Masks work. There is widespread evidence from the field of occupational health, the SARS epidemic, and other outbreaks that wearing masks protects us from germs and interrupts the transmission of disease from sick to healthy people.
https://www.bostonglobe.com/2020/03/19/opinion/guidance-against-wearing-masks-coronavirus-is-wrong-you-should-cover-your-face/
https://www.bostonglobe.com/2020/03/19/opinion/guidance-against-wearing-masks-coronavirus-is-wrong-you-should-cover-your-face/