“It has never been shown that wearing surgical face masks decreases postoperative wound infections. On the contrary, a 50% decrease has been reported after omitting face masks.”
Tunevall TG. Postoperative wound infections and surgical face masks: a controlled study. World J Surg. 1991 May-Jun;15(3):383-7; discussion 387-8. https://doi.org/10.1007/BF01658736.