Randomized clinical trials of community mask use are challenging to conduct because of ethical and practical considerations. Observational studies have substantial limitations but can be instructive per an article published in the American Medical Association’s journal (JAMA) on October 26, 2020. To understand the rationale for mask-wearing to prevent SARS-CoV-2 transmission, it is helpful to understand how the virus spreads from person to person. SARS-CoV-2 is primarily transmitted by respiratory droplets exhaled by infected individuals; these droplets span a spectrum of sizes. Larger droplets fall out of the air relatively quickly while close to the source, usually within a 6-foot distance. Smaller droplets, often referred to as aerosols are also present at close range but may remain in the air over time and great distances, decreasing in concentration as they move outward from their source.
Recent evidence suggests that up to 40% to 45% of people infected with SARS-CoV-2 may never be symptomatic but still can transmit the virus. Viral spread from people without symptoms may account for more than 50% of transmission events in COVID-19 outbreaks. Since it has now become evident that individuals capable of transmitting SARS-CoV-2 cannot be identified solely by the presence of symptoms, universal mask-wearing in the community for source control is recommended.
Per the American Medical Association, “return to normalcy will require the widespread acceptance and adoption of mask earing and other inexpensive and effective interventions as part of the COVID-19 prevention toolbox.” Remember, this “toolbox” includes physical distancing, hand hygiene, adequate ventilation and avoiding crowded spaces. Stay the course, stay strong, stay well, stay safe, mask up, and stay tuned!