tag:theconversation.com,2011:/es/topics/surgical-mask-77251/articlesSurgical mask – The Conversation2023-02-06T19:04:54Ztag:theconversation.com,2011:article/1989922023-02-06T19:04:54Z2023-02-06T19:04:54ZYes, masks reduce the risk of spreading COVID, despite a review saying they don’t<figure><img src="https://images.theconversation.com/files/508261/original/file-20230206-504-kijojf.jpg?ixlib=rb-1.1.0&rect=0%2C68%2C4593%2C2984&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.pexels.com/photo/calm-black-woman-with-coffee-wearing-medical-mask-standing-in-metro-6280959/">Pexels/Uriel Mont</a></span></figcaption></figure><p>The question of whether and to what extent face masks work to prevent respiratory infections such as COVID and influenza has split the scientific community for <a href="https://www.baltimoresun.com/news/bs-xpm-2007-03-06-0703060040-story.html">decades</a>. </p>
<p>Although there is strong evidence face masks <a href="https://www.sciencedirect.com/science/article/pii/S0020748920301139?via%3Dihub">significantly reduce transmission of such infections</a> both in health-care settings and in the community, some experts do not agree. </p>
<p>An updated <a href="https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006207.pub6/full">Cochrane Review</a> published last week is the latest to suggest face masks don’t work in the community. </p>
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<p>However there are problems with the review’s methodology and its underpinning assumptions about transmission. </p>
<p>The Cochrane Review combined randomised controlled trials (RCTs) using <a href="https://ebn.bmj.com/content/16/1/3">meta-analysis</a>. RCTs test an intervention in one group and compare it with a “control” group that doesn’t receive the intervention or receives a different intervention. A meta-analysis pools the results of multiple studies. </p>
<p>This approach assumes (a) RCTs are the “best” evidence and (b) combining results from multiple RCTs will give you an average “effect size”.</p>
<p>But RCTs are only the undisputed gold standard for certain <em>kinds</em> of questions. For other questions, a mix of study designs is better. And RCTs should be combined in a meta-analysis <em>only</em> if they are all addressing the same research question in the same way. </p>
<p>Here are some reasons why the conclusions of this Cochrane Review are misleading. </p>
<h2>It didn’t consider how COVID spreads and how masks work</h2>
<p>COVID, along with influenza and many other respiratory diseases, is transmitted primarily <a href="https://theconversation.com/covid-how-the-disease-moves-through-the-air-173490">through the air</a>. </p>
<p>Respirators (such as N95s) are designed and regulated to prevent airborne infections by fitting <a href="https://theconversation.com/high-filtration-masks-only-work-when-they-fit-so-we-created-a-new-way-to-test-if-they-do-155987">closely to the face</a> to prevent air leakage and by filtering out 95% or more of potential infectious particles. </p>
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Read more:
<a href="https://theconversation.com/high-filtration-masks-only-work-when-they-fit-so-we-created-a-new-way-to-test-if-they-do-155987">High-filtration masks only work when they fit – so we created a new way to test if they do</a>
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<p>In contrast, surgical masks are designed to prevent splatter of fluid on the face and are loose-fitting, causing unfiltered air to leak in through the gaps around the mask. The filtration of a surgical mask is not regulated. </p>
<p>In other words, respirators are designed for respiratory protection and cloth and surgical masks are not. </p>
<p>The review starts with an assumption that masks provide respiratory protection, which is flawed. An understanding of these differences should inform both studies and reviews of those studies. </p>
<h2>The studies addressed quite different questions</h2>
<p>A common mistake in meta-analysis is to combine apples and oranges. If apples work but oranges don’t, combining all studies in a single average figure may lead to the conclusion that apples do not work. </p>
<p>This Cochrane Review combined RCTs where face masks or respirators were worn <em>part</em> of the time (for example, when caring for patients with known COVID or influenza: “occasional” or “targeted” use) with RCTs where they were worn at <em>all</em> times (“continuous use”). </p>
<p>Because both SARS-CoV-2 and influenza viruses are airborne, an unmasked person could be infected anywhere in the building and even after an infectious patient has left the room, especially since some people have <a href="https://www.pnas.org/doi/10.1073/pnas.2109229118">no symptoms</a> while contagious. </p>
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<img alt="Clinicians in PPE pulls up her gloves" src="https://images.theconversation.com/files/508255/original/file-20230206-21-bn9aws.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/508255/original/file-20230206-21-bn9aws.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=480&fit=crop&dpr=1 600w, https://images.theconversation.com/files/508255/original/file-20230206-21-bn9aws.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=480&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/508255/original/file-20230206-21-bn9aws.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=480&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/508255/original/file-20230206-21-bn9aws.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=603&fit=crop&dpr=1 754w, https://images.theconversation.com/files/508255/original/file-20230206-21-bn9aws.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=603&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/508255/original/file-20230206-21-bn9aws.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=603&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The results will depend on whether they’re occasionally or continuously used.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/hYcSP6SpoK0">Unsplash/Viki Mohamad</a></span>
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<p>Most RCTs of masks and N95s included in the review have not had a <a href="https://jamanetwork.com/journals/jama/fullarticle/184819">control arm</a> – therefore finding no difference could indicate equal efficacy or equal inefficacy. </p>
<p><a href="https://jamanetwork.com/journals/jama/fullarticle/2749214">Studies</a> examining wearing a surgical mask or respirator (such as an N95) only when in contact with sick people or when doing a high-risk procedure (occasional use) have generally shown that, when worn in this way, there is no difference. </p>
<p>An RCT comparing occasional versus continuous use of respirators in health care workers <a href="https://www.atsjournals.org/doi/10.1164/rccm.201207-1164OC?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubme">showed</a> N95 respirators and surgical masks were equally <em>ineffective</em> when only worn occasionally by hospital workers. They had to wear them <em>all the time at work</em> to be protected. </p>
<p>We also combined only apples and apples in a <a href="https://onlinelibrary.wiley.com/doi/10.1111/irv.12474">meta-analysis</a> of two RCTs conducted in exactly the same way and measuring the same interventions and outcomes. We found N95 respirators provide <em>significant protection</em> against respiratory infections when surgical masks did not, even against infections assumed to be “droplet spread”. </p>
<h2>Most trials addressed only half the question</h2>
<p>Face masks and respirators work in two ways: they protect the wearer from becoming infected <em>and</em> they prevent an infected wearer from spreading their germs to other people. </p>
<p>Most RCTs in this Cochrane Review looked only at the former scenario, not the latter. In other words, the researchers had asked people to wear masks and then tested to see if those people became infected. </p>
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Read more:
<a href="https://theconversation.com/as-viral-infections-skyrocket-masks-are-still-a-tried-and-true-way-to-help-keep-yourself-and-others-safe-195788">As viral infections skyrocket, masks are still a tried-and-true way to help keep yourself and others safe</a>
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<p>A previous <a href="https://pubmed.ncbi.nlm.nih.gov/20092668/">systematic review</a> found face masks worn by sick people during an influenza epidemic reduced the risk of them transmitting the infection to family members or other carers. Preventing an infection in one person also prevents onward transmission to others within a closed setting, which means such RCTs should use a special method called “cluster randomisation” to account for this. </p>
<p>Data from a RCT of N95 respirator use by <a href="https://journals.sagepub.com/doi/full/10.1177/0300060516665491?rfr_dat=cr_pub++0pubmed&url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org">health workers</a> showed even their unmasked colleagues were protected. Yet some of the trials included in the review did not use cluster randomisation.</p>
<h2>The new paper combined health and community settings</h2>
<p>This is another apples-plus-oranges issue. Different settings have widely differing risks of transmission, since airborne particles build up when sick patients are exhaling the virus in <a href="https://theconversation.com/heres-where-and-how-you-are-most-likely-to-catch-covid-new-study-174473">underventilated, crowded settings</a> especially if many infected people are present (such as in a hospital). </p>
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<p>A genuine protective effect of masks or respirators shown in a RCT in a high-risk setting will be obscured if that trial is combined in a meta-analysis with several other RCTs that were conducted in low-risk settings. </p>
<p>A large <a href="https://www.science.org/doi/10.1126/science.abi9069">RCT in the community in Bangladesh</a> found face masks reduced the risk of infection by 11% overall and 35% in people over 60 years. In contrast, in <a href="https://onlinelibrary.wiley.com/doi/10.1111/irv.12474">hospitals</a>, N95 reduce risk by 67% against bacterial infections and 54% against viral infections.</p>
<p>Viruses like influenza also vary substantially from year to year – some years there is very little influenza, and if a RCT is conducted during such a year, it will not find enough infections to show a difference. The review failed to account for such seasonal effects.</p>
<h2>But did they actually wear the mask?</h2>
<p>The authors of the Cochrane Review acknowledged compliance with masking advice was poor in most studies. In the real world, we can’t force people to follow medical advice, so RCTs should be analysed on an “intention to treat” basis. </p>
<p>For example, people who are prescribed the active drug but who choose not to take it should not be shifted to the placebo group for the analysis. But if in a study of masking, most people don’t actually wear them, you can’t conclude that <em>masks</em> don’t work when the study shows no difference between the groups. You can only conclude that the <em>mask advice</em> didn’t work in this study. </p>
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<img alt="Woman fits a facemask" src="https://images.theconversation.com/files/508256/original/file-20230206-17-y18dj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/508256/original/file-20230206-17-y18dj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/508256/original/file-20230206-17-y18dj7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/508256/original/file-20230206-17-y18dj7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/508256/original/file-20230206-17-y18dj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/508256/original/file-20230206-17-y18dj7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/508256/original/file-20230206-17-y18dj7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">People don’t always wear masks when advised to do so.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/woman-wearing-face-mask-3873197/">Pexels/Polina Tankilevitch</a></span>
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<p>There is a great deal of <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0246317">psychological evidence</a> on why people do or don’t choose to comply with advice to mask and how to improve uptake. The science of masking needs to separate the impact of the <em>mask itself</em> from the impact of the <em>advice to mask</em>. </p>
<p>Mask-wearing <a href="https://www.ijidonline.com/article/S1201-9712(21)00274-5/fulltext">goes up</a> substantially to over 70% if there is an actual mandate in place.</p>
<h2>It didn’t include other types of research</h2>
<p>A comprehensive review of the evidence would also include other types of study besides RCTs. For example, a <a href="https://www.sciencedirect.com/science/article/pii/S0140673620311429">large systematic review</a> of 172 various study designs, which included 25,697 patients with SARS-CoV-2, SARS, or MERS, concluded masks were effective in preventing transmission of respiratory viruses. </p>
<p>Well-designed <a href="https://www.cdc.gov/mmwr/volumes/71/wr/mm7106e1.htm?s_cid=mm7106e1_w">real-world studies</a> during the pandemic showed any mask reduces the risk of COVID transmission by 50–80%, with the highest protection offered by N95 respirators. </p>
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Read more:
<a href="https://theconversation.com/which-mask-works-best-we-filmed-people-coughing-and-sneezing-to-find-out-143173">Which mask works best? We filmed people coughing and sneezing to find out</a>
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<p><a href="https://pubmed.ncbi.nlm.nih.gov/20095070/">Many lab-based studies</a> have shown respirators are superior to masks at preventing airborne respiratory infections and the <a href="https://thorax.bmj.com/content/75/11/1024.long">incremental superiority</a> from a single to two layered cloth mask to a three-layered surgical mask in blocking respiratory aerosols.</p>
<h2>Yes, masks reduce the spread of COVID</h2>
<p>There is strong and consistent evidence for the effectiveness of masks and (even more so) respirators in protecting against respiratory infections. Masks are an important protection against serious infections. </p>
<p>Current COVID vaccines protect against death and hospitalisation, but do <a href="https://fortune.com/well/2023/01/06/kraken-xbb15-omicron-covid-variant-most-transmissible-yet-could-spawn-more-immune-evasive-variants-study-china-vaccine-monoclonal-antibodies-breakthrough-infection/">not prevent infection</a> well due to waning vaccine immunity and substantial immune escape from new variants. </p>
<p>A systematic review is only as good as the rigour it employs in combining similar studies of similar interventions, with similar measurement of outcomes. When very different studies of different interventions are combined, the results are not informative.</p><img src="https://counter.theconversation.com/content/198992/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>C Raina MacIntyre receives funding from mask manufacturer Detmold for testing of their masks and is on an advisory board for mask manufacturer Ascend. She receives funding from Sanofi for investigator-driven influenza research, and from NHMRC and MRFF. She has been an expert advisor for Ontario Nurses Association (ONA) In the matter of a proceeding under the Labour Relations Act, 1995 between ONA and Hamilton Health Sciences Corporation.
</span></em></p><p class="fine-print"><em><span>Abrar Ahmad Chughtai had testing of filtration of masks by 3M for his PhD. 3M products were not used in his research. He also has worked with Paftec on research in respirators (no funding was involved).</span></em></p><p class="fine-print"><em><span>Dr Fisman has served as an expert witness for the Ontario Nurses Association and the Elementary Teachers' Federation of Ontario in legal challenges related to safer working conditions in healthcare and schools. Dr. Fisman has served on advisory boards for Pfizer, Astrazeneca, Merck, Seqirus and Sanofi vaccines against SARS-CoV-2, influenza, and S. pneumoniae. He holds current funding from the Canadian Institutes for Health Research and Health Canada.</span></em></p><p class="fine-print"><em><span>Trish Greenhalgh receives funding from UK National Institute for Health and Care Research and the NIHR School for Primary Care Research. She is affiliated with University of Oxford and University of Oslo. She has served as an unpaid adviser tot he philanthropic fund BALVI and is a member of Independent SAGE. </span></em></p>An updated Cochrane Review suggests face masks don’t reduce the spread of COVID in the community. But there are several reasons why this conclusion is misleading.C Raina MacIntyre, Professor of Global Biosecurity, NHMRC Principal Research Fellow, Head, Biosecurity Program, Kirby Institute, UNSW SydneyAbrar Ahmad Chughtai, Senior lecturer, UNSW SydneyDavid Fisman, Professor in the Division of Epidemiology, University of TorontoTrish Greenhalgh, Professor of Primary Care Health Sciences, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1815822022-04-20T19:36:25Z2022-04-20T19:36:25ZShould you wear a mask on a plane, bus or train when there’s no mandate? 4 essential reads to help you decide<figure><img src="https://images.theconversation.com/files/458911/original/file-20220420-25-qleeh8.jpg?ixlib=rb-1.1.0&rect=187%2C130%2C5120%2C3082&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">It is now up to individuals whether to wear masks in airports and other mass transit areas.</span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/TravelMaskMandate/28ce57b3790b493190c8409bf0cd06d0/photo?Query=mask%20plane&mediaType=photo&sortBy=&dateRange=Anytime&totalCount=469&currentItemNo=22">AP Photo/Evan Vucci</a></span></figcaption></figure><p>On April 18, 2022, a judge in Florida <a href="https://www.cnn.com/us/live-news/federal-mask-mandate-airlines-04-19-22/index.html">struck down the federal mandate requiring passengers on mass transit to wear masks</a>. While the U.S. Centers for Disease Control and Prevention still recommends that passengers mask up while on planes, trains or buses, it is no longer a requirement. When asked whether people should wear masks on planes, President Joe Biden replied: “<a href="https://www.cnn.com/us/live-news/federal-mask-mandate-airlines-04-19-22/index.html">That’s up to them</a>.”</p>
<p>The Conversation has been covering the science of masks since the beginning of the pandemic. Masking may no longer be required on mass transit, but you can always choose to still wear a mask. For those worried about being exposed to SARS-CoV-2 or developing COVID-19, below are highlights from four articles exploring the benefits of wearing a mask and how to get the most protection from wearing one. </p>
<h2>1. Masks can protect the person wearing them</h2>
<p>A lot of the reason for wearing a mask is to protect others. But early on in the pandemic, <a href="https://profiles.ucsf.edu/monica.gandhi">Monica Gandhi, a professor of medicine</a> at the University of California, San Francisco, explained how masks can protect the wearer, too.</p>
<p>“When you wear a mask – even a cloth mask – you typically are <a href="https://dx.doi.org/10.7326%2FM20-2567">exposed to a lower dose of the coronavirus</a> than if you didn’t,” Gandhi writes. “Both <a href="https://doi.org/10.1073/pnas.2009799117">recent experiments in animal models</a> using coronavirus and nearly a <a href="https://doi.org/10.1038/nri2802">hundred years of viral research</a> show that <a href="https://theconversation.com/cloth-masks-do-protect-the-wearer-breathing-in-less-coronavirus-means-you-get-less-sick-143726">lower viral doses usually mean less severe disease.</a>”</p>
<p>Though it’s only one of many factors, “the amount of virus that you’re exposed to – called the viral inoculum, or dose – has <a href="https://doi.org/10.1038/nri2802">a lot to do with how sick you get</a>. If the exposure dose is very high, the immune response can become overwhelmed,” explains Gandhi. “On the other hand, if the initial dose of the virus is small, the immune system is able to contain the virus.”</p>
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Read more:
<a href="https://theconversation.com/cloth-masks-do-protect-the-wearer-breathing-in-less-coronavirus-means-you-get-less-sick-143726">Cloth masks do protect the wearer – breathing in less coronavirus means you get less sick</a>
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<p>The better the mask, the lower the exposure dose. And in the many months since Gandhi wrote that story, a lot of work has been done to determine which kinds of masks are most effective. </p>
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<a href="https://images.theconversation.com/files/458910/original/file-20220420-18-nanbe4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An N95, surgical and cloth mask." src="https://images.theconversation.com/files/458910/original/file-20220420-18-nanbe4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/458910/original/file-20220420-18-nanbe4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=413&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458910/original/file-20220420-18-nanbe4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=413&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458910/original/file-20220420-18-nanbe4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=413&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458910/original/file-20220420-18-nanbe4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=519&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458910/original/file-20220420-18-nanbe4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=519&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458910/original/file-20220420-18-nanbe4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=519&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Not all masks offer the same amount of filtration.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/protective-face-masks-commonly-used-during-2020-royalty-free-image/1248294245?adppopup=true">Gaelle Beller Studio/Moment via Getty Images</a></span>
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<h2>2. What makes for a good mask?</h2>
<p>The first thing to consider when wearing a mask is whether it’s a good one. <a href="https://scholar.google.com/citations?hl=en&user=MaEhNkQAAAAJ">Christian L'Orange is a professor of mechanical engineering</a> and has been testing different masks for the state of Colorado since the pandemic started. He explains that there are two things that make for a protective mask. “First, there’s the ability of the material to capture particles. The second factor is the fraction of inhaled or exhaled air leaking out from around the mask – essentially, how well a mask fits.”</p>
<p>When it comes to these two attributes, L'Orange says, “<a href="https://theconversation.com/what-is-the-best-mask-for-covid-19-a-mechanical-engineer-explains-the-science-after-2-years-of-testing-masks-in-his-lab-175481">the N95 and KN95 masks are the best option</a>.” This performance has a lot to do with the materials they are made from. “These fibers are very tightly packed together so the gaps a particle must navigate through are very small. This results in a high probability that particles will end up touching and sticking to a fiber as they pass through a mask. These polypropylene materials also often <a href="https://www.thomasnet.com/articles/machinery-tools-supplies/what-is-melt-blown-extrusion/">have a static charge</a> that can help attract and catch particles.”</p>
<p>Fit is the second important factor for a mask. As L'Orange writes, “a mask can offer protection only if it doesn’t leak.” N95s and KN95s are stiff and seal much better than other masks.</p>
<p>If you don’t have access to an N95 or KN95, surgical masks should be your second choice. They are made of densely woven material, but they don’t seal perfectly. Cloth masks should be your last choice because of their generally loose weave and bad fit. But there are ways to improve the performance of surgical and cloth masks. </p>
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Read more:
<a href="https://theconversation.com/what-is-the-best-mask-for-covid-19-a-mechanical-engineer-explains-the-science-after-2-years-of-testing-masks-in-his-lab-175481">What is the best mask for COVID-19? A mechanical engineer explains the science after 2 years of testing masks in his lab</a>
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<h2>3. How to make a mask fit well</h2>
<p>“No matter how good a mask’s material is, it won’t work well if it doesn’t fit well,” writes <a href="https://scholar.google.com/citations?user=fZJWmF8AAAAJ&hl=en&oi=ao">Scott Schiffres, a mechanical engineer</a> at Binghamton University.</p>
<p>There are <a href="https://theconversation.com/cdc-says-masks-must-fit-tightly-and-two-are-better-than-one-153778">two ways to improve the fit and performance of surgical and cloth masks</a>. The first, explains Schiffres, is simply wearing two masks. “Double-masking is wearing a cotton mask over a medical-procedure mask.” This can greatly improve the fit and add a little bit more filtration. The second approach is to knot and tuck a surgical mask so that it fits better. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/OD-jy7M6tEc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Knotting and tucking a surgical mask can make it fit much better.</span></figcaption>
</figure>
<p>As Schiffres explains in his article, “Knotting and tucking entails tying a knot in the elastic loops that go over your ears, close to where they attach to the mask. Then, you tuck the extra mask fabric into the gap that is often present where the ear loops attach to the mask, and flatten that part as much as possible. Both of these tricks make a better fit and <a href="https://www.cdc.gov/mmwr/volumes/70/wr/mm7007e1.htm?s_cid=mm7007e1_w">decrease the mask-wearers’ exposure to potentially infectious aerosols by 95%</a> as compared with wearing no mask at all. That’s a <a href="https://doi.org/10.1017/dmp.2013.43">15% improvement over the 80% efficiency found when using a single surgical mask</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/cdc-says-masks-must-fit-tightly-and-two-are-better-than-one-153778">CDC says masks must fit tightly – and two are better than one</a>
</strong>
</em>
</p>
<hr>
<h2>4. Breakthrough cases and new variants</h2>
<p>The final consideration when deciding to wear a mask isn’t about you. Doing so can protect others. </p>
<p><a href="https://scholar.google.com/citations?user=XY7DNtgAAAAJ&hl=en&oi=ao">Sara Sawyer</a>, <a href="https://www.colorado.edu/pac/arturo-barbachano-guerrero">Arturo Barbachano-Guerrero</a> and <a href="https://scholar.google.com/citations?user=l2lpnYkAAAAJ&hl=en&oi=ao">Cody Warren</a> are virologists and biologists at the University of Colorado Boulder. In <a href="https://theconversation.com/alpha-then-delta-and-now-omicron-6-questions-answered-as-covid-19-cases-once-again-surge-across-the-globe-174703">a recent story</a>, they write that omicron "is often able <a href="https://doi.org/10.1038/s41586-021-04385-3">to evade existing immunity</a> long enough to start an infection, cause symptoms and transmit onward to the next person.” “This explains why reinfections and vaccine <a href="https://www.cdc.gov/coronavirus/2019-ncov/vaccines/effectiveness/why-measure-effectiveness/breakthrough-cases.html">breakthrough infections</a> seem to be more common with omicron.”</p>
<p>Case numbers are low for now, and therefore so is the risk of catching or transmitting the coronavirus. But it is not zero; some places have higher risk than others, and new variants can come on quickly. As the team writes, all new variants that spread widely – so-called <a href="https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-classifications.html#anchor_1632154493691">variants of concern</a> – are likely to be highly transmissible.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/alpha-then-delta-and-now-omicron-6-questions-answered-as-covid-19-cases-once-again-surge-across-the-globe-174703">Alpha then delta and now omicron – 6 questions answered as COVID-19 cases once again surge across the globe</a>
</strong>
</em>
</p>
<hr>
<p>The person next to you on the plane might not be wearing a mask and, as it stands, that is their choice to make. If you want to lower your own chances of catching or spreading the coronavirus, there are still a number of reasons to wear a well-fitting, high-quality mask. </p>
<p><em>Editor’s note: This story is a roundup of articles from The Conversation’s archives.</em></p><img src="https://counter.theconversation.com/content/181582/count.gif" alt="The Conversation" width="1" height="1" />
Despite the halt to the federal mask mandate for mass transit, people may still choose to protect themselves. For those who do, the type of mask and how well it fits matter.Daniel Merino, Associate Breaking News Editor and Co-Host of The Conversation Weekly PodcastLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1772292022-02-24T02:40:02Z2022-02-24T02:40:02ZHow to get the most out of your N95 mask or other respirator<figure><img src="https://images.theconversation.com/files/447952/original/file-20220223-19-lwpq4w.jpg?ixlib=rb-1.1.0&rect=2%2C0%2C995%2C661&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/n95-filtering-face-mask-white-medical-1651463458">Shutterstock</a></span></figcaption></figure><p>Although mask mandates are <a href="https://www.theguardian.com/australia-news/2022/feb/22/victoria-queensland-mask-rules-mandate-nsw-covid-restrictions-omicron-cases-peak">lifting in some states</a>, many people will continue to wear masks to protect themselves and others from the more <a href="https://smw.ch/article/doi/smw.2022.w30133">transmissible</a> Omicron variant. </p>
<p>For instance, they might be visiting a loved one in hospital, travelling on a plane or bus, or still need to wear one at work in hospitality or retail.</p>
<p>Any mask is better than none. However, a type of mask known as a respirator is <a href="https://onlinelibrary.wiley.com/doi/10.1111/j.1750-2659.2011.00198.x">more effective</a> at preventing the spread of SARS-CoV-2 (the virus that causes COVID) than a cloth or surgical mask, provided you use it properly.</p>
<p>Here is a practical guide to getting the most out of your respirator.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/time-to-upgrade-from-cloth-and-surgical-masks-to-respirators-your-questions-answered-174877">Time to upgrade from cloth and surgical masks to respirators? Your questions answered</a>
</strong>
</em>
</p>
<hr>
<h2>What is a respirator?</h2>
<p>Respirators are designed to fit your face closely to help prevent you breathing in airborne particles through the gaps around the edges. </p>
<p>They are made of a plastic with an electrostatic charge that repels viral particles, preventing at least 95% of particles from getting through.</p>
<p>They are made to a specific <a href="https://www.fda.gov/medical-devices/personal-protective-equipment-infection-control/n95-respirators-surgical-masks-face-masks-and-barrier-face-coverings#s3">manufacturing standard</a>. Depending on where they are certified, they <a href="https://breathesafeair.com/mask-ratings/">may be called</a> N95 (in the USA), P2 (Australia or New Zealand), FFP2 (Europe), KF94 (Korea) or KN95 (China). </p>
<p>Some have a cup shape; others look like a <a href="https://advantechsterilizers.ca/product/halyard-fluidshield-n95-respirator-mask-46767-46827/">duck bill</a> due to the way they stick out.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1416601279191674883"}"></div></p>
<h2>Who can use a respirator?</h2>
<p>Adults can use respirators but the US Food and Drug Administration (FDA) does not <a href="https://www.fda.gov/medical-devices/personal-protective-equipment-infection-control/n95-respirators-surgical-masks-face-masks-and-barrier-face-coverings#s3">recommend them for children</a>. That’s because they are not designed for smaller face sizes so may not provide full protection.</p>
<p>Facial hair, unfortunately, <a href="https://www.fda.gov/medical-devices/personal-protective-equipment-infection-control/n95-respirators-surgical-masks-face-masks-and-barrier-face-coverings#s3">interferes with the fit</a>. That’s because the edge of the respirator cannot form a tight seal around the face and chin.</p>
<p>If you don’t want to remove your beard or moustache, use a surgical mask. Or you can <a href="https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2778913">double mask</a> by wearing a cloth mask over a surgical mask.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1481661722293329924"}"></div></p>
<h2>Which respirator is best?</h2>
<p>This depends on personal preference and size. Try a few different types to find one that fits well. P2 respirators found in hardware stores are often in larger sizes that suit men. Chemists sell others that might better suit a smaller face. </p>
<p>Look for an adjustable nose piece and <a href="https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2772936">straps that go over the back of the head</a> rather than loops that go over the ears. This will ensure a tighter fit. </p>
<p>Do not buy respirators with valves because they do not prevent the release of viral particles into the air. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-wear-a-mask-in-the-heat-169941">How to wear a mask in the heat</a>
</strong>
</em>
</p>
<hr>
<h2>Watch out for counterfeits</h2>
<p>Avoid a false sense of security when wearing respirators, as they won’t have been professionally “fit tested” the way they would be for health workers. </p>
<p>When buying respirators online, look out for <a href="https://www.cdc.gov/niosh/npptl/usernotices/counterfeitResp.html">counterfeit</a> <a href="https://www.cdc.gov/niosh/npptl/topics/respirators/disp_part/n95list1.html">products</a>. For example, avoid individual respirators with unmarked packaging, or boxes with an FDA logo, as use of the logo to market products <a href="https://www.fda.gov/about-fda/website-policies/fda-logo-policy">is prohibited</a>. The box should include the <a href="https://www.cdc.gov/niosh/npptl/topics/respirators/disp_part/default.html">manufacturer’s name and address</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-the-best-mask-for-covid-19-a-mechanical-engineer-explains-the-science-after-2-years-of-testing-masks-in-his-lab-175481">What is the best mask for COVID-19? A mechanical engineer explains the science after 2 years of testing masks in his lab</a>
</strong>
</em>
</p>
<hr>
<h2>How do I put one on?</h2>
<p>The US <a href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/use-n95-respirator.html">Centers for Disease Control and Prevention</a> advises you: </p>
<ul>
<li><p>wash or sanitise your hands before putting on the respirator </p></li>
<li><p>check the respirator for any tears, holes or moisture. Never use one that is damaged or wet</p></li>
<li><p>separate the elastic straps, then hold the respirator in your hand with the nose piece at the top </p></li>
<li><p>place the respirator over your nose and mouth</p></li>
</ul>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/447953/original/file-20220223-27-pac5i9.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Person placing respirator over nose and mouth" src="https://images.theconversation.com/files/447953/original/file-20220223-27-pac5i9.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/447953/original/file-20220223-27-pac5i9.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=372&fit=crop&dpr=1 600w, https://images.theconversation.com/files/447953/original/file-20220223-27-pac5i9.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=372&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/447953/original/file-20220223-27-pac5i9.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=372&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/447953/original/file-20220223-27-pac5i9.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=467&fit=crop&dpr=1 754w, https://images.theconversation.com/files/447953/original/file-20220223-27-pac5i9.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=467&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/447953/original/file-20220223-27-pac5i9.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=467&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Place respirator over nose and mouth.</span>
<span class="attribution"><a class="source" href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/use-n95-respirator.html">CDC</a></span>
</figcaption>
</figure>
<ul>
<li>place one elastic loop at the top of your head, near the crown, and the other at the base, below your ears. Make sure the straps lay flat, are not twisted and are not criss-crossed</li>
</ul>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/447954/original/file-20220223-13-1e21dhc.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Person placing respirator elastic straps over the back of the head" src="https://images.theconversation.com/files/447954/original/file-20220223-13-1e21dhc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/447954/original/file-20220223-13-1e21dhc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=380&fit=crop&dpr=1 600w, https://images.theconversation.com/files/447954/original/file-20220223-13-1e21dhc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=380&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/447954/original/file-20220223-13-1e21dhc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=380&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/447954/original/file-20220223-13-1e21dhc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=478&fit=crop&dpr=1 754w, https://images.theconversation.com/files/447954/original/file-20220223-13-1e21dhc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=478&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/447954/original/file-20220223-13-1e21dhc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=478&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">One elastic loop goes at the top of the head, the other at the base.</span>
<span class="attribution"><a class="source" href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/use-n95-respirator.html">CDC</a></span>
</figcaption>
</figure>
<ul>
<li>adjust the flexible strip across your nose and cheeks, pressing on each side of the nose with the fingertips of both hands to mould it to your face</li>
</ul>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/447956/original/file-20220223-13-w6rokm.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Press down with your fingers across the nose and cheek" src="https://images.theconversation.com/files/447956/original/file-20220223-13-w6rokm.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/447956/original/file-20220223-13-w6rokm.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=381&fit=crop&dpr=1 600w, https://images.theconversation.com/files/447956/original/file-20220223-13-w6rokm.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=381&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/447956/original/file-20220223-13-w6rokm.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=381&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/447956/original/file-20220223-13-w6rokm.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=479&fit=crop&dpr=1 754w, https://images.theconversation.com/files/447956/original/file-20220223-13-w6rokm.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=479&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/447956/original/file-20220223-13-w6rokm.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=479&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Use fingertips to mould respirator to face.</span>
<span class="attribution"><a class="source" href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/use-n95-respirator.html">CDC</a></span>
</figcaption>
</figure>
<ul>
<li><p>check the edges to make sure there are no creases or hair stuck under the edge</p></li>
<li><p>perform a “<a href="https://www.health.qld.gov.au/__data/assets/pdf_file/0035/974294/p2-n95-fit-check.pdf">fit check</a>”. Take a quick deep breath in, which should cause the respirator to suck inwards. Then breathe out, which should re-inflate it. If your glasses fog up, if you feel air coming in or going out around the edges, or the respirator does not suck in, there is not a good seal. Try repositioning it and “fit check” again</p></li>
<li><p>sanitise your hands after putting on your respirator. Once on, avoid touching the front, which may be contaminated. If you do, sanitise your hands again.</p></li>
</ul>
<h2>Can I re-use them?</h2>
<p>While respirators are labelled for single use, they can be reused outside health-care settings with care:</p>
<ul>
<li><p>the more you reuse a respirator the more likely it is to <a href="https://www.ajicjournal.org/article/S0196-6553(11)00770-X/fulltext">fail</a> because the wear on the elastic straps causes a poorer fit or components break. Most are good for at least five wears but some can go for at least 20 </p></li>
<li><p>have several on the go and alternate them on different days. Store each one after use in its own paper bag, to allow it to dry out between uses </p></li>
<li><p>remove the respirator if it gets wet. When removing, touch only the straps. Move the respirator away from your face so you don’t contaminate your skin or hair</p></li>
<li><p>when the respirator loses its fit, gets damaged or has been used too often, pop it in the bin.</p></li>
</ul>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/have-you-stopped-wearing-reusable-fabric-masks-heres-how-to-cut-down-waste-without-compromising-your-health-175243">Have you stopped wearing reusable fabric masks? Here's how to cut down waste without compromising your health</a>
</strong>
</em>
</p>
<hr>
<h2>What not to do</h2>
<ul>
<li><p>don’t <a href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/use-n95-respirator.html">wash or microwave</a> your respirator. This interferes with its <a href="https://www.mdpi.com/1660-4601/19/2/641/htm">electrostatic charge</a> and ability to <a href="https://www.wired.com/story/the-physics-of-the-n95-face-mask/">filter viruses</a> </p></li>
<li><p>don’t store it in a plastic bag as it will not dry out between uses. </p></li>
</ul>
<p>Respirators reduce the spread of SARS-CoV-2 but will not stop it alone. It is essential to stay home if unwell, get fully vaccinated, physically distance where possible, regularly wash or sanitise your hands, and if coughing or sneezing, do so into your elbow.</p><img src="https://counter.theconversation.com/content/177229/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Thea van de Mortel teaches into the graduate Infection Prevention and Control program at Griffith University.</span></em></p><p class="fine-print"><em><span>Peta-Anne Zimmerman is a Board Director of the Australasian College for Infection Prevention and Control, Co-Director of the Collaborative for the Advancement of Infection Prevention and Control, and is the Program Advisor of the Griffith University Graduate Infection Prevention and Control Programs.</span></em></p>If you’re thinking of upgrading from a cloth or surgical mask to a respirator, here’s what you need to know.Thea van de Mortel, Professor, Nursing and Deputy Head (Learning & Teaching), School of Nursing and Midwifery, Griffith UniversityPeta-Anne Zimmerman, Senior Lecturer/Program Advisor Griffith Graduate Infection Prevention and Control Program, Griffith UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1754812022-01-25T19:43:00Z2022-01-25T19:43:00ZWhat is the best mask for COVID-19? A mechanical engineer explains the science after 2 years of testing masks in his lab<figure><img src="https://images.theconversation.com/files/442356/original/file-20220124-13-tvy45q.jpg?ixlib=rb-1.1.0&rect=0%2C700%2C5592%2C2859&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Not all masks offer the same level of protection for you and those around you.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/high-angle-view-of-masks-on-white-background-royalty-free-image/1226906207?adppopup=true">Martin Barth/EyeEm via Getty Images</a></span></figcaption></figure><p><em>The Centers for Disease Control and Prevention has changed its guidelines about masks and respirators a number of times over the past two years and gave its most recent update on Jan. 14, 2022. The update states that cloth face coverings offer the least protection from the coronavirus compared with surgical masks or N95-style masks. <a href="https://scholar.google.com/citations?user=MaEhNkQAAAAJ&hl=en&oi=ao">Christian L'Orange is a mechanical engineer</a> who has been testing the performance of masks for the state of Colorado since the beginning of the pandemic. He explains the new CDC guidelines and the science of what makes for a good mask.</em></p>
<h2>1. What changed in the CDC guidelines?</h2>
<p>The CDC <a href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/types-of-masks.html">currently recommends</a> that you “wear the most protective mask you can that fits well and that you will wear consistently.” The question, then, is what type of mask offers the best protection for you – by filtering the air you breathe in – and for those around you – by filtering the air you breathe out?</p>
<p>The CDC’s updated guidelines clearly lay out the <a href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/types-of-masks.html">hierarchy of protection</a>: “Loosely woven cloth products provide the least protection, layered finely woven products offer more protection, well-fitting disposable surgical masks and KN95s offer even more protection, and well-fitting NIOSH-approved respirators (including N95s) offer the highest level of protection.”</p>
<p>From a performance standpoint, the <a href="https://doi.org/10.1093/annhyg/meq044">N95 and KN95 masks are the best option</a>. While <a href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover-guidance.html">supply chain limitations</a> led to the CDC recommending people not wear N95s early in the pandemic, today they are easily obtainable and should be your first choice if you want the most protection. </p>
<p>The biggest change in the new guidelines has to do with cloth masks. Previous guidance from the CDC had said that some cloth masks could offer <a href="https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/masking-science-sars-cov2.html">acceptable levels of protection</a>. The new guidance still acknowledges that cloth masks can offer a small amount of protection but places them at the very bottom of the bunch.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/442355/original/file-20220124-21-3h1min.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A tangled mass of fibers, as seen through a microscope." src="https://images.theconversation.com/files/442355/original/file-20220124-21-3h1min.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/442355/original/file-20220124-21-3h1min.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/442355/original/file-20220124-21-3h1min.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/442355/original/file-20220124-21-3h1min.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/442355/original/file-20220124-21-3h1min.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/442355/original/file-20220124-21-3h1min.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/442355/original/file-20220124-21-3h1min.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">N95 masks are made from a tangled web of tiny plastic fibers that are very effective at trapping particles.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:%D0%92%D0%BD%D0%B5%D1%88%D0%BD%D0%B8%D0%B9_%D1%81%D0%BB%D0%BE%D0%B9_%D0%BC%D0%B5%D0%B4%D0%B8%D1%86%D0%B8%D0%BD%D1%81%D0%BA%D0%BE%D0%B9_%D0%BC%D0%B0%D1%81%D0%BA%D0%B8_(%D0%BF%D0%BE%D0%BB%D1%8F%D1%80%D0%B8%D0%B7%D0%B0%D1%86%D0%B8%D1%8F).jpg#/media/File:%D0%92%D0%BD%D0%B5%D1%88%D0%BD%D0%B8%D0%B9_%D1%81%D0%BB%D0%BE%D0%B9_%D0%BC%D0%B5%D0%B4%D0%B8%D1%86%D0%B8%D0%BD%D1%81%D0%BA%D0%BE%D0%B9_%D0%BC%D0%B0%D1%81%D0%BA%D0%B8_(%D0%BF%D0%BE%D0%BB%D1%8F%D1%80%D0%B8%D0%B7%D0%B0%D1%86%D0%B8%D1%8F).jpg">Alexander Klepnev via Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>2. What’s the difference between N95, surgical and cloth mask materials?</h2>
<p>The effectiveness of a mask – how much protection a mask provides the wearer – is a combination of two major elements. First, there’s the ability of the material to capture particles. The second factor is the fraction of inhaled or exhaled air leaking out from around the mask – essentially, how well a mask fits. </p>
<p>Most mask materials can be thought of as a tangled net of small fibers. Particles passing through a mask are stopped when they physically touch one of those fibers. N95s, KN95s and surgical masks are purpose-built to be effective at removing particles from air. Their fibers are typically made from melt-blown plastics, often polypropylene, and the strands are tiny – often less than <a href="https://doi.org/10.1016/B978-185617375-9/50004-3">four thousandths of an inch (10 micrometers) in diameter</a> – or approximately one third the width of a human hair. These small fibers create a large amount of surface area within the mask for filtering and collecting particles. Although the specific construction and thickness of the materials used in N95, KN95 and surgical masks can vary, the filter media used are often quite similar.</p>
<p>These fibers are very tightly packed together so the gaps a particle must navigate through are very small. This results in a high probability that particles will end up touching and sticking to a fiber as they pass through a mask. These polypropylene materials also often have a <a href="https://www.thomasnet.com/articles/machinery-tools-supplies/what-is-melt-blown-extrusion/">static charge</a> that can help attract and catch particles. </p>
<p>Cloth masks are typically made of common woven materials such as cotton or polyester. The fibers are often large and less densely packed together, meaning particles can <a href="https://doi.org/10.1021/acsnano.0c05025">easily pass through the material</a>. Adding more layers can help, but stacking layers has a <a href="https://doi.org/10.1080/02786826.2020.1817846">diminishing return</a> and the performance of a cloth mask, even <a href="https://jv.colostate.edu/masktesting/">with multiple layers</a>, will still typically not match that of surgical mask or N95.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/442358/original/file-20220124-27-1ch5axg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A side view of man wearing a surgical mask" src="https://images.theconversation.com/files/442358/original/file-20220124-27-1ch5axg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/442358/original/file-20220124-27-1ch5axg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/442358/original/file-20220124-27-1ch5axg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/442358/original/file-20220124-27-1ch5axg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/442358/original/file-20220124-27-1ch5axg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/442358/original/file-20220124-27-1ch5axg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/442358/original/file-20220124-27-1ch5axg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Surgical masks are made of good materials but are hard to seal against the face and often allow air to escape past a person’s cheeks.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/men-wear-masks-to-prevent-pollution-pollution-royalty-free-image/1186031353?adppopup=true">Krisanapong Detraphiphat/Moment via Getty Images</a></span>
</figcaption>
</figure>
<h2>3. How much does fit matter for masks?</h2>
<p>Fit is the other major component in how effective a mask is. Even if the materials used in a mask were perfect and it removed all particles from the air that passed through it, a mask can offer protection only if it doesn’t leak.</p>
<p>When you breathe in and out, air will always take the path of least resistance. If there are any gaps between a mask and someone’s face, a substantial fraction of every breath will seep out through those gaps and the mask will <a href="https://doi.org/10.1021/acs.est.0c07291">provide relatively little protection</a>. </p>
<p>Many cloth mask designs simply do not seal well. They are not stiff enough to push against the face, there are gaps where the mask doesn’t even come in contact with the face and it is not possible to cinch them tightly enough against the skin to form a decent seal.</p>
<p>But leaking is a concern for all masks. Although the materials used in surgical masks are quite effective, they often bunch and fold on the sides. These gaps provide an easy route for air and particles to leak out. Knotting and tucking surgical masks or wearing a cloth mask over a surgical mask can both <a href="https://www.nytimes.com/article/double-masking-tips-coronavirus.html">significantly reduce leakage</a>.</p>
<p>N95 masks aren’t immune to this problem either; if the nose clip isn’t securely pushed against your face, the mask is leaking. What makes N95s unique is that a <a href="https://www.fda.gov/medical-devices/personal-protective-equipment-infection-control/n95-respirators-surgical-masks-face-masks-and-barrier-face-coverings">specific requirement</a> of the N95 certification process is making sure the masks can form a good seal.</p>
<h2>4. What is different about omicron?</h2>
<p>The mechanics of how masks function is likely no different for omicron than any other variant. The difference is that the omicron variant <a href="https://www.cdc.gov/coronavirus/2019-ncov/variants/omicron-variant.html">is more easily transmitted</a> than previous variants. This high level of infectiousness makes wearing good-quality masks and wearing them correctly to limit the chances of catching or spreading the coronavirus that much more critical.</p>
<p>[<em>Over 140,000 readers rely on The Conversation’s newsletters to understand the world.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-140ksignup">Sign up today</a>.]</p>
<p>Unfortunately, the attributes that make for a good mask are the very things that make masks uncomfortable and not very stylish. If your cloth mask is comfy and light and feels like you are wearing nothing at all, it probably isn’t doing much to keep you and others safe from the coronavirus. The protection offered by a high-quality, well-fitting N95 or KN95 is the best. Surgical masks can be very effective at filtering out particles, but getting them to fit correctly can be tricky and makes the overall protection they will provide you questionable. If you have other options, cloth masks should be a last choice.</p><img src="https://counter.theconversation.com/content/175481/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christian L'Orange receives funding associated with the testing and evaluation of testing masks including fee-for-service testing and funding from the World Health Organization.</span></em></p>The CDC’s updated mask guidelines say that cloth masks offer the least protection from COVID-19. Differences in the materials masks are made from and the ways they fit are the reason.Christian L'Orange, Assistant Research Professor of Mechanical Engineering, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1699412021-11-24T03:31:44Z2021-11-24T03:31:44ZHow to wear a mask in the heat<figure><img src="https://images.theconversation.com/files/433580/original/file-20211123-20-1cxhigv.jpg?ixlib=rb-1.1.0&rect=2%2C1%2C995%2C664&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/family-attractive-pineapples-wearing-face-mask-1685952682">Shutterstock</a></span></figcaption></figure><p>Summer is on its way and you might be wondering how you’re going to wear a mask as the weather gets warmer.</p>
<p>Which mask is best? Is there anything you can do to prevent “<a href="https://www.dailycardinal.com/article/2021/02/how-to-handle-macne?ct=content_open&cv=cbox_latest">macne</a>”? How can you stop the ear loops from chafing? How do you prevent your sunglasses fogging up? </p>
<p>Here are some practical tips to keep you comfortable while helping you stay safe.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/which-mask-works-best-we-filmed-people-coughing-and-sneezing-to-find-out-143173">Which mask works best? We filmed people coughing and sneezing to find out</a>
</strong>
</em>
</p>
<hr>
<h2>Which mask is best in the heat?</h2>
<p><a href="https://www.bmj.com/content/372/bmj.n432">Disposable surgical masks</a> are more effective at filtering out viruses than cloth masks but to remain effective they should only be used once. Cloth masks are not quite as effective but can be washed and reused. </p>
<p>According to the World Health Organization, cloth masks <a href="https://www.bmj.com/content/372/bmj.n432">should have three layers</a>. The inner layer should be soft cotton as this is <a href="https://theconversation.com/how-do-i-know-if-my-mask-actually-works-what-about-the-candle-test-144124">more comfortable on the face</a>. This is also more absorbent, and less irritating, than synthetic materials. <a href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/types-of-masks.html">Cloth masks</a> with synthetic material in the inner layer will also increase sweating, so avoid these.</p>
<p>All masks become less effective when damp – from the damp air you exhale and from your sweat. The best mask to wear in the heat is the one you are most likely to wear.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/433595/original/file-20211124-21-10ufex3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Cloth masks laid out on a yellow background" src="https://images.theconversation.com/files/433595/original/file-20211124-21-10ufex3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/433595/original/file-20211124-21-10ufex3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/433595/original/file-20211124-21-10ufex3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/433595/original/file-20211124-21-10ufex3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/433595/original/file-20211124-21-10ufex3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/433595/original/file-20211124-21-10ufex3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/433595/original/file-20211124-21-10ufex3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">If you choose a cloth mask, make sure the inner layer is made from soft cotton.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/flat-lay-design-colorful-fashion-face-1683124312">Shutterstock</a></span>
</figcaption>
</figure>
<h2>Sweating, wearing masks and macne</h2>
<p>Wearing a mask can affect your skin in a number of ways. It <a href="https://pubmed.ncbi.nlm.nih.gov/32605056/">increases skin temperature</a> and sweating, which can worsen acne or other skin conditions. That’s where the term “macne” or “<a href="https://www.wired.com/story/mascne-causes-and-treatments/">mascne</a>” comes from.</p>
<p>Mask wearing also <a href="https://pubmed.ncbi.nlm.nih.gov/33217053/">increases production of sebum</a> (skin oil), which can clog pores. </p>
<p>Masks can cause friction if they don’t fit well. They can also cause sensitivity reactions if the innermost layer is made from synthetic fibres, and depending on how you wash them.</p>
<p>While it might seem odd, your skin also <a href="https://pubmed.ncbi.nlm.nih.gov/33813749/">gets drier</a> under a mask. That’s possibly because the humidity under the mask disrupts the normal skin barrier. </p>
<p><strong>What to do</strong></p>
<p>If you want to wear a cloth mask, a soft cotton-lined one is recommended to reduce the risk of skin irritation. <a href="https://www.aad.org/public/everyday-care/skin-care-secrets/face/prevent-face-mask-skin-problems">Dermatologists also recommend</a> avoiding makeup, such as some foundation and face powder, when wearing a mask, to avoid clogging the pores.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1300116312371408898"}"></div></p>
<p>Dermatologists <a href="https://www.aad.org/public/everyday-care/skin-care-secrets/face/prevent-face-mask-skin-problems">also recommend</a> washing your mask regularly, preferably after each use. If you are prone to skin conditions use a laundry detergent for sensitive skin to wash your mask, as normal laundry detergents contain perfumes and chemicals that can cause skin reactions. Avoid using fabric softeners for the same reason. </p>
<p>Dermatologists also <a href="https://www.aad.org/public/everyday-care/skin-care-basics/care/face-washing-101">suggest</a> washing your face morning and night with lukewarm water and a mild cleanser and avoiding irritating solutions such as retinoids or aftershave. A <a href="https://www.aad.org/public/everyday-care/skin-care-secrets/face/prevent-face-mask-skin-problems">moisturiser</a> before and after mask wearing can help rehydrate the skin; ensuring your mask fits snugly will reduce friction.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/13-insider-tips-on-how-to-wear-a-mask-without-your-glasses-fogging-up-getting-short-of-breath-or-your-ears-hurting-143001">13 insider tips on how to wear a mask without your glasses fogging up, getting short of breath or your ears hurting</a>
</strong>
</em>
</p>
<hr>
<h2>Avoid sore ears</h2>
<p>When you wear a mask for extended periods, the elastic loops can cause painful pressure on the backs of your ears.</p>
<p>To prevent this, use <a href="https://www.usatoday.com/videos/tech/problemsolved/2021/01/05/use-paper-clips-save-your-ears-face-mask-loop-pressure/4130220001/">paper clips</a> to join the loops together at the back of your head, taking the pressure off your ears.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1251910401219940352"}"></div></p>
<p>Another nifty solution is to use a <a href="https://www.businessinsider.com.au/headband-that-holds-up-face-mask-healthcare-workers-2020-4">headband with buttons</a> or paper clips attached. You attach the ear loops to the buttons/paper clips rather than putting the loops over your ears.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1247989374194720769"}"></div></p>
<h2>How do you stop your sunnies fogging up?</h2>
<p>People who wear prescription glasses will be used to avoiding fogging while wearing a mask. The same advice applies to people wearing sunglasses.</p>
<p>Sunnies fog up when you wear a mask because the warm water vapour in your breath comes out the top of your mask <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3293317/">and condenses</a> on your lenses.</p>
<p>Prevent the moist air from reaching your sunnies by:</p>
<ul>
<li><p>resting them on the mask rather than above the mask. The pressure of the sunnies reduces the chance of vapour exiting the top of the mask</p></li>
<li><p>pinching the top of the surgical mask to improve the fit around the top of your nose. If using a cloth mask, insert a pipe cleaner in the top to shape the mask over the nose</p></li>
<li><p>using soft tape suitable for skin to tape down the top of the mask. If you do this, test the tape somewhere else on your body first to make sure you don’t have a reaction to it.</p></li>
</ul>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1461730641125548033"}"></div></p>
<p>Other anti-fogging strategies include:</p>
<ul>
<li><p>using anti-fogging wipes or spray on the lenses, which you can buy over the counter from your local pharmacy or at an optometrist</p></li>
<li><p>making your own anti-fogging effect by rubbing a thin layer of liquid soap or shaving cream across the inside of each lens.</p></li>
</ul>
<p>Use anti-fogging solutions with care, though, as some may damage any anti-glare or anti-UV films on the lens. Check with your optometrist if unsure.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/cant-get-your-kid-to-wear-a-mask-here-are-5-things-you-can-try-166648">Can't get your kid to wear a mask? Here are 5 things you can try</a>
</strong>
</em>
</p>
<hr>
<h2>In a nutshell</h2>
<p>Whether you choose to wear a cloth or surgical mask this summer, these simple tips will help this become more comfortable as the temperatures rise, you sweat more and your skin may become more irritated.</p>
<p>But make sure you wear your mask correctly. Wearing it <a href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/types-of-masks.html">under your nose</a> makes it completely ineffective. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/its-easy-to-judge-but-some-people-really-cant-wear-a-mask-143258">It's easy to judge. But some people really can't wear a mask</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/169941/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Thea van de Mortel teaches into the Griffith University postgraduate Infection Prevention and Control program. </span></em></p>Here are some practical tips to keep you comfortable while helping you stay safe.Thea van de Mortel, Professor, Nursing and Deputy Head (Learning & Teaching), School of Nursing and Midwifery, Griffith UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1441242020-08-12T05:38:52Z2020-08-12T05:38:52ZHow do I know if my mask actually works? What about the ‘candle test’?<figure><img src="https://images.theconversation.com/files/352426/original/file-20200812-21-11becbd.jpg?ixlib=rb-1.1.0&rect=0%2C1%2C1000%2C664&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pensive-thoughtful-woman-wearing-protection-handmade-1689043420">Shutterstock</a></span></figcaption></figure><p>With mask wearing in public compulsory in Victoria and recommended in New South Wales, many Australians are buying, wearing or making face masks for the first time.</p>
<p><a href="https://www.theguardian.com/australia-news/2020/aug/06/hundreds-of-types-of-face-masks-withdrawn-from-sale-in-australia-amid-safety-fears">Reports</a> of counterfeit or potentially substandard masks on the market may lead some people to question whether their surgical or cloth mask actually works.</p>
<p>So what can you look out for when buying a mask to make sure it does what it’s supposed to do? </p>
<p>And how can you test one you’ve bought or made?</p>
<h2>What do I look for in a surgical mask?</h2>
<p>Surgical masks (also known as medical masks) are usually made of three or four layers, most commonly polypropylene. </p>
<p>Ideally, they should meet <a href="https://www.tga.gov.au/post-market-review-face-masks-overview">Australian standards</a> for how well they filter and how resistant they are to water.</p>
<p>Only masks the Therapeutic Goods Administration (TGA) approves as medical products (officially known as medical devices) can be used in hospitals.</p>
<p>If a mask meets Australian standards as a medical device, <a href="https://www.tga.gov.au/behind-news/regulation-personal-protective-equipment-and-covid-19">you will see</a> a label on the packaging, plus a code indicating the standards it has met, such as:</p>
<ul>
<li><p>AS/NZS 4381:2015</p></li>
<li><p>ASTM F2101-14 or EN 14683:2014</p></li>
<li><p>ISO 22609 or ASTM F1862/F1862M-13.</p></li>
</ul>
<p>If your surgical mask says “not for medical use”, it doesn’t necessarily mean it’s useless. It just means it has not been submitted to the TGA for approval as a medical device.</p>
<p>If that’s the case, you can assess it using one of the methods below.</p>
<h2>What do I look for in a cloth mask?</h2>
<p>Cloth masks are non-medical devices. But they can be <a href="https://wwwnc.cdc.gov/eid/article/26/10/20-0948_article">designed</a> to be reasonably protective.</p>
<p>If you’re buying one online or making one yourself, check <a href="https://www.bloomberg.com/news/articles/2020-07-23/homemade-face-masks-work-best-with-multiple-layers-study-finds?sref=3ZPWSuyv">how many layers</a> it has. A single-layered mask is better than no covering, but <a href="https://thorax.bmj.com/content/early/2020/07/24/thoraxjnl-2020-215748">two layers</a> are better than one, and three layers are better than two. <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31142-9/fulltext">More than three layers</a> are better still.</p>
<p>Look for a fine weave, high thread count and dense material. Flimsy or see-through material, or material with large gaps, is not adequate because droplets and aerosols can pass through the gaps.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/which-mask-works-best-we-filmed-people-coughing-and-sneezing-to-find-out-143173">Which mask works best? We filmed people coughing and sneezing to find out</a>
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<p>For a cloth mask, pure cotton is not a good choice for the outer layer, as it is absorbent. If someone else is coughing and sneezing near you, you want your mask to block those droplets rather than enable them to pass through the mask and infect you. A polyester or cotton-polyester blend is a better choice for this outer layer.</p>
<p>So for cloth masks, <a href="https://www.dhhs.vic.gov.au/sites/default/files/documents/202007/Design%20and%20preparation%20of%20cloth%20mask_0.pdf">aim for</a> at least three layers, including a water-resistant outer layer. The inner layer can be cotton, as that makes it more comfortable to wear, because it will absorb moisture from your breathing.</p>
<p>Check also that your mask fits well around your face. If you have gaps around the edges of your mask, you can breathe in unfiltered, contaminated air. </p>
<p>Look to see if there’s a nose bridge piece or other adjustable edge to help mould the mask around your nose and the top of your cheeks. If your mask is loose-fitting, a <a href="https://www.medrxiv.org/content/10.1101/2020.04.17.20069567v2">nylon stocking</a> over the top can improve the fit and seal. </p>
<p>And remember to wash your cloth mask daily.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/13-insider-tips-on-how-to-wear-a-mask-without-your-glasses-fogging-up-getting-short-of-breath-or-your-ears-hurting-143001">13 insider tips on how to wear a mask without your glasses fogging up, getting short of breath or your ears hurting</a>
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<h2>How can I test my mask at home?</h2>
<p><strong>Test for good filtration and fit</strong></p>
<p>For filtration and fit, you can do some rather <a href="https://makermask.org/diy-mask-tests/">time-consuming experiments</a> at home.</p>
<p>But a much simpler method is the candle test, popularised by US science educator <a href="https://www.billnye.com/">Bill Nye</a>. If you can blow out a candle while wearing your mask, that’s a fail.</p>
<p>It means your mask doesn’t adequately stop the flow of air. If you can blow air out, air can also leak inward just as easily. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/pKk9GFur4Hc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Put on your mask, light a candle, then try to blow out the flame.</span></figcaption>
</figure>
<p><strong>Test for water resistance</strong></p>
<p>The virus is carried on water droplets expelled when infected people talk, cough and sneeze. If these droplets land on your mask, you want the outer layer to repel them. </p>
<p>A TGA-approved mask will be water resistant. But <a href="https://makermask.org/diy-mask-tests/">not all</a> other masks are. So you can test a non-approved surgical mask or cloth mask at home. </p>
<p>If a drop of water on the outside surface is absorbed straight away, <a href="https://makermask.org/diy-mask-tests/">that’s a fail</a>. If the drop forms a bead, the mask is water-resistant.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/how-should-i-clean-my-cloth-mask-143974">How should I clean my cloth mask?</a>
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<p>Whether you go for a surgical mask that’s an approved medical device, an unapproved surgical mask, or a cloth mask, these simple tips should help you assess it before leaving the house.</p>
<p>Masks are a simple method for helping <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31142-9/fulltext">reduce transmission</a> of the virus that causes COVID-19, alongside physical distancing, hand-washing and other infection control measures. If enough people wear them, they may even help <a href="https://www.sciencedirect.com/science/article/pii/S0025556420300560">avoid a lockdown</a>.</p><img src="https://counter.theconversation.com/content/144124/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>C Raina MacIntyre receives funding from NHMRC (Principal Research Fellowship and Centre for Research Excellence), the Medical Research Futures Fund (research grant on bushfire smoke and facemasks) and has received funding from Sanofi and Seqirus in the past five years for investigator driven research on influenza. She has consulted for Australian mask manufacturer, Detmold in 2020.</span></em></p>A few simple pointers can help you spot a quality mask from a dud.C Raina MacIntyre, Professor of Global Biosecurity, NHMRC Principal Research Fellow, Head, Biosecurity Program, Kirby Institute, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1250232019-10-17T12:26:21Z2019-10-17T12:26:21ZCan surgical masks protect you from getting the flu?<figure><img src="https://images.theconversation.com/files/296215/original/file-20191009-3887-1m0nugj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/740799304?src=rsSkShA7HtJrr4kUP1m1mA-1-64&size=medium_jpg">Tupungato/Shutterstock</a></span></figcaption></figure><p>Australia has just suffered a severe flu season, with <a href="https://www.immunisationcoalition.org.au/news-media/2019-influenza-statistics/?gclid=EAIaIQobChMIhZ6bmsmg5QIVleR3Ch0PXA2qEAAYASAAEgL9CvD_BwE">299,211 laboratory-confirmed cases</a>, at last count, and <a href="https://www.mprnews.org/story/2019/10/08/flu-season-is-on-its-way-what-we-can-learn-from-australias-deadly-season">662 deaths</a>. This might be a sign of what’s to come for the UK and US as the virus spreads to the northern hemisphere. </p>
<p>Flu season in the UK runs from December to March, but can start as early as October, so finding ways to avoid catching the bug start around now. The usual method is to get the flu jab. But the flu vaccine is usually only around <a href="https://www.gov.uk/government/news/flu-vaccine-effectiveness-in-2017-to-2018-season">15% effective</a>, so people will be looking for a belt-and-braces approach to avoid getting infected. </p>
<p>The flu virus is <a href="https://www.cdc.gov/flu/about/disease/spread.htm">mainly spread</a> by droplets expelled from the mouths and noses of infected people when they cough, sneeze or talk. These droplets can spread up to six feet away. </p>
<p>It may seem intuitive that if you wear a surgical mask you could stop the virus from getting into your lungs. And certainly that’s how most masks are marketed online. One flu surgical face mask even boasts: “Protect against the Deadly H1N1 swine flu that has killed many world wide and other bacteria and viruses in the air.”</p>
<p>Surgical masks were <a href="https://aornjournal.onlinelibrary.wiley.com/doi/abs/10.1016/S0001-2092%2808%2971359-0?sid=nlm%3Apubmed">first introduced</a> in the operating theatre in the late 1800s, usually made out of two layers of gauze. The masks first found their public appeal during the Spanish flu outbreak of 1918 – an epidemic that killed around <a href="https://www.history.com/topics/world-war-i/1918-flu-pandemic">50m people</a>. </p>
<p>The logic of wearing a surgical mask must surely be: if it works for surgeons, it must work for me. The problem is, the mask isn’t intended to protect the surgeon. It’s intended to stop droplets from the surgeon’s mouth or nose getting into the patient’s wound and causing sepsis. But despite their use for more than a century, their prophylactic effectiveness is <a href="https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD002929.pub3/full">in doubt</a>. Indeed, a <a href="https://www.sciencedirect.com/science/article/pii/S2214031X18300809">recent study</a> showed that surgical masks can be a source of bacterial contamination in the operating theatre. Although they are designed to trap bacteria shed by the surgeon’s nose and mouth, the study found bacteria on the exterior of used masks. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/297360/original/file-20191016-98640-afv11x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/297360/original/file-20191016-98640-afv11x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/297360/original/file-20191016-98640-afv11x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/297360/original/file-20191016-98640-afv11x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/297360/original/file-20191016-98640-afv11x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/297360/original/file-20191016-98640-afv11x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/297360/original/file-20191016-98640-afv11x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Masks are to protect the patient, not the surgeon.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/1152711362?src=SGT7Kwt9Lf4cVmVJbbdgsQ-1-20&size=medium_jpg">Gorodenkoff/Shutterstock</a></span>
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<h2>Impractical</h2>
<p>Surgical masks are sometimes referred to as courtesy masks, suggesting that some people wear them for the same altruistic reason surgeons wear them: to stop others getting their germs. But as the studies in operating theatres show, this benefit is dubious. And given that many people describe the flu as like being hit by a truck, it is unlikely that people will be strolling around town with a mask on when they’re at their most infectious – <a href="https://www.cdc.gov/flu/about/disease/spread.htm">three to four days after symptoms begin</a>. They’ll be tucked up in bed, sweating and aching.</p>
<p>One way masks could stop you getting the flu is by stopping your hand touching your mouth or nose. Aside from inhaling droplets, you can also get the flu from touching anything with the flu virus on it – the armrests on public transport, say – and then touching your face. And people touch their faces a lot without even realising it. A study from New South Wales found that people touch their faces about <a href="https://www.ncbi.nlm.nih.gov/pubmed/25637115">23 times an hour</a>.</p>
<p>There’s one weak point in this plan: you can also get the flu from touching your eye with your contaminated hand. And even to stop the hand to mouth/nose transmission, you’d have to wear a mask 24/7, regularly disposing of the old ones while trying to avoid touching your face. And wearing masks can feel unpleasant and make communication difficult. So they’re not very practical. One study found that only <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2662657/">21% of people</a> are able to keep masks on for the recommended time.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/297362/original/file-20191016-98666-1fssj0w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/297362/original/file-20191016-98666-1fssj0w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=451&fit=crop&dpr=1 600w, https://images.theconversation.com/files/297362/original/file-20191016-98666-1fssj0w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=451&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/297362/original/file-20191016-98666-1fssj0w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=451&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/297362/original/file-20191016-98666-1fssj0w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/297362/original/file-20191016-98666-1fssj0w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/297362/original/file-20191016-98666-1fssj0w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The flu virus can last 24 hours on hard surfaces.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/1113162941?src=74IgZ9inlJSQEedZc5vo2A-1-4&size=medium_jpg">chanonnat srisura/Shutterstock</a></span>
</figcaption>
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<h2>No strong evidence</h2>
<p>A study that is often cited as evidence that surgical masks work is a randomised trial from 2009 that compared surgical masks with a specialist mask called an N95 respirator – a mask that fits snugly and filters at least 95% of very small (0.3 micron) particles. </p>
<p>The study, <a href="https://jamanetwork.com/journals/jama/fullarticle/184819">published in JAMA</a>, found that surgical masks were as effective as N95 respirators at preventing the flu, which is to say, not all that effective because, of the 446 nurses who took part in this study, nearly one in four (24%) in the surgical mask group still got the flu as did 23% of those who wore the N95 respirator. And, because both groups wore masks, it’s impossible to say how they would have fared compared with not wearing a mask at all.</p>
<p>Basically, there is no strong evidence to support well people wearing surgical masks in public. Or as the US Centers for Disease Control and Prevention <a href="https://www.cdc.gov/flu/professionals/infectioncontrol/maskguidance.htm">put it</a>: “No recommendation can be made at this time for mask use in the community by asymptomatic persons, including those at high risk for complications, to prevent exposure to influenza viruses.” </p>
<p>The best thing you can do to stop getting the flu is to regularly <a href="https://www.cdc.gov/features/handwashing/index.html">wash your hands</a>, and try to avoid touching your face.</p><img src="https://counter.theconversation.com/content/125023/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Manal Mohammed does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Retailers are selling ‘anti-virus masks’ but there is no strong evidence that they can stop the spread of flu.Manal Mohammed, Lecturer, Medical Microbiology, University of WestminsterLicensed as Creative Commons – attribution, no derivatives.