A 1981 study published in the Annals of the Royal College of Surgeons of Englandlooked at the effects of masks on post-operative wound infections in a forty-bed surgical ward. All kinds of surgeries were performed there: cholecystectomies, gastrectomies, thyroidectomies, bowel resections, prostatectomies, herniorrhaphies, cystoscopies, bronchoscopies, and gastroscopies. No masks were worn in the operating room for the six-month period from March-August 1980.
The number of post-operative wound infections dramatically decreased.