The main health agency in the United States is now suggesting a possible link between vaccines and autism, which has been repeatedly denied, echoing the theories of Donald Trump's controversial Secretary of Health, a reversal condemned by scientists on Thursday.
In a website update late Wednesday, the Centers for Disease Control and Prevention (CDC) radically changed their response on the subject.
Until now, the agency had been pointing out that many studies have "demonstrated that there is no link between vaccination and the development of an autism spectrum disorder," a conclusion shared by the WHO and major scientific bodies.
But on Thursday this text had been largely replaced by talking points echoing those of Health Minister Robert Kennedy Jr., who has been spreading conspiracy theories about vaccines, particularly those against Covid-19, for years.
The agency now states that its previous denial was "not based on evidence" and accuses health authorities of ignoring studies supporting such a link.
This is despite years of research demonstrating the absence of a causal link between vaccinations and autism or other neurodevelopmental disorders.
– “Middle Ages” –
"This is extremely worrying," Helen Tager-Flusberg, an autism specialist at Boston University, told AFP.
"I feel like we are going back to the Middle Ages (...) we are undermining science by linking it to political interests," she laments, warning that this change will create unnecessary fears among parents and discourage them from vaccinating their children.
"We are going to see a significant increase in deadly childhood diseases," she warns, while some, like measles, are already making a strong comeback in the country due to declining vaccination rates.
Other experts and healthcare workers strongly condemned the measure, deeming the agency now untrustworthy, while anti-vaccine groups thanked the minister.
Within the CDC, people were "very worried and angry," a member of an employees' union told AFP.
The site was also confusing because it still contained the statement "vaccines do not cause autism", a condition set earlier this year by a Republican senator to support the nomination of Robert Kennedy Jr.
A physician by training, Bill Cassidy reaffirmed on X Thursday that "any statement to the contrary" was "false, irresponsible and actively contributes to worsening the health of Americans."
– “Harmful myth” –
"By diverting attention to factors that we know for certain do NOT cause autism, we are depriving families of the answers they deserve," he continued, without ever naming the minister.
The false theory linking autism to a childhood vaccine – the one against measles, mumps and rubella (MMR) – comes from a rigged study published in 1998, which was subsequently retracted and repeatedly refuted.
“More than 40 high-quality studies” have since been conducted “on more than 5.6 million people,” Susan Kressly, president of the American Academy of Pediatrics, said in a statement Thursday.
And to emphasize: "Anyone who repeats this harmful myth is either misinformed or intentionally trying to mislead parents."
Since taking office, Robert Kennedy Jr. has initiated a profound overhaul of American health agencies with massive layoffs and budget cuts and has promised to establish the causes of what he calls an "epidemic" of autism.
This commitment worries experts because of the complexity of the subject but also because of the role that could be played by discredited figures appointed by the minister, including David Geier, a researcher convinced of such a link.
The latter, who was found guilty of practicing medicine without a proper degree, produced several studies on the subject whose methodology, data and results have been strongly contested.
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