MacIntyre, C.R., and Chughtai, A.A. (2015). Facemasks for the Prevention of Infection in Healthcare and Community Settings. (Abstract only.) BMJ. 350:h694.
The authors summarize the available data on face mask use, noting how there is a lack of uniformity among the studies done to date, and a lack of data on the cost-effectiveness of face mask use. They discuss how the recommendations and language used varies across guidelines, and recommend areas for future research.