Massachusetts September 23, 2021 5:09 pm As Pfizer Vaccine Booster Gets Approved, Many Questions Remain As booster shot approvals are rolling in from the federal government, what doctors are saying about who should get more shots — or their first ones. US & World Videos 4:17 Police presence grows at pro-Palestinian encampment at Northeastern 5:39 Billerica police sergeant hit and killed by excavator during construction detail 2:31 Celtics preparing for pivotal Game 3 against Heat in Miami 2:37 Quincy detective resigns amid allegations of ‘unwelcome, sexually explicit conduct' 4:07 Officer hit and killed while working construction detail in Billerica, authorities say