Science is not black and white. It’s more complicated and more exciting. It’s a constant process of exploration. An adventure into the unknown. Scientists come up with theories about what might be going on, and then test them. They don’t always get it right. Far from it. But inch by inch, testing, failing and trying again, they make progress.

Robert F Kennedy Jr, during Senate confirmation hearings for the role of secretary at the Department of Health and Human Services (HHS), seemed to get that. Those who feared what a vaccine sceptic might do in that role breathed again. “I’m going to empower the scientists at HHS to do their job and make sure that we have good science that is evidence based … I’m not going to substitute my judgment for science,” he said.

Yet now, without good explanation or sound science, he is cutting $500m of research funding for mRNA vaccines, claiming that they “fail to protect effectively against upper respiratory infections like Covid and flu”. In fact, no Covid vaccine fully protects against infection, but they have been shown to prevent deaths in billions of people. The 22 contracts that will be cancelled include one with Moderna for a vaccine against bird flu, which many fear could trigger the next human pandemic (and there will be one). Instead, federal funds will go to vaccines developed in more traditional ways.

Either Mr Kennedy lied to Congress or he has a different understanding of science and evidence from most scientists, unpicking what they thought was uncontestable. The childhood vaccine schedule is being reconsidered, and mandating the measles vaccine is being questioned in spite of fatal outbreaks in the US. He has sacked the Centers for Disease Control vaccine advisory panel and replaced it with many people known to have sceptical views.

Mr Kennedy is particularly hostile to the mRNA vaccines against Covid-19, panning them in 2021 as the “deadliest vaccines in history”, wrongly claiming that half those suffering the rare side-effect of myocarditis would die or need heart transplants within five years. The vast majority have quickly recovered. Until 2023, he chaired an anti-vaccine organisation called Children’s Health Defense, where he petitioned the Food and Drug Administration to rescind the licence of all Covid-19 vaccines and compared mandating vaccines to Nazi oppression in the second world war.

This is the stuff of internet scares; labyrinthine tangles of misinformation dotted with odd inaccurate nuggets of quasi-science. It doesn’t compare with the evidence base for mRNA vaccines, which went through clinical trials on hundreds of thousands of people and have since been used to vaccinate billions.

Experts agree that the mRNA vaccines were a stunning breakthrough that allowed people to be protected in record time from Covid-19. They contain messenger RNA, a tiny bit of genetic code that teaches the immune system to fight the virus. No need to grow the virus in hen’s eggs, which takes months. The “plug and play” technology can be adapted against other viruses, such as flu, including some that devastate populations in poor countries. The inventors won the Nobel prize in 2023.

Mr Kennedy’s cancellation of funding not only stymies much research but also feeds worldwide doubt in mRNA vaccines. We are all the losers. Humanity needs these vaccines. Other countries need to step up with money and reassurance to try to heal this latest breach between science and nonsense. And Mr Kennedy is clearly unfit for the job he holds.

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