Robert F. Kennedy Jr. appeared before senators Wednesday for his first confirmation hearing as President Donald Trump’s nominee for health and human services secretary, facing a grilling from Democrats on his views on vaccines and abortion.

Kennedy sought to defend himself in his opening statement from the expected lines of questioning, prompting a brief eruption from a protester in the gallery.

“News reports have claimed that I am anti-vaccine or anti-industry,” Kennedy said.

“You are!” the person yelled before being ushered out of the chamber.

Kennedy continued: “I am neither; I am pro-safety. I worked for years to raise awareness about the mercury and toxic chemicals in fish, but that didn’t make me anti-fish. All of my kids are vaccinated, and I believe vaccines have a critical role in health care.”

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After another disruption from a protestor, the crowd was warned the hearing would adjourn to allow police to investigate if there were further outbursts from the audience.

Kennedy and Sen. Ron Wyden, D-Ore., the ranking member of the Senate Finance Committee, engaged in a heated exchange as Wyden attempted to nail down Kennedy’s stance on the measles vaccine.

“Is measles deadly, yes or no?” Wyden asked Kennedy, who did not directly answer the question. Kennedy contended again that he was not anti-vaccine.

Wyden pressed Kennedy on his comments in a 2023 podcast in which he said, “There’s no vaccine that is safe and effective.”

“Mr. Kennedy, all of these things cannot be true. So are you lying to Congress today when you say you are pro-vaccine?” Wyden said.

Kennedy claimed that statements he made on podcasts have “been repeatedly debunked.”

He also contended he would not dissuade Americans from getting certain vaccines

“I support the measles vaccine. I support the polio vaccine. I will do nothing as HHS Secretary that makes it difficult or discourages people from taking anything,” Kennedy said.

At another point, Sen. Michael Bennet, D-Colo., grew fiery as he challenged Kennedy on some of his past statements.

“Did you say that Lyme disease is highly likely, a materially engineered bioweapon? Did you say Lyme disease is a highly likely militarily engineered bioweapon?”

“I probably did say that,” Kennedy said.

Bennet then asked Kennedy about his past comments supporting abortion rights. When Kennedy began to quibble, Bennet interrupted.

“This matters!” Bennet said, his voice rising. “This is a job where it is life and death … for families all over this country.”

At another point, as he faced questioning from Sen. Catherine Cortez Masto, D-Nev., Kennedy was asked whether federal law protects a pregnant woman’s right to emergency care if she has a life-threatening, incomplete miscarriage in an emergency room in a state where abortion is restricted.

“I don’t know,” Kennedy said. “The answer is I don’t know.”

While Democrats largely focused in Kennedy’s views on vaccines and diseases, conservatives had raised concerns about his past support for abortion rights.

Last year, while he was running as an independent candidate for president, Kennedy told a podcast host that he would support allowing women to have abortions at full term, if that was there choice.

But just days later, he walked his position back, writing in a post on X that “abortion should be legal up until a certain number of weeks, and restricted thereafter.”

On Wednesday, under questioning from Sen. James Lankford, R-Okla., Kennedy said he believed states should control abortion. He then outlined Trump’s stances on abortion, including wanting to end federal funding and late term abortions.

“I serve at the pleasure of the president. I’m going to implement his policies.”

At one point, Kennedy spoke about the rise in chronic diseases and ingredients in food, but also noted that his “boss” likes to eat a McDonald’s cheeseburger and drink a Diet Coke.

“You should be able to do that,” Kennedy said to some chuckles at Trump’s penchant for eating fast-food. “But you should know what the impacts are on your family and your health.”

While several of Trump’s Cabinet picks have generated controversy, Kennedy is unique in that he has drawn outside opposition from both the right and left.

He has been the subject of negative paid ad campaigns, with liberals criticizing his anti-vaccine positions and conservatives decrying his stances on abortion. Physicians and Nobel laureates have publicly warned about him, accused him of politicizing science.

And on the eve of his hearing before the Senate Finance Committee, he received a stinging rebuke from his own family.

On Tuesday, his cousin Caroline Kennedy wrote a scathing letter asking the Senate to deny his confirmation. She described him as a “predator” who once delighted in a “perverse scene of despair and violence,” placing baby chickens and mice into a blender to feed his hawks. She also accused him of enticing other family members into addiction.

“Bobby is addicted to attention and power,” she wrote. “Bobby preys on the desperation of parents of sick children — vaccinating his own kids while building a following by hypocritically discouraging other parents from vaccinating theirs.”

The letter was addressed to the chairs and the ranking members of the Finance Committee, which will vote on his nomination before it goes to the full Senate floor, and the Committee on Health, Education, Labor and Pensions, which will hold a second hearing with Kennedy on Thursday.

He must clear an expansive array of hurdles this week as he seeks to be confirmed to one of the most influential positions in the U.S. government. As head of HHS, Kennedy would oversee powerful agencies, including the Centers for Disease Control and Prevention, the Food and Drug Administration, the National Institutes of Health and the Centers for Medicare & Medicaid Services.

Kennedy can afford to lose the support of only three Republicans if Democrats unite against him when the full Senate votes on his nomination. So far, no Republican senators have publicly opposed him.