The CDC’s vaccines and autism webpage was changed to include language suggesting that vaccines may cause autism, contradicting years of scientific evidence showing no causal link. The sudden change prompted an outcry from leading autism researchers that the site was revised to include false and scientifically unsound information. 

A blue box at the top of the agency’s website now states that “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 changes are aligned with the long-stated views of Health and Human Services Secretary Robert F. Kennedy Jr., who has repeatedly questioned the safety of certain vaccines in defiance of a long-standing body of research that contradicts his claims.

“Let me be clear: CDC scientists were not behind this change to the website. This is a tragic moment for this country,” Sean O’Leary, MD, chair of the American Academy of Pediatrics (AAP) Committee on Infectious Diseases, said during a press briefing.

“For decades, we could rely on CDC to provide the American public with the best available science. Now, our federal government is using it as an apparatus to spread falsehoods and lies,” O’Leary added. 

Discredited Studies Cited

The updated CDC webpage now states, falsely, that “studies supporting a link have been ignored by health authorities.” 

“Fifteen studies using the CDC's own data show that vaccines don't cause autism. Another dozen studies from other countries show the same,” David S. Mandell, ScD, professor and director, University of Pennsylvania Perelman School of Medicine, Philadelphia, and member of the executive committee of the Coalition of Autism Scientists, said in a statement.

Mandell noted that the two “ignored” studies referenced by the CDC were conducted by a discredited father–son team: Mark Geier, an MD whose medical license was revoked, and his son David Geier, who holds a bachelor’s degree in biology and has no medical degree or license. 

Helen Tager-Flusberg, PhD, who also serves on the executive committee of the Coalition of Autism Scientists, said she suspects the CDC’s action is “in anticipation of an announcement of new findings from data mining carried out by Geier and his colleagues.”

The updated webpage also states that HHS has begun a comprehensive review of the causes of autism, “including the debunked link to vaccines” — a move announced in September that alarmed experts who argue the issue has long been resolved.

Fueling Fear and Confusion 

Tager-Flusberg said the revised CDC page contains significant misinformation and misrepresents the scientific evidence, which has consistently shown that neither vaccines nor vaccine adjuvants such as thimerosal or aluminum — past or present — cause autism or increase autism risk.

This action represents a “new and devastating turn by the CDC, which has been effectively dismantled” by the Secretary of HHS, who has “eliminated thousands of scientists and replaced them with known leaders of the ‘anti-vax’ movement,” she added. 

Tager-Flusberg warned that the statement could create confused parents and healthcare providers that could potentially harm children’s health. 

AAP President Susan J. Kressly, MD, said the AAP “stands with members of the autism community who have asked for support in stopping this rumor from spreading any further.”

The conclusion of more than 40 high-quality studies involving over 5.6 million people is “clear and unambiguous. There’s no link between vaccines and autism. Anyone repeating this harmful myth is misinformed or intentionally trying to mislead parents,” Kressly said. 

“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,” Kressly added. 

In a statement, the American Psychiatric Association reiterated that “vaccines do not cause autism, and that claims of any such association have been repeatedly discredited in peer-reviewed studies.”