A review of available literature demonstrated the benefit of medical face masks in preventing transmission of SARS, influenza and COVID-19.  The study involved a meta-analysis of twelve primary publications. 

The authors concluded that medical face masks should be mandated for healthy individuals to prevent transmission of respiratory infections.  The efficacy of medical face masks to reduce the incidence rate of respiratory infections depends on compliance.  Medical face masks should be used in combination with other preventive modalities including hand washing, social distancing and PPE.  Medical face masks are superior to cloth but if purpose-manufactured masks are unavailable, cloth covering is recommended in community settings but requiring a high level of compliance.

*Chaabna, K.et al Face mask using community settings to prevent respiratory infection transmission: A rapid review and meta-analysis International Journal of Infectious Diseases 104:198-206 DOI:.org/10.016/j.ijid.22.09.1434