Under RFK Jr, CDC Turns Against Scientific Consensus On Autism And Vaccines, Incorrectly Claiming Lack Of Evidence

Vaccines do not cause autism

Numerous large-scale studies have investigated the possibility of a link between vaccines and autism. Overwhelmingly, they have found no evidence to support any link. There is no credible scientific evidence to suggest any mechanism by which childhood immunizations may cause autism.

In contrast, the one paper that initially suggested the link, published in The Lancet in 1998, was found to be fraudulent and flawed. It was fully retracted by the journal and the lead author, Andrew Wakefield, subsequently had his medical license revoked.  

The CDC used to be in lockstep with the scientific establishment on this, stating clearly that vaccines do not cause autism. 

Autism is complex and presents very differently in different people. Scientists have not yet reached an agreement on precisely what causes autism, but most agree that there are probably a number of different genetic and environmental factors that come into play while a fetus is developing in the womb. 

Certain signs of autism tend to become recognizable in children around the ages of 12 to 18 months. It is a coincidence that this happens to also be the age at which children receive several routine vaccines. Some autistic children may have appeared to be following a typical developmental trajectory until this age, but there’s no good reason to believe vaccines have any role to play in behavioral changes that may be observed.

These are the facts. But the current US administration – following the appointment of Robert F. Kennedy Jr, a noted and outspoken vaccine skeptic, as Health and Human Services (HHS) Secretary – has demonstrated a single-minded determination to identify the causes of what it calls “the autism epidemic”. Even this language is rejected by leading autism advocacy groups, who object to the characterization of autism as a “disease”. 

Recent months have seen Secretary Kennedy demanding that a science journal retract a huge study that added to the body of evidence that aluminum-containing ingredients in vaccines are safe (the journal refused), as well as President Trump announcing “bold actions” that included advising pregnant people, contrary to all medical consensus, to avoid taking Tylenol (paracetamol). 

In response to that pronouncement, Mel Merritt, the Head of Policy and Campaigns at the UK’s National Autistic Society, said this: “The incessant misinformation about autism from President Trump and Robert F Kennedy Jr risks undermining decades of research by respected experts in the field.”

“This is dangerous, it’s anti-science, and it’s irresponsible.”

HHS and vaccines

That Secretary Kennedy was skeptical about vaccine science was known long before his appointment. As HHS secretary, he has incorrectly claimed that the MMR vaccine contains “aborted fetus debris”. He has called for all new vaccines to undergo placebo-controlled trials, ignoring the compelling scientific and ethical reasons why this is not always done. 

He has also slashed funding to mRNA vaccine researchers, citing misinformation about how these vaccines work.

Under Kennedy’s tenure, acting director of the CDC Jim O’Neill endorsed comments made by the President, recommending that parents eschew MMR vaccines in favor of separate measles, mumps, and rubella shots – something pediatric health experts do not recommend.

So concerned were they by the misinformation coming from government sources, scientists banded together to form the Vaccine Integrity Project in April 2025, with the stated aim of “safeguarding vaccine use in the US.”

However, during his confirmation hearings for the post of HHS secretary, Kennedy did draw one red line. As reported by journalist Dan Diamond in a post on Bluesky, to win the vote of Senator Bill Cassidy (R-La.), Kennedy committed not to alter CDC website language around autism and vaccines.

Apparently in deference to this, the relevant CDC webpage (at time of writing) contains the subheading “Vaccines do not cause autism” followed by an asterisk, which links to the following statement: “The header ‘Vaccines do not cause autism’ has not been removed due to an agreement with the chair of the U.S. Senate Health, Education, Labor, and Pensions Committee that it would remain on the CDC website.”

Why confidence in vaccines matters

As we saw recently with changes to the CDC’s guidance on COVID-19 vaccines and some childhood immunizations, this wording change is likely to sow confusion at the very least, and probably further mistrust of vaccines in some quarters. 

Encouraging recent polling from the Pew Research Center does indicate broad support for childhood immunizations in the US, though support has slipped among adults identifying as Republicans. 

Meanwhile, vaccine-preventable diseases are in their comeback era. Canada just lost its measles elimination status after nearly 30 years, with the US forecast to be not too far behind after surpassing 1,500 reported cases this year. 

Pertussis, or whooping cough, cases are reportedly at a level 25 times as high as was seen at the same point in 2023. 

The 2024 flu season was especially brutal, and though 2025-26 is predicted to be more moderate, there’s never any certainty – Japan has been seeing higher than average case numbers for the early part of the season, and any dip in vaccination rates could see certain groups hit harder than expected. 

Citizens look to agencies like the CDC for guidance on how best to protect their health. With this change in wording, it finds itself out of step with other major national and global health bodies – including the World Health Organization. It’s also now at odds with the scientific consensus on this question of a link between autism and vaccines – a question many thought had been settled long ago.