Masks are Effective. Here’s Why:
Facial coverings can help slow the spread of COVID-19 when they are worn correctly (covering the nose and mouth) and combined with other tools like social distancing and frequent hand washing (see CDC guidance here).
Watch this video to learn how the virus that causes COVID-19 spreads and how masks block the exhaled droplets that the virus travels in.
A few things we know about masks: Viruses are quite small, and they don’t float around alone. They travel in droplets of moisture when we exhale. Masks DO block these droplets of moisture that carry the virus when we exhale, which is why they work to limit the spread of COVID-19.
When someone with COVID-19 is not wearing a mask, droplets leave their mouth and nose when they exhale and much of the moisture evaporates quickly in the open air. Then, the virus can float around in micro-droplets that are too small for masks to filter out. These micro-droplets can be carried for long distances by air currents and other people can breathe in the virus easily.
This is why masks are so important: a cotton mask will catch the exhaled large droplets that carry the virus BEFORE the droplets evaporate. Remember: ‘my mask protects you, your mask protects me!’
Also, any exhaled droplets that do get through the mask will have less momentum. The mask slows the droplets down and they won’t travel as far. This is the reason it is important to also keep 6 feet of distance from other people.
A bandana, a cloth mask, or an N95 mask all do a good job of blocking exhaled droplets.
Even when we do not feel sick, wearing a mask is important because COVID-19 can spread without detection. Almost half of infections are likely to come from people who have no symptoms at all (read more about that here).
In summary, masks will not stop the pandemic on their own but they can help a lot! The best way to keep COVID-19 from spreading is to 1) avoid gatherings as much as possible, 2) wear a mask that covers your nose and mouth in public, 3) keep 6 feet of distance from other people, and 4) wash hands frequently.
Centers for Disease Control and Prevention. How to Protect Yourself and Others. Updated Nov 3, 2020. https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/prevention.html
Why masks work. July 4, 2020. https://www.youtube.com/watch?v=0Tp0zB904Mc
Oran, Daniel P., and Eric J. Topol. “Prevalence of Asymptomatic SARS-CoV-2 Infection: A Narrative Review.” Annals of Internal Medicine (2020). https://doi.org/10.7326/M20-3012
University of Maryland Medical System. Wearing a Mask: Myths and Facts. Accessed Nov 3, 2020. https://www.umms.org/coronavirus/what-to-know/masks/wearing-mask