Of the many unorthodox positions taken by Robert F. Kennedy Jr., US President-elect Donald Trump’s nominee to head the Department of Health and Human Services, none worries US public-health experts more than his embrace of the anti-vaccine movement. If he assumes the position, he could influence the leadership of agencies in charge of approving, recommending and distributing vaccines in the US. Plus, Kennedy, who emerged as one of the leading voices in the anti-vaccine movement during the Covid-