Walk right in/Sit right down/Daddy, let your mind roll on. The 2021 version would be: Walk right in/Sit right down/Daddy (and Mommy) let your sleeves roll up. After a winter of discontent and vaccination-appointment disappointment, COVID-19 vaccines are suddenly available in abundance. Vaccination sites are taking walk-ins, mass vaccination sites are shutting down and local efforts are in motion to bring the vaccine to the people if the people can’t come to the vaccine. The shape of things to come is evident in Massachusetts, where the state will be closing four of seven mega-vaccination clinics in June and shifting its emphasis to the harder-to-reach populations. The plan includes working through 22 regional collaboratives, increasing doses sent to primary-care doctors, and expanding mobile vaccination clinics in hard-hit areas.