WATCH: Sen. Barrasso presses RFK Jr. on whether policy decisions are based on science or politics

Sen. John Barrasso, R-Wyo., questioned Health and Human Services Secretary Robert F. Kennedy Jr.’s vaccine policies during a hearing Thursday about President Donald Trump’s health care agenda.

Watch Barrasso’s comments in the player above.

As one of the handful of doctors on the Senate Committee on Finance, Barrasso said vaccines have saved an estimated 154 million lives globally over the last 50 years.

“I’m a doctor. Vaccines work,” Barrasso said, before recalling Kennedy’s promise in his confirmation hearings for health secretary that he would uphold the highest standards for vaccines.

“Since then, I’ve grown deeply concerned,” the senator said, citing recent measles outbreaks, leadership at the National Institutes of Health questioning the use of mRNA vaccines, and the White House’s ouster of the Centers for Disease Control and Prevention’s director Susan Monarez.

Barrasso asked what safeguards are in place to “ensure decisions are based solely on science and not politics.”

“Americans have lost faith in CDC, and we need to restore that faith, and we’re going to do that by telling the truth and not through propaganda,” Kennedy said. “I’m making them understand that everything that we say is true.”

Kennedy appeared before the committee a day after more than 20 medical societies and organizations called for his resignation. They cited “repeated efforts to undermine science and public health,” most recently the firing of Monarez over vaccine science and the resulting resignations of other leaders at the organization.

During his tenure, the health secretary and former anti-vaccine advocate has narrowed long-standing U.S. vaccine recommendations. He’s also replaced a key panel of medical experts with his hand-picked candidates ahead of the start of the respiratory virus season in the United States.