Washington DC - Donald Trump on Thursday tapped anti-vaccine activist and conspiracy theorist Robert F. Kennedy Jr. as his secretary of health in the latest provocative nomination from the incoming Republican president.

Trump announced on his Truth Social platform that he was "thrilled" to name Kennedy.

Moving quickly since his election last week, Trump has embarked on a campaign of political shock and awe as he rolls out an administration designed to upend – and in some cases literally dismantle – the US government.

Several of Trump's choices for top jobs – including a TV news anchor at the helm of the Pentagon and an ally embroiled in sexual misconduct allegations for attorney general – have unnerved Washington.

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Kennedy, a scion of the famous political family who is popularly known as RFK Jr., is a longtime environmental campaigner who abandoned a fringe bid for the presidency to endorse Trump against Democratic candidate Kamala Harris.

Trump has said he wants Kennedy to "go wild" in changing healthcare.

Kennedy (70) who has posted shirtless photos to boast of his weight-lifting prowess, argues that fundamental change is needed to the way Americans eat, exercise, and use medicines.

If approved by the Senate, which Trump's Republican Party controls, he will take over the Health and Human Services Department, a mammoth institution with a budget of close to $2 trillion.

In his statement, Trump said Kennedy will "Make America Great and Healthy Again!"

The 78-year-old president-elect echoed many of Kennedy's talking points, saying "Americans have been crushed by the industrial food complex and drug companies who have engaged in deception, misinformation, and disinformation."

"Mr Kennedy will restore these Agencies to the traditions of Gold Standard Scientific Research, and beacons of Transparency, to end the Chronic Disease epidemic," Trump said.

The nomination will meet serious opposition, given Kennedy's history of promoting medical conspiracy theories – including the disproven claim that childhood vaccines cause autism – and saying that the Covid-19 vaccine was deadly.