The Remaining by D.J. Molles - four books of infectious apocalypse fun!
The hero is a special forces dude who was part of a program designed to provide pragmatic national continuity in the event of apocalyptic disaster. He, and Coordinators like him, get sent down into personal bunkers to hole up when news of national threats pops up, and usually they are recalled when the disasters turn out to be not so big. Only this time, it was huge! A bacteria that turns the higher level areas of the brain to mush, and the poor infected into a rabid, instinctual killer, is loose, and spreads so fast that two weeks later, when Lee lets himself out of his bunker and his mission begins, nearly everyone is gone!
It's really interesting reading the books. Aside from the fun story with great pacing and detail, the writing is occasionally clunky and heavy handed. Like, sometimes you come across a sentence that really should have been edited out. And I say, WHAT OF IT! This is sophistication in the making. It's like watching a writer get better as he goes.