Evidence for vaccine booster shots isn't clear, as Biden moves ahead anyway

The U.S. will begin rolling out booster shots in a matter of weeks with one major sticking point to resolve: It’s not entirely clear yet that third shots are needed.

The U.S. is poised to begin rolling out booster shots in a matter of weeks, with still one major sticking point to resolve: It's not entirely clear yet that third shots are needed. President Joe Biden recently vowed to begin deploying boosters the week of Sept. 20, pending a green light from federal regulators. But health experts advising the government on that decision say the August announcement by Biden's political appointees came as somewhat of a surprise. It also was unclear, they said, why that date was chosen at all. Evidence for boosters is still mixed, and announcing a timetable -- while likely popular with much of the public -- put independent government regulators in a corner by suggesting they would sign off no matter what.