There is no proof of that. We don't even know if he's truly an average virus that kills the host over time. He is an intelligent virus we've never seen in our world that controls the mind within a few minutes, you shouldn't automatically assume he has the same biology as other viruses and jump to conclusions. And even if what you said is true that is even more reason to infect those humans as he'll probably need more skills and experience doing these sort of things for future reference.since he's a virus, he should also be slowly killing his own body so he'd need to swap bodies over and over