COVID-19: Considerations for Wearing Masks

• CDC recommends that people wear masks in public places; B. in public transport and in local transport, at events and meetings as well as wherever they are in the vicinity of other people.
• Masks can help keep people with COVID-19 from spreading the virus to others.
• Masks are most likely to reduce the spread of COVID-19 when used extensively by people in public places.
• Masks should NOT be worn by children under the age of 2, or by anyone who has difficulty breathing, is unconscious, incapacitated, or otherwise unable to remove the mask without assistance.
• Masks with exhalation valves or vents should NOT be worn to prevent the person wearing the mask from transmitting COVID-19 to anyone else (source control).

Evidence of the effectiveness of masks

Masks are recommended as a simple barrier to prevent breath droplets from getting into the air and onto others if the person wearing the mask coughs, sneezes, speaks, or raises their voice. This is known as source control. This recommendation is based on what we know about the role of respiratory droplets in the spread of the virus that causes COVID-19, coupled with new evidence from clinical and laboratory studies showing that masks reduce the spraying of droplets when over Nose and mouth are worn. COVID-19 mainly spreads among people who are in close contact with one another (within about 6 feet). Therefore, the use of masks is especially important in environments where people are close together or social distance is difficult to maintain. The CDC's recommendations for masks will be updated as new scientific knowledge becomes available.

Who should wear a mask?

General public

• CDC recommends that everyone ages 2 and up wear a mask in public facilities and around people who do not live in your household, especially when other social distancing measures are difficult to maintain.
• COVID-19 can be spread by people who don't have symptoms and don't know they are infected. For this reason, it is important that everyone in public facilities wear masks and practice social distancing (at least 10 feet from other people).
• While masks are highly recommended to help reduce the spread of COVID-19, CDC recognizes that there are certain instances where wearing a mask may not be possible. In these cases, adjustments and alternatives should be considered where possible (see examples below).

People who know or think they have COVID-19

• If you have COVID-19 or think you may have COVID-19, do not visit public areas. Stay home except for 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 with other people or animals, wear a mask (even in your home).
• The mask prevents a sick person from spreading the virus to others. It helps keep respiratory droplets in check and prevent them from reaching other people.

Caregivers for people with COVID-19

Who shouldn't wear a mask

Masks should Not be worn by:

• Children under 2 years
• Anyone who has difficulty breathing
• Anyone who is unconscious, incapacitated, or otherwise unable to remove the mask without assistance

Feasibility and adjustments

CDC recognizes that wearing masks may not be possible in every situation or for some people. In some situations, wearing a mask can aggravate physical or mental health, lead to a medical emergency, or raise significant safety concerns. Whenever possible, adjustments and alternatives should be considered to improve the feasibility of wearing a mask or to reduce the risk of spreading COVID-19 when wearing a mask is not possible.

For example,

• People who are deaf or hard of hearing, or who care for or interact with a hearing impaired person, may not be able to wear masks if they rely on reading to communicate. Use a clear mask in this situation. If a clear mask isn't available, see if you can use written communication, use subtitles, or reduce background noise to allow communication while wearing a mask that will block your lips.
• Some people, such as people with intellectual and developmental disabilities, mental illness, or other sensory sensitivities, may have trouble wearing a mask. You should contact your doctor for advice on wearing masks.
• Younger children (e.g., preschool or early elementary school age) may not be able to wear a mask properly, especially over long periods of time. Wearing masks can be prioritized during times when it is difficult to maintain a 6-foot distance from others (e.g., during carpool drop-off or pick-up, or while waiting in line at school). Ensuring the correct mask size and fitting, as well as reminding and educating children frequently about the importance and proper use of masks can help resolve these issues.
• People should not wear masks when engaging in activities that may cause the mask to get wet, such as walking around. B. when swimming on the beach or at the pool. A damp mask can make breathing difficult. During activities such as swimming, it is particularly important to keep a physical distance from others in the water.
• People who do high-intensity activities like running may not be able to wear a mask if it causes breathing difficulties. If you cannot wear a mask, perform the activity in a location with better ventilation and air exchange (such as outdoors or indoors) and where you can be physically separated from other people.
• Individuals working in an environment where masks increase the risk of heat-related illness or may create safety concerns due to the introduction of a hazard (e.g., belts caught in machinery) can contact an occupational health and safety officer to determine the appropriate one to identify mask for their setting. Outdoor workers can prioritize the use of masks when they are in close contact with other people, e.g. B. during group trips or shift meetings, and remove masks if social distancing is possible. More information can be found here and below.

Masks are and are a critical preventive measure most Essential in times when social distancing is difficult. If masks cannot be used, take other measures to reduce the risk of the spread of COVID-19, 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 prevent breath droplets from reaching others to aid 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 the expulsion of breath droplets that can reach others. This type of mask does not prevent the person wearing the mask from transmitting COVID-19 to others. Hence CDC is not recommended Use source control masks when they have an exhalation valve or vent.

Face protection

• A face shield is mainly used to protect the eyes of the person who wears it. It is not currently known what protection a face shield can provide to nearby people from the wearer's breath being sprayed. There is currently insufficient evidence to demonstrate the effectiveness of face shields for source control. Hence CDC is currently not recommended Use of face shields as a replacement for masks.
• However, wearing a mask may not be possible for some people in every situation; B. for deaf or hard of hearing people or for people who care for a hearing impaired person or interact with them. Here are some considerations for those who need to wear a face shield instead of a mask:
  • Although the evidence for face shields is limited, the available data suggests that the following face shields may offer better source control than others:
    • Face shield that wraps around the sides of the wearer's face and extends under the chin.
    • Face protection with hood.
  • Face protection wearers should wash their hands before and after removing the face protection and should not touch their eyes, nose and mouth while removing.
  • Disposable face shields are for single use only and should be disposed of in accordance with the manufacturer's instructions.
  • Reusable face shields should be cleaned and disinfected after each use according to the manufacturer's instructions or the CDC face shield cleaning instructions.
  • Plastic face shields for newborns and young children are NOT recommended.

Surgical masks

Masks are not surgical masks or respirators. These are currently critical consumables that should remain reserved for healthcare workers and other medical first responders, as recommended in current CDC guidelines. Also, masks are not a suitable substitute for them in workplaces where surgical masks or respirators are recommended or required and available.

Current studies:

• Rothe C., Schunk M., Sothmann P. et al. Transmission of the 2019-nCoV infection from an asymptomatic contact in Germany. The New England Journal of Medicine. 2020; 382 (10): 970- 971. PMID: 32003551external symbol
• Zou L., Ruan F., Huang M. et al. SARS-CoV-2 viral load in upper respiratory tract samples from infected patients. The New England Journal of Medicine. 2020; 382 (12): 1177-1179. PMID: 32074444external symbol
• 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 symbol
• Bai Y., Yao L., Wei T. et al. Suspected asymptomatic carrier transmission of COVID-19. Jama. 2020. PMID: 32083643external symbol
• Kimball A. HK, Arons M. et al. Asymptomatic and Presymptomatic SARS-CoV-2 Infections in Long Term Care Residents – King County, Washington, March 2020. MMWR Weekly Report on Morbidity and Mortality. 2020; ePub: March 27, 2020. PMID: 32240128external symbol
• Wei WE LZ, Chiew CJ, Yong SE, Toh MP, Lee VJ. Presymptomatic Transmission of SARS-CoV-2 – Singapore, January 23 to March 16, 2020. MMWR Weekly Report on Morbidity and Mortality. 2020; ePub: April 1, 2020. PMID: 32271722external symbol
• Li R., Pei S., Chen B. et al. A significant undocumented infection facilitates the rapid spread of the novel coronavirus (SARS-CoV2). Science (New York, NY). 2020. PMID: 32179701external symbol
• Furukawa NW, Brooks JT, Sobel J. Advice on Supporting Coronavirus 2 Transmission with Severe Acute Respiratory Syndrome 2 During Presymptomatic or Asymptomatic (published online before going to press, 2020 May 4th). Emerg Infect Dis. 2020; 26 (7): 10.3201 / eid2607.201595. shortcut
• Oran DP, Topol Prevalence of Asymptomatic SARS-CoV-2 Infection: A Narrative Review (published online before going to press June 3, 2020). Ann Intern Med. 2020; M20-3012. PMID: 32491919external symbol
• National Academies of Science, Engineering and Medicine. 2020. Rapid expert consultation on the possibility of the spread of SARS-CoV-2 through bioaerosol during the COVID-19 pandemic (April 1, 2020). Washington, DC: The National Academies Press. https://doi.org/10.17226/25769external symbol.
• Schwartz KL, Murti M., Finkelstein M. et al. Missing COVID-19 transmission on an international flight. CMAJ. 2020; 192 (15): E410. PMID: 32392504external symbol
• Anfinrud P, Stadnytskyi V, Bax CE, Bax A. Visualization of speech-generated oral liquid droplets with laser light scattering. N Engl J Med. 2020 April 15 doi: 10.1056 / NEJMc2007800. PMID: 32294341external symbol
• Davies A, Thompson KA, Giri K, Kafatos G, Walker J, Bennett A.. Testing the effectiveness of homemade masks: would they protect in a pandemic influenza? Disaster Med Public Health Prep. 2013; 7 (4): 413- 8. PMID: 24229526external symbol
• Konda A, Prakash A, Moss GA, Schmoldt M, Grant GD, Guha S. Aerosol filtration efficiency of common materials used in respirators. ACS Nano. 2020, April 24th. PMID: 32329337external symbol
• Aydin O, Emon B, Saif MTA. Performance of fabrics for homemade masks against the spread of respiratory infections by droplets: a quantitative mechanistic study. medRxiv preprint doi: https://doi.org/10.1101/2020.04.19.20071779, published on April 24, 2020.
• Ma QX, Shan H., Zhang HL, Li GM, Yang RM, Chen JM. Potential Benefits of Wearing Masks and Immediate Hand Hygiene in Combating SARS-CoV-2. J Med Virol. 2020. PMID: 32232986external symbol
• Leung, N.H.L., Chu, D.K.W., Shiu, E.Y.C. et al. Respiratory viral excretion on exhalation and effectiveness of face masks. Nat Med. 2020. PMID: 32371934external symbol
• Johnson DF, Druce JD, Birch C, Grayson ML. A quantitative evaluation of the effectiveness of surgical and N95 masks for filtering the influenza virus in patients with acute influenza infection. Clin Infect Dis. 2009 Jul 15; 49 (2): 275-2. 7. PMID: 19522650external symbol
• 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 symbol