Stamina type check, maybe buy a Willpower type check for "I don't have time for this!" determination, with failure resulting in a negative modifier to all rolls for bloody days?
Thinking a bit wider, there's a vast spread of normal diseases that player characters are never in any danger of. I don't recall ever seeing a Call of Cthulhu character with TB, or a Werewolf with lockjaw. If characters get sick, it's A Big Deal, and probably a curse or an alien bioweapon or something.
Mundane illness is generally ignored, left to the players, or maybe the GM could discuss it with them. I can see suggesting something like Buffy, Killed By Death where our hero saves the day while hospitalised with flu.