Rewriting a page on the CDC website to assert a false statement The revelation that vaccines can cause autism has unleashed an outpouring of anger and anguish from doctors, scientists and parents who say Health and Human Services Secretary Robert F. Kennedy Jr. is undermining trust in an agency they have long relied on for impartial scientific evidence.
Many scientists and public health officials fear that the Centers for Disease Control and Prevention website, which now baselessly claims that health authorities previously ignored evidence linking vaccinations and autism, foreshadows a larger and more dangerous attack on childhood vaccinations.
“It's not over yet,” said Helen Tager-Flusberg, professor emeritus of psychology and brain sciences at Boston University. She noted that Kennedy hired several longtime anti-vaccine activists and researchers to review vaccine safety at the Centers for Disease Control and Prevention (CDC). According to her, their study should take place soon.
“They crunch the data, and the result is, 'We'll show you that vaccines actually cause autism,'” said Tager-Flusberg, who led the research team. protection group of more than 320 autism scientists are concerned about Kennedy's actions.
Kennedy's vaccine advisory committee is set to meet next month to discuss whether to abandon recommendations that children receive a dose of hepatitis B vaccine within hours of birth and make other changes to the CDC-approved vaccination schedule. Kennedy argued—erroneously, scholars say—that vaccine ingredients cause conditions such as asthma and peanut allergies, in addition to autism.
The updated CDC webpage will be used to support efforts to phase out most childhood vaccines, said Angela Rasmussen, a virologist at the University of Saskatchewan and editor-in-chief of the journal Vaccine. “It will be presented as evidence even though it is completely fictitious,” she said.
Kennedy personally ordered the site change. he told The New York Times. The CDC's developmental disabilities group was not asked to provide input on the changes, according to Abigail Tye, executive director of the National Public Health Coalition, a group that includes current and former CDC and HHS officials.
Scientists ridiculed the site's claim that research “does not rule out the possibility that childhood vaccines cause autism.” Although more than 25 large studies have found no link between vaccines and autism, it is scientifically impossible to prove otherwise, says David Mundell, director of the Center for Autism Research at the Children's Hospital of Philadelphia.
The new claim on the web page that “studies supporting a link were ignored by health authorities” apparently refers to the work of anti-vaxxer David Geyer and his father Mark, who died in March, Mundell said. Their research has was widely rejected and even ridiculed. David Geyer one of the outside experts Kennedy was hired to review safety data at the Centers for Disease Control and Prevention (CDC).
Asked about evidence that scientists hid studies showing a link, HHS spokesman Andrew Nixon pointed to old reportssome of which called for further study of the possible connection. When asked about a specific study showing a connection, Nixon did not respond.
Expert reaction
Infectious disease experts, pediatricians and public health officials condemned the change to the CDC's website. Although Kennedy made no secret of his disdain for established science, the change was a punch in the gut because the Centers for Disease Control and Prevention (CDC) has always dealt with objective scientific information, they say.
Kennedy and his “nihilistic Dark Age compatriots turned the CDC into an anti-vaccine propaganda arm,” said Amesh Adalja, a senior fellow at the Johns Hopkins Center for Health Security.
“On one hand, this is not surprising,” said Sean O'Leary, a professor of pediatrics and infectious diseases at the University of Colorado. “On the other hand, this is a tipping point where they are clearly using the CDC as an apparatus to spread lies.”
“The CDC website has been lobotomized,” Atul Gawande, an author and surgeon at Brigham and Women's Hospital, told KFF Health News.
The CDC “is now a zombie organization,” said Demetre Daskalakis, former director of the CDC's National Center for Immunization and Respiratory Diseases. The agency has lost about a third of its staff this year. Entire units were destroyed, and their leadership was fired or forced to resign.
Kennedy is “moving from evidence-based decision making to evidence-based decision making,” Daniel Jernigan, former director of the CDC's National Center for Emerging and Zoonotic Infectious Diseases, said at a Nov. 19 briefing. Thanks to Kennedy and his team, terminology including “radical transparency” and the “scientific gold standard” has been “turned on its head,” he said.
Cassidy goes silent.
The new web page appears to openly mock Sen. Bill Cassidy (R-Louisiana), the physician who chairs the Senate Health, Education, Labor and Pensions Committee. Cassidy voted in committee to confirm Kennedy after saying he had secured an agreement that the longtime anti-vaccine activist would not make significant changes to CDC vaccine policy after taking office.
He said the agreement included a promise that the CDC would not remove claims from its website that vaccines do not cause autism.
The new autism page is still headed by the statement “Vaccines do not cause autism,” but with an asterisk associated with a notice that the phrase was kept on the site only “by agreement” with Cassidy. The rest of the page contradicts the title.
“What Kennedy did to the CDC website and to the American people makes Senator Cassidy a complete and utter fool,” said Mark Rosenberg, a former CDC official and assistant surgeon general.
On November 19 at the Capitol, before changes were made to the CDC website, Cassidy answered several unrelated questions from reporters but ended the conversation when asked about the possibility that Kennedy's Advisory Committee on Immunization Practices might recommend against giving newborns a dose of hepatitis B vaccine.
“I need to come in,” he said before entering the hearing room without answering.
Cassidy expressed dismay at the actions of the vaccine advisory committee but avoided directly criticizing Kennedy or admitting that the secretary had reneged on commitments he made before the confirmation vote. Cassidy said Kennedy also promised to maintain the children's vaccination schedule until confirmed.
The senator criticized changes to the CDC website in a November 20 address. publish on Xalthough he did not mention Kennedy.
“What parents need to hear right now is that vaccines for measles, polio, hepatitis B and other childhood diseases are safe and effective and do not cause autism,” he said in the post. “Any statement to the contrary is incorrect, irresponsible, and actively makes Americans worse off.”
Leading autism research and advocacy groups, including the Autism Science Foundation, the Autism Society of America, and Autism Self Advocacy Networkissued statements condemning the site.
“The CDC's web page previously stated that vaccines do not cause autism. Yesterday they changed it,” ASAN said in a statement. “It says there is some evidence that vaccines can cause autism. It says public health officials are ignoring that evidence. It's false.”
What Research Shows
Parents often notice symptoms of autism in the second year of a child's life, which happens after several vaccinations. “This is a natural history of autism symptoms,” Tager-Flusberg said. “But in their minds there was a perfect child who was suddenly taken away from them, and they are looking for an external reason.”
When speculation about a link between autism and the measles, mumps and rubella vaccine, or vaccines containing the mercury-based preservative thimerosal, surfaced around 2000, “scientists didn’t dismiss it out of hand,” said Tager-Flusberg, who has researched autism since the 1970s. “We were shocked and felt it was important to figure out how to quickly investigate.”
Since then, research has clearly established that autism results from genetics or fetal development. Although gaps in knowledge remain, studies have shown that premature birth, elderly parents, viral infections and the use of certain medications during pregnancy – although not Tylenolevidence suggests are associated with an increased risk of autism.
But beyond the body of data showing the health risks of smoking, there are few scientific examples, more definitive than many of the world's studies, that “have failed to demonstrate that vaccines cause autism,” said Bruce Gellin, former director of the Office of the National Vaccine Program.
Kennedy's changes to the CDC website and other HHS actions will undermine confidence in vaccines and lead to increased disease, said Jesse Goodman, a former chief scientist at the FDA and now a professor at Georgetown University.
This sentiment was echoed by Alison Singer, mother of an autistic adult and co-founder of the Autism Science Foundation. “If you're a new mom and don't know about the latest 30-year research, you might say, 'The government says we need to study whether vaccines cause autism. Maybe I'll wait and not get vaccinated until we know,” she said.
The CDC website misleads parents, puts children at risk and diverts resources from promising leads, said Paul Offit, director of the Vaccine Education Center at Children's Hospital of Philadelphia. “Kennedy thinks he's helping kids with autism, but he's doing the opposite.”
Many critics say their only hope is that cracks in President Donald Trump's governing coalition could lead to a shift away from Kennedy, whose team has reportedly clashed with some White House officials as well as Republican senators. The survey also showed that most The American public does not trust Kennedy and does not consider it a health authority, but Trump himself approval rating has dropped sharply since he returned to the White House.
But anti-vaccine activists applauded the CDC's updated webpage. “Finally, the CDC is starting to acknowledge the truth about this disease that affects millions,” said Mary Holland, CEO of Children's Health Defense, an advocacy group that Kennedy founded and led before entering politics. Fox News Digital. “The truth is there is no evidence, no science to support the claim that vaccines do not cause autism.”
Celine Gounder, Amanda Seitz and Amy Maxman contributed to this report.
[Update: This article was updated at 4:30 p.m. ET on Nov. 21, 2025, to reflect new reporting by The New York Times.]
