Moncef Slaoui, leader of U.S. vaccine push, says he'll quit if politics trumps science

On a nice day in early May, Moncef Slaoui was sitting by his pool when he received a phone call that would dramatically change his life—converting him from a retired executive of a big pharmaceutical company to the scientific leader of the Trump administration’s Operation Warp Speed, a multibillion-dollar crash program to develop a vaccine in record time.