Well I think, in answer to your question puzzled about why isn’t anyone talking about what happens if the vaccines are less effective- we’ve only just discovered this.
Like last month.
Until December, I think everyone thought we had a bit more time. Until December, it was changing (mutating) quite slowly.
The variant first discovered in the U.K., so far looks like it won’t affect vaccine efficacy.
The variant first found in South Africa and the variant first found in Brazil (simultaneously discovered in travellers from Japan) both contain an additional mutation which may lead to some reduced vaccine efficacy but probably nothing too dreadful.
The vaccines cause your body to produce a range of antibodies that bind to lots of different sites on the “spike protein”. So even if a site changes, the vaccines should still work.
It was always known that, eventually, the vaccines would need to be tweaked to adjust for new variants which were so different that existing vaccines were no longer efficacious enough.
We also know how to do it. We have better systems than ever before.
We know that the new vaccines allow this to be done extremely quickly (particularly the RNA vaccines). We’re talking weeks. Manufacture is a bigger problem ( more like months to get new vaccines manufactured and safety tested).
So it’s not necessarily these three variants (UK, SA, Brazil) that are a problem for vaccines per se , but it is the rate at which they’ve appeared, independently, and with so many mutations all in one go, arriving at similar changes.
To be honest, there’s not a lot that can be said right now and we still need to learn so much more.
We can’t know which new variants will arise, what they will look like and how much they will reduce vaccine efficacy. The possibilities are endless. The virus certainly has the upper hand there.
What we can do is up modelling, our surveillance, reduce transmission ( because more transmission = more opportunity to mutate) and get ready to act.