The Centers for Disease Control and Prevention (CDC) updated its webpage on autism and vaccines on Wednesday, stating a link between the two has been ignored despite many studies finding no such link.

For years, the federal health agency had worked to combat misinformation and disinformation spread about an alleged association between autism and various vaccines or their ingredients.

A previous version of the webpage reads, "Studies have shown that there is no link between receiving vaccines and developing autism spectrum disorder (ASD). No links have been found between any vaccine ingredients and ASD."

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However, the current version of the webpage reflects previous claims made by Health and Human Services Secretary Robert F. Kennedy Jr. despite numerous existing studies showing no association.

It now states, "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."

The webpage claims studies supporting a link "have been ignored by health authorities" and that HHS is conducting a "comprehensive assessment of the causes of autism."'

In response to a request for comment, an HHS spokesperson pointed ABC News to the updated language, adding, "We are updating the CDC's website to reflect gold standard, evidence-based science."

The first header on the webpage still reads "Vaccines do not cause Autism," but is followed by a footnote explaining that it has not been removed due to an agreement made with Sen. Bill Cassidy, R-La., chair of the Senate Health, Education, Labor, and Pensions Committee.

During Kennedy's Senate confirmation hearings earlier this year, he refused to acknowledge that vaccines don't cause autism, which led Cassidy to say he was "struggling" with his vote.

Cassidy, a physician, eventually voted to advance Kennedy's nomination that led to his confirmation, but has since expressed concerns with vaccine policy changes at the CDC and HHS.

In a post on X on Thursday, Cassidy wrote that vaccines for diseases, including measles, polio and hepatitis B "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 it's important to understand the causes of autism, including genetic predisposition and expressed dismay 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 webpage drew strong rebuke from doctors, infectious disease specialists, vaccine policy experts and the pediatric community.

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"Despite everything this administration has done to attack public health and science in the past 10 months, I am still shocked to see these statements -- which contradict decades of scientific research -- on the CDC website," Dr. Fiona Havers, a former CDC official who worked on vaccine policy and led the CDC's tracking of hospitalizations from COVID-19 and RSV, told ABC News.

Havers said that before Kennedy took over HHS, changes to CDC communications would be reviewed and vetted by several experts.

Now, "CDC scientists have been sidelined completely. RFK Jr. is abusing his position as HHS Secretary and is now using CDC as a platform to spread anti-vaccine propaganda," she said.

Doctors said the updated webpage repeats common anti-vaccine talking points, including suggesting that the measles, mumps, rubella (MMR) vaccine may be linked to autism or that vaccines given to infants in their first six months of life might be associated with the disorder.

The webpage also suggests a possible connection between autism and aluminum adjuvants, or a substance added to some vaccines to boost an immune response, despite no established link between the two.

"I think that all of us in the medical and scientific community no longer trust the CDC because they're no longer trustworthy," Dr. Paul Offit, director of the Vaccine Education Center at Children's Hospital of Philadelphia, told ABC News. "[The webpage] ignores the data that have clearly shown that, for example, measles, mumps, rubella vaccine doesn't cause autism, that aluminum adjuvants don't cause autism. ... I mean, there's study after study after study."

Major medical groups, including the American Academy of Pediatrics, also pushed back against the change. Dr. Susan Kressly, president of the organization, said that, since 1998, more than 40 high-quality studies involving more than 5.6 million people have been conducted in an attempt to find a link between vaccines and autism.

"The conclusion is clear and unambiguous," Kressly said in a statement. "There's no link between vaccines and autism. Anyone repeating this harmful myth is misinformed or intentionally trying to mislead parents. 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."