Common cold?

[jasper]

Gotta go with @Sealorn on this. Being effected by a cold is not very heroic, or interesting.

Jasper does not put his finger under LordEntrails nose..
ACHOOOOO!!!!!!!!!!!!!!!!!!!!!!!
After the fight scene cut away to high flying shot of Lord and Jasper dead bodies. Their entrails are scattered over the court yard. THE END. Roll credits.

edit to add
I would add.
Before stealth checks roll d20 against the dm. If dm wins you at disadvantage. If you have buddyit a straight roll.

 

[delericho]

Like other posters, I wouldn't bother with a mechanical representation. If a player chose to describe his character as having a cold, I'd take the opportunity to use that as flavour text when describing successes/failures.