The Royal Society’s Face mask report says if correctly used face masks, including homemade cloth masks, can contribute to reducing viral transmission. Masks can offer an important tool for contributing to the management of community transmission of Covid19 within the general population. The report says evidence supporting their potential effectiveness comes from 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.
Link to report: https://rs-delve.github.io/reports/2020/05/04/face-masks-for-the-general-public.html
A comprehensive study shows wearing masks significantly reduces the number of infections, far more than other measures such as social distancing. It shows that airborne transmission is highly virulent and dominates the spread of COVID-19. It reveals that the difference with and without masks represents the determinant in shaping the trends of the pandemic.
Link to article: https://www.pnas.org/content/early/2020/06/10/2009637117
Comparison of face mask use recommendations by different health authorities. Despite the consistency in the recommendation that symptomatic individuals and those in health-care settings should use face masks, differences in recommendations were observed for the general public and community settings. Evidence that face masks can provide effective protection against respiratory infections in the community is scarce. However, face masks are widely used by medical workers as part of droplet precautions when caring for patients with respiratory infections. The study suggests vulnerable individuals avoid crowded areas and use surgical face masks rationally when exposed to high-risk areas.
Link to article: https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(20)30134-X/fulltext