The Centers for Disease Control and Prevention quietly revised wording on its website to say a connection between childhood vaccines and autism “cannot be ruled out,” a reversal of the long-standing agency position that vaccines do not cause autism. The change has prompted alarm from doctors, public health experts and vaccine advocates who say the claim has been repeatedly disproven by extensive research.
Health Secretary Robert F. Kennedy Jr., who has long promoted the debunked link between vaccines and autism, has overseen broader shifts at federal health agencies that critics say undermine confidence in established immunization programs. Public health officials warn the timing is especially dangerous because childhood vaccination rates have slipped in parts of the country and outbreaks of measles and pertussis (whooping cough) have re-emerged.
Medical and scientific groups reacted sharply. Dr. Susan J. Kressly, president of the American Academy of Pediatrics, said the new language spreads false information and urged the CDC to stop amplifying claims that sow doubt about routine childhood immunizations. She noted that since 1998 researchers across seven countries have conducted more than 40 high-quality studies involving over 5.6 million people, and those studies found no causal link between vaccines and autism.
In comments to NPR, a Department of Health and Human Services spokesperson repeated the revised phrasing and said the department has launched a comprehensive review of autism causes, including possible biological mechanisms and potential causal links. The Autism Science Foundation criticized the new wording as a misunderstanding of what counts as evidence, saying vaccines have been among the most thoroughly studied environmental factors in autism research. Dr. Paul Offitt, director of the Vaccine Education Center at the Children’s Hospital of Philadelphia, described the language as misleading and reflective of anti-vaccine talking points.
Former CDC official Dr. Demetre Daskalakis said career scientists at the agency were blindsided by the change and that those scientists did not participate in drafting it. Two current CDC staffers, speaking anonymously for fear of retaliation, called the updates a red flag that vaccine information on the agency website may no longer be reliable and described the changes as “anti-science.”
Earlier this year, Kennedy dismissed the members of the CDC’s Advisory Committee on Immunization Practices (ACIP) and appointed a new slate. That new committee has already recommended removing thimerosal from some flu vaccines, despite longstanding evidence showing no safety problem, and is studying potential major shifts such as dropping aluminum adjuvants that boost vaccine response and separating the combined MMR vaccine into individual shots—moves experts say lack scientific support and would disrupt effective childhood vaccination schedules. The committee is also considering delaying the hepatitis B vaccine given at birth, reversing a long-standing practice that protects infants from a virus that can cause liver failure and cancer.
Under the current leadership, federal actions have also made accessing COVID-19 vaccines more difficult and halted some grant funding for new mRNA vaccine research. The article also notes that the Trump administration promoted its own controversial theories, including suggested links between acetaminophen and autism and the use of leucovorin to treat autism, ideas lacking strong evidence.
The CDC’s page still displays a header reading “Vaccines do not cause autism*” with a footnote explaining the header remains because of an agreement with the chair of the Senate Health, Education, Labor and Pensions Committee. That chair, Sen. Bill Cassidy, posted that vaccines for measles, polio, hepatitis B and other childhood diseases “are safe and effective and will not cause autism,” and called contrary statements “wrong, irresponsible, and actively makes Americans sicker.”
Vaccine proponents warn that the website revision and other administration actions could further erode public trust in immunizations, increase vaccine hesitancy, and put children at greater risk. If current trends continue, experts say the U.S. could lose its hard-won progress in controlling diseases like measles.