Surgeons wear it so that their breath/mouth droplets don't end up in patient's intenstines while performing a surgery, causing an infection. For that purpose a

Surgeons wear it so that their breath/mouth droplets don't end up in patient's intenstines while performing a surgery, causing an infection. For that purpose a single surgical mask can last hours (i.e. it keeps droplets on the inner surface of the mask). If they have to perform surgery on highly dangerous patients, they use hazmat suits instead: https://qph.fs.quoracdn.net/main-qimg-9bd2e88c4296be54e7f845276ffdc3b0-c https://qph.fs.quoracdn.net/main-qimg-9bd2e88c4296be54e7f845...