so abc 7 morning news anchor kamasi aron examines what life could be like in the world of vaccine havests. >> reporter: it's the dream on the horizon, a world without masks where you glide through the airport or sit down to dinner wherever you want. the question now is, will you need a so-called vaccine passport to get there, proof that you've had the shot? some experts say it doesn't have to. >> if it comes out with a relatively high acceptance rate, like 60%, 70% of people, miller time. we're done. >> reporter: what if vaccinations begin to slow? infectious disease expert dr. george rutherford of ucsf says the problems would begin if many months go by and some groups still have trouble getting a shot, or a significant number choose not to, leaving us short of the majority needed to reach an overall herd immunity. at that point, some worry about a potential scenario of vaccine haves and have nots. >> you're the ones get to see the giants play, you're the one who will get to go to the a's game, the one who gets to go to a restaurant and to the movie theater. you're the one that united a