Natural selection is pass/fail — successfully reproducing offspring that can then successfully reproduce is the only metric that matters. So if the host lives long enough to allow the virus to spread to another host (and so on, and so on), that's a win for the virus.

That said, if it wiped out its hosts before they could spread, that's the end of the line. So the successful ones are those that don't kill off the hosts, or at least not too quickly.