> I wonder how many people in zombie apocalypse (of a viral kind) would just infect themselves voluntarily to avoid getting chewed by the horde of zombies.

Probably very few. Infecting yourself is pretty much an equivalent of killing yourself. Except in movies they often make it look like an extremely painful, prolonged, and torturous way of doing so. But I imagine quite many will resort to other methods of accomplishing the same end-result.