It would be nice to wear some of these other masks, but the current state of the game seems to necessitate the wearing of a plague mask.
Would it be possible to add vaccinations? Whether it be an npc that charges an exorbitant amount or a cash shop item (similar to wills and estate planning) It could be a skill in the medicine tree with a npc item to keep the costs up.
If you dint want it permanent make it last a month or two before you need a booster?
Would give a use for blood of a diseased person.