The World Health Organization (WHO) chief has accused United States President Donald Trump of ignoring “decades of evidence” with his push to overhaul US childhood vaccination policy. Trump’s Health Secretary Robert F Kennedy Jr has long promoted a disproven link between the MMR shot and autism. But Tedros said the science is “unequivocal” and that “vaccines including the MMR vaccine are safe and do not cause autism”. The WHO chief also warned that “delaying vaccines or separating doses unnecessarily does not make vaccination safer and can leave children unprotected.” Since joining the Trump administration, Kennedy has launched a sweeping review of longstanding vaccines, rewritten the childhood immunisation schedule, and slashed funding for new vaccine development.