Robert F. Kennedy Jr. faced intense questioning from senators during his second day of confirmation hearings for the position of Health and Human Services Secretary, with his stance on vaccine safety emerging as a critical point of contention.

During Thursday's Senate Health, Education, Labor and Pensions Committee hearing, Republican Chairman Bill Cassidy, a physician, pressed Kennedy to unequivocally state that measles and hepatitis B vaccines do not cause autism. Kennedy repeatedly declined to provide a direct answer, instead stating he would support vaccines 'if the data shows they are safe.'

Senator Bernie Sanders (I-Vt.) followed up with similar questioning, expressing concern over Kennedy's reluctance to acknowledge the established scientific consensus on vaccine safety. 'The studies are there,' Sanders emphasized, calling Kennedy's responses 'very troubling.'

In an emotional moment, Senator Maggie Hassan (D-N.H.) shared her personal experience as the mother of a 36-year-old son with cerebral palsy. 'Not a day goes by when I don't worry whether something I did as a parent led to his condition,' Hassan said, choking up. She criticized Kennedy for 'relitigating and churning settled science,' arguing that his position impedes progress in understanding and treating autism.

Kennedy's confirmation faces uncertain prospects, particularly as he requires broad Republican support in the closely divided Senate. If all Democrats oppose his nomination, he can only afford to lose three Republican votes. Chairman Cassidy's vote remains notably uncertain, as he shared a personal story about a patient whose liver failure could have been prevented by '$50 of vaccines.'

The nominee maintained his position as 'pro-safety' rather than 'anti-vaccine,' though his responses to direct questions about vaccine safety and autism drew criticism from both sides of the aisle. The hearings also covered other crucial health policy matters, including abortion medication policies and the management of Medicare and Medicaid programs.