During the Senate confirmation hearings earlier this year, it became clear that the man nominated by Donald Trump to become Secretary of Health and Human Services was completely unfit to run America’s leading public-health agency. Now that he has been confirmed, it is time to reckon with the likely consequences of that decision.

Robert F. Kennedy, Jr. insists he’s not anti-vaccine and that he just wants to ensure that vaccines are safe. But defending his a priori conviction that vaccines are unsafe requires him to ignore the results of large, rigorous studies indicating otherwise and to rely on bad evidence and debunked claims that support his preferred position. No medical intervention is entirely without risk, but any risk incurred by the administration of a licensed vaccine pales in comparison to the risk posed by the disease it addresses.

But Kennedy knows that his inflammatory statements about the dangers of vaccines will be more compelling to many people than dry recitations of rigorous studies demonstrating their efficacy and safety. And his pronouncements on health and disease display boundless hubris combined with an uncanny ability to be wrong. He routinely employs absolutist language as he dismisses well-established facts in favour of preposterous and unsupported claims:

• During a 2024 podcast, Kennedy said, “The polio vaccine contained a virus called simian virus 40, SV40. It’s one of the most carcinogenic materials that is known to man. In fact, it’s used now by scientists around the world to induce tumors in rats and guinea pigs in labs. But it was in that vaccine—98 million people who got that vaccine, and my generation got it, and now you’ve had this explosion of soft tissue cancers in our generation that killed many, many, many, many more people than polio ever did. So if you say to me, ‘The polio vaccine, was it effective against polio?’ I’m going to say, ‘Yes.’ And if you say to me, ‘Did it kill more people … did it cause more death than averted?’ I would say, ‘I don’t know, because we don’t have the data on that.’”