Hate to be the one to tell you this, but a magic vaccine, by itself, may not 100% "work", as you appear to have reworked the meaning of work. Masks have always been a part of a multiple set of strategies that if all are followed, may significantly hinder further spread. There has always been the problem of people refusing to wear masks, improperly wearing their masks, wearing something that does not serve the purposes of a mask, etc. Not even to mention those who refuse to use the other strategies (i.e. some refuse to keep socially distant, some refuse to wash their hands although this may be a holdover of their refusal to ever wash their hands, even before the pandmic). Maybe WDW could sponsor a "Maskless Day" (like other special days) and see if they could get CM's to sign up for shifts.