i think you should lay off that typical cliche where any virus would turn you into an overly aggressive creature that could infect other people by simply biting them. (not saying that's your case, but that's so you know)
i'd like to see more, what you've got now is like the brief introduction of a movie, or a book, in this case.
also, your possible antagonists should be portrayed as normal people. take the last of us as an example, there's no real evil people, it's just a bunch of guys trying to survive in such a cruel world.
i think you should scrap that idea where you "become the virus" or something. what i think would be cool was if there was some sort of disease that would kill you if you didn't take special medication, like zombrex in dead rising.
but the problem is that the virus/bacteria/fungus is extremely contagious, such as a flu, and the disease spread so quickly that farmaceutical industries couldn't keep up.
in all that mess, there were people who were immune to that disease, but their blood could be used to produce that same medication that keeps everyone else alive, which results in these people being constantly hunted by the rest of the world.
idk just som ideas