A surgical mask, also known as a medical face mask, is a personal protective equipment worn by health professionals during medical procedures to prevent airborne transmission of infections between patients and/or treating personnel, by blocking the transmission of pathogens (primarily bacteria and viruses) shed in respiratory droplets and aerosols from the wearer's mouth and nose. They act as an additional barrier for the airway and are not usually designed (unless N95-rated) to completely prevent the wearer from inhaling smaller airborne pathogens, but could be still protective by filtering out and trapping most of the droplets that carry them. There is a predominance of evidence that surgical masks protect both the wearer (by filtering the inhaled air) and bystanders (by blocking down forceful exhalations from the wearer that can spread pathogens afar).Surgical masks were originally designed to protect medical personnel from accidentally breathing or swallowing in splashes or sprays of bodily fluids, but the effectiveness of surgical masks against influenza-like infections has not been confirmed by high-quality randomized controlled trials. Commonly seen surgical masks vary greatly by quality and levels of protection. Despite their name, not all surgical masks are appropriate to be used during surgery. Surgical masks may be labeled as surgical, isolation, dental or medical procedure masks. Chinese health officials distinguish between medical (non-surgical) and surgical masks.Surgical masks are made of a nonwoven fabric created using a melt blowing process. They came into use in the 1960s and largely replaced cloth facemasks in developed countries.