DELVE Initiative of Royal Society of UK has published a document with evidence supporting the use of Face Masks with data supporting their potential effectiveness based on analysis of: (1) the incidence of asymptomatic and pre-symptomatic transmission; (2) the role of respiratory droplets in transmission, which can travel as far as 1-2 meters; and (3) studies of the use of homemade and surgical masks to reduce droplet spread.
Their analysis suggests that the use of face masks could reduce onward transmission by asymptomatic and pre-symptomatic wearers if widely used in situations where physical distancing is not possible or predictable, contrasting to the standard use of masks for the protection of wearers. If correctly used on this basis, face masks, including homemade cloth masks, can contribute to reducing viral transmission.
