“…This review summarizes a century of evidence on the efficiency of cloth and cloth masks to reduce transmission of droplets and aerosols ( Supplemental Table , available online at http://www.mayoclinicproceedings.org ). 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 We argue that this body of work should inform decisions in the context of reducing the transmissibility of COVID-19. Physical distancing, hand washing, and disinfection of surfaces remain the cornerstones of policy, and we stress that we are not discussing cloth masks as a means of relaxing these interventions or as a replacement for formal personal protective equipment (PPE) for high-risk workers.…”