Well, insofar as my understanding of the lore goes, there can be no “cure” in the sense that you mean because it is not some otherworldly disease or infection that turns people into zombies. Gtaguy was trying to explain that what turns corpses into zombies is the alien goo-creatures that are possessing them, using them as puppets. If you die, you become a zombie. Period. The only way to prevent becoming possessed is to either destroy the corpse beyond being of any use to the goo, or simply stay alive.
The reason you need to take antibiotics after being bitten is simply because your wound becomes infected from natural irritants and bacteria, same thing that can happen to any wound you could get in real life if you don’t clean it.
Kind of spoiler-y if you weren’t already aware of that, and I apologise for it, but I feel it needed to be said.
Not that there’s anything inherently wrong or bad about your idea, as it is it just doesn’t really work with the established lore.
(In an unrelated note, this is my first post. Hello everybody!)
