Simple surgical masks protect wearers also remind wearers not to touch their mouth or nose, which could otherwise transfer viruses and bacteria after having touched a contaminated surface (fomite).

Simple surgical masks protect wearers from being splashed in the mouth with body fluids.They can also reduce the spread of infectious droplets (carrying bacteria or viruses) that are created when the wearer coughs or sneezes. They are not designed to protect the wearer from inhaling such particles. They will trap some particles but are much less effective than respirators, which are designed for this purpose.

If used correctly, facemasks and respirators may help reduce the risk of getting influenza, but they should be used along with other preventive measures, such as avoiding close contact and maintaining good hand hygiene.

Information on the effectiveness of facemasks and respirators for the control of influenza in community settings is extremely limited. Thus, it is difficult to assess their potential effectiveness in controlling swine influenza A (H1N1) virus transmission in these settings. ...

Safety guidelines for healthcare workers recommend the wearing of a face-fit tested respirator mask conforming to United States standard NIOSH N95 or European standard EN 149 FFP3 in the vicinity of pandemic-flu patients, to reduce the exposure of the wearer to potentially infectious aerosols and airborne liquid droplets.