You know what's depressing?
I would not likely survive in a post-apocalyptic setting. How could I ever manage to fend off wild animals and zombies when my body is spending so much energy fighting off itself?!?
Unless we were in World War Z.
Then my illnesses would be a positive trait and they would simply leave me alone.
Those zombies don't want my blood anyways.
Kinda scary if you really think about it though.