Vincent Price in the story of I Am Legend or The Omega Man. I've not seen the Will Smith one, but I've seen Charlton Heston in The Omega Man a few times. This version is explicit about it being a "vampire virus" whereas the Heston version they seem more zombie like. But here, they act zombie like, moving slowly, are rather weak, but they don't like garlic or mirrors, so I don't know.
The movie opens with a voice-over section showing Price as the only man on Earth for three years, what he does to prepare for the undead, gets food, etc, then moves into flashback where we see what happened (they spend a lot more time on this than The Omega Man does), then he meets a gal. Is she infected or is she immune like he is?
Filmed in Italy, this is well shot, if a bit clumsy in places, and Vincent Price is remarkably subdued.