The US Senate is preparing to grill Robert F. Kennedy Jr. over his views on health issues, as members debate and vote on his nomination to the health secretary post by President Donald Trump.

Former-Democrat-turned-Trump-supporter is due to be faced with his history of promoting vaccine conspiracy theories and misinformation in a Senate hearing later on Wednesday.

The 71-year-old also faces concerns raised by a conservative group founded by former vice president Mike Pence, who are questioning his past donations to organizations supporting abortion access. The controversial issue among Republican senators could cost him dear votes.

The politician suspended his independent presidential campaign in 2024, throwing his weight behind Trump, despite hailing from the prominent Democratic Kennedy family, whose members have publicly denounced him for his politics and views.

Cousin warns Senate RFK Jr. is a 'predator'

The latest of the Kennedy family to publicly lash out at RFK Jr. was his cousin Caroline, the daughter of assassinated former President John F. Kennedy.

In a letter to the senators urging them to vote against her cousin's nomination as health secretary, she described him as a "predator" who is addicted to power.

"His basement, his garage, and his dorm room were the centers of the action where drugs were available, and he enjoyed showing off how he put baby chickens and mice in the blender to feed his hawks," wrote Kennedy, a former ambassador.

"It was often a perverse scene of despair and violence."

The health secretary nominee has openly addressed his heroin use and pleaded guilty to bringing the drug aboard a plane in 1984.

RFK Jr. now "preys on the desperation of parents of sick children," his cousin said, adding that he has vaccinated his own children, despite discouraging others from vaccinating theirs.

In her letter, Caroline Kennedy also addressed a lawsuit her cousin filed against pharmaceutical company Merck over Gardasil, its human papillomavirus vaccine that prevents cervical cancer. He made more than $850,000 (roughly €816,809) last year for his role in building the case.

"In other words, he is willing to enrich himself by denying access to a vaccine that can prevent almost all forms of cervical cancer and which has been safely administered to millions of boys and girls," she wrote.

"Unlike Bobby, I try not to speak for my father — but I am certain that he and my uncle Bobby, who gave their lives in public services, and my uncle Teddy, who devoted his Senate career to improving health care, would be disgusted," she wrote.

RFK Jr.'s controversial health conspiracies

The politician has been labeled as dangerously unqualified, with critics taking jabs at his promotion of debunked claims linking measles vaccines to autism, and suggesting that HIV does not cause AIDS.

Many also pointed to his financial interests in law firms suing pharmaceutical companies.

Recently, RFK Jr. tried to soften his vaccine skepticism, as he started pursuing political posts, in an effort to erase two-decades' worth of promoting vaccine conspiracy theories that culminated with his rejection of the COVID-19 shots as the "deadliest ever made."

Among his other eccentric statements is that he exclusively drinks raw milk, claiming it "advances human health." The controversial stance faces unprecedented scrutiny with the spread of bird flu among US cattle, contaminating unpasteurized milk.

rmt/rc (AFP, AP)