With ardent anti-vaccine activist Robert F. Kennedy Jr. as the country’s top health official, a federal webpage that previously laid out the ample evidence refuting the misinformation that vaccines cause autism was abruptly replaced Wednesday with an anti-vaccine screed that promotes the false link.
It’s a move that is sure to be celebrated by Kennedy’s fringe anti-vaccine followers, but will only sow more distrust, fear, and confusion among the public, further erode the country’s crumbling vaccination rates, and ultimately lead to more disease, suffering, and deaths from vaccine-preventable infections, particularly among children and the most vulnerable.
On the Centers for Disease Control and Prevention’s website titled “Autism and Vaccines,” the previous top “key point” accurately reported that: “Studies have shown that there is no link between receiving vaccines and developing autism spectrum disorder (ASD).”
But, under Kennedy, the top “key point” is now the erroneous statement: “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 Department of Health and Human Services, which oversees the CDC, did not respond to questions from Ars Technica about the change, including why it appears to be dismissing the substantial number of high-quality studies providing evidence that there is no association between lifesaving immunizations and the neurodevelopmental disorder. It also did not address questions of whether CDC scientists were included in the rewrite.
An emailed response attributed to HHS spokesperson Andrew Nixon said, “We are updating the CDC’s website to reflect gold standard, evidence-based science.”
The Washington Post reported overnight that five anonymous agency officials said career scientists at the CDC were unaware of the changes prior to the update and were not consulted on the content.
“Intentionally trying to mislead parents”
The newly defaced page claims that “health authorities” have “ignored” data supporting a link between autism and vaccines. The page goes on to cherry-pick a few fringe studies while making aluminum adjuvants a prime suspect for the imagined link.
The “Background” section claims that half of parents of autistic children “believe” vaccines caused their child’s condition. The claim is backed by a study that surveyed 77 parents nearly 20 years ago. The page then goes on to mention federal reviews, most recently from 2021, that point out areas where there’s limited data. The federal reviews are based on studies from the Institute of Medicine, which is the defunct name for the National Academy of Medicine. The National Academies changed the name in 2015; the most recent IOM study referenced on the new CDC site is from 2014.
The page notes that the federal and old IOM reports evaluated the measles, mumps, and rubella (MMR) vaccine and found “a high strength of evidence that there is no association with autism spectrum disorders.” But it then goes on to argue why the “high strength” evidence is actually weak. It then confusingly launches into criticism of aluminum adjuvants, which the MMR vaccine does not contain.
The page singles out diphtheria, tetanus, and pertussis vaccines (DTap, Tdap, and Td), which do contain aluminum as an adjuvant. But a high-quality study of 1.2 million children published this year found that exposure to the teeny amounts of aluminum in vaccines had no links to autism or other conditions.
After that study was published, Kennedy—who has no medical or scientific background—demanded it be retracted, as it refuted his beliefs. The journal that published the article, the Annals of Internal Medicine, rejected the demand, finding no faults with the study. Outside health experts and scientists have praised the study as being of high quality and “solid.”
The new CDC page ends with a strange asterisked note explaining why a subhead from the past accurate webpage remained, stating: “Vaccines do not cause autism*.” The note explains that this was left to uphold an agreement between Kennedy and Senator Bill Cassidy, who cast a critical vote to confirm Kennedy as health secretary. HHS did not respond to Ars Technica’s question of how the rest of the page upholds the agreement.
Since the changes to the website came to light late Wednesday, medical and health experts have expressed dismay, anger, and disbelief at the change. In a statement, President of the American Academy of Pediatrics Susan Kressly blasted the CDC’s new page, calling the link “false.”
“Since 1998, independent researchers across seven countries have conducted more than 40 high-quality studies involving over 5.6 million people. The conclusion 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.
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. The American Academy of Pediatrics stands with members of the autism community who have asked for support in stopping this rumor from spreading any further.”

