Originally Posted by These guys

It's taking that from the original comic books. It does add a lot of extra elements, in my opinion. In addition to people bitten, now everyone who dies is affected – this is completely apocalyptic for the human race. If people were to begin trying to repopulate and slowly wipe out the undead threat, they'd always have to worry about the reanimation of those who have passed on, even naturally. A body can't be left alone as a body, the brain stem must be destroyed or they're coming back. Basically, while it may not change the entire course of the show, it gives death that much more of a bite. You may not live twice, but you'll have to be killed twice.