Note: Coughing and large droplets are note the issue beause breathing exhales more virus in fine aerosols than coughing. Finer aerosols bypass masks and nose to the lungs. Since masks nebulise particles, the solution is ventilation, not face masks.
The global pandemic of COVID-19, caused by severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]) has been associated with infections and deaths among health-care workers. There have been conflicting recommendations from health authorities on the use of masks or respirators to protect health-care workers. When I first reviewed personal respiratory protection against tuberculosis for health-care workers more than 20 years ago, there was very little information on infectious aerosols. Since then, colleagues in various disciplines have provided a wealth of data. The purpose of this Viewpoint is to review the scientific literature on the aerosols generated by individuals with respiratory infections, and to discuss how these data inform the optimal use of masks, respirators, and other infection-control measures to protect health-care workers from those aerosols. This is not a review of the literature on the use of surgical masks or respirators, as several have been done already.