Medical workers -> high risk groups -> other frontline workers -> vaccine funding group priorities -> paying customers -> those who want it -> those who don’t want it (some possibility of this happening in certain places).
The size of each group matters too, but roughly along the lines. If one is much smaller than another ahead in the list (e.g. funding group priorities), it would be an argument to push them forward.
Aramis ~
Oxford vaccine:
Investigators also noted fewer vaccinated participants developed asymptomatic COVID-19, a finding that, while not conclusive, suggests the shot could help slow the spread of the coronavirus as well.