most of the research in the past decade or so shows that the only person protected by OR masks is the wearer. Scandanavian resarch study indicated that the patients were just as safe from staff when the masks were not worn. Most of the protective equipment used in the OR performs a useful service, shoe covers and masks however, apparently are not. I wish I could tell you where that study was published, but I have long forgotten. You can check out the CDC site and the OSHA sites for some research info. Good luck on your study