On Tuesday, Moncef Slaoui, chief science advisor for Operation Warp Speed, the federal government's $18 billion vaccine development initiative, estimated that the majority of U.S. citizens could receive a coronavirus vaccine by June

"Hopefully by the middle of the year, I hope most Americans will have been immunized," he said. "Which means the level of hesitancy that exists currently will have been decreased because people will have learned more information...about the vaccine."