The secret of it's application is to use it early before virus multiplicates in cells - not in high doses when it's already too late (as it's common in hospital trials which handle only late cases of Covid).
I just visited (for one full day) a friend who's wive had Covid and was present in the house. He also was in the active transmission phase. But Ivermectin prophylaxis together with iodine prophylaxis did save my PCR! So no infection has been confirmed!