How Do Face Masks Control the Spread of Disease?

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She joined Britannica in 2006 and...</div> </a> <div data-popper-arrow></div> </div> <span class="btn btn-link editor-link p-0 qa-byline-link gtm-byline font-12 byline-contributor text-decoration-underline"> Kara Rogers</span></div> <div class="font-serif font-12 text-gray-700"> <span class="qa-fact-checked-by">Fact-checked by</span> <div class="editor-popover popover p-0"> <a class="d-block p-20 font-12" href="/editor/The-Editors-of-Encyclopaedia-Britannica/4419" > <div class="editor-title font-16 font-weight-bold">The Editors of Encyclopaedia Britannica</div> <div class="editor-description font-12 font-serif mt-5 text-black">Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors.</div> </a> <div data-popper-arrow></div> </div> <span class="btn btn-link editor-link p-0 qa-byline-link font-12 "> The Editors of Encyclopaedia Britannica</span></div></div> </div> <article class="topic-content content mt-20"><figure class="md-assembly md-feature-assembly print-false" data-type="1" data-descid="1"><div class="md-assembly-wrapper card-media " data-type="image"><a href="https://cdn.britannica.com/15/215715-050-496D93EB/Women-wearing-facemasks-while-walking-outdoors-Milan-Italy-February-2020-coronavirus-COVID-19.jpg" target="_blank" class="gtm-assembly-link position-relative d-flex align-items-center justify-content-center " data-href="*"><img src="https://cdn.britannica.com/15/215715-050-496D93EB/Women-wearing-facemasks-while-walking-outdoors-Milan-Italy-February-2020-coronavirus-COVID-19.jpg?w=600&q=60" alt="People wearing surgical masks (also called face mask or medical masks or safety masks) walk through the city center of Milan, Italy on Feb. 23, 2020. Coronavirus disease COVID-19 pandemic" data-width="1600" data-height="1065" loading="eager"><button class="magnifying-glass btn btn-circle position-absolute shadow btn-white top-10 right-10" aria-label="Zoom in"><em class="material-icons link-blue" data-icon="zoom_in"></em></button></a></div><figcaption class=""><div class="md-assembly-caption text-muted font-14 font-serif line-clamp"><span><button class="js-more-btn d-none btn btn-unstyled font-12 bg-white js-content" aria-label="Toggle more/less fact data"><span class="link-blue">(more)</span></button></span></div><cite class="credit d-block mt-5">© Alberto Mihai/Dreamstime.com</cite></figcaption></figure><p class="topic-paragraph">Face masks have long been used in health care, often for the simple reason that they protect doctors and nurses from splashes of body fluids during procedures but also for the purpose of blocking the transmission of respiratory droplets. Thanks to the coronavirus disease 2019 (<a href="https://www.britannica.com/science/COVID-19" class="md-crosslink " data-show-preview="true">COVID-19</a>) <a href="https://www.britannica.com/science/pandemic" class="md-crosslink " data-show-preview="true">pandemic</a>, however, face masks have become a critical form of personal protection not just for doctors, nurses, and patients but for ordinary people out for a walk or off to pick up groceries.</p><span class="MOD1"></span><p class="topic-paragraph">But do face masks really protect against the spread of infectious respiratory diseases, like <a href="https://www.britannica.com/science/SARS" class="md-crosslink " data-show-preview="true">SARS</a> and COVID-19? And, if so, just how effective are they?</p><span class="MOD2"></span><p class="topic-paragraph">When it comes to controlling the spread of respiratory illnesses, face masks can help. <a class="external" target="_blank" rel="noopener" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2190272/" data-show-preview="true">A study from 2008</a> found that surgical masks were 68 percent effective in blocking the transmission of SARS, while N95 masks (a type of respirator mask that filters airborne particulate matter) were more than 90 percent effective. Proper fit and the use of certain materials are important for achieving this level of effectiveness.</p><span class="MOD3"></span><p class="topic-paragraph"><a class="external" target="_blank" rel="noopener" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2440799/" data-show-preview="true">However, even masks that are not perfectly fitted</a> or that are homemade can help limit the transmission of large respiratory droplets emitted through sneezing or coughing. In April 2020, in response to the ongoing spread of COVID-19, the U.S. <a class="external" target="_blank" rel="noopener" href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover.html" data-show-preview="true">Centers for Disease Control and Prevention (CDC) issued recommendations</a> on the use of simple cloth masks made from materials in the home. High demand for face masks, accompanied by a shortage in surgical and N95 masks, warranted closer evaluation of the role cloth masks could serve in stemming disease spread.</p><span class="MOD4"></span><p class="topic-paragraph"><a class="external" target="_blank" rel="noopener" href="https://www.nap.edu/download/25776" data-show-preview="true">An expert consultation on the effectiveness of cloth masks</a> published in early April 2020 indicated that the type of fabric used and its thickness could influence how well cloth masks work in preventing disease transmission. But the assessment also suggested that there are important trade-offs to consider. For example, thick fabrics or multiple layers of fabric are more likely to catch small aerosolized particles—the types of small particles sometimes trapped by surgical and more frequently by N95 masks—but they also are more difficult to wear, given their high degree of breathing resistance. A mask that is uncomfortable is likely to be pulled down or worn incorrectly, undermining its potential effectiveness.</p><span class="MOD5"></span><p class="topic-paragraph">Of course, ultimately underlying the ability of face masks to prevent disease transmission is human behavior. Even if a mask is fundamentally effective in trapping infectious particles, it is still up to the individual to wear it properly. People must also be aware that if their cloth masks trap significant moisture, the masks need to be cleaned or disposed of to prevent viral contamination of surfaces.</p><span class="MOD6"></span><p class="topic-paragraph">Learn more about cloth masks and how to use them to help prevent the spread of disease:</p><span class="MOD7"></span><p class="topic-paragraph"><a class="external" target="_blank" rel="noopener" href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover.html" data-show-preview="true">Recommendation Regarding the Use of Cloth Face Coverings, Especially in Areas of Significant Community-Based Transmission</a> (CDC)</p><span class="MOD8"></span><p class="topic-paragraph"><a class="external" target="_blank" rel="noopener" href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/diy-cloth-face-coverings.html" data-show-preview="true">Use of Cloth Face Coverings to Help Slow the Spread of COVID-19</a> (CDC)</p><span class="MOD9"></span><span class="AM-END-OF-ARTICLE am-inline"></span></article> </div> </div> </div> <aside class="cm-rightrail d-none d-md-block ad-rail"></aside> </div> </div> </div> </div> </main> <div class="grid gx-0"> <div class="col"> <div class="md-loading hidden display-4 font-weight-normal"></div> <div class="text-center my-20 mb-100"> <button class="md-infinite-load-next btn btn-blue" data-value="next-page">Load More</button> </div> </div> <div class="col-md-da-320 hidden-xs"> </div> </div></div> </div> </main> <div id="md-footer"></div> <noscript><iframe src="//www.googletagmanager.com/ns.html?id=GTM-5W6NC8" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript> <script type="text/javascript" id="_informizely_script_tag"> var IzWidget = IzWidget || {}; (function (d) { var scriptElement = d.createElement('script'); scriptElement.type = 'text/javascript'; scriptElement.async = true; scriptElement.src = "https://insitez.blob.core.windows.net/site/f780f33e-a610-4ac2-af81-3eb184037547.js"; var node = d.getElementById('_informizely_script_tag'); node.parentNode.insertBefore(scriptElement, node); } )(document); </script>  <script> window.ap3c = window.ap3c || {}; var ap3c = window.ap3c; ap3c.cmd = ap3c.cmd || []; ap3c.cmd.push(function() { ap3c.init('ZO4siT4cLwnykPnzZWJtd3Byb2Q', 'https://engage.email.britannica.com/'); ap3c.track({v: 0}); }); ap3c.activity = function(act) { ap3c.act = (ap3c.act || []); ap3c.act.push(act); }; var s, t; s = document.createElement('script'); s.type = 'text/javascript'; s.src = "https://engage.email.britannica.com/app.js"; t = document.getElementsByTagName('script')[0]; t.parentNode.insertBefore(s, t); </script> <script class="marketing-page-info" type="application/json"> {"pageType":"Story","templateName":"COMPANION","pageNumber":1,"pagesTotal":11,"pageId":7731,"pageLength":null,"initialLoad":true,"lastPageOfScroll":false} </script> <script class="marketing-content-info" type="application/json"> [] </script> <script src="https://cdn.britannica.com/mendel-resources/3-130/js/libs/jquery-3.5.0.min.js?v=3.130.14"></script> <script type="text/javascript" data-type="Init Mendel Code Splitting"> (function() { $.ajax({ dataType: 'script', cache: true, url: 'https://cdn.britannica.com/mendel-resources/3-130/dist/story-page.js?v=3.130.14' }); })(); </script> <script class="analytics-metadata" type="application/json"> {"leg":"B","adLeg":"B","userType":"ANONYMOUS","pageType":"Story","pageSubtype":"COMPANION","articleTemplateType":null,"gisted":false,"pageNumber":1,"hasSummarizeButton":false,"hasAskButton":false} </script> <script type="text/javascript"> EBStat={accountId:-1,hostnameOverride:'webstats.eb.com',domain:'www.britannica.com', json:''}; </script> <script type="text/javascript"> ( function() { $.ajax( { dataType: 'script', cache: true, url: '//www.britannica.com/webstats/mendelstats.js?v=1' } ) .done( function() { try {writeStat(null,EBStat);} catch(err){} } ); })(); </script> <div id="bc-fixed-dialogue"></div> </body> </html>

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How Do Face Masks Control the Spread of Disease? | Britannica