Massachusetts October 19, 2021 11:28 am COVID Q&A: Top Doctors Talk Vaccine Mix & Match, Efficacy and School Mask Mandates Top Boston doctors talk about the “mix and match” approach to COVID vaccine booster shots, variations in vaccine efficacy and school mask mandates. US & World Videos 2:09 Concord rejects middle school name change honoring Black abolitionist 2:41 Has Kristi Noem's dog-killing story taken her out of the race for Donald Trump's running mate? 2:10 High school senior elected to school committee 1:36 How to keep the big game from ruining your sleep 2:36 Celtics blow out Cavs in Game 1