How Well Do Homemade Masks Protect You From Coronavirus?

With that, the Centers for Disease Control and Prevention (CDC), together with the World Health Organization (WHO), recommend the use of homemade, cloth, or fabric masks for the general public. Due to the shortage of supplies, the CDC and WHO strongly recommend  that surgical masks and N95 masks should be reserved for health care providers as well as for anyone who has or may have been infected with COVID-19 or who is caring for someone who has or may have COVID-19.

Hence, the question now is how effective are homemade, cloth, or fabric masks in protecting against SARS-CoV-2? This article will provide an insight on the scientific data on the effectiveness of homemade or cloth face masks against COVID-19.

What are Homemade or DIY Cloth masks?

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A homemade mask serves as an alternative to surgical masks or respirators that are designed in order to trap respiratory droplets that are released into the air when the wearer talks, coughs or sneezes. In addition to that, it serves as a protective barrier in order to protect the wearer from inhaling droplets released by other people that may possibly have infectious pathogens. The most effective homemade masks are commonly made of effective fabrics such as tightly woven fabrics like cotton and cotton blends, are breathable, and have at least two or three fabric layers. A homemade mask with several layers will stop more droplets from getting through the mask or escaping from it. Lastly, less effective homemade masks are usually single layers that are made of fabrics that are loosely woven like loose knit fabrics.

What does science say about Homemade masks?

A study by MacIntyre et al. in 2015 compared the efficacy of locally manufactured and double-layered cotton cloth masks to medical masks. The study showed that the rates of infection were consistently higher among those in the cloth mask group than in the medical mask and control groups. This finding suggests that those who wear cloth masks have higher infection risks. Researchers have concluded that the poor performance may have been a result of the lack of washing the masks frequently or because of the moisture and contamination to the cloth masks. It is good to note that for this study, both surgical and cloth masks were utilized by some participants in the control group, but the findings of poor performance of cloth masks continued in post hoc analysis when the data of all participants who used medical masks from both the control and the medical mask groups were compared with all participants who utilized only a cloth mask from both the control and the cloth mask groups.

Several studies also examined the filtration capacity of homemade or cloth masks. This includes the study of Chungtai et al. in 2013 who found out that the effectiveness of cloth masks in filtering out microorganisms is commonly lower compared to that of medical masks and N95 respirators. Furthermore, the same researchers were also able to conclude that the filtration effectiveness of homemade or cloth masks are greatly dependent on several factors including thread count, number of layers, fabric type, and resistance to water or blood. In addition to that, van der Sande et al. in 2008 tested surgical and homemade masks for their ability to block bacterial and viral aerosols. Although less than that of medical or surgical masks, their findings confirmed that homemade masks are able to block microbial and respiratory droplets. Furthermore, their study also showed that homemade masks produced out of cotton give better protection compared to homemade masks made out of gauze. Researchers strongly recommend that homemade masks should fit snugly against the face to increase its filtration capacity and total effectiveness.

Scientific Recommendation on Usage of Homemade Masks During the COVID-19 Pandemic

The primary transmission routes for SARS-CoV-2 are thought to be close contact and inhalation of respiratory droplets. With that, the WHO highly recommends wearing medical masks during routine care and using respirators during aerosol-generating procedures and other high-risk situations. Ideally, all frontline healthcare workers are mandated to use N95 respirators. However, due to shortages during the COVID-19 Pandemic, the CDC later recommended respirator use for high-risk situations only and that healthcare workers could utilize a surgical mask but may be at increased risk if they choose to do so. Therefore, evidence supports that surgical or N95 respirators should be reserved for healthcare workers.

For the general public, the CDC and WHO recommends the usage of homemade or cloth masks that have filters in them. However, they should be utilized only as a last resort when medical or surgical masks are not available for public use. This is recommended because homemade cloth masks can be produced in large quantities in a short time. They can also be reused after being decontaminated by several techniques such as washing in hot water with soap, using bleach, isopropyl alcohol, or hydrogen peroxide, autoclaving or microwaving, and application of ultraviolet radiation or dry heat.

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Furthermore, as stated above, it must be noted that the protection offered by homemade cloth masks are greatly dependent on proper mask use as well as by selection of fabric and design of the masks for water or blood resistance, filtration, and fit. A study conducted by Konda et al. in 2020 has shown that homemade masks made with multiple layers with water-resistant fabric, high thread counts, and finer weave offer more protection compared to homemade masks that are single-layer with no filters. The CDC and WHO also strongly recommend that fit should be ensured in homemade masks to make sure that it can offer a higher degree of protection. Poorly fitted homemade masks produce gaps on the sides that can cause air to flow through the gaps instead of flowing through the masks. This results in poor effectiveness in blocking possible infectious contaminants in the air.

In social and public settings, the WHO and CDC recommends the usage of homemade masks in two different ways. First, they may be utilized by sick persons in order to reduce the transmission of infection. This is termed as source control. So in areas of high transmission that have low supply of surgical or medical masks, homemade masks can be used as a source control which may prevent spread of infection from persons with asymptomatic, presymptomatic, or mild infections. Second, homemade face masks may be utilized by healthy individuals in order to protect them from being infected with respiratory droplets that may possibly carry infectious pathogens. A randomized controlled trial conducted by MacIntyre in 2015 actually has shown masks in general to be effective in closed community settings, with and without the practice of hand hygiene. With that, universal face mask use, whether medical or homemade, may be beneficial especially in settings where differentiating asymptomatic from healthy persons in the community is challenging.

At the end of the day, the general public should be educated about homemade cloth mask use because such masks may provide users a false sense of protection. Wearing a face mask, staying at home if possible, observing social distancing, practicing hand hygiene, and taking a vaccine  are still the best ways in order to protect oneself from being infected with SARS-CoV-2. Hence, wearing a homemade mask is only one of the strategies that can help all of us to end this pandemic once and for all.

References:

1. Centers for Disease Prevention and Control. 2021. Guidance for Wearing Masks. Retrieved from: https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover-guidance.html. Retrieved on 13 May 2021.
2. Chughtai  AA, Seale  H, MacIntyre  CR. Use of cloth masks in the practice of infection control—evidence and policy gaps. Int J Infect Control. 2013;9:1–12.
3. 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;14:6339–47.
4. MacIntyre  CR, Chughtai  AA. Facemasks for the prevention of infection in healthcare and community settings. BMJ. 2015;350(apr09 1):h694
5. MacIntyre  CR, Seale  H, Dung  TC, Hien  NT, Nga  PT, Chughtai  AA, et al. A cluster randomised trial of cloth masks compared with medical masks in healthcare workers. BMJ Open. 2015;5:e006577
6. Mayo Clinic. 2020.How Well Do Face Masks Protect Against Coronavirus?. Retrieved from: https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-mask/art-20485449. Retrieved on 13 May 2021.
7. University of California San Francisco. 2020. Still Confused About Masks? Here’s the Science Behind How Face Masks Prevent Coronavirus. Retrieved from: https://www.ucsf.edu/news/2020/06/417906/still-confused-about-masks-heres-science-behind-how-face-masks-prevent. Retrieved on 13 May 2021.
8. van der Sande  M, Teunis  P, Sabel  R. Professional and home-made face masks reduce exposure to respiratory infections among the general population. PLoS One. 2008;3:e2618
9. World Health Organization. 2020. Coronavirus Disease (COVID-19) Advice For The Public: When And How To Use Masks. Retrieved from: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public/when-and-how-to-use-masks. Retrieved on 13 May 2021.