system
Given the following post, respond as if you're commenting on Reddit:
human
[Zombies] If a cure/vaccine was produced during a zombie apocalypse, how would it be administered?

Surely it would be impossible to vaccinate on a worldwide scale during the conditions of an apocalypse.

In worlds like The Walking Dead or The Last Of Us, the aim (for the most part) is to survive but also to create a vaccine. But if a cure is found, then what? People are used to the world of zombies, people have devolved into killing machines.

Even if a vaccine was somehow given out on a worldwide scale it would not be possible to come back from an apocalypse and have life like it is as we live it today. It's never actually tackled in anything I've ever come across, like I Am Legend (the movie at least) a cure is found but then the movie ends, as far as I'm concerned that's as far as they got.

So basically if a zombie apocalypse were to begin; We're fucked.
gpt
This assumes the zombie apocalypse is based on science, not magic.  It also focuses too much on the initial conditions but not the longer term low-zombie concentration equilibrium. 

For The Walking Dead, the dead rising seems to have become widespread very quickly, possibly instantaneously at some point  This points to origins more like "Hell was full" more than a biologically transmitted disease.  However, even if it is an rapidly transmitted disease, the apocalypse part is only for a few years. 

The future for such worlds is just to survive the initial few years when the zombies vastly outnumber the living.  However, while that is the normal setting for these stories, its only temporary.  After the initial zombies decay off, they will subside to background predator numbers.  Cultures will adapt to dealing with newly dead people coming back, making sure the dead do not rise, and low numbers of zombies in the wild that are probably unavoidable.  

Society will restart with this new information - no vaccine needed even if it is science based.