The announcement that Donald Trump has appointed Robert F Kennedy as the US secretary of health and human services has sent shock waves through the health and scientific community. Kennedy ran as an independent presidential candidate before bowing out and supporting Trump’s run in exchange for an influential position, so we have a pretty good idea of his positions on public health.

The main goal Kennedy has trumpeted recently is to “Make America healthy again”. At face value, it’s a noble aim. That’s the essence of public health: how to reduce risk factors for disease and mortality at a population level and improve the quality of health and wellbeing. But behind this slogan comes a darker, conspiracy-laden agenda. As someone who has spent a lot of time researching global public health, these are the positions I believe could be the most dangerous.

Anti-vaxxer views

Kennedy is well known as a prominent anti-vaxxer. He has claimed that vaccines can cause autism, and also said that “there’s no vaccine that is safe and effective”. He called the Covid-19 vaccine the “deadliest vaccine ever made”. None of these claims are true: repeat studies have shown that the MMR vaccine does not cause autism, we have numerous safe and effective vaccines against childhood killers such as whooping cough and measles, and the Covid-19 vaccines have saved millions of lives globally.

Much of what he is saying is what people want to hear: being anti-vax is increasingly a way to build a fanbase. I have seen this as a scientist: if you talk about childhood vaccinations, you get daily abuse. If you talk about the dangers of vaccines, you can end up with a cult following, as Russell Brand and Andrew Wakefield have. It’s not even clear that Kennedy personally believes what he’s saying: guests invited to a holiday party at his home in December 2021 were told to be vaccinated or tested for Covid-19 (he blamed his wife).

The big question is about how much harm he can do in the next few years as the man who oversees health agencies in the US. Will he roll back budgetary allocations for vaccination campaigns? Eliminate research into new vaccines? With avian flu continuing to spread in mammals and birds, will he support the stockpiling and rollout of H5N1 vaccines if necessary in a future outbreak or pandemic? If his appointment is approved, experts say that vaccines will be “the first issue on the table”.

The “benefits” of raw milk

Similarly, he has tweeted about the benefits of raw milk, which has become a bizarre Maga talking point generally. Raw milk consumption is a risk factor for a number of dangerous illnesses from E coli to salmonella, but is even more worrying with the widespread infection of dairy herds in the US. While pasteurisation has been shown to kill the H5N1 virus in milk and prevent its ability to infect, raw milk retains its pathogens. This year, 24 cats who drank raw milk on a farm become infected by avian flu; 12 died and 12 suffered from blindness, difficulty breathing and other serious health problems. This is when we need federal agencies to regulate what is being sold to the public and ensure clear communication of the health risks. Instead, raw milk demand has gone up, with some vendors claiming that “customers [are] asking for H5N1 milk because they want immunity from it”. (There’s a certain irony in the logic behind vaccination – training our immune system in how to respond to a pathogen – being used in this situation.)

Anti-pharmaceutical conspiracy theories

Part of the problem of the “Make America healthy again” campaign is that it contains nuggets of truth within a larger false narrative. We know that the prices charged by “big pharma” in the US are a problem – but instead of thinking this is a conspiracy to medicate the public when that’s not in their best interests, it’s worth reflecting on how the UK has managed to negotiate more reasonable prices. This is where government can have real power: ensuring fair prices for healthcare providers and individuals, and going after the extraordinary profit margins of pharmaceutical companies. But instead of taking this on – for instance, Trump could have negotiated Covid-19 vaccine prices in his first presidency – it is easier to demonise all pharma companies. Many of them of course play a valuable role in trialling and bringing drugs and vaccines to market. They just need to be regulated.

Taking on these ideas will be a challenge when their proponent is leading US health policy. How do you try to engage with those who believe things that are simply not true? It’s hard: a recent Nature study found that the more time you spend on the internet trying to validate what is true and not true, you more you go down the rabbit hole of false information. Those who believe outlandish theories are generally people who think of themselves as more intelligent than the average person, have a lot of time to do their own research on the internet, and are convinced that everyone else is being duped.

The US has a big health problem. Life expectancy is going dramatically backwards, Covid-19 killed a huge number of working-age Americans and trust in the federal government is at 23%. But the solution, if we look to healthier countries such as Denmark and South Korea, involves basic public health interventions, access to affordable medical care and trust in government. And not drinking raw milk.

• Prof Devi Sridhar is chair of global public health at the University of Edinburgh

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