The federal Centers for Disease Control and Prevention changed a key webpage about autism, shifting from a firm statement that vaccines do not cause the condition to language that suggests health officials may have ignored possible links. However, health experts say there is no evidence to support the implication, calling the move confusing and harmful to Americans.
Now the CDC has updated its page to say that “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.”
Meanwhile, pediatricians and vaccine researchers say autism is one of the most heavily studied childhood conditions and that no credible research shows a connection.
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The change shifts from decades of CDC guidance and years of scientific review, during which the agency has said for years that vaccines do not cause autism and noted that large population studies have found no link.
Several scientists told NBC News they were stunned by the Trump administration’s messaging about vaccines connected to autism. “This is madness,” Dr. Sean O’Leary, head of the American Academy of Pediatrics’ infectious diseases committee, told NBC News.
O’Leary said environmental causes have been reviewed many times, and none show vaccines are involved.
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What is autism?
Autism is a developmental condition that affects communication, behavior and social interaction.
The CDC estimates that about one in 36 children in the United States has autism. Studies have also found that Black children are often diagnosed later and sometimes have less access to developmental services, raising concerns about disparities in care.
The updated page kept the heading “Vaccines do not cause Autism” but added an asterisk saying the title remained only because of an agreement with Senator Bill Cassidy, a Louisiana Republican, during Health Secretary Robert F. Kennedy Jr.’s confirmation hearings, as reported by NBC News.
Kennedy has been known for his anti-vaccine views. Some disease experts say the new CDC language appears intended to send a message to his supporters. Dr. Amesh Adalja of Johns Hopkins told NBC News, “He’s signaling to his tribe that he’s there and he’s doing their bidding.”
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Feds make changes
The Trump administration pushed for a new study on what causes autism. Autism researchers say the condition is driven by genetics, biology and environmental factors that do not include vaccines.
The update to the CDC webpage comes ahead of a December 4 vaccine advisory committee meeting, where members are expected to vote on changes to the hepatitis B vaccine schedule for newborns. The committee delayed an earlier vote in September.
Earlier in the year, the administration also ordered the CDC to remove content related to diversity, equity and inclusion across its site. Not all pages have been updated. A separate CDC page for parents still says there is no relationship between vaccines and autism.
A former CDC official told NBC News the agency’s shift will erode public trust. “In my deepest heart, this is the day CDC died,” the official said. They noted that many Americans won’t pay attention to technical differences between pages.
Concerns about selective research citations
Scientists say the updated webpage cites older or disputed research while overlooking stronger studies that show no connection between vaccines and autism. For example, the page mentions a 2014 paper suggesting aluminum in infant vaccines might be associated with autism. But researchers said the study is not considered strong evidence and has been challenged for design issues.
The page also points to a 2010 study that found newborn boys vaccinated for hepatitis B had a higher risk of autism. That study relied on parent surveys instead of medical records and has been widely criticized.
Advocacy groups say the CDC’s new language fuels stigma. The Autism Science Foundation said it was “appalled” by the update and told NBC News that the message spreads misinformation that hurts families.
Many experts warn that the sudden shift could confuse parents at a time when misinformation spreads quickly online, and vaccine hesitancy is already high.
