A Centers for Disease Control and Prevention webpage received widespread attention after a major update was posted on November 20, 2025. The “vaccine safety” section was changed to state that the claim “Vaccines do not cause autism” is not an evidence-based statement, contradicting long-standing scientific consensus. The revision appeared on the CDC site, which operates under the U.S. Department of Health and Human Services. The Autism Science Foundation released a statement saying the new wording misrepresented established research and ignored decades of studies showing no connection between vaccines and autism. The American Academy of Pediatrics supported this view and noted that scientific evidence had produced a clear conclusion. Several former CDC officials reported that scientific staff inside the agency had been unaware of the modification, raising concerns about a bypass of standard review procedures. The update drew additional scrutiny because HHS is currently led by Secretary Robert F. Kennedy Jr., who has a history of questioning vaccine safety.

The revised page did not cite new data and instead argued that earlier studies suggesting a link had been dismissed by health authorities. An HHS spokesperson stated that a comprehensive review of autism research had begun, including examinations of possible biological mechanisms. Former CDC leaders warned that the update indicated a move toward “decision-based evidence,” a description used to express concern about ideological influence. The site still displays the headline “Vaccines do not cause autism,” but an added asterisk explains that it remains due to an agreement with a Senate committee. Experts stated that this development, reported on November 21, 2025, could influence public trust, scientific transparency, and the credibility of future health communication, creating a potentially contentious and consequential situation.