So everyone's infected? [George sounds a little more eager than she probably should, since everyone already having the potential to become a zombie isn't really a good thing. But it does mean that depending on how long this kid has been here with no outbreaks, there might actually be something in place keeping that infection from spreading.]

It's the same for us. The virus is in everyone, but it's inert right up until it isn't. Dying is one way to amplify, but bites, zombie fluids, or even someone else's blood can set it off too. Bleach is humanity's new best friend.