The Centers for Disease Control and Prevention (CDC), long regarded as a global beacon of scientific rigor and public health leadership, has ignited fierce controversy by revising its website to suggest that infant vaccines may cause autism—a claim that decades of scientific research have repeatedly debunked. The change, made public on November 19, 2025, and widely reported the following day, has triggered alarm among scientists, pediatricians, autism advocates, and many lawmakers, who warn that the move risks undermining public trust and could fuel outbreaks of preventable diseases.
Until this week, the CDC’s official stance was clear: “Studies have shown that there is no link between receiving vaccines and developing autism spectrum disorder (ASD). No links have been found between any vaccine ingredients and ASD.” But the new language, now displayed on the CDC’s vaccine and autism page, asserts, “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 page goes further, stating, “Studies supporting a link have been ignored by health authorities.”
This abrupt reversal comes under the watch of Health and Human Services (HHS) Secretary Robert F. Kennedy Jr., a longtime vaccine skeptic whose views have been widely criticized by the medical community. According to FactCheck.org, the CDC’s revised webpage leans into the discredited idea that vaccines might cause autism, citing a 2014 study with ties to anti-vaccine groups and downplaying the robust evidence supporting vaccine safety. The new site even argues that “no studies” demonstrate that seven vaccines given before age one do not cause autism, and it questions the strength of evidence from studies on the measles, mumps, and rubella (MMR) vaccine.
Critics have not minced words. Dr. Paul Offit, an infectious disease specialist at Children’s Hospital of Philadelphia and co-inventor of the rotavirus vaccine, told CIDRAP News, “The CDC is being weaponized to promote RFK Jr.’s anti-vaccine point of view. So why should you trust it?” He added, “This is absolute insanity and a bizarre moving of the goalposts.” Dr. David S. Mandell, a psychiatry professor at the University of Pennsylvania, compared the CDC’s logic to saying, “You haven’t proven that ghosts don’t exist,” highlighting the impossibility of proving a negative in science.
For many in the public health community, the CDC’s about-face represents a “tragic day.” Michael T. Osterholm, director of the University of Minnesota’s Center for Infectious Disease Research and Policy, lamented, “Ideology has replaced science as the means for addressing life-saving research and best practices that save lives.” Dr. Jake Scott, an infectious disease expert at Stanford, warned that the new message “will cause real harm,” predicting that some parents will delay or skip vaccines, leading to the return of preventable diseases in communities with low vaccination rates.
The CDC’s revised page also removed longstanding scientific reviews of vaccine safety, instead echoing conspiracy theories that claim government scientists have hidden the truth about vaccines. Dr. Peter Hotez, co-director of the Texas Children’s Hospital Center for Vaccine Development, described the move as straight from the “wellness influencer industry playbook,” saying, “It’s not enough to push the snake oil. You have to discredit mainstream biomedical science and portray scientists as public enemies or cartoon villains, and that’s what Kennedy’s seeking to do.”
The changes were reportedly made without consulting career CDC scientists, who were caught off guard. Debra Houry, the CDC’s former chief medical officer, told CIDRAP News, “Scientists were not involved in any of these decisions, and when you remove science from scientific information you get ideology.” She revealed that she had recently advised health journalists not to trust CDC information on autism, a stark warning from a former insider.
Meanwhile, HHS Communications Director Andrew Nixon defended the update, describing it as a “common-sense update that brings CDC’s website in line with our commitment to transparency and gold standard science.” Yet Nixon declined to answer questions about the timing of the change or who exactly was involved, according to reporting by Axios and FactCheck.org.
Notably, the CDC webpage still retains a prominent subheading, “Vaccines do not cause autism,” now marked with an asterisk. A footnote explains this was kept following an agreement with Senator Bill Cassidy (R-La.), a physician and staunch vaccine supporter, during Kennedy’s contentious confirmation process. Cassidy’s vote was critical in moving Kennedy’s nomination forward, after Kennedy promised not to remove CDC statements asserting vaccine safety. On November 20, Cassidy took to the social platform X to reaffirm, “Vaccines for measles, polio, hepatitis B and other childhood diseases are safe and effective and will not cause autism. Any statement to the contrary is wrong, irresponsible, and actively makes Americans sicker.”
The ripple effects of the CDC’s reversal have been swift and severe. The American Academy of Pediatrics (AAP), representing thousands of pediatricians nationwide, reiterated, “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,” said AAP president Dr. Susan J. Kressly in a statement quoted by FactCheck.org.
Autism advocacy groups have also condemned the change. Alison Singer, president of the Autism Science Foundation, declared, “No environmental factor has been better studied as a potential cause of autism. The facts don’t change because the administration does. At this point it’s not about doing more studies; it’s about being willing to accept what the existing study data clearly show.” Sam Brandsen, an autistic scientist and parent, added, “Even if vaccines were the cause of autism—which I don’t believe—I would much rather have my child be his wonderful autistic self and have vaccine protection against deadly diseases than try to withhold necessary vaccines out of a fear of autistic traits.”
Experts are particularly concerned about the CDC’s use of cherry-picked and methodologically weak studies to cast doubt on vaccine safety. The agency now cites a 2014 study suggesting a correlation between aluminum in vaccines and autism, despite stronger research, including a 2019 Danish study of over 1.2 million children, showing no such link. Anders Hviid, who co-authored the Danish research, told FactCheck.org, “Our results do not support an association between autism and the aluminum content of infant vaccines.” He criticized the CDC’s selective use of data, warning that it amounts to a “giant fishing expedition.”
The fallout extends beyond science, threatening the credibility of federal health institutions and sowing confusion among parents. Ari Ne’eman, a Harvard health policy professor, remarked to CIDRAP News, “It gives people justifiable cause to be suspicious about anything that comes out from this administration regarding the science of autism.”
As the debate rages, the CDC’s new position stands in stark contrast to the overwhelming scientific consensus. The agency’s shift, driven by political pressure and ideology, has left many in the public health community and beyond wondering how far trust in America’s most important health institutions can be stretched before it snaps. For now, the facts remain: vaccines save lives, and the evidence shows they do not cause autism.
