Adams, who served as surgeon general during the first Trump administration, said Kennedy's assertions about the efficacy of mRNA vaccines are "simply not true."

This was one in a continuing line of moves that have put Kennedy's vaccine skepticism into public policy, though scientists say the vaccines are safe.

Former U.S. Surgeon General Jerome Adams — who served in President Trump's first term — tells "Face the Nation with Margaret Brennan" that "people are going to die" if the U.S. backs away from mRNA research,