How well do face masks protect against coronavirus?
Get answers to your questions about face masks, including how to use them properly.By Mayo Clinic Staff
Can face masks help slow the spread of the coronavirus (SARS-CoV-2) that causes COVID-19? Yes. Face masks combined with other preventive measures, such as frequent hand-washing and physical distancing, can help slow the spread of the virus.
The U.S. Centers for Disease Control and Prevention (CDC) recommends fabric masks for the general public. The CDC says that N95 masks should be reserved for health care providers.
The World Health Organization (WHO) recommends medical masks for health care workers as well as for anyone who has or may have COVID-19 or who is caring for someone who has or may have COVID-19.
The WHO also recommends medical masks for individuals who are at a higher risk of becoming seriously ill with COVID-19, such as people in their 60s and older, and people of any age with significant health problems.
How do the different types of masks work?
Also called surgical masks, these are loosefitting disposable masks. They're meant to protect the wearer from contact with droplets and sprays that may contain germs. A medical mask also filters out large particles in the air when the wearer breathes in.
To make medical masks more form-fitting, knot the ear loops where they attach to the mask. Then fold and tuck the unneeded material under the edges.
An N95 mask is a type of respirator. It offers more protection than a medical mask does because it filters out both large and small particles when the wearer inhales.
Because N95 masks have been in short supply, the CDC has said they should be reserved for health care providers. Health care providers must be trained and pass a fit test before using an N95 mask. Like surgical masks, N95 masks are intended to be disposable. However, researchers are testing ways to disinfect and reuse them.
Some N95 masks, and even some cloth masks, have valves that make them easier to breathe through. Unfortunately, these masks don't filter the air the wearer breathes out. For this reason, they've been banned in some places.
A cloth mask is intended to trap respiratory droplets that are released when the wearer talks, coughs or sneezes. It also acts as a barrier to protect the wearer from inhaling droplets released by others.
The most effective cloths masks are made of multiple layers of tightly woven fabric like cotton. A mask with layers will stop more droplets from getting through your mask or escaping from it.
How to get the most from your mask
The effectiveness of cloth and medical masks can be improved by ensuring that the masks are well fitted to the contours of your face to prevent leakage of air around the masks' edges.
Masks should be snug over the nose, mouth and chin, with no gaps. You should feel warm air coming through the front of the mask when you breathe out. You shouldn't feel air coming out under the edges of the mask.
Masks that have a bendable nose strip help prevent air from leaking out of the top of the mask.
Some people choose to wear a disposable mask under their cloth mask. In that case, the cloth mask should press the edges of the disposable mask against the face. Don't add layers if they make it hard to breathe or obstruct your vision.
Proper use, storage and cleaning of masks also affects how well they protect you. Follow these steps for putting on and taking off your mask:
- Wash or sanitize your hands before and after putting on your mask.
- Place your mask over your mouth and nose and chin.
- Tie it behind your head or use ear loops. Make sure it's snug.
- Don't touch your mask while wearing it.
- If you accidentally touch your mask, wash or sanitize your hands.
- If your mask becomes wet or dirty, switch to a clean one. Put the used mask in a sealable bag until you can get rid of it or wash it.
- Remove the mask by untying it or lifting off the ear loops without touching the front of the mask or your face.
- Wash your hands immediately after removing your mask.
- Regularly wash cloth masks in the washing machine or by hand. (They can be washed along with other laundry.)
And don't forget these precautions:
- Don't put masks on anyone who has trouble breathing or is unconscious or otherwise unable to remove the mask without help.
- Don't put masks on children under 2 years of age.
- Don't use face masks as a substitute for physical distancing.
What about face shields?
The CDC doesn't recommend using face shields instead of masks because it's unclear how much protection shields provide. However, wearing a face mask may not be possible in every situation. If you must use a face shield instead of a mask, choose one that wraps around the sides of your face and extends below your chin.
Feb. 13, 2021
See more In-depth
- Your guide to masks. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/about-face-coverings.html. Accessed Feb. 2, 2021.
- Coronavirus disease (COVID-19) advice for the public: When and how to use masks. World Health Organization. https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public/when-and-how-to-use-masks. Accessed Feb. 2, 2021.
- Considerations for wearing masks. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover-guidance.html. Accessed Feb. 1, 2021.
- N95 respirators and surgical masks (face masks). U.S. Food and Drug Administration. https://www.fda.gov/medical-devices/personal-protective-equipment-infection-control/n95-respirators-and-surgical-masks-face-masks. Accessed Feb. 2, 2021.
- Greenhalgh T, et al. Face masks for the public during the covid-19 crisis. BMJ. 2020; doi:10.1136/bmj.m1435. BMJ. 2020; doi:10.1136/bmj.m1422.
- Mahase E. Covid-19: What is the evidence for cloth masks? BMJ. 2020; doi:10.1136/bmj.m1422.
- Feng S, et al. Rational use of face masks in the COVID-19 pandemic. Lancet Respiratory Medicine. 2020; doi:10.1016/S2213-2600(20)30134-X.
- Cowling BJ, et al. Impact assessment of non-pharmaceutical interventions against coronavirus disease 2019 and influenza in Hong Kong: An observational study. Lancet Public Health. 2020; doi.org/10.1016/S2468-2667(20)30090-6.
- Howard J, et al. An evidence review of face masks against COVID-19. Proceedings of the National Academy of Sciences. 2021; doi:10.1073/pnas.2014564118.
- Personal protective equipment: Questions and answers. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/hcp/respirator-use-faq.html. Accessed Feb. 2, 2021.
- Chu DK, et al. Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: A systematic review and meta-analysis. The Lancet. 2020; doi:10.1016/S0140-6736(20)31142-9.
- Tso RV, et al. Importance of face masks for COVID-19: A call for effective public education. Clinical Infectious Diseases. 2020; doi:10.1093/cid/ciaa593.
- Lyu W, et al. Community use of face masks and COVID-19: Evidence from a natural experiment of state mandates in the US. Health Affairs. 2020; doi:10.1377/hlthaff.2020.00818.
- McIntosh K. Coronavirus disease 2019 (COVID-19): Epidemiology, virology, and prevention. https://www.uptodate.com/contents/search. Accessed Feb. 2, 2021.
- Transmission of SARS-CoV-2: Implications for infection prevention precautions. World Health Organization. https://www.who.int/publications/i/item/modes-of-transmission-of-virus-causing-covid-19-implications-for-ipc-precaution-recommendations. Accessed Feb. 2, 2021.
- Gandhi M, et al. Uniting infectious disease and physical science principles on the importance of face masks for COVID-19. Med (NY). 2021; doi:10.1016/j.medj.2020.12.008.
- Verma S, et al. Visualizing droplet dispersal for face shields and masks with exhalation valves. Physics of Fluids. 2020; doi:10.1063/5.0022968.
- Perencevich EN, et al. Moving personal protective equipment into the community: Face shields and containment of COVID-19. JAMA. 2020; doi:10.1001/jama.2020.7477.
- Clase CM, et al. Forgotten technology in the COVID-19 pandemic: Filtration properties of cloth and cloth masks. Mayo Clinic Proceedings. 2020; doi:10.1016/j.mayocp.2020.07.020.
- Darby S, et al. COVID-19: Mask efficacy is dependent on both fabric and fit. Future Microbiology. 2021; doi:10.2217/fmb-2020-0292.
- Improve how your mask protects you. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/your-health/effective-masks.html. Accessed Feb. 10, 2021.
- Brooks JT, et al. Maximizing Fit for Cloth and Medical Procedure Masks to Improve Performance and Reduce SARS-CoV-2 Transmission and Exposure, 2021. Morbitity and Mortality Weekly Report. 2021; doi:http://dx.doi.org/10.15585/mmwr.mm7007e1.