Contributor: Peter Bakes, MD Educational Pearls: Recent study looked at if mask wearing protects the mask wearer from infection This group found 1.8% of mask wearers got COVID while 2.1% of non-mask wearers became infected, which was not statistically significant This was not statistically significant and has been used to justify not wearing masks by some groups While the numbers look small, it's close to a 20% reduction in infections for the mask wearers The results reported had concerns for being underpowered, meaning the studies population may not be big enough to draw definitive conclusions Many limitations of study including how wearing a mask may protect others Unfortunately, studies like these can lead to misinterpretation and distortion References Bundgaard H, Bundgaard JS, Raaschou-Pedersen DET, von Buchwald C, Todsen T, Norsk JB, Pries-Heje MM, Vissing CR, Nielsen PB, Winsløw UC, Fogh K, Hasselbalch R, Kristensen JH, Ringgaard A, Porsborg Andersen M, Goecke NB, Trebbien R, Skovgaard K, Benfield T, Ullum H, Torp-Pedersen C, Iversen K. Effectiveness of Adding a Mask Recommendation to Other Public Health Measures to Prevent SARS-CoV-2 Infection in Danish Mask Wearers : A Randomized Controlled Trial. Ann Intern Med. 2020 Nov 18. doi: 10.7326/M20-6817. Epub ahead of print. PMID: 33205991. Summarized by Jackson Roos, MS4 | Edited by Erik Verzemnieks, MD   The Emergency Medical Minute is excited to announce that we are now offering AMA PRA Category 1 credits™ via online course modules. To access these and for more information, visit our website at www.emergencymedicalminute.com/cme-courses/ and create an account.