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. 2020 Nov 13;22(11):e21372. doi: 10.2196/21372

Table 8.

The COVID-19 infection rates (%) and potential pairwise risk compensating effect among the four nonpharmaceutical interventions with RR and P values from exact tests.

Nonpharmaceutical interventions Participants, n (%) RRa (95% CI) P value
Handwashing (no) 0.03 (0.003-0.26) .002

Mask wearing (no) 13 (23.1)


Mask wearing (yes) 147 (0.7)

Handwashing (yes) 0.11 (0.04-0.29) <.001

Mask wearing (no) 95 (5.3)


Mask wearing (yes) 4865 (0.6)

Proper coughing (no) 0.02(0.004-0.08) <.001

Mask wearing (no) 11 (36.4)


Mask wearing (yes) 318 (0.6)

Proper coughing (yes) 0.18 (0.05-0.57) .02

Mask wearing (no) 76 (3.9)


Mask wearing (yes) 3749 (0.7)

Social distancing (no) 0.17 (0.06-0.45) .002

Mask wearing (no) 96 (6.3)


Mask wearing (yes) 958 (1.0)

Social distancing (yes) 0.03 (0.01-0.11) .002

Mask wearing (no) 12 (16.7)


Mask wearing (yes) 4054 (0.5)

Proper coughing (no) 0.33 (0.08-1.35) .13

Handwashing (no) 74 (4.1)


Handwashing (yes) 373 (1.3)

Proper coughing (yes) 0.42 (0.10-1.72) .21

Handwashing (no) 118 (1.7)


Handwashing (yes) 5879 (0.7)

Social distancing (no) 0.25 (0.73-0.86) .05

Handwashing (no) 58 (5.2)


Handwashing (yes) 996 (1.3)

Social distancing (yes) 0.38 (0.12-1.21) .11

Handwashing (no) 205 (1.5)


Handwashing (yes) 6899 (0.6)

Social distancing (no) 0.29(0.09-0.91) .048

Proper coughing (no) 90 (4.4)


Proper coughing (yes) 776 (1.3)

Social distancing (yes) 0.58 (0.21-1.63) .30

Proper coughing (no) 357 (1.1)


Proper coughing (yes) 5221 (0.7)

aRR: risk ratio.