R0 is for the delta variant is 6 - 7, ergo herd immunity (1-1/R0) is 0.833 - 0.857.
So, yes, it kinda works like that.
So, yes, it kinda works like that.
But we'll probably do vaccinations, wait for more aggressive mutations, add facemasks, wait for more aggressive mutations, and so on, until we have a super-virus.