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Makeshift Masks Versus KN95s

April 24, 2020

Makeshift Masks Versus KN95s

Need to upgrade your facial protection to professional-grade KN95s or disposable surgeon masks? The/Studio is a responsibly-sourced, verified seller of protective personal equipment to international companies, family businesses, military groups and individuals. Place your order here.


By Nidiane Martinelli, PhD

Lately, the world has changed in a blink. We’v gone from normal days to self-isolation and numerous recommendations to protect ourselves and the others against an omnipresent enemy: SARS-CoV-2, Coronavirus Disease or COVID-19. So far, there is no effective and proved treatment against this new respiratory syndrome and also there is no vaccine to prevent us from contracting it. The most effective way is to prevent the virus to infect us is not get in contact with it.

The Centers for Disease Control and Prevention (CDC) published various guidelines to help people understand how they can be better protected. One measure is the recommendation for the use of face masks by general public, not only health workers. This started after scientific evidence that a significant portion of individuals with coronavirus lack symptoms (“asymptomatic”) and that even those who eventually develop symptoms can transmit the virus to others before showing symptoms.

After this recommendation, thousands of people started posting on social media steps on how to sew a homemade face-mask from 100% cloth and people are forming armies of sewers around the globe to help. This is admirable and bring us hope that in times of despair humanity flourish and we stick together. The use of cloth masks build a sense of protection and solidarity the communities.

But while wearing a face-mask made of fabric, known as non-medical masks, is better than nothing, people should understand and bear in mind that the effectiveness of these masks have not been completely evaluated. According to the World Health Organization (WHO), there is no current scientific evidence to make a recommendation for or against the use of cloth masks in the current pandemic. 

The use of medical masks or N95/KN95 respirators are however, are proven to be preferable over the cloth masks. Now — let’s first understand the difference among a medical mask and a KN95 respirator. Surgical or medical masks are not respirators, and they undergo a different regulatory and certification process. Surgical masks are intended to use to protect both the patients and health care personnel from expired respiratory droplets from the wearer. The fiber diameters, porosity, and filter thicknesses found in surgical masks are designed with significantly lower levels of particle collection efficiencies compared to respirators. The Food and Drug Administration (FDA) guidances and tests for surgical masks are thus different from respirators: for example, FDA does not recommend or require any test of fit for surgical masks, while it is a requirement for respirators. 

Respirators are subjected to pass more stringent tests in order to provide very high levels of particle filtering. During the COVID-19 pandemia, health authorities refer to these kind of masks as N95, FFP2, KN95, etc.  In the United States the most common respirator is the N95 (NIOSH-42CFR84), while in China the same respirator is called KN95 (China GB2626-2006). Recently a technical bulletin was published by 3M stating the similarities among different respirators and standards that varies among countries as well, including the N95 and KN95. This report shows that N95 and KN95 respirators are both certified to function very similarly to one another based in numerous performance tests. 

For example: KN95 respirators have to pass a test called filter performance. In this test, the filter of KN95s is evaluated to measure the reduction in particles that passes through the filter. Since droplets of saliva, sneezes or coughs from contaminated people produce contaminated droplets and aerosols, wearing a KN95 mask would increase protection. The KN95 respirators have the 95 number because on the filter performance tests they block more than 95% of the aerosols from passing through. To state it (very) simply: the chance of a contaminated droplet to pass trough it is only 5%. This test is very important because viruses like the COVID-19 are spread through aerosols from contaminated people and the use of a KN95 would increase the protection for the wearer.

Unfortunately, while masks and KN95 respirators are subject to different tests to prove their efficiency, these tests are not applied to cloth masks. Even more, data from two small laboratory studies suggest that cloth face covers do not block COVID-19 particles spread by patients with COVID-19 who coughed while wearing cloth face masks. 

The only weapon so far in the battle against COVID-19 is prevention. On top of social distancing to avoid contaminate or being contaminated by COVID-19 is the use of  effective protective equipment such as KN95 respirators. Accordingly to the WHO, the potential advantages of the use of mask by healthy people in the community setting includes reducing potential exposure risk from infected person during the “pre-symptomatic” period and stigmatization of individuals wearing mask for source control. Based on the facts above, KN95 respirators are able to provide a very effective barrier against COVID-19 when used correctly.

Nidiane Martinelli  has a Master’s in Cardiovascular Sciences and PhD in Molecular Biology and Genetics from Federal University of Rio Grande do Su. Her work ranges from cellular culture and animal models up to human studies.

Need to upgrade your facial protection to professional-grade KN95s or disposable surgeon masks? The/Studio is a responsibly-sourced, verified seller of protective personal equipment to international companies, family businesses, military groups and individuals. Place your order here.


References:

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 [published online ahead of print, 2020 Mar 31]. J Med Virol. 2020;10.1002/jmv.25805. doi:10.1002/jmv.25805

Zhou ZG, Yue DS, Mu CL, Zhang L. Mask is the possible key for self-isolation in COVID-19 pandemic [published online ahead of print, 2020 Apr 8]. J Med Virol. 2020;10.1002/jmv.25846. doi:10.1002/jmv.25846

Wang J, Du G. COVID-19 may transmit through aerosol [published online ahead of print, 2020 Mar 24]. Ir J Med Sci. 2020;1–2. doi:10.1007/s11845-020-02218-2

MacIntyre C Raina, Chughtai Abrar Ahmad. Facemasks for the prevention of infection in healthcare and community settings BMJ 2015; 350 :h694

Centers for Disease Control and Prevention — https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/diy-cloth-face-coverings.html accessed on April, 17th, 2020.

Emergency Care Research Institute – https://www.ecri.org/coronavirus-covid-19-outbreak-preparedness-center accessed on April, 17th, 2020.

World Health Organization — https://www.who.int/publications-detail/advice-on-the-use-of-masks-in-the-community-during-home-care-and-in-healthcare-settings-in-the-context-of-the-novel-coronavirus-(2019-ncov)-outbreak  accessed on April, 17th, 2020.

Comparison of FFP2, KN95, and N95 and Other Filtering Face piece Respirator Classes http://multimedia.3m.com/mws/media/323208O/n95-particulate-respirators-1860-1860s-1870-faqs.pdf accessed on April, 17th, 2020.

Centers for Disease Control and Prevention — https://blogs.cdc.gov/niosh-science-blog/2009/10/14/n95/ accessed on April, 17th, 2020.

Food and Drug Administration — https://www.fda.gov/regulatory-information/search-fda-guidance-documents/surgical-masks-premarket-notification-510k-submissions accessed on April, 18th, 2020.

Reusability of Facemasks During an Influenza Pandemic: Facing the Flu (2006). Chapter: 2 Characteristics of Respirators and Medical Masks — https://www.nap.edu/read/11637/chapter/4#32 accessed on April, 17th, 2020.

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