[curryst]

My layman's interpretation is that variants are kind of a stepping stone to a strain. Viruses do mutate constantly, but I would guess that many (maybe most) of those mutations are effectively a no-op. It's a mutation in a dormant region, so it does nothing. Of the mutations that occur in an active region, some will be bad, and those mutations die out.

So I would think we're really only concerned with mutations in active regions that impact viability. We don't really care about mutations that decrease viability, since they'll generally be overcome by more viable versions of the virus naturally.

The question with this particular mutation is whether it's a variant or a strain. I.e. is this new variant more infectious? Which would make it a strain, not a variant.