 2025. https://www.cdc.gov/vaccine-safety/about/autism.html

2. Institute of Medicine. Adverse Effects of Pertussis and Rubella Vaccines. The National Academies Press; 1991:151-152. https://doi.org/10.17226/1815

3. Institute of Medicine of the National Academies. Adverse Effects of Vaccines: Evidence and Causality. The National Academies Press; 2012:545-546. https://doi.org/10.17226/13164

4. Safety of Vaccines Used for Routine Immunization in the United States. Agency for Healthcare Research and Quality;2014:133. https://doi.org/10.23970/AHRQEPCERTA215