I was thinking about that yeaterday, how they dealt with the outbreak. I haven't read the comics though, just saw the movie.
But those zombies were crazy in the movie. Like swarms of ants. They were a bit different from the other zombies different universe's have to deal with
The book is nothing like the movie. The book covers an entire apocalypse from start to finish. The movie is just a shitty C level action movie.