In the five months since he was confirmed as Trump’s secretary of health and human services, the wayward scion of America’s most celebrated political dynasty has decimated the ranks of the country’s public health employees, slashed research on everything from future mRNA vaccines to the persistent form of the coronavirus known as “long Covid”, fired all the scientists responsible for making vaccine recommendations and consistently promoted a passionately held belief – contradicted by decades of research – that autism is a preventable disease most probably caused by vaccines or by a mercury-based preservative injected with them.

The medical establishment is not just appalled; it expects people to die. Arguably, they already have: a measles outbreak in rural Texas early this year has grown to 159 cases, including 22 people hospitalised and an unvaccinated child who died. New figures from the US Centers for Disease Control (CDC) show 1,319 confirmed cases of measles across 40 states. The outbreak was caused by low vaccination rates, but Kennedy encouraged families to take vitamin A and cod liver oil, neither viewed by doctors as appropriate or effective treatments.

Ostensibly Kennedy came into office with a mandate to “make America healthy again” by concentrating less on infectious diseases and more on chronic conditions such as obesity, diabetes and autism, which he cites as powerful evidence that the world’s richest country is too sick for its own good.

Instead of picking fights with food giants about additives in the nation’s diet, though, or campaigning to improve the nutritional value of school lunches he once likened to “toxic soup”, Kennedy has so far prioritised his personal mistrust of vaccines and turned government doctors and ­scientists, not the pharmaceutical industry, into targets for retribution. It is nothing less, say his critics, than a war on science.

Fiona Havers, a government epidemiologist who resigned because she could not tolerate what she called a “corrupted” environment around vaccine approvals, said Kennedy and his colleagues had taken a sledgehammer to scientific best practices, and it would end up killing people.

Jeremy Faust, a Harvard public health expert, characterised Kennedy’s decision to withdraw the US from Gavi, a global vaccine initiative that has saved millions of lives, as “one of the deadliest decisions ever made by any American”.

When Kennedy unilaterally declared that children and pregnant women no longer needed to be vaccinated against Covid, the American Academy of Pediatrics and other groups sued his department, alleging “an assault on science, public health and evidence-based medicine”.

Far from being stung by such criticism, Kennedy appears to welcome establishment disapproval, and has been equally outspoken in return. He has accused Anthony Fauci, the seasoned scientific adviser to presidents of both parties, of orchestrating a “historic coup d’état against western democracy” with his response to the pandemic. After taking office, he has called the department’s regulatory and research agencies “sock puppets” of the pharmaceutical industry.

“The derision with which senior leadership now speaks about these people is extraordinary – that they are not acting in the best interests of the American public and are actually the enemy,” said Sarah Despres, a public health veteran who served as a senior health and human services adviser under President Joe Biden.

“This can only sow chaos and confusion with the public. If you were to ask a pregnant woman if she should get the Covid vaccine now, or if she can, she wouldn’t know. When something big happens – and something will happen – no one will know what the right source of information is.”

In many ways, nothing that Kennedy has done is surprising. For two decades he has alienated even his own family members with his embrace of the anti-vax movement. The day before his Senate confirmation hearing, his cousin Caroline released a letter attacking his character and describing his views on vaccines as “dangerous and wilfully misinformed”.

Indeed, he likened the movement to a second US revolution, in which casualties were inevitable. He told a libertarian conference in 2021: “There’s a lot worse things than dying.”

In an early sign of his intentions, he appointed a well-known advocate for the anti-vax movement, David Geier, to write a report on the debunked links between vaccines and autism. At the same time, he slashed 10,000 of the 82,000 jobs in his department and vowed to cut another 10,000 – moves widely interpreted as an assault on science, not a serious attempt to streamline a large bureaucracy.

The CDC, which works to contain and combat infectious diseases globally, remains without a leader, and the National Institutes of Health, one of the world’s most prestigious government research organisations, has lost about 40% of its funding.

Kennedy’s anti-science, slash-and-burn approach is particularly frustrating to autism campaigners, who had hoped he was sincere about answering the question of what causes the condition – answers that might go a long way towards steering many parents and adult sufferers away from conspiracy theories.

But what those advocates have seen is a gutting of research funds. Instead of deepening work into genetic causes of autism, Kennedy has indulged his obsession with one thing scientists are now quite confident does not cause autism: childhood vaccination.

“[Kennedy] acts as if there’s a single environmental toxin that nobody who has been studying autism for the past 25 years has been able to find,” said Alison Singer of the Autism Science Foundation. “We are in fact making really good progress in finding the causes of autism, and yet the administration that says it wants to find the causes is decimating the scientific infrastructure of university-based research.”

Discouraging the vaccination of pregnant women was counterproductive, Singer argued, because research indicates that rubella, flu or Covid during pregnancy could be aggravating factors for autism. Proposing a registry of Americans with autism without explaining its purpose, as Kennedy’s department did in April, risked alarming people and deterring parents from seeking help for their autistic children, she added.

“RFK Jr is a data denier,” Singer argued. “There’s this hypothesis he’s had for 20 years that vaccines cause autism and he disregards anything that contradicts it. You can’t be so entrenched in your own beliefs that you can’t see the data in front of you.”

In going against that data, Kennedy has also politicised the country’s public health – a process Trump himself began during the Covid pandemic by floating untested remedies like injecting disinfectant or “hit[ting] the body with … very powerful light” and conflating medical expertise with the elitism of what he calls the “radical left”.

Now Kennedy is justifying many of his most radical policy shifts as a response to “waste, administrative bloat and duplication” created by the Democrats under President Biden – the implication being that attacking the experts and attacking Democrats amount to the same thing.

In so doing, he may be destroying the decades-long, widely held presumption that government medical researchers and advisers have only the public interest at heart and are above the political fray – something more science-minded future administrations may not be able to reverse. Kennedy is not alone in accusing past US governments of cosying up to the pharmaceutical industry and engaging in what he calls a “carefully planned militarisation and monetisation” of the nation’s health. But he is the first person with such views to run the $1.7tn health department.

“Once public health becomes politicised, then it’s game over,” Despres said. “There’s just no way to come back from that.”

The cost of this shift is likely to be measured in an uptick in food-borne illnesses, infectious diseases and global disease outbreaks that in ordinary political times could come back to haunt those responsible. It is unclear, though, how much the usual rules work in a Trump administration that often seems to revel in the chaos it is creating.

“These are people who aren’t thinking ahead,” said Dorit Reiss, a law professor at the University of California in San Francisco who has written extensively about the anti-vax movement. “We are putting ourselves at very real risk, and I don’t think they care.”

Photographs by Michael M Santiago/Getty and Ben Hendren/Bloomberg/Getty