The Centers for Disease Control and Prevention (CDC) has updated its webpage on vaccines and autism with new claims undermining the public health agency’s longtime position that vaccines do not cause the condition—garnering swift condemnation from public health advocates and the Senate's top healthcare legislator.
The new version of the webpage claims that studies have not definitively ruled out a link between vaccines and autism, though the medical community's consensus is that the alleged claim has been debunked. Finding the cause of autism has long been a priority of Department of Health and Human Services (HHS) Secretary Robert F. Kennedy Jr.
The webpage now also says that by promoting the statement “vaccines do not cause autism,” the CDC had failed to adhere to the Data Quality Act, which requires agencies to release truthful information to the public.
“This is a common-sense update that brings CDC’s website in line with our commitment to transparency and gold standard science,” HHS spokesperson Andrew Nixon said in a statement to Fierce Healthcare.
“As the updated page explains, the claim that ‘vaccines do not cause autism’ is not supported by comprehensive evidence, as studies to date have not definitively ruled out potential associations. Some research suggesting possible biologic mechanisms has been ignored or dismissed by public health agencies, and HHS is committed to finding a definitive answer,” Nixon said.
HHS will continue to fund research to search for a biologic connection between childhood vaccines and autism. It will look for a connection related to “aluminum adjuvants, risks for certain children with mitochondrial disorders, harms of neuroinflammation, and more,” the webpage reads. It will also update the website with “gold-standard science” on the topic.
"The CDC’s site updates are part of that broader effort to ensure all public-facing information reflects ongoing scientific inquiry," Nixon said.
The CDC, currently under the acting direction of Jim O’Neill, lays out a timeline of academic research on the potential for a link between vaccines given to infants and the development of autism. Many of the studies it lists concluded that the evidence was inadequate to prove or deny a link between childhood vaccines and autism.
The webpage lists research done on two categories of vaccines: DTaP, HepB, Hib, IPV and PCV; and the measles, mumps and rubella vaccine.
The CDC cites studies that came out of the National Childhood Vaccine Injury Act of 1986, which required federal researchers to study the link between pertussis, an ingredient in vaccines, and 11 conditions, including autism. It says the studies, conducted by the HHS and the National Academies of Medicine, do not rule out a causal link.
The webpage also says the HHS has previously thrown out studies that have found a link because of the studies' designs or “methodological limitations.”
“There are still no studies that support the claim that any of the 20 doses of the seven infant vaccines recommended for American children before the first year of life do not cause autism," the website reads. "These vaccines include DTaP, HepB, Hib, IPV, PCV, rotavirus, and influenza.”
The bottom of the updated CDC webpage contains a note saying that the agency did not fully remove the headline statement “vaccines do not cause autism” because of a pledge RFK Jr. made to Senator Bill Cassidy, M.D., R-La., to secure his confirmation by the Senate—though the statement is preceded by bullet points disputing the claim. Cassidy has also criticized RFK Jr.'s changes to the CDC's vaccine advisory group and raised concerns over claims from now-departed CDC officials that the secretary was overriding agency experts and standard evidence-based procedures.
Cassidy, in a Thursday afternoon X post, said it's important for the federal government to investigate the "real causes of autism" and pushed back on the changes.
"I’m a doctor who has seen people die from vaccine-preventable diseases," the senator wrote. "What parents need to hear right now is vaccines for measles, polio, hepatitis B and other childhood diseases are safe and effective and will not cause autism. Any statement to the contrary is wrong, irresponsible, and actively makes Americans sicker."
Cassidy added that studies have outlined "a genetic predisposition when a mom who’s pregnant is exposed to environmental toxins which can increase a child’s risk of autism. It’s deeply troubling that, according to HHS officials, they appeared to have canceled hundreds of millions in research on autism genetics. Redirecting attention to factors we definitely know DO NOT cause autism denies families the answers they deserve."
The updated website claims that the rise in the rates of childhood autism since the 1980s corresponds to the increase in the number of vaccines required by the CDC’s childhood vaccine schedule.
Richard H. Hughes IV, a partner at law firm Epstein, Becker & Green and a national thought leader on vaccines, attributes the rise in autism to changing diagnostic criteria.
"The so-called 'autism epidemic' was driven primarily by changes in diagnostic criteria in the DSM-III-R (1987) and DSM-IV (1994), which broadened the definition of autism," Hughes wrote in Health Affairs. "These changes lead to more autism diagnoses and the reclassification of individuals previously diagnosed with other conditions."
Hughes is currently representing physician professional organizations in a lawsuit against the health secretary seeking to wind back changes to COVID-19 vaccination and the recommendations of a key vaccine advisory panel he had remade with researchers sharing his skepticism of vaccine safety.
The American Academy of Pediatrics, one of the plaintiff groups in that case, said the updates included "false information suggesting vaccines cause autism."
"Anyone repeating this harmful myth is misinformed or intentionally trying to mislead parents," President Susan Kressly said in a statement. "We call on the CDC to stop wasting government resources to amplify false claims that sow doubt in one of the best tools we have to keep children healthy and thriving: routine immunizations."
Paul Offit, M.D., director of the Vaccine Education Center at the Children’s Hospital of Philadelphia and previously an advisor to the CDC on vaccine recommendations, panned the changes.
"RFK Jr. uses a technicality in the scientific method to assure that no one can 'prove' that he’s wrong," Offit wrote in a Substack post. "But he is wrong. Vaccines, probably the best studied of all environmental influences, have never been shown to cause autism. It is now fair to say that vaccines don’t cause autism. And that I can’t fly.
"If RFK Jr. wanted to be honest with the American public, he would make it clear on the CDC’s website that chicken nuggets also might cause autism, which has never been and will never be disproven," Offit wrote.
The CDC webpage change comes on the heels of an announcement by the HHS in September that taking Tylenol during pregnancy is correlated with the infant’s development of autism spectrum disorder.
At the time of that announcement, the American Psychiatric Association (APA) slammed RFK Jr. for the false statement and his other suggestions regarding the causes of autism, including childhood vaccines.
“It is essential that the administration prioritizes evidence-based support for individuals on the autism spectrum and invests in long-term comprehensive research about the disorder. Vaccines do not cause autism,” the APA wrote. “Claims of any such association have been repeatedly discredited in peer reviewed studies. Autism is a complex disorder, and it is incorrect to imply that a handful of studies have established causation."
Public health groups feared the appointment of RFK Jr. to the nation’s top health post because of his widely disputed views on vaccines and autism and because they feared he would stop parents from giving their children vaccines.
“Throughout his career, Mr. Kennedy has shown poor judgment and a consistent disregard for scientific evidence when he has knowingly made baseless claims and promoted misinformation about the safety and effectiveness of lifesaving vaccines,” the American Public Health Association had written (PDF) in a letter to Senate leaders in January.
Editor's Note: This story has been updated with a statement from a HHS spokesperson.