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Volume 26, Number 8—August 2020

The Practice of Wearing Surgical Masks during the COVID-19 Pandemic

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To the Editor: We read with interest the meta-analysis conducted by Xiao et al. (1) that found no significant reduction in influenza transmission with the use of surgical masks in the community, based on 10 randomized controlled trials. Nevertheless, mechanistic studies found that surgical masks could prevent transmission of human coronavirus and influenza virus infections if worn by infected persons (2). The authors pointed out the limitations of their study: small sample size and suboptimal adherence in the mask-wearer group (1). Recommendations on masks in the community vary across countries during the coronavirus disease (COVID-19) pandemic (3); studies have reported mixed results (2,4,5).

Epidemiologic data may provide an alternative insight. As of April 3, 2020, Taiwan recorded 348 COVID-19 cases (1.46/100,000 population), of which 48 (13.8%) were local cases. Singapore recorded 1,114 cases (19.07/100,000 population), of which 572 (51.3%) were local cases. Taiwan and Singapore both employed stringent measures. Taiwan recommended the use of masks early in the pandemic. In contrast, Singapore did not recommend the use of masks until April 3 and initiated its Stay Home policy on April 7.

Before the 2003 severe acute respiratory syndrome coronavirus epidemic in Taiwan, only persons with open tuberculosis wore masks in public. During the epidemic, wearing a mask in public was stigmatized. Thereafter, we educated the public to wear masks as a practice of respiratory hygiene. Although evidence is limited for their effectiveness in preventing transmission of severe acute respiratory syndrome coronavirus 2, either for source control or to reduce exposure, the wearing of masks by healthy persons may prevent potential asymptomatic or presymptomatic transmission (3). This marginal reduction in transmission may produce substantial results, particularly when it is implemented early. Taiwan had the foresight to create a large stockpile of medical and surgical masks; other countries or regions might now consider doing so as part of future pandemic plans (3).

Mr. Chiang is a medical student at National Taiwan University. His primary research interests are epidemiology and prevention of communicable diseases.


Cho-Han Chiang, Cho-Hung Chiang, Cho-Hsien Chiang, and Yee-Chun ChenComments to Author 
Author affiliations: National Taiwan University College of Medicine, Taipei, Taiwan (Cho-Han Chiang, Y.-C. Chen); Fu-Jen Catholic University, Taipei (Cho-Hung Chiang); Chung Shan Medical University, Taichung, Taiwan (Cho-Hsien Chiang); National Taiwan University Hospital, Taipei (Y.-C. Chen)



  1. Xiao  J, Shiu  EYC, Gao  H, Wong  JY, Fong  MW, Ryu  S, et al. Nonpharmaceutical measures for pandemic influenza in nonhealthcare settings—personal protective and environmental measures. Emerg Infect Dis. 2020;26:96775. DOIPubMedGoogle Scholar
  2. Leung  NHL, Chu  DKW, Shiu  EYC, Chan  KH, McDevitt  JJ, Hau  BJP, et al. Respiratory virus shedding in exhaled breath and efficacy of face masks. Nat Med. 2020 Apr 3 [Epub ahead of print]. DOIGoogle Scholar
  3. Feng  S, Shen  C, Xia  N, Song  W, Fan  M, Cowling  BJ. Rational use of face masks in the COVID-19 pandemic. Lancet Resp Med. In press 2020. DOIGoogle Scholar
  4. Ng  K, Poon  BH, Kiat Puar  TH, Shan Quah  JL, Loh  WJ, Wong  YJ, et al. COVID-19 and the risk to health care workers: a case report. Ann Intern Med. 2020 Mar 16 [Epub ahead of print]. DOIPubMedGoogle Scholar
  5. Bae  S, Kim  MC, Kim  JY, Cha  HH, Lim  JS, Jung  J, et al. Effectiveness of surgical and cotton masks in blocking SARS–CoV-2: a controlled comparison in 4 patients. Ann Intern Med. 2020 Apr 6 [Epub ahead of print]. DOIPubMedGoogle Scholar


Cite This Article

DOI: 10.3201/eid2608.201498

Original Publication Date: April 23, 2020

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Table of Contents – Volume 26, Number 8—August 2020

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Please use the form below to submit correspondence to the authors or contact them at the following address:

Yee-Chun Chen, Department of Internal Medicine, National Taiwan University Hospital No. 7 Chung-Shan South Rd, Taipei, Taiwan

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Page created: April 23, 2020
Page updated: July 18, 2020
Page reviewed: July 18, 2020
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