Using two masks and ensuring that the mask fits snugly on the face appear to lead to a significant reduction in an individual’s exposure to the coronavirus, suggest laboratory experiments by U.S. health officials.

Experiments were carried out by the U.S. Centers of Disease Control and Prevention (CDC) in January to determine the protection provided by wearing a cloth mask over a three-ply medical mask, and by knotting the ear loops of a surgical mask followed by wrapping the excess material close to the face. Both the methods were found to limit the exposure to infected aerosols by over 90% in laboratory simulation environment. Wearing a mask was also shown to help reduce exposure to aerosol particles the size of droplets that are known to spread COVID-19, in comparison with wearing no mask… (Reuters, February 10, 2021)