Top Republican 'struggling' with RFK Jr.'s nomination over Kennedy's vaccine views

Kennedy has a prolific history of anti-vaccine comments, including false claims linking them to autism. But as he seeks to lead HHS, he's shifting his stance.

He told lawmakers on Wednesday he's not "anti-vaccine" but rather "pro-safety." He also pledged not to do anything to discourage Americans from taking the measles or polio vaccine, despite openly questioning those immunizations in the past.

Kennedy is likely to continue to try to distance himself from some of his more controversial claims during today's hearing as he seeks out 51 yes votes on his nomination.

Cassidy, a doctor from Louisiana, is the chairman of the Senate HELP Committee.

During Wednesday's hearing with the Senate Finance Committee, Cassidy had a tense exchange with Kennedy over Medicare and Medicaid.

Leaving the hearing, Cassidy wouldn't say whether he was satisfied with his answers.

"I'm not commenting on anything about RFK until after all the process is over," Cassidy told ABC's Allison Pecorin.

Kennedy can only afford to lose three Republican votes, should all Democrats oppose his nomination -- as is expected.

Trump's pick to be health secretary faces a second straight day of questions from senators tasked with his confirmation.

Kennedy appears at 10 a.m. ET before the Senate Health, Education, Labor and Pensions Committee.

He's likely to continue to face pushback from Democrats, and even some Republicans, on his past comments about vaccines, abortion and more.

Read more about the key takeaways from his first hearing on Wednesday here.

Republican senators largely rallied to RFK Jr.'s defense, claiming he put concerns about his previous anti-vaccine rhetoric "to bed" during his tense confirmation hearing.

Sen. Roger Marshall R-Kan., a physician, brushed off the nominee's history of pushing vaccine misinformation when asked by ABC News.

"I think you're mischaracterizing. I think what Bobby Kennedy Jr. has always said is he wants the truth out there," he responded. "Right now, Americans don't trust what's coming out of the CDC."

Republicans defended Kennedy's history of promoting what his critics call other public health "conspiracy theories." Kennedy, for example, has falsely claimed COVID-19 was ethnically targeted to spare "Ashkenazi Jews and Chinese [people]."

"All the things he was accused of being a conspiracy theorist on, figured out to be the truth," Sen. Ron Johnson, R-Wisc., said.

On vaccines, Democrats said Kennedy was flip-flopping on a life-and-death issue.

"I mean, that's all politics, and it's all about creating obfuscation. It is not as he says about science, and he would be a lot better off if we have somebody in that job to who is for all the science," Sen. Michael Bennett D-Colo., told ABC News.

-ABC News' Jay O'Brien