President-elect Donald Trump on Thursday nominated longtime conspiracy theorist and vaccine skeptic Robert F. Kennedy Jr., who is popularly known as RFK Jr., to lead the Department of Health and Human Services (HHS).

HHS is a massive agency that oversees everything from the safety of drugs, vaccines and food to medical research and the social safety net programs Medicare and Medicaid.

Kennedy ran as an independent in this year's US presidential election. He dropped out in August and endorsed Trump in exchange for a role in the Republican's administration.

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

"For too long, Americans have been crushed by the industrial food complex and drug companies who have engaged in deception, misinformation, and disinformation when it comes to public health," the president-elect wrote in announcing the selection.

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

What do we know about RFK Jr.?

The scion of a famous Democratic dynasty, Kennedy made a name for himself as an environmental lawyer, successfully taking on big corporations like DuPont and Monsanto.

Over the past two decades, he's increasingly devoted his energy to promoting claims about vaccines that are at odds with the overwhelming consensus of scientists.

These include the disproven claim that childhood vaccines cause autism. He has also said that the COVID-19 vaccine is deadly and suggested that the coronavirus itself was "ethnically targeted" to harm blacks and whites while sparing "Ashkenazi Jews and Chinese."

Kennedy insists he is not anti-vaccine and claims he has never told the public to avoid vaccinations. But he has repeatedly made his opposition to vaccines clear and has said, "There's no vaccine that is safe and effective" and has urged people to resist federal guidelines on when kids should get vaccinated.

The World Health Organization says vaccines prevent as many as 5 million deaths each year.

Kennedy said he would call on water agencies to stop adding fluoride to drinking water. Fluoride strengthens teeth and is viewed as a major health success.

He made a variety of other claims not backed by science, such as questioning whether HIV causes AIDS and suggesting antidepressants lead to school shootings.

Bizarre stories also surrounded his personal life. These include his statement that a worm once entered his "brain and ate a portion of it and then died."

And this year, he raised eyebrows by admitting he was behind the long-unsolved mystery of a dead bear dumped in New York's Central Park a decade ago.

dh/sms (AP, AFP, Reuters, dpa)