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Author Notes:

Brian M. Gurbaxani, Email: buw8@cdc.gov

B.M.G., A.N.H., and R.B.S. conceived the study. B.M.G. and A.N.H. did the background research and wrote the primary draft of the manuscript. A.N.H. served as the primary statistician for the project, adapted and modified the models and methods, and programmed the models and equations in R. B.M.G. and P.P. served as secondary statisticians and provided critical review of the models and equations, and B.M.G. provided some ancillary models and equations. B.M.G. and A.N.H. contributed equally to the paper. All authors helped pull together the parameters needed for the models from the primary literature and other sources, and all authors contributed to writing and critical review of the final manuscript.

The authors would like to thank all reviewers at the CDC who added to the clarity of the final manuscript, as well as other members of the CDC COVID-19 Response Modeling and Analytics Task Force for helpful discussions. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention (CDC).

The authors declare no competing interests.


Research Funding:

All authors are employees of the CDC—no external funding was needed.


  • COVID-19
  • Humans
  • Masks
  • SARS-CoV-2
  • Textiles
  • United States

Evaluation of different types of face masks to limit the spread of SARS-CoV-2: a modeling study


Journal Title:

Scientific Reports


Volume 12, Number 1


, Pages 8630-8630

Type of Work:

Article | Final Publisher PDF


We expanded a published mathematical model of SARS-CoV-2 transmission with complex, age-structured transmission and with laboratory-derived source and wearer protection efficacy estimates for a variety of face masks to estimate their impact on COVID-19 incidence and related mortality in the United States. The model was also improved to allow realistic age-structured transmission with a pre-specified R0 of transmission, and to include more compartments and parameters, e.g. for groups such as detected and undetected asymptomatic infectious cases who mask up at different rates. When masks are used at typically-observed population rates of 80% for those ≥ 65 years and 60% for those < 65 years, face masks are associated with 69% (cloth) to 78% (medical procedure mask) reductions in cumulative COVID-19 infections and 82% (cloth) to 87% (medical procedure mask) reductions in related deaths over a 6-month timeline in the model, assuming a basic reproductive number of 2.5. If cloth or medical procedure masks’ source control and wearer protection efficacies are boosted about 30% each to 84% and 60% by cloth over medical procedure masking, fitters, or braces, the COVID-19 basic reproductive number of 2.5 could be reduced to an effective reproductive number ≤ 1.0, and from 6.0 to 2.3 for a variant of concern similar to delta (B.1.617.2). For variants of concern similar to omicron (B.1.1.529) or the sub-lineage BA.2, modeled reductions in effective reproduction number due to similar high quality, high prevalence mask wearing is more modest (to 3.9 and 5.0 from an R0 = 10.0 and 13.0, respectively). None-the-less, the ratio of incident risk for masked vs. non-masked populations still shows a benefit of wearing masks even with the higher R0 variants.

Copyright information:

© This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply 2022

This is an Open Access work distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/rdf).
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