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.

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."

If anyone needed a reminder that US health secretary and fervent anti-vaccine advocate Robert F. Kennedy Jr. has no background in science or medicine, look no further than the video he posted on social media Tuesday evening.