This covers both coughing and sneezing, since the game mechanics are identical.

Affliction [20] 
    Coughing [+20%] 
    Malediction (As Regular Spell) [+100%] 
    Based on Activation Roll [+5%] 
    Magical [-10%] 
    Spell Components [-20%] 
        Must say "cough" in Latin 
        Must gesture with hands 
Level 2 [25] 
    Increase Malediction to Speed/Range table [+50%] 
Level 3 [30] 
    Add Area Effect (2 yard radius) [+50%] 
Level 4-7 [35/40/45/50] 
    Increase Area Effect by 1 step [+50%]