A family feud involving America’s most storied political dynasty has played out in Canberra, with outgoing US Ambassador to Australia Caroline Kennedy labelling her cousin Robert F. Kennedy jnr’s vaccine scepticism as “dangerous”.

Consistent with his pattern of unorthodox cabinet picks, Donald Trump has tapped Mr Kennedy to become his health secretary, putting a conspiracy theorist and alternative therapies advocate in charge of administering US food and drug regulations and its shambolic healthcare system.