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.

When COVID-19 cases were surging, Dr. David Wohl saw patients "hungry for air" fill UNC hospital wards. What most saved lives, he said, were vaccines developed with unprecedented speed using mRNA technologies.

The federal government’s decision to slash $500 million in funding for mRNA vaccine research has sparked concern among health experts.