Table 2 Incidence rate ratios (IRR) at 2-month intervals of new infections among masked vs. non-masked population for the ancestral strain (R0 = 2.5).

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

 

2 months

4 months

6 months

Type of mask

IRR

N95 respirator

0.47

0.47

0.47

Medical procedure

0.66

0.66

0.68

Cloth mask

0.69

0.7

0.72

Gaiter

0.69

0.7

0.72

Bandana

0.76

0.78

0.8

  1. Each row represents a scenario in which all mask-wearing individuals are assumed to wear the specified type of mask. Wearer protection efficacy is assumed to be half of source control efficacy. It assumes 60% of the susceptible population < 65 years old are wearing masks, 80% of those ≥ 65 years old wear masks, and both rates increase 10% for both detected and infected persons (whether symptomatic or asymptomatic).
  2. IRR Incidence rate ratio.
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