• CDC recommends that people wear masks in public settings, like on public and mass transportation, at events and gatherings, and anywhere they will be around other people.
  • Masks may help prevent people who have COVID-19 from spreading the virus to others.
  • Masks are most likely to reduce the spread of COVID-19 when they are widely used by people in public settings.
  • Masks should NOT be worn by children under the age of 2 or anyone who has trouble breathing, is unconscious, incapacitated, or otherwise unable to remove the mask without assistance.
  • Masks with exhalation valves or vents should NOT be worn to help prevent the person wearing the mask from spreading COVID-19 to others (source control).

Evidence for Effectiveness of Masks

Masks are recommended as a simple barrier to help prevent respiratory droplets from traveling into the air and onto other people when the person wearing the mask coughs, sneezes, talks, or raises their voice. This is called source control. This recommendation is based on what we know about the role respiratory droplets play in the spread of the virus that causes COVID-19, paired with emerging evidence from clinical and laboratory studies that shows masks reduce the spray of droplets when worn over the nose and mouth. COVID-19 spreads mainly among people who are in close contact with one another (within about 6 feet), so the use of masks is particularly important in settings where people are close to each other or where social distancing is difficult to maintain. CDC’s recommendations for masks will be updated as new scientific evidence becomes available.

Who Should Wear A Mask?

 General public

 People who know or think they might have COVID-19

  • If you are sick with COVID-19 or think you might have COVID-19, do not visit public areas. Stay home except to get medical care. As much as possible stay in a specific room and away from other people and pets in your home. If you need to be around other people or animals, wear a mask (including in your home).
  • The mask helps prevent a person who is sick from spreading the virus to others. It helps keep respiratory droplets contained and from reaching other people.

Caregivers of people with COVID-19

Who Should Not Wear a Mask

Masks should not be worn by:

  • Children younger than 2 years old
  • Anyone who has trouble breathing
  • Anyone who is unconscious, incapacitated, or otherwise unable to remove the mask without assistance

Feasibility and Adaptations

CDC recognizes that wearing masks may not be possible in every situation or for some people. In some situations, wearing a mask may exacerbate a physical or mental health condition, lead to a medical emergency, or introduce significant safety concerns. Adaptations and alternatives should be considered whenever possible to increase the feasibility of wearing a mask or to reduce the risk of COVID-19 spreading if it is not possible to wear one.

For example,

Masks are a critical preventive measure and are most essential in times when social distancing is difficult. If masks cannot be used, make sure to take other measures to reduce the risk of COVID-19 spread, including social distancing, frequent hand washing, and cleaning and disinfecting frequently touched surfaces.

Masks with Exhalation Valves or Vents

The purpose of masks is to keep respiratory droplets from reaching others to aid with source control. However, masks with one-way valves or vents allow air to be exhaled through a hole in the material, which can result in expelled respiratory droplets that can reach others.  This type of mask does not prevent the person wearing the mask from transmitting COVID-19 to others. Therefore, CDC does not recommend using masks for source control if they have an exhalation valve or vent.

Face Shields

Surgical Masks

Masks are not surgical masks or respirators. Currently, those are critical supplies that should continue to be reserved for healthcare workers and other medical first responders, as recommended by current CDC guidance. Masks also are not appropriate substitutes for them in workplaces where surgical masks or respirators are recommended or required and available.

Recent Studies:

  • Rothe C, Schunk M, Sothmann P, et al. Transmission of 2019-nCoV Infection from an Asymptomatic Contact in Germany. The New England journal of medicine. 2020;382(10):970-971. PMID: 32003551external icon
  • Zou L, Ruan F, Huang M, et al. SARS-CoV-2 Viral Load in Upper Respiratory Specimens of Infected Patients. The New England journal of medicine. 2020;382(12):1177-1179. PMID: 32074444external icon
  • Pan X, Chen D, Xia Y, et al. Asymptomatic cases in a family cluster with SARS-CoV-2 infection. The Lancet Infectious diseases. 2020. PMID: 32087116external icon
  • Bai Y, Yao L, Wei T, et al. Presumed Asymptomatic Carrier Transmission of COVID-19. Jama. 2020. PMID: 32083643external icon
  • Kimball A HK, Arons M, et al. Asymptomatic and Presymptomatic SARS-CoV-2 Infections in Residents of a Long-Term Care Skilled Nursing Facility — King County, Washington, March 2020. MMWR Morbidity and mortality weekly report. 2020; ePub: 27 March 2020. PMID: 32240128external icon
  • Wei WE LZ, Chiew CJ, Yong SE, Toh MP, Lee VJ. Presymptomatic Transmission of SARS-CoV-2 — Singapore, January 23–March 16, 2020. MMWR Morbidity and Mortality Weekly Report. 2020;ePub: 1 April 2020. PMID: 32271722external icon
  • Li R, Pei S, Chen B, et al. Substantial undocumented infection facilitates the rapid dissemination of novel coronavirus (SARS-CoV2). Science (New York, NY). 2020. PMID: 32179701external icon
  • Furukawa NW, Brooks JT, Sobel J. Evidence Supporting Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 While Presymptomatic or Asymptomatic [published online ahead of print, 2020 May 4]. Emerg Infect Dis. 2020;26(7):10.3201/eid2607.201595. Link
  • Oran DP, Topol Prevalence of Asymptomatic SARS-CoV-2 Infection: A Narrative Review [published online ahead of print, 2020 Jun 3]. Ann Intern Med. 2020;M20-3012. PMID: 32491919external icon
  • National Academies of Sciences, Engineering, and Medicine. 2020. Rapid Expert Consultation on the Possibility of Bioaerosol Spread of SARS-CoV-2 for the COVID-19 Pandemic (April 1, 2020). Washington, DC: The National Academies Press. https://doi.org/10.17226/25769external icon.
  • Schwartz KL, Murti M, Finkelstein M, et al. Lack of COVID-19 transmission on an international flight. CMAJ. 2020;192(15):E410. PMID: 32392504external icon
  • Anfinrud P, Stadnytskyi V, Bax CE, Bax A. Visualizing Speech-Generated Oral Fluid Droplets with Laser Light Scattering. N Engl J Med. 2020 Apr 15. doi:10.1056/NEJMc2007800. PMID: 32294341external icon
  • Davies A, Thompson KA, Giri K, Kafatos G, Walker J, Bennett A. Testing the efficacy of homemade masks: would they protect in an influenza pandemic? Disaster Med Public Health Prep. 2013;7(4):413-8. PMID: 24229526external icon
  • Konda A, Prakash A, Moss GA, Schmoldt M, Grant GD, Guha S. Aerosol Filtration Efficiency of Common Fabrics Used in Respiratory Cloth Masks. ACS Nano. 2020 Apr 24. PMID: 32329337external icon
  • Aydin O, Emon B, Saif MTA. Performance of fabrics for home-made masks against spread of respiratory infection through droplets: a quantitative mechanistic study. medRxiv preprint doi: https://doi.org/10.1101/2020.04.19.20071779, posted April 24, 2020.
  • Ma QX, Shan H, Zhang HL, Li GM, Yang RM, Chen JM. Potential utilities of mask-wearing and instant hand hygiene for fighting SARS-CoV-2. J Med Virol. 2020. PMID: 32232986external icon
  • Leung, N.H.L., Chu, D.K.W., Shiu, E.Y.C. et al.Respiratory virus shedding in exhaled breath and efficacy of face masks. Nat Med. 2020. PMID: 32371934external icon
  • Johnson DF, Druce JD, Birch C, Grayson ML. A quantitative assessment of the efficacy of surgical and N95 masks to filter influenza virus in patients with acute influenza infection. Clin Infect Dis. 2009 Jul 15;49(2):275-7. PMID: 19522650external icon
  • Green CF, Davidson CS, Panlilio AL, et al. Effectiveness of selected surgical masks in arresting vegetative cells and endospores when worn by simulated contagious patients. Infect Control Hosp Epidemiol. 2012;33(5):487‐494. PMID: 22476275external icon

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