Should all of us wear cloth masks?
YES, when in public and when near other people, especially when in enclosed spaces. Breathing, talking, coughing, and sneezing all produce both droplets and aerosols carrying large amounts of virus. Fabric masks are effective in limiting droplet transmission of COVID-19. If everyone wore a homemade face-covering of some sort, these virus particles would not be expelled by the wearer in such large quantities and we could significantly slow the transmission of this virus down.
Masks, along with SOCIAL DISTANCING and AVOIDING ENCLOSED SPACES are critical to slowing the spread of COVID-19.
Transmission is particularly high indoors. We should AVOID enclosed spaces with groups of people. This means bars, restaurants, small stores with lots of people, etc.
How is COVID-19 spread? By asymptomatic, pre-symptomatic and symptomatic people.
COVID-19 is highly contagious. If you are infected, you will not know it for at least several days or possibly for up to 14 days. Some people never get symptoms. From 40% - 50% of all transmission of the COVID-19 virus comes from people who have no symptoms! New strains of the COVID-19 virus, which are more highly infectious, have been identified in the U.S.
Breathing, talking, coughing, and sneezing all produce both droplets and aerosols carrying large amounts of virus. Droplets fall onto surfaces where they may contaminate hands, which later bring virus to the mucus membranes of the nose, mouth, and eyes and cause infection. Cloth masks may block droplet transmission and they also prevent the wearer from touching his/her mouth, nose, and eyes.
Aerosols, which contain very tiny particles of virus, hang in the air for a long time and can be breathed in by others. Aerosolized particles get smaller as the expelled moisture droplets evaporate, leaving very tiny particles that are not filtered by a homemade or surgical mask face covering. For protection from these tiny aerosolized particles, N95 masks and goggles and PPE are necessary. These must be preserved for health care providers.
How do cloth masks reduce COVID-19 transmission?
Cloth masks help in 3 VERY IMPORTANT ways:
Will cloth masks stop aerosol transmission of COVID-19?
Cloth masks have very little effect on aerosol transmission because they cannot filter out the tiny virus particles and because the particles go around a mask that does not have a seal (as N95 masks do).
That's why we need SOCIAL DISTANCING and avoidance of enclosed spaces. Social distancing (remaining at least 6' away from other people) is critically important and will be necessary for a long time.
Please do your part. Wear a mask whenever you are near other people. And please make cloth masks for others and support our effort to protect both health care workers and community members.
... along with social distancing, hand washing, avoiding enclosed areas with groups of people, and staying isolated when sick, we could slow transmission greatly... and maybe even stop it entirely!
Check out this great video about how masks work.