Appologies "Fandom User", but your comment makes no sense. It seems to come down to grammatical errors, please try to reformulate your point and post it again. I'd like understand what you are trying to say. To me Reed's idea makes sense, and probably works. However, if it merely reverts its state by returning what was removed, it is possible it does not. His question is a valid one, and you answer does as of yet not deny it.
PS. What he asked was if reapplying the perk made it register as something that hit an undead. Not if reapplying vampirism over again changed anything. The original statement claimed the perks had to be taken afterwards to have any effect(strange it does not update the status, but then Skyrim has a ton of these bugs).