.@Merck CEO Ken Frazier speak @HarvardHBS: Difficult scale #vaccine 2 global population 7+ bn &amp; how distribute where hard 2 reach some populations such as the last mile. $MRK #COVID19 #coronavirus #health #safety $JNJ $AZN $PFE $GSK $MRNA $NVAX @HBSAlumni #business #money #Stock