[fattire]

Yeah I guess I was asking if having only partial-immunity effectively acts as a filter or creates pressure so that rarer mutated strains make it through and are given a pathway to infection/reproduction.

From your response: "It might culture a strain that's better at infecting folks for whom the vaccine doesn't prove effective, if there's a common factor there and the virus can use it." it sounds like the answer is yes.

[syntheticnature]

It might make it through, but in that case it would be better adapted for those the vaccine didn't work on; this could actually make it less infectious for those the vaccine would work on, so it's questionable whether it would be any better or worse overall.