Cloth face mask

Cloth face mask
Denim facemask from Clovis, California (transparent version).png
A homemade cloth face mask made out of a piece of denim textile
Other names Fabric mask

A cloth face mask is a mask made of common textiles, usually cotton, worn over the mouth and nose. Cloth face masks are recommended by public health agencies for disease "source control" in epidemic situations to protect others from virus laden droplets in infected mask wearers' breath, coughs, and sneezes. Because they are less effective than surgical masks or N95 masks in protecting the wearer against viruses, they are not considered to be personal protective equipment by public health agencies. They are used by the general public in household and community settings as perceived protection against both infectious diseases and particulate air pollution.

Cloth face masks were routinely used by healthcare workers starting from the late 19th century until the mid 20th century. In the 1960s they fell out of use in the developed world in favor of modern surgical masks, but their use has persisted in developing countries. During the COVID-19 pandemic, their use in developed countries was revived as a last resort due to shortages of surgical masks and respirators.

Usage

Guidance from the U.S. Centers for Disease Control and Prevention on using and making cloth masks during the COVID-19 pandemic [1]

Prior to the COVID-19 pandemic, reusable cloth face masks were predominantly used by healthcare workers in developing countries and were especially prominent in Asia. Cloth face masks contrast with surgical masks and respirators such as N95 masks, which are made of nonwoven fabric formed through a melt blowing process, and are regulated for their effectiveness.[2] Like surgical masks, and unlike respirators, cloth face masks do not provide a seal around the face.[3]

In healthcare settings, they are used on sick patients as source control to reduce disease transmission through respiratory droplets, and by healthcare workers when surgical masks and respirators are unavailable. Cloth face masks are only recommended for use by healthcare workers as a last resort if supplies of surgical masks and respirators are exhausted.[3] They are also used by the general public in household and community settings as perceived protection against both infectious diseases and particulate air pollution and to contain the wearer's exhaled virus laden droplets.[3][4]

Several types of cloth face masks are available commercially, especially in Asia.[4] Homemade masks can also be improvised using bandanas,[1] T-shirts,[1][2] handkerchiefs,[2] scarves,[2] or towels.[5]

Recommendations

Two French cloth masks certified by AFNOR. The white mask is made of polypropylene and the black one is made of cotton.

The World Health Organization (WHO) recommends that cloth face masks should be worn in public where social distancing is not possible to help stop the spread of coronavirus. It notes that wearing a cloth face mask is just one of a range of tools that can be used to reduce the risk of transmission.[6] The US Center for Disease Control, along with Johns Hopkins University School of Medicine, The Mayo Clinic, and Cleveland Clinic all concur with this recommendation.[7][8][9][10] The World Health Organization also recommended that those aged over 60 years old or with underlying health risks require more protection and should wear medical masks in areas where there is community transmission.[6]

The World Health Organization recommends using masks with at least three layers of different materials. Two spunbond polypropylene layers are also believed to offer adequate filtration and breathability.[11] When producing cloth face masks, two parameters should be considered: filtration efficiency of the material and breathability. The filter quality factor known as "Q" is commonly used as an integrated filter quality indicator. It is a function of filtration efficiency and breathability, with higher values indicating better performance. Experts recommend Q-factor of three or higher.[11]

Comparison of materials for fabric masks [11]
Material (source) Structure Initial
Filtration
Efficiency (%)
Initial
Pressure
drop (Pa)
Filter
quality
factor, Q
(kPa-1)
Polypropylene (interfacing material) spunbond 6 1.6 16.9
Cotton (sweater) knit 26 17 7.6
Cotton (T-shirt) knit 21 14.5 7.4
Polyester (toddler wrap) knit 17 12.3 6.8
Cotton (T-shirt) woven 5 4.5 5.4
Cellulose (tissue paper) bonded 20 19 5.1
Cellulose (paper towel) bonded 10 11 4.3
Silk (napkin) woven 4 7.3 2.8
Cotton (handkerchief) woven 1.1 9.8 0.48
Cotton, gauze woven 0.7 6.5 0.47
Nylon (exercise pants) woven 23 244 0.4

Effectiveness

Cloth face masks can be used for source control to reduce disease transmission arising from the wearer's respiratory droplets, but are not considered personal protective equipment for the wearer[12][13] as they typically have very low filter efficiency.[14][15] There are no standards or regulation for self-made cloth face masks.[15]

As of 2015, there had been no randomized clinical trials or guidance on the use of reusable cloth face masks.[3][5] Most research had been performed in the early 20th century, before disposable surgical masks became prevalent. One 2010 study found that 40–90% of particles in the 20–1000 nm range penetrated a cloth mask and other fabric materials.[14] The performance of cloth face masks varies greatly with the shape, fit, and type of fabric,[4] as well as the fabric fineness and number of layers.[5] As of 2006, no cloth face masks had been cleared by the U.S. Food and Drug Administration for use as surgical masks.[2] A Vietnamese study of healthcare workers compared influenza-like illness outcome among those wearing cloth masks versus medical masks.[16] They concluded that cloth masks were ineffective at preventing transmission in high-risk clinical settings. Although discouraged in clinical settings, cloth masks can still serve a vital role in reducing disease transmission in public settings according to a systematic review.[17]

The primary role of masks worn by the general public is to "stop those who are already infected broadcasting the virus into the air around them."[18] This is of particular importance with the COVID-19 pandemic, as silent transmission seems to be a key feature of its rapid spread. For example, of the people on board the Diamond Princess cruise ship, 634 people were found to be infected—52% had no symptoms at the time of testing, including 18% who never developed symptoms.[19] Political controversy has caused much confusion over mask mandates for coronavirus. The World Health Organization has encouraged policy makers to consider mask orders especially in areas of high population density with limited testing and Contact tracing capabilities.[11] Primary research from countries such as Germany and Thailand have shown significant decreases in case rates with widespread mask compliance.[20][21] It is important to note that mask wearers are more likely to engage in other hygiene measures such as hand washing and Social distancing. Best practice is to implement multiple prevention techniques to reduce risk, as characterized by the Swiss cheese model.

An experiment carried out in 2013 by Public Health England, that country's health-protection agency, found that a commercially made surgical mask filtered 90% of virus particles from the air coughed out by participants, a vacuum cleaner bag filtered out 86%, a tea towel blocked 72% and a cotton t-shirt 51%—though fitting any DIY mask properly and ensuring a good seal around the mouth and nose is crucial.[22][18] The use of common fabrics in making face masks has been tested.[23][24][25][26] Filter efficiency can be improved with multiple layers, high weave density, and a mix of different types of fabrics. Cotton is the most commonly used material, and filter efficiencies can reach >80% for particles <300 nm with fabric combinations such as cotton-silk, cotton-chiffon, or cotton-flannel.[26] The most protective cloth masks need at least three layers with a hydrophilic inner layer (i.e. cotton) to absorb moisture from the wearer's breathing and hydrophobic outer layers (i.e. polyester).[11] Masks should be washed frequently at the highest permitted temperature depending on the fabric.

History

During the 1918 flu pandemic, a streetcar conductor in Seattle refuses a person who attempts to board without wearing a mask.

The use of face masks during surgery was pioneered in 1897 by French surgeon Paul Berger and Polish surgeon Jan Mikulicz-Radecki.[27][28] Masks came into use to protect against infectious diseases in the early 20th century.[3][5] A design by Wu Lien-teh, who worked for the Chinese Imperial Court during the 1910–11 Manchurian pneumonic plague outbreak, was the first that protected users from bacteria in empirical testing; it inspired masks used during the 1918 flu pandemic.[29] The first study of mask use by healthcare workers took place in 1918.[3][5] In the 1940s, face masks made from cheesecloth were used to protect nurses from tuberculosis.[30]

Cloth masks were largely supplanted by modern surgical masks made of nonwoven fabric in the 1960s,[2][5] although their use continued in developing countries.[3] They were used in Asia during the 2002–2004 SARS outbreak, and in West Africa during the 2013–2016 Ebola epidemic.[3]

COVID-19 pandemic

Rhode Island National Guardsmen sew face masks during the COVID-19 pandemic, April 6, 2020.

During the COVID-19 pandemic, multiple countries recommended the use of cloth masks to reduce the spread of the virus.

On June 5, WHO has changed its advice on face masks, recommending that fabric masks should be worn by general public where social distancing is not possible (e.g., on public transport, in shops or in other confined or crowded environments).[11][31] Public mask wearing has been most effective in countries where there is high compliance and cultural acceptance.[32]

References

  1. ^ a b c "Use of Cloth Face Coverings to Help Slow the Spread of COVID-19". U.S. Centers for Disease Control and Prevention. April 4, 2020. Retrieved April 5, 2020. This article incorporates text from this source, which is in the public domain.
  2. ^ a b c d e f Reusability of Facemasks During an Influenza Pandemic: Facing the Flu. Washington, D.C.: National Academies Press. July 24, 2006. pp. 6, 36–38. doi:10.17226/11637. ISBN 978-0-309-10182-0.
  3. ^ a b c d e f g h MacIntyre, C. R.; Chughtai, A. A. (April 9, 2015). "Facemasks for the prevention of infection in healthcare and community settings" (PDF). BMJ. 350 (apr09 1): h694. doi:10.1136/bmj.h694. ISSN 1756-1833. PMID 25858901.
  4. ^ a b c Shakya, Kabindra M.; Noyes, Alyssa; Kallin, Randa; Peltier, Richard E. (May 1, 2017). "Evaluating the efficacy of cloth facemasks in reducing particulate matter exposure" (PDF). Journal of Exposure Science & Environmental Epidemiology. 27 (3): 352–357. doi:10.1038/jes.2016.42. ISSN 1559-064X. PMID 27531371.
  5. ^ a b c d e f Chughtai, Abrar Ahmad; Seale, Holly; MacIntyre, Chandini Raina (June 19, 2013). "Use of cloth masks in the practice of infection control – evidence and policy gaps". International Journal of Infection Control. 9 (3). doi:10.3396/IJIC.v9i3.020.13. ISSN 1996-9783.
  6. ^ a b "Coronavirus: WHO advises to wear masks in public areas". BBC. June 6, 2020.
  7. ^ "Recommendation Regarding the Use of Cloth Face Coverings, Especially in Areas of Significant Community-Based Transmission". CDC. April 3, 2020.
  8. ^ "5 Myths About Coronavirus and Face Masks, Debunked. Are you wearing yours the right way?". Cleveland Clinic. June 4, 2020.
  9. ^ "COVID-19: How much protection do face masks offer?". Mayo Clinic. May 28, 2020.
  10. ^ "Coronavirus Face Masks & Protection FAQs". Johns Hopkins School of Medicine. June 25, 2020.
  11. ^ a b c d e f "Advice on the use of masks in the context of COVID-19". WHO. June 5, 2020.
  12. ^ "FAQs on the Emergency Use Authorization for Face Masks (Non-Surgical)". U.S. Food and Drug Administration. April 26, 2020. Retrieved May 21, 2020.
  13. ^ "Meat and Poultry Processing Workers and Employers". U.S. Centers for Disease Control and Prevention. April 26, 2020. Retrieved May 8, 2020.
  14. ^ a b Rengasamy S, Eimer B, Shaffer RE (2010). "Simple Respiratory Protection—Evaluation of the Filtration Performance of Cloth Masks and Common Fabric Materials Against 20–1000 nm Size Particles". Annals of Occupational Hygiene. Oxford University Press. 54 (7): 789–798. doi:10.1093/annhyg/meq044. ISSN 0003-4878.
  15. ^ a b "Using face masks in the community - Reducing COVID-19 transmission from potentially asymptomatic or pre-symptomatic people through the use of face masks". European Centre for Disease Prevention and Control. April 8, 2020. Retrieved May 21, 2020.
  16. ^ MacIntyre, C. R.; Seale, H.; Dung, T. C.; Hien, N. T.; Nga, P. T.; Chughtai, A. A.; Rahman, B.; Dwyer, D. E.; Wang, Q. (April 22, 2015). "A cluster randomised trial of cloth masks compared with medical masks in healthcare workers". BMJ Open. 5 (4): e006577–e006577. doi:10.1136/bmjopen-2014-006577. ISSN 2044-6055.
  17. ^ Mondal, Agnibho; Das, Arnavjyoti; Goswami, Rama Prosad (May 11, 2020). "Utility of Cloth Masks in Preventing Respiratory Infections: A Systematic Review". dx.doi.org. Retrieved July 8, 2020.
  18. ^ a b "Should the public wear masks to slow the spread of SARS-CoV-2?". The Economist. ISSN 0013-0613. Retrieved April 20, 2020.
  19. ^ "How important is "silent spreading" in the covid-19 epidemic?". The Economist. ISSN 0013-0613. Retrieved April 20, 2020.
  20. ^ Mitze, Timo; Kosfeld, Reinhold; Rode, Johannes; Wälde, Klaus (June 29, 2020). "Face Masks Considerably Reduce Covid-19 Cases in Germany". dx.doi.org. Retrieved July 8, 2020.
  21. ^ Doung-ngern, Pawinee; Suphanchaimat, Rapeepong; Panjagampatthana, Apinya; Janekrongtham, Chaiwisar; Ruampoom, Duangrat; Daochaeng, Nawaporn; Eungkanit, Napatchakorn; Pisitpayat, Nichakul; Srisong, Nuengruethai (June 12, 2020). "Associations between wearing masks, washing hands, and social distancing practices, and risk of COVID-19 infection in public: a cohort-based case-control study in Thailand". dx.doi.org. Retrieved July 8, 2020.
  22. ^ Davies, Anna; Thompson, Katy-Anne; Giri, Karthika; Kafatos, George; Walker, Jimmy; Bennett, Allan (May 22, 2013). "Testing the Efficacy of Homemade Masks: Would They Protect in an Influenza Pandemic?". Disaster Medicine and Public Health Preparedness. 7 (4): 413–418. doi:10.1017/dmp.2013.43. ISSN 1935-7893. PMC 7108646. PMID 24229526.
  23. ^ van der Sande, Marianne; Teunis, Peter; Sabel, Rob (July 9, 2008). Pai, Madhukar (ed.). "Professional and Home-Made Face Masks Reduce Exposure to Respiratory Infections among the General Population". PLoS ONE. Public Library of Science (PLoS). 3 (7): e2618. doi:10.1371/journal.pone.0002618. ISSN 1932-6203.
  24. ^ Davies, Anna; Thompson, Katy-Anne; Giri, Karthika; Kafatos, George; Walker, Jimmy; Bennett, Allan (May 22, 2013). "Testing the Efficacy of Homemade Masks: Would They Protect in an Influenza Pandemic?". Disaster Medicine and Public Health Preparedness. Cambridge University Press (CUP). 7 (4): 413–418. doi:10.1017/dmp.2013.43. ISSN 1935-7893. PMC 7108646.
  25. ^ "Simple Respiratory Protection—Evaluation of the Filtration Performance of Cloth Masks and Common Fabric Materials Against 20–1000 nm Size Particles". The Annals of Occupational Hygiene. Oxford University Press (OUP). June 28, 2010. doi:10.1093/annhyg/meq044. ISSN 1475-3162.
  26. ^ a b Konda, Abhiteja; Prakash, Abhinav; Moss, Gregory A.; Schmoldt, Michael; Grant, Gregory D.; Guha, Supratik (April 24, 2020). "Aerosol Filtration Efficiency of Common Fabrics Used in Respiratory Cloth Masks". ACS Nano. American Chemical Society (ACS). doi:10.1021/acsnano.0c03252. ISSN 1936-0851.
  27. ^ Bruno J Strasser; Thomas Schlich (May 22, 2020), "A history of the medical mask and the rise of throwaway culture", The Lancet, 396 (10243): 19–20, doi:10.1016/S0140-6736(20)31207-1
  28. ^ Lowry, H. C. (November 1, 1947). "Some Landmarks in Surgical Technique". The Ulster Medical Journal. 16 (2): 102–13. PMC 2479244. PMID 18898288.
  29. ^ Wilson, Mark (March 24, 2020). "The untold origin story of the N95 mask". Fast Company. Retrieved March 27, 2020.
  30. ^ McNett, Esta H. (January 1, 1949). "The Face Mask in Tuberculosis: How the cheese-cloth face mask has been developed as a protective agent in tuberculosis". AJN the American Journal of Nursing. 49 (1): 32–36. ISSN 0002-936X.
  31. ^ "Coronavirus: WHO advises to wear masks in public areas". BBC News. June 6, 2020.
  32. ^ Howard, J., et al. (2020). Face Masks Against COVID-19: An Evidence Review. doi:10.20944/preprints202004.0203.v1

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