Although mRNA vaccines saved millions of lives during the COVID-19 pandemic, U.S. Health Secretary Robert F. Kennedy Jr. incorrectly argued they are ineffective to justify the Department of Health and Human Service's recent decision to cancel $500 million in government-funded research projects to develop new vaccines using the technology.

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.