Prior to the First Outbreak zombies were a popular topic of popular culture. They were the focus of innumerable movies, books, comics, computer games and even music. Most everyone enjoyed these works and thought to themselves, "Gee, this is all good and fun, but it'll never happen in real life. I mean, really, how can the dead come back to life?"
While science has yet to determine the causative agent of zombieism (be it viral, bacterial or other) it is interesting to note that for all its fanciful speculation, pre-outbreak fiction got was right about a great deal about zombie behavior and anatomy... but it was also dreadfully wrong on some very salient points. (See Revenant, Zombie Hunting.)
Of course zombie fiction is still a part of our collective cultural landscape, though now it usually takes the form of adaptations of actual events and persons. Horror fiction, as was known before the outbreak, has pretty much fallen by the wayside and been replaced by stories about prospectors and hobos.