Masks and Coronavirus Disease 2019 (COVID-19)

Recent studies suggest that coronavirus disease 2019 (COVID-19) may be transmitted by infected persons even in the absence of symptoms of disease. While social distancing and good hand hygiene are the most important methods to prevent virus transmission, new guidelines state that healthy individuals can consider wearing masks in public settings, particularly when physical distancing is difficult (like in grocery stores or pharmacies). Primary benefits of wearing a mask include limiting the spread of the virus from someone who knows or does not know they have an infection to others. Masks also remind others to continue practicing physical distancing. However, nonmedical masks may not be effective in preventing infection for the person wearing them. Masks should not be worn by children younger than 2 years or by individuals who are unable to remove the mask by themselves or are unconscious.

What Kind of Face Mask Can I Wear?

Unless you are sick, a health care worker, or caring for someone who has COVID-19, medical masks (including surgical face masks and N95s) are not recommended. Because of shortages, medical masks should be prioritized for health care workers providing care for patients. Cloth face coverings can be made from household items such as 2 layers of cotton fabric, T-shirts, bandanas, or bedsheets. Masks should be secured with ear loops or ties. Whatever material a face mask is made from, it should fit well and cover the nose and mouth. The mask should not restrict the wearer’s ability to breathe.

How Do I Wear a Face Mask?

Before putting on a face mask, wash your hands with soap and water for at least 20 seconds or use an alcohol-based hand sanitizer (with at least 60% alcohol). Without touching the front of the mask, secure the ties behind your ears or head. While wearing the mask, do not touch the mask or your face. When removing the mask, take off the ear loops or ties first. Do not touch the front of the mask or your face when removing the mask. After removing the mask wash your hands with soap and water for at least 20 seconds (or use hand sanitizer). Face masks should be washed routinely with soap and water or laundry detergent to prevent contamination. Wearing a mask in public should always be accompanied by remaining at least 6 feet away from others and practicing good hand hygiene.

For More Information

Centers for Disease Control and Prevention
www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/diy-cloth-face-coverings.html

The JAMA Patient Page is a public service of JAMA. The information and recommendations appearing on this page are appropriate in most instances, but they are not a substitute for medical diagnosis. For specific information concerning your personal medical condition, JAMA suggests that you consult your physician. This page may be photocopied noncommercially by physicians and other health care professionals to share with patients. To purchase bulk reprints, email reprints@jamanetwork.com.

Article Information

Published Online: April 17, 2020. doi:10.1001/jama.2020.6437

Conflict of Interest Disclosures: Dr Aronoff reported receiving funding from the National Center for Advancing Translational Sciences, Pfizer, Cayman Chemical Co, March of Dimes, National Institute of Allergy and Infectious Diseases, and Eunice Kennedy Shriver National Institute of Child Health and Human Development and serving as an advisory board consultant for Summit Therapeutics, NAEJA-RGM Pharmaceuticals, BLC, and Sanofi Pasteur. Dr Desai reported no disclosures.

Sources: Omer SB, Malani P, Del Rio C. The COVID-19 pandemic in the US: a clinical update. JAMA. Published online April 6, 2020. doi:10.1001/jama.2020.5788

Bourouiba L. Turbulent gas clouds and respiratory pathogen emissions: potential implications for reducing transmission of COVID-19. JAMA. Published online March 26, 2020. doi:10.1001/jama.2020.4756

Bai Y, Yao L, Wei T, et al. Presumed asymptomatic carrier transmission of COVID-19. JAMA. 2020;323(14):1406-1407. doi:10.1001/jama.2020.2565

4 Comments for this article

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April 18, 2020

Proper Mask is Fundamentally Useful

Dr Narayan Bahadur Basnet, MBBS, MPA, PG Ped, Ph.D. | Children's Medical Diagnosis Center (CMDC), Chabahil, Kathmandu, Nepal. Web: www.cmdc.com.np

I am a regular user of two-layered locally-made cotton mask for the last 15 years specially when I go out of my residence and work in my clinic. I experienced that it helped me - to decrease atmospheric pollution prevailing in my city for the last several years, to decrease possible respiratory tract infection, to decrease unwanted smelling and to some extent, to decrease indirect smoking (I am a non-smoker). When I encounter seasonal flu or common cold patients in my clinic I further increase the duration of the use of mask and I have definitely experienced less respiratory infections. After reading COVID-19 endemic in China I further geared up precaution on respiratory health of myself and my patients along with physical distancing (I do not prefer the word ‘social distancing’ since no patients like social/familial distancing during sickness!), and proper hand washing. I made a brochure for patients focusing on the proper use of masks, physical distancing, proper hand washing, avoid touching the face, personal hygiene, use of sanitary toilet, environmental sanitation of the area of living, nutrition and psychological care of possible COVID-19 patient.
Proper use of an adequately prepared mask not only helps to prevent COVID-19 but also many respiratory and inhalational problems especially common in developing countries and/or any circumstances wherever/whenever transmission of respiratory illness increases. I found the article very useful and timely. Thank you.

Reference

(1) Basnet NB. A token of health insurance for all: Hand washing and sanitary toilets. In: Matsui M, editor. Treasure English Series, Grade 5 (Lesson 8), Shizuoka, Japan: Zkai Publishers, Inc, 2005 (a textbook of English for Japanese high school students):p.84-95.

CONFLICT OF INTEREST: None Reported

April 18, 2020

Potential Risks When Some Special People Wear Masks

Zheng Zhaoshi, PH.D. M.D. | No. 1 Department of Neurology, The Third Hospital of Jilin University

As more asymptomatic patients with SARS-CoV-2 infection are found in the world, wearing N95 masks is undoubtedly an effective respiratory protective measure (1). However, wearing an N95 mask for a long time may bring potential risks and even complications that are difficult to eliminate.

Oxygen concentration inhaled by healthy subjects wearing a surgical mask covering an N95 respirator decreases to about 17%, and the concentration of carbon dioxide increases to about 1.2% - 3% in a short period of light work (2-3). Although participants did not show any obvious changes in physical function and did not have any discomfort ratings, the average carbon dioxide concentration inhaled was far higher than the limit of 0.1% of indoor carbon dioxide concentration in many countries. With prolonged mask wearing, untoward reactions may gradually appear. In another long-term study, after wearing an N95 mask for 12 hours the CO2 concentration of subjects increased to 41.0 mmHg, far higher than the baseline value of 32.4mm Hg at the beginning of the test (4). The subjects mainly reported headache, dizziness, feeling tired and communication obstacles. In real life, the situations and time of wearing masks are much longer than the above experimental research settings.

Therefore, when taking strong measures to prevent and control COVID-19 we should also pay attention to implementation of individualized strategies. Pregnant women and patients with basic respiratory diseases are the most vulnerable groups. These high-risk groups should try to choose a way of isolation away from others. Many kindergartens and middle schools in many provinces of China have begun to resume classes or plan to resume classes in the near future. Most of them require students to wear masks during the school period. It is questionable that students wear masks for a long time, especially for the children in low school years.

We declare no conflict of interest.

Reference
1. Offeddu V, Yung C F, Low M S, et al.Effectiveness of Masks and Respirators Against Respiratory Infections in Healthcare Workers: A Systematic Review and Meta-Analysis.Clinical Infectious Diseases, 2017, 65(11): 1934-1942. doi: 10.1093/cid/cix681

2. Roberge R J, Coca A, Williams W J, et al. Surgical mask placement over N95 filtering facepiece respirators: physiological effects on healthcare workers[J]. Respirology, 2010, 15(3): 516-521. doi:10.1111/j.1440-1843.2010.01713.x

3. Sinkule E J, Powell J B, Goss F L, et al.Evaluation of N95 Respirator Use with a Surgical Mask Cover: Effects on Breathing Resistance and Inhaled Carbon Dioxide.Annals of Occupational Hygiene, 2013, 57(3): 384-398. doi:10.1093/annhyg/mes068

4. Rebmann T, Carrico R, Wang J, et al.Physiologic and other effects and compliance with long-term respirator use among medical intensive care unit nurses. American Journal of Infection Control, 2013, 41(12): 1218-1223. doi:10.1016/j.ajic.2013.02.017.

CONFLICT OF INTEREST: None Reported

April 23, 2020

Masks Block Speech-Generated Droplets That May Contain Virus

Bebe Hound, PhD | Self-Employed

According to a recent NJEM article, normal speaking generates thousands of droplets that vary widely in size and may contain infectious virus particles. "Whereas large droplets fall quickly to the ground, small droplets can dehydrate and linger as “droplet nuclei” in the air, where they behave like an aerosol and thereby expand the spatial extent of emitted infectious particles (1)."

Wearing a simple cloth mask, even one just covering the mouth, blocks emission of these droplets at the source, including those droplets which then, through evaporation, become airborne and linger in the air.

REFERENCE

1. https://www.nejm.org/doi/full/10.1056/NEJMc2007800 with video

CONFLICT OF INTEREST: None Reported

May 23, 2020

Healthy Individuals May Benefit From Wearing Masks

Ming Chen, MD | University of Michigan

I am glad to see JAMA now provides a better recommendation than the previous patient page's “Face masks should not be worn by healthy individuals to protect themselves from acquiring respiratory infection because there is no evidence to suggest that face masks worn by healthy individuals are effective in preventing people from becoming ill” (1).

In an email to JAMA I'd previously written:

"The absence of evidence is not the evidence of absence. There is no solid evidence of failure of preventing people from becoming ill by wearing surgical masks.

The US CDC and many Health organizations recommend against wearing surgical masks by healthy individuals even in a crowded gathering “because air still can go around the edges of the not-so-tight seal of surgical masks, therefore they do not provide adequate protection”. Yet, no organizations would recommend against washing hands because it does not remove “all” of bacteria from your hands, or would recommend against using alcohol swab because it does not “100%” kill bacteria. The small amount of air leaking around the edges (tiny cross-section area) of surgical masks is in no comparison to the air carrying aerosols and fine droplets from an infected patient coming right into our face through the much larger cross-section area in front of us!

The US Surgeon general Dr. Jerome Michael Adams claimed “wearing surgical masks actually increases your risk of getting infected, because you may touch your face more”. This is a baseless assertion. Teaching the public how to correctly wearing surgical masks is exactly the responsibility of CDC and various Health organizations.

In a systematic review and meta-analysis, Jeffrey D. Smith et al. found that: “although N95 respirators appeared to have a protective advantage over surgical masks in laboratory settings, there were insufficient data to determine definitively whether N95 respirators are superior to surgical masks in protecting health care workers against transmissible acute respiratory infections in clinical settings (2)." This falls into many examples where the results of laboratory experiments cannot fully translate into clinical practice.

While it is true that “face masks should be reserved for those who need them because masks can be in short supply during periods of widespread respiratory infection”, the article (1) should have stopped there in listing the reasons for not recommending healthy individuals wear surgical masks and should not have offered alternative explanations.

Public health instruction from a scientific journal as prestigious as JAMA should appear with solid scientific evidence.

REFERENCE

1. Medical Masks, March 4, 2020, JAMA. 2020; 323(15):1517-1518. doi:10.1001/jama.2020.2331.
2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4868605/pdf/1880567.pdf

CONFLICT OF INTEREST: None Reported

Masks and Coronavirus Disease 2019 (COVID-19)

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