The former presidential candidate will now oversee key health agencies with about 80,000 employees and a trillion-dollar budget. Lawmakers on both sides of the aisle had questioned his baseless health claims and vaccine scepeticism.

But on Thursday, Kennedy was confirmed by a vote of 52-48. No Democrats backed him. Former Senate Majority Leader Mitch McConnell was the lone Republican to vote against Kennedy.

His confirmation marks another win for Trump as he seeks to rapidly overhaul almost every level of government.

The Senate is putting in late nights and early mornings as they hurry to round out the president’s cabinet by confirming his remaining nominees.

Kennedy is the second cabinet pick to be confirmed this week after Tulsi Gabbard, another controversial pick, was confirmed as director of National Intelligence in a narrow Senate vote on Wednesday.

He will now oversee agencies such as the Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA), the National Institutes of Health (NIH) and the Centers for Medicare and Medicaid Services.

Kennedy will also be charged with overseeing the US health industry which includes food safety, pharmaceuticals, public health and vaccinations. He ran for the White House himself in 2024 as an independent, but dropped out and backed Trump.

The president’s decision to tap Kennedy to lead the federal health agency drew scepticism among several Republicans. Many questioned Kennedy’s past comments casting doubt on immunisations, his ties to groups making unsubstantiated health claims and his views on abortion.

Kennedy is the founder of the anti-vaccine group Children’s Health Defense, which gained prominence in the US for casting doubt on the safety and efficacy of childhood vaccinations and making the discredited claim that the shots are linked to autism.

Kennedy, the nephew of former President John F Kennedy, has denied that he is anti-vaccination, pointing to the fact that his own children are immunised. He insisted during his confirmation hearings that he merely supports more stringent studies and safety tests for injections.

Some Republicans have praised Kennedy for his criticism over the use of food additives and push to curb big pharma

During the hearings, lawmakers also grilled Kennedy on his promotion of health misinformation and knowledge of the US healthcare system.

He was asked to explain his stance on abortion, as he previously indicated that he was in favour of abortion rights. He responded by telling lawmakers he agreed with Trump that access to abortion should be controlled by individual states and that “every abortion is a tragedy”.

The exchange drew scrutiny from Democrats who accused Kennedy of “selling out” his pro-choice values in order to secure President Trump’s nomination.

One of his hearings was interrupted by shouting protesters. But he also received loud applause when promising to make America healthy again, a slogan used by Trump’s administration.

Ahead of the hearing, Caroline Kennedy – the cousin of Robert F Kennedy Jr – urged US senators to reject him as the next health and human services secretary. She said Kennedy’s views on vaccines disqualify him from the role of being one of America’s leading health policymakers.

Yet it wasn’t enough to dissuade several Republicans, who previously withheld their support from Kennedy but wound up approving his nomination during Thursday’s vote.

Many eyes were on Louisiana Senator Bill Cassidy, a Republican, who chairs the Senate Health Committee.

Cassidy, a doctor, previously indicated that he was struggling with Kennedy’s stance on vaccines. He voted to confirm Kennedy on Thursday.

“We need to make America healthy again, and it is my expectation that Secretary Kennedy will get this done,” Cassidy posted on X after the vote.

Others closely watched McConnell, a Kennedy critic and polio survivor. McConnell had warned Kennedy not to undermine the polio vaccine.

He voted against confirmation on Thursday.

“Individuals, parents, and families have a right to push for a healthier nation and demand the best possible scientific guidance on preventing and treating illness,” McConnell said in a statement. “But a record of trafficking in dangerous conspiracy theories and eroding trust in public health institutions does not entitle Mr. Kennedy to lead these important efforts.”

The Senate continues moving forward with Trump’s nominees. After confirming Kennedy, lawmakers took up a procedural vote advancing the nomination of Howard Lutnick as the next Secretary of Commerce.

This tees up the final vote for his confirmation to take place by the end of the week.

Lawmakers are also expected to take up the nomination of Kash Patel, Trump’s controversial choice to lead the Federal Bureau of Investigation (FBI), after the pick received approval from a key committee on Thursday.

The vote split along party lines, 14-13, with all Republicans on the Senate Finance Committee voting in favour of the vaccine sceptic who threw his support behind Donald Trump after ending a presidential bid of his own and whose health expertise has been questioned.

Kennedy’s nomination will now move to a vote of the full US Senate, which Republicans control 53-47.

Senators questioned Kennedy about his views on vaccines and other health issues and tested his knowledge about US public health infrastructure.

During the hearings he insisted that he was not opposed to vaccines, nor a conspiracy theorist, but that he supports more stringent safety tests.

But senators zeroed in on his past comments, including a podcast appearance where he said: “There’s no vaccine that is safe and effective.”

Senator Bernie Sanders, an independent who organises and works with Democrats, praised RFK Jr’s “Make America Healthy Again” slogan. But the senator then later showed pictures of baby clothes printed with anti-vaccine messages sold by Children’s Health Defence, an organisation that Kennedy headed until recently.

Kennedy responded that he no longer has oversight of the group.

Although RFK Jr’s testimony last week did not win over any Democrats to his side, he did manage to win the crucial support of Louisiana Republican Senator Bill Cassidy.

Cassidy, a doctor, had expressed scepticism about Kennedy’s nomination, but ultimately supported him during Tuesday’s committee hearing, clearing the way for a full Senate vote.

The message, shared through social media, was sent to senators ahead of RFK Jr’s questioning by senators on Wednesday in what could prove a contentious first confirmation hearing.

“I have known Bobby my whole life; we grew up together,” she wrote. “It’s no surprise that he keeps birds of prey as pets because he himself is a predator.”

Caroline Kennedy added that her cousin’s views on vaccines disqualify him from the role of being one of America’s leading health policymakers. RFK Jr has yet to respond.

In the message – published in video form online and sent to senators in a letter – Caroline Kennedy said her decision to speak out was prompted by her concerns about the high-profile role he could have in the Trump administration if confirmed.

The president, by contrast, has vowed that his nominee will “make America great and healthy again” by restoring US health agencies to “the traditions of gold standard scientific research”.

The health and human services secretary oversees agencies including the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA), the latter of which has some 18,000 employees.

“He lacks any relevant government, financial, management, or medical experience,” Caroline Kennedy said. “His views on vaccines are dangerous and wilfully misinformed.”

RFK Jr has long been a vaccine sceptic and has baselessly claimed there is a link between vaccines and autism. He has, however, recently said jabs are “not going to be taken away from anybody” – and that his aim is to improve the science on vaccine safety, which he believes has “huge deficits”.

He could face questions from senators in Wednesday’s hearing about this topic, and his plans for targeting junk food – an issue on which he has wider public support.

Explaining her “predator” comment, Caroline Kennedy alleged that “Bobby preys on the desperation of parents of sick children, vaccinating his own kids while building a following, hypocritically discouraging other parents from vaccinating theirs”.

RFK Jr has previously been quoted saying he would “pay anything” to turn back time and not vaccinate his own children.

Raising further concerns about RFK Jr’s “personal qualities”, Caroline Kennedy claimed her cousin “encouraged” siblings and cousins “down the path of substance abuse”.

RFK Jr has publicly spoke about his past struggle with drug addiction including heroin use. He plead guilty to bringing heroin onto a plane in 1984.

The letter also makes an historical claim of animal cruelty against RFK Jr. “His basement, his garage, and his dorm room were the centres 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,” Caroline Kennedy wrote. “It was often a perverse scene of despair and violence.”

Caroline Kennedy – a former US ambassador to Australia and Japan – also said both her father, former President John F Kennedy, and her uncle Robert Kennedy, would be “disgusted” by her cousin’s actions.

RFK Jr briefly ran for president last year as an independent after initially launching a Democratic primary bid. He eventually suspended his campaign, endorsing Trump.