CDC changes website to promote debunked vaccines-autism link

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The Centers for Disease Control and Prevention has updated its website to promote the widely debunked claim that vaccines may cause autism.

State of play: The agency's webpage on vaccines and autism, updated Wednesday, now says the statement that vaccines don't cause autism "is not an evidence-based claim because studies have not ruled out the possibility that infant vaccines cause autism."

"Studies supporting a link have been ignored by health authorities," the website continues.
HHS in September released plans to contract with Rensselaer Polytechnic Institute to research connections between vaccines and autism.

Career scientists at the agency were not consulted about the changes and were caught off guard by them, the Washington Post reported.

The CDC site previously said studies showed there was no connection between receiving vaccines and developing autism.

What they're saying: HHS communications director Andrew Nixon said the agency updated the site to reflect "gold standard, evidence-based science."

He did not respond to questions about the timing of the change or who was involved.

Zoom in: The CDC website still has a heading that reads "Vaccines do not cause autism" followed by an asterisk. A note further down says the header hasn't been removed "due to agreement with the chair of the U.S. Senate Health, Education, Labor, and Pensions Committee that it would remain on the CDC website."

During his confirmation process, Kennedy struck an agreement with committee chair Sen. Bill Cassidy (R-La.) that he would not dismantle vaccine safety systems or remove government vaccine guidance.

Cassidy's office did not immediately respond to a request for comment.

Yesterday, the Centers for Disease Control radically rewrote a website addressing false claims linking vaccines to autism. Previously, the CDC had correctly stated that a strong scientific consensus has concluded that vaccines are not associated with autism. The website now falsely claims that this statement is “not evidence-based” and that “studies supporting a link between vaccines and autism have been ignored by health authorities”. These are lies.

Vaccines are important for protecting the public from dangerous infectious diseases. Claiming that vaccines cause autism discourages parents from vaccinating their children, resulting in the unnecessary spread of infectious diseases and the resurgence of illnesses that have long been controlled by the widespread adoption of vaccines. Declining vaccination rates stemming from HHS Secretary Robert F. Kennedy’s consistent lies since taking office endanger disabled and otherwise medically vulnerable people. The lie that vaccine components cause autism has led to scientifically dubious “treatments” that have harmed and killed autistic people for years.

The science is clear. As the American Academy of Pediatrics stated, “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.”

The CDC under HHS Secretary Robert F. Kennedy Jr. and Acting CDC director Jim O’Neill has proven that it can no longer be trusted to provide truthful information about health to the American public. We deserve public health information we can trust to help us make important health care decisions for ourselves and with our loved ones. The only way to begin to rebuild the trust that HHS has broken is to remove Secretary Kennedy and Acting Director O’Neill from office immediately.

While we fight for the CDC to return to a practice of sharing factual public health information, we encourage everyone in our community to instead rely on information from the American Academy of Pediatrics and their HealthyChildren.org resource, the American College of Obstetricians and Gynecologists, the Children’s Hospital of Philadelphia (CHOP) Vaccine Education Center, immunize.org, and the American Public Health Association. ASAN will continue to provide information to our community from trustworthy sources.

Health and Human Services Secretary Robert F. Kennedy Jr. said he personally directed the Centers for Disease Control and Prevention to cast aside its long-held position that vaccines do not cause autism.

The move marks an unusual instance of a Health secretary unilaterally establishing public health guidance, undermining a long-held consensus from mainstream researchers and doctors and coming in an area where Kennedy has shown significant interest for decades.

In an interview with The New York Times published Friday, Kennedy argued that while studies have shown that some vaccines do not cause autism, the absence of more rigorous testing of all vaccines means the question of whether vaccines cause autism cannot be answered definitively.



“The whole thing about ‘vaccines have been tested and there’s been this determination made,’ is just a lie,” Kennedy said. “The phrase ‘Vaccines do not cause autism’ is not supported by science.”

The change on the CDC’s website on Wednesday reversed a conclusion drawn from decades of research by vaccine scientists done, in part, to combat misinformation about vaccines and their potential link to autism. Before leading the nation’s public health agencies, Kennedy and the anti-vaccine activist groups he worked with were among the leading proponents of vaccine misinformation.

Kennedy’s order to change the CDC language puts him at further odds with Sen. Bill Cassidy (R-La.), a doctor and the chair of the Senate committee that oversees public health agencies whose support was critical to Kennedy’s confirmation as HHS secretary. In explaining his support for Kennedy at the time, Cassidy said Kennedy promised the CDC would not remove guidance on its website saying vaccines do not cause autism.

Kennedy told The New York Times he had spoken to Cassidy about the change, and that Cassidy “disagreed with the decision.” He added that he would be “happy to” oblige Cassidy’s desire for Kennedy to appear before his committee.

Critics of the reversal argued that changing the CDC’s guidance could raise unsubstantiated fears about vaccine safety. Kennedy dismissed those concerns, arguing that reframing the nature of studies on vaccines and autism may promote greater vaccine use.

“I think the way to drive up vaccine utilization, ultimately, is to be honest with people,” he said. “My job is not to gaslight Americans but to give them accurate information about the state of the science.”

The American Medical Association (AMA) and other groups warned that recent changes to the CDC website may ignite a dangerous surge in vaccine misinformation and erode public trust.

"Despite recent changes to the CDC website, an abundance of evidence from decades of scientific studies shows no link between vaccines and autism," said AMA Trustee Sandra Adamson Fryhofer, MD, in a statement. "The AMA is deeply concerned that perpetuating misleading claims on vaccines will lead to further confusion, distrust, and ultimately, dangerous consequences for individuals and public health."

Kennedy's persistent promotion of a vaccine-autism link has stood in direct opposition to decades of studies involving millions of children that have consistently found no evidence of a connection.

The Infectious Diseases Society of America (IDSA) condemned the CDC's move as "reckless and harmful," saying that the change is "deeply troubling because it is false and lacks transparency."

"There is no scientific rationale for CDC to change its long-standing assertion that there is no link between vaccines and autism. This change is not driven by science but by politics and will only serve to increase mistrust in science and medicine," the IDSA continued.

"Vaccine misinformation has dangerous effects," the group stressed. "Right now, the ongoing measles outbreak in the United States is putting the country on the verge of losing its long-held status as having eliminated measles," it pointed out.

The American Academy of Pediatrics (AAP) emphasized the seriousness of vaccine misinformation. "Anyone repeating this harmful myth is misinformed or intentionally trying to mislead parents," AAP President Susan Kressly, MD, said in a statement.

"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 unified front, organizations including the IDSA, AAP, the American Academy of Family Physicians, and the American College of Physicians joined forces to sound an alarm.

"This false rumor distracts from pressing, urgent issues in children's health. Amplifying this claim and encouraging unnecessary investigations only worsens parents' fears; it will not lead to better therapies, improved support for caregiving families, or changes in health care, education, and society in ways that would help children with autism thrive," the organizations said.

"Today, our organizations reject this latest attempt to create fear around routine childhood immunizations. Vaccines rank among our greatest medical success stories. Thanks to vaccines, serious diseases that once made thousands sick every year and caused life-long health issues have become rare. We cannot risk losing this progress," they noted.

The American Academy of Neurology (AAN) pressed the CDC to revert to its prior guidance.

"It is vital that the public rely on evidence-based guidance to have a clear understanding of the causes of autism spectrum disorders and associated risk factors," the AAN stated. "As experts in autism spectrum disorders, we continue to be deeply concerned with the CDC and Health and Human Services (HHS) efforts that undermine science and evidence-based medicine."

I spoke with five CDC staffers on Thursday and Friday to find out their reactions to the announcement. While they declined to be identified for fear of retaliation, they all said that they and their colleagues were shocked and dismayed by the misinformation put forth on the new page. “It’s horrifying, it’s embarrassing, it’s scary, it’s heartbreaking—it’s all of those things,” said a staffer at the CDC’s Injury Center. “To see our agency being used to spread lies and misinformation is a gut punch,” a CDC communicator with the National Center for Immunization and Respiratory Disease wrote in a message. “People will be harmed by this—parents will decide not to vaccinate their kids because of false information, and kids will get sick and die as a result.”

Another longtime CDC employee who works in communications said, “The best way I can put it is it feels like we’re on a hijacked airplane.”

I spoke with five CDC staffers on Thursday and Friday to find out their reactions to the announcement. While they declined to be identified for fear of retaliation, they all said that they and their colleagues were shocked and dismayed by the misinformation put forth on the new page. “It’s horrifying, it’s embarrassing, it’s scary, it’s heartbreaking—it’s all of those things,” said a staffer at the CDC’s Injury Center. “To see our agency being used to spread lies and misinformation is a gut punch,” a CDC communicator with the National Center for Immunization and Respiratory Disease wrote in a message. “People will be harmed by this—parents will decide not to vaccinate their kids because of false information, and kids will get sick and die as a result.”

Another longtime CDC employee who works in communications said, “The best way I can put it is it feels like we’re on a hijacked airplane.”

Several employees noted that there had been no warning about the new page before it was posted—in fact, said the NCIRD staffer, even department leadership had “only learned about it today when somebody saw it the same way everybody else did.”

The concerns about the Autism and Vaccines page are only the latest blow to morale at the CDC. First came the appointment of Kennedy, who formerly ran an anti-vaccine activist group. Then there were the waves of layoffs, and after that, a record-breaking government shutdown. Several of the people with whom I spoke, some who had been with the CDC for years, said that morale at the agency was so low that they and most of their colleagues were currently looking for new jobs. “I changed my mind 20 times over the course of one meeting about whether I’m going to quiet quit and look for something else while still collecting a paycheck as long as I can, versus lean in and fight and try to protect the possibility of doing good work in the future,” said the Injury Center staffer. “I think people are starting to see that we can’t fulfill our mission here, like it’s becoming more and more clear and loud and unavoidable with each day.”

On the other hand, the longtime communications staff member said, “We’re still getting really important health information out, and if I leave, that will stop, and I don’t want to leave CDC when so many experienced people have left—or been forced out.”

Everyone with whom I spoke emphasized that the new page does not reflect the work or viewpoints of the vast majority of CDC employees. “The bulk of staff who work here still believe the same science and want to do the same good public health,” said someone with the CDC’s National Center for Chronic Disease Prevention and Health Promotion. They emphasized that their actual day-to-day work had not been compromised, though some worried that it soon could be.

When asked if the CDC was still a reliable source of public-health information, the employees said that most of the public-facing information remained unchanged. A critical problem was that there didn’t appear to be a good way for the public to discern the difference between accurate and politicized messaging. “I don’t know how they would distinguish that,” the Chronic Center staffer said. “There’s not a disclaimer saying posts were approved by political appointees and not by career scientists, so I don’t know.”

“It’s really easy from inside the agency to know what is real information and what has just been added there for political reasons,” added the longtime communications staffer. “But I can see that it would be really hard if you’re outside the agency to know the difference.”

It is hard to keep track of how many times the CDC has revised its language, its guidance, or its sense of what counts as evidence in the autism world. And maybe “hard to keep track” is the point. Science moves. People panic. Institutions adjust. Then the public tries to make sense of it all while raising kids, teaching them, or trying to understand themselves a little better.

The CDC’s most recent shift about autism arrived with that familiar blend of relief and unease (CDC, 2025). Relief because it signals an attempt to reconcile policy with findings that have piled up for decades. Unease because every time the ground moves, people wonder if the science is changing or if the public explanation is finally catching up. You can feel that tension in any corner of the internet where parents compare notes. The quiet question behind the louder ones is, "What does this change mean for my kid, my students, myself?" The trouble is that autism research has never marched in a straight line.

The Long View: Cohort Studies That Changed the Map
Some of the most important work in autism research happens at a pace that barely registers in the news cycle. MoBa, the Norwegian Mother and Child Cohort Study, has watched more than 100,000 pregnancies unfold since the late 1990s, tracing how prenatal conditions ripple into neurodevelopment years later (Magnus and team, 2006). Nested inside it, the Autism Birth Cohort Study has been peeling back the layers between genetic variants and early behavioral signals (Stoltenberg and team, 2010).

Across the Atlantic, the CDC’s own SEED project examined how autism risk occurs across diverse American communities (Schendel and colleagues, 2012). In the Netherlands, the Generation R Study has been following children since fetal life, mapping the earliest threads of brain development and psychiatric vulnerability (Jaddoe and colleagues, 2012). The Earli study focuses on infants with elevated risk for autism, teasing apart environmental exposures, epigenetic fingerprints, and early behaviors (Newschaffer, Croen, Daniels, and colleagues, Fallin, 2012). And the UK’s ALSPAC study has, for decades now, offered a window into how prenatal factors and family context shape developmental outcomes (Boyd and colleagues, 2013).

Look long enough at these projects, and you stop searching for a single culprit. Autism never belonged to one cause. The data insist on a messier truth: genes, environment, family history, neurodevelopmental timing, and the unpredictable ways a child grows into their own mind.

A Genetic Story That Refuses Simplicity
This is why the CDC’s update feels less like a sharp turn and more like a slow, overdue adjustment. Consider Spark, the massive genetic study I wrote about earlier. With hundreds of thousands of participants, Spark has exposed the sheer variety of genetic routes that can lead to autism. Some participants carried high-impact variants. Others carried inherited ones that operate softly, almost in the background. What emerges is not a single pathway but a branching set of routes, overlapping and intertwining.

A decade ago, the public conversation still leaned on the idea of rare mutations carrying most of the weight. Spark shattered that. It showed that autism is stitched together from hundreds of genetic influences, each contributing its own slight push or pull. The field is moving toward a future in which a substantial portion of autism cases can be tied to identifiable genetic sources, though the story will always be more mosaic than map.

The Cognitive Angle That Helps Explain the Rest
Then there is the mental world itself. Daniel Schacter’s work isn’t about autism directly, yet it hangs over this conversation like the missing piece of a diagram. Memory, he argued, is not a perfect recording but a reconstruction. We build the past as much as we recall it. Imagination pulls from the same neural machinery. Autistic cognition, with its vivid detail memory and its sometimes different rhythm in weaving those details into broader stories, makes more sense in that light. Researchers Sophie Lind, Dermot Bowler, and Laura Crane saw this in their work: autistic imagination and episodic memory orbit the same sun, just at a slightly different distance.

Once you combine Schacter’s ideas with Spark’s findings and the cohort studies’ decades of data, the picture sharpens. Autism is a developmental trajectory shaped by genetics, environment, brain architecture, and the way memory and imagination take form. The CDC’s new framing isn’t a reinvention. It’s a reconciliation. The institution is inching toward the complexity researchers have been describing for a long time. Families deserve that clarity, not tidy answers. We all deserve something closer to the truth.