Sen. Bill Cassidy, the top Republican on the Senate Committee on Health, Education, Labor and Pensions, concluded Thursday's hearing by saying he was "struggling" with the nomination due to Kennedy's vaccine positions. Kennedy notably refused to say vaccines don't cause autism as he faced pointed question from lawmakers.

Robert F. Kennedy Jr. spent two days this week insisting to senators that he’s not anti-vaccine. He said that he instead supports vaccinations and will follow the science in overseeing the $1.7 trillion Department of Health and Human Services, which, among other duties, oversees vaccine research, approval and recommendations.

Robert F. Kennedy Jr., the nephew of the late President John F. Kennedy and the son of former Attorney General and Sen. Robert F. Kennedy Sr., was a Democrat for most of life. He began his 2024 presidential campaign as a Democrat,