There will be new variants. Trying to vaccinate as near to everyone as you can possibly get and keeping cases low before the new variants emerge and take over is the strategy. The alternative is we don't even get through that much of the population before it starts all over again.C) even with the above, there WILL be new variants, just like there is with flu, so, a degree of risk will always be present.
The E484K mutation has appeared multiple places on earth independently on timescales of a year/months (uncertainty). It's only 7 months to September. We do have to be quite careful on this one.