Roll mechanics

[Sidushi]

Hi,

 

How does the mechanics of re-roll work for spells, So I cast AOE as a wizard  and I have my team there e.g.

 

Fetid Caress:

 

Target:

Paralyzed for 10.0 sec | Accuracy vs. Fortitude

 

AoE:

Sickened for 15.0 sec | Accuracy vs. Fortitude

 

Is there only initial roll vs Fortitude and if my characters succeed they will not be sickened, or because it is AOE and lasts 15 secs roll will be repeated every second in the area and if I fail at 15th second of its duration,it will still last 15secs on the character?

Edited May 17, 2018 by Sidushi