Even among the chaos generated by Donald Trump’s recent cabinet picks, one stands out for the extensive suffering and lasting institutional damage it may cause: his choice of Robert F. Kennedy jnr to lead the Health and Human Services Department.

Modern public health is one of civilisation’s great achievements. In 1900, up to 30 per cent of infants in some US cities never made it to their first birthday. Since that time, vaccines, sanitation and effective medications have eliminated many previously commonplace illnesses and consigned others to extreme rarity.