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.

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.