MORE: What we know about the safety, efficacy of mRNA vaccines amid recent scrutiny. Infectious disease experts told ABC News that mRNA technology has been very successful in prev

While anti-vaxxers are thrilled, experts warn that defunding mRNA development takes away our already-proven best weapon against future pandemics.

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