Moderna Inc. shares are selling off Wednesday, after the Trump administration took aim at the science behind the biotechnology company’s vaccines and said it would cancel some contracts and stop funding mRNA drug development.

The U.S. health secretary ordered an end to new mRNA development efforts just after UTMB published new research showing its effectiveness.

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.