There is no firm evidence that surgical masks serve to prevent the infection of wounds during surgical operations. This may have implications for their use as a preventative measure against the spreading of the Covid-19 virus.
J R Soc Med. 2015 Jun; 108(6): 223–228.
Unmasking the surgeons: the evidence base behind the use of facemasks in surgery
Charlie Da Zhou, Pamela Sivathondan and Ashok Handa2
Ann R Coll Surg Engl. 1981 Nov; 63(6): 390–392.
Is a mask necessary in the operating theatre?
Neil W M Orr