The CDC revised its vaccine guidance to include wording critics say echoes anti-vaccine rhetoric by suggesting studies have not definitively ruled out a vaccine-autism link. Public-health experts and autism researchers say the preponderance of high-quality evidence—including a 2019 Danish study of more than 650,000 children and a 2025 study on aluminum adjuvants—finds no connection. The edits have drawn sharp criticism from scientists and former CDC officials, who warn the changes could erode vaccine confidence and lead to more preventable disease. Observers are calling for the agency to restore clear, evidence-based messaging.
CDC Website Edits Spark Alarm by Suggesting Uncertainty About Vaccines and Autism
The CDC revised its vaccine guidance to include wording critics say echoes anti-vaccine rhetoric by suggesting studies have not definitively ruled out a vaccine-autism link. Public-health experts and autism researchers say the preponderance of high-quality evidence—including a 2019 Danish study of more than 650,000 children and a 2025 study on aluminum adjuvants—finds no connection. The edits have drawn sharp criticism from scientists and former CDC officials, who warn the changes could erode vaccine confidence and lead to more preventable disease. Observers are calling for the agency to restore clear, evidence-based messaging.
09:45 AM, 11/21/2025Health
The U.S. Centers for Disease Control and Prevention recently revised its public guidance on vaccines to include language critics say mirrors anti-vaccine talking points and leaves open the possibility of a link between childhood vaccines and autism. The edits — including a bullet stating that the claim "vaccines do not cause autism is not an evidence-based claim" — have prompted sharp concern from public-health experts and former agency staff.
What changed
The updated CDC page adds wording that highlights perceived scientific uncertainty about whether infant vaccines or vaccine components could cause autism. It also emphasizes that more research and a broad HHS review of autism causes are under way. The main heading, "Vaccines do not cause Autism," remains on the page but is marked with an asterisk referring readers to a footnote about a commitment to keep that header in place.
Expert reactions
Researchers and public-health leaders have pushed back. Alison Singer, president and co-founder of the Autism Science Foundation, said the scientific community relies on the preponderance of evidence: many rigorous studies consistently show no connection between vaccines and autism. "You can’t do a scientific study to show that something does not cause something else," she said, adding that the best available research is conclusive and it’s time to move on.
"All we can do in the scientific community is point to the preponderance of the evidence—the number of studies, the fact that the studies are so conclusive. These studies all agree. They’re very clear, and it’s time to move on." — Alison Singer
Pediatrician and vaccine expert Dr. Paul Offit noted that scientific studies rarely provide absolute negative proof, but said the breadth of evidence supports vaccine safety. Dr. Peter Hotez called the edits a replay of long-debunked claims about MMR, thimerosal and aluminum, describing the changes as a dangerous distortion of public-health messaging. Former CDC official Dr. Demetre Daskalakis said staff were blindsided and called the revisions a "national embarrassment." Dr. Sean O'Leary warned the wording risks lowering vaccination rates and increasing preventable illness.
HHS spokesperson Andrew Nixon said the agency is "updating the CDC’s website to reflect gold standard, evidence-based science." Others, including Dr. Marty Makary, urged candid communication about uncertainty without overstating risks, arguing that absolutist language can erode trust.
What the evidence shows
The scientific record contains numerous high-quality studies and reviews finding no association between routine childhood vaccines and autism. One of the largest analyses, a Danish cohort study published in 2019 involving more than 650,000 children born between 1999 and 2011, found no increased risk of autism after measles-mumps-rubella (MMR) vaccination. That finding held across multiple subgroup analyses and after adjustment for factors such as family history of autism.
A separate Danish study published in 2025 examined aluminum adjuvants in vaccines and found no association with any of 50 chronic disorders, including neurodevelopmental conditions. Critics of the CDC edits say the updated page selectively emphasizes small uncertainties or supplementary data while omitting or downplaying large, robust studies.
Policy and public-health implications
Public-health leaders fear the changes could undermine vaccine confidence. Routine childhood vaccination coverage has fallen in recent years, and outbreaks of measles and pertussis have resurfaced in some communities. Several experts also pointed to personnel choices and new reviews of government vaccine data led by individuals with long-standing anti-vaccine ties as evidence the updates may reflect a broader shift in policy and messaging.
Bottom line
The overwhelming majority of credible research supports the conclusion that vaccines do not cause autism. Many scientists say the CDC should restore clear, evidence-based language that reflects that consensus to preserve public trust and protect children from preventable disease.