Instead of THE GUBBMINT being evil by LOCKING EVERYTHING DOWN in some scary QUARANTINE ZONE or the like, imagine a "got to build up zombie bite immunity" response, or one with pseudoscientific treatments, or pretty much anything so can feel like things are back to normal while zombies are just a thing that continues happening.
Add your own ideas if you like.
Oh yea that's right, I had the two confused, it's been a couple years since I read that book