Best pandemic movies?

[karsten]

For no reason whatsoever today, I just randomly and completely by chance happened to be wondering what the best pandemic-related movies might be.

I suppose that there would be two kinds:

1) movies about pandemics qua pandemics (relatively realistic)

and

2) movies with other sorts of contagions as pandemic-metaphors (i.e., zombie/creature flicks, World War Z, I Am Legend, that sort of thing).

The latter are certainly entertaining because, well, monsters!

I've seen a lot of those (the films, not the monsters).

But what are everyone's favorite movies in the first category? That is, movies that treat pandemics as realistically as possible? You know, challenges that preppers might face, infrastructure breakdown and ensuing results, etc. Any recommendations?

I know that there's even a film simply titled Pandemic, but haven't seen it.