Robert F. Kennedy Jr. is facing a contentious confirmation hearing for his nomination to lead the U.S. Department of Health and Human Services, despite his past support for anti-vaccine conspiracy theories and lack of a firm stance on abortion access.

Over many years, Kennedy has been clear about his beliefs on vaccines in dozens of interviews, podcasts and social media posts.

Over rigorous questioning from senators Wednesday, Robert F. Kennedy Jr. laid out his vision to lead the Department of Health and Human Services, while backtracking on his past statements in support of abortion and against vaccines.