The effectiveness of surgical face masks: what the literature shows.

The use and withdrawal of surgical face masks in recent years has occurred in an ad hoc manner that is incompatible with evidence-based practice. Much of the literature on masks consists of anecdotal evidence or summaries of previous studies. The rationale for wearing masks has shifted from protection of the patient to protection of the health care professional wearing the mask. Currently there is little evidence that wearing a surgical mask provides sufficient protection from all the hazards likely to be encountered in an acute health care setting: the use of a respirator and face shield should be considered depending on the circumstances.