Unless the patient presents a truly astounding infectious risk, almost certainly not. Surgical masks are not valved. However, the fact that theatres have a trul

Unless the patient presents a truly astounding infectious risk, almost certainly not. Surgical masks are not valved. However, the fact that theatres have a truly huge and mind boggling amount of air handling equipment on the floor above them, directing highly sterile and laminar air flow directly down to the floor from all angles, definitely does help this not matter as much...in an operating theatre, at least, not an aircraft.