A Jamaican virus infects a small town and only a bunch of stoners can save their family and friends from becoming zombies by rounding them up and getting them high.

The logline kind of reads more like a comedy (or comedy-horror). Even though this could work as an ensemble piece, it would be nice to see a main protagonist.

The question I have is, so we know that getting high will prevent you from becoming a zombie, but then, what do you do with those who already are zombies? Will the protagonist(s) be fighting them off while being high?

I can imagine them doing that, which is kind of why this reads more like a comedy.

When small town stoners realize they are immune to the spreading virus, [protagonist] must lead a group of potheads to [goal]

Ok, sounds good. Can you rewrite it, so it's primarily about that one character?