Author, title and type of study

Population and type of surgery

Trial setting and co-interventions

Outcome measures, no. of wound infections

Comments, opinions and limitations

Study 1 [26] (Primary research)

660 patients undergoing clean surgery

Operating room. Mask versus No mask

Wound infection. No. not specified.

Scrubbed staff not included in the trial.

Study 2 [17] (Systematic review)

1429 undergoing elective surgery

Operating room. Mask versus No mask

Wound infection. No. not specified.

Unit of analysis error present

Study 3 [3] (Systematic review)

2113 patients undergoing clean surgery

Operating room. Mask versus No mask

Wound infection. No. not specified.

Unit of analysis error present