Earlier quoted context omitted.
I don't think the virus could ever be stopped with today's vaccines, even if everyone was vaccinated. Data from fully or almost fully vaccinated countries clearly show that this doesn't eliminate the virus. It of course helps, but we have to depart from the idea that the "zero covid" strategies work.
I don’t know. You don’t need 100% efficacy to achieve herd immunity (obviously I’m not an epidemiologist and my terms are imprecise) if you have a sufficiently vaccinated population. I generally agree that we should depart from a covid zero strategy, but not because the vaccines aren’t effective; rather, because too many people are making decisions based on FUD and there doesn’t seem like much that can be done about…
Treshold of herd immunity depends on transmitability. For delta variant, if r=6 estimates are true, you would need 100% of population vaccinated in last 5 months (because after that infection immunity drops too low).