A Centers for Disease Control and Prevention webpage that once stated unequivocally that vaccines do not cause autism has been rewritten, now suggesting without evidence that health authorities “ignored” possible links between the shots and autism.

“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 new language states. The change was posted Wednesday and was first reported by The Wall Street Journal.

The webpage also notes that the Department of Health and Human Services has launched “a comprehensive assessment” to examine the causes of autism. It’s unclear what the assessment will be or how it will be conducted.

HHS spokesman Andrew Nixon said the website had been updated “to reflect gold standard, evidence-based science.” A question about how the agency defines such science was not immediately answered.

Pediatricians and vaccine experts have long said that autism is among the most studied childhood conditions and that no credible research has ever suggested a link between it and vaccines.

It also remains unclear who made the changes or from where the new information originated.

The Autism Science Foundation said in a statement that the group is “appalled” by the change, calling it “anti-vaccine rhetoric and outright lies about vaccines and autism.”

“The CDC has always been a trustworthy source of scientifically-backed information but it appears this is no longer the case,” Alison Singer, ASF’s president, said in the statement. “Spreading this misinformation will needlessly cause fear in parents of young children who may not be aware of the mountains of data exonerating vaccines as a cause of autism and who may withhold vaccines in response to this misinformation, putting their children at risk to contract and potentially die from vaccine preventable diseases.”

The change in messages wasn’t reflected across the CDC’s website. A page for parents states that “scientific studies and reviews continue to show no relationship between vaccines and autism.”

This is a developing story. Please check back for updates.

This article was originally published on NBCNews.com