I did not notice COVID affecting the pouch at all, but my body didn't react that strongly to the strain-it just felt kind of like a weird cold because I also experienced a cooling sensation, kind of like a river flowing through my upper respiratory system..and it was kind of pleasant, oddly. The last time I was exposed (my husband got it and we did no separating/quarantining) I didn't get it.
Not sure if it is related, but I have been taking a supplement called "Immy" which is supposed to help your immune system and gut health. My pouch has been pretty happy since I started that except an occasional yeastiness, which I have always had since pre-pouch. Could be a coincidence that I didn't get COVID, though.