std's? if she goes to bars with chris and acts like one of the guys taking guys she wants here and there for her satisfaction like miltary guys do and she catches something will her virus heal her from it?
Considering Sherry's virus can heal any wound internal or external, it's also quite believable that it also resists all diseases and infections. Jake may not have the super healing factor, but his body contains Wesker unique genetic makeup, which makes him immune to pretty much everything, and even allows him to absorb viruses and potentially gain powers, like his father if he decided to inject himself with a virus.
When facing a zombie apocalypse, don't join up with a group. Why? Because you'll end up blowing your own head off due to all the pointless drama caused within.