Cloth Masks May Prevent Transmission of COVID-19
Authors: Kouji H. Harada, Mariko Harada Sassa
Journal: Annals of Internal Medicine (2021)

LettersApril 2021Cloth Masks May Prevent Transmission of COVID-19FREEKouji H. Harada, PhD, MPH, Mariko Harada Sassa, MD, PhDKouji H. Harada, PhD, MPHKyoto University Graduate School of Medicine, Kyoto, JapanSearch for more papers by this author, Mariko Harada Sassa, MD, PhDKyoto University Graduate School of Medicine, Kyoto, JapanSearch for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/L21-0088 SectionsAboutVisual AbstractPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail TO THE EDITOR: We appreciate Clase and colleagues' (1) efforts to show the potential efficacy of cloth masks in filtering virus-containing aerosols. The effect of wearing masks in the community to prevent coronavirus disease 2019 (COVID-19) is worth investigating. However, we have several concerns.Clase and colleagues cite an unpublished review (2) on the effects of face masks and state that integrated odds ratios were between 0.81 and 0.95. Three of the 4 cited odds ratios were derived in home environments where a member of the household was infected with influenza-like illness. Only 1 odds ratio integrated from 3 studies done in a university residence and during the hajj pilgrimage was 0.94 (95% CI, 0.75 to 1.19).Even if wearing masks reduces the risk for transmission by 6%, extrapolating how this measure will benefit the general community is difficult. Public health interventions requiring that populations wear masks may reduce transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) without harm. If authorities can spend sufficient funds, advocacy and distribution of materials are feasible. However, implementation of physical distancing, hand hygiene, and sanitation is not perfect. How should authorities allocate resources? The cost-effectiveness of cloth masks should be evaluated in comparison to that of other options.References1. Clase CM, Fu EL, Joseph M, et al. Cloth masks may prevent transmission of COVID-19: an evidence-based, risk-based approach [Editorial]. Ann Intern Med. 2020;173:489-91. [PMID: 32441991]. doi: 10.7326/M20-2567 LinkGoogle Scholar2. Brainard JS, Jones N, Lake I, et al. Facemasks and similar barriers to prevent respiratory illness such as COVID-19: a rapid systematic review. medRxiv. Preprint posted online 6 April 2020. doi:10.1101/2020.04.01.20049528 Google Scholar Comments 0 Comments Sign In to Submit A Comment Author, Article, and Disclosure InformationAuthors: Kouji H. Harada, PhD, MPH; Mariko Harada Sassa, MD, PhDAffiliations: Kyoto University Graduate School of Medicine, Kyoto, JapanDisclosures: Authors have reported no disclosures of interest. Forms can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=L21-0088. PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetailsSee AlsoCloth Masks May Prevent Transmission of COVID-19: An Evidence-Based, Risk-Based Approach Catherine M. Clase , Edouard L. Fu , Meera Joseph , Rupert C.L. Beale , Myrna B. Dolovich , Meg Jardine , Johannes F.E. Mann , Roberto Pecoits-Filho , Wolfgang C. Winkelmayer , and Juan J. Carrero Cloth Masks May Prevent Transmission of COVID-19 George FitzGerald Cloth Masks May Prevent Transmission of COVID-19 Maxwell G. Anderson Cloth Masks May Prevent Transmission of COVID-19 Catherine M. Clase , Edouard L. Fu , Meg Jardine , Johannes F.E. Mann , Juan J. Carrero Metrics April 2021Volume 174, Issue 4 Page: 579 Keywords COVID-19 Disclosure Hygiene Odds ratio Population statistics Prevention, policy, and public health Sanitation ePublished: 20 April 2021 Issue Published: April 2021 Copyright & PermissionsCopyright © 2021 by American College of Physicians. All Rights Reserved.PDF downloadLoading ...