Kennedy's condition is called spasmodic dysphonia, which is a neurologic disorder that can affect the voice and speech by causing the muscles that generate a person’s voice to go into periods of spasm, according to Penn Medicine. It is a lifelong condition, but can be improved with treatment in some cases, according to Penn Medicine.

Kennedy managed to allay the concerns of several key GOP senators over his anti-vaccine activism. Mitch McConnell was the lone Republican to vote against him.

The US Senate on Thursday voted to approve Robert F. Kennedy Jr. as the secretary of the Department of Health and Human Services, clearing the way for one of President Donald Trump’s more controversial Cabinet appointments.