There is irony of a dark kind in the fact that Robert F Kennedy Jr’s appointment as US health secretary comes at a time when his country is on the verge of losing its measles-free status.

Over the last decade, Mr Kennedy’s not-for-profit group known as the Children’s Health Defense, has vigorously promoted the debunked claim that MMR vaccines cause autism, which critics say has contributed to the significant decline in vaccination rates.

There have been a series of measles outbreaks in the US in recent years, but the latest is in Texas, where this week authorities reported 10 new cases, bringing the total to 58.

A further eight cases had been reported in New Mexico three days earlier.