Demographic and other characteristics by arm of randomisation
| Variable | Medical mask (% and 95% CI) (n=580) | Cloth mask (% and 95% CI) (n=569) | Control (% and 95% CI) (n=458) |
|---|---|---|---|
| Gender (male) | 112/580 19.3 (16.2 to 22.8) | 133/569 23.4 (20.0 to 27.1) | 112/458 24.5 (20.6 to 28.7) |
| Age (mean) | 36 (35.6 to 37.3) | 35 (34.6 to 36.3) | 36 (35.1 to 37.0) |
| Education (postgraduate) | 114/580 19.7 (16.5 to 23.1) | 99/569 17.4 (14.3 to 20.8) | 78/458 17.0 (13.7 to 20.8) |
| Smoker (current/ex) | 78/580 13.4 (10.8 to 16.5) | 79/569 13.9 (11.1 to 17.0) | 66/458 14.4 (11.3 to 18.0) |
| Pre-existing illness* | 66/580 11.4 (9.0 to 14.2) | 70/569 12.3 (9.8 to 15.3) | 47/458 10.3 (7.8 to 13.4) |
| Influenza vaccination (yes) | 21/580 3.6 (2.4 to 5.4) | 21/569 3.7 (2.4 to 5.6) | 15/458 3.3 (2.0 to 5.3) |
| Staff (doctors) | 176/580 30.3 (26.6 to 34.3) | 165/569 29.0 (25.3 to 32.9) | 134/458 29.3 (25.1 to 33.7) |
| Number of hand washings per day (geometric mean)† | 14 (13.8 to 15.4) | 11 (10.9 to 11.9) | 12 (11.5 to 12.7) |
| Number of patients had contact with (median and range)‡ | 21 (0 to 540) | 21 (0 to 661) | 18 (3 to 199) |
*Includes asthma, immunocompromised and others.
†‘Hand wash’ variable was created by taking average of the number of hand washes performed by a healthcare worker (HCW) over the trial period. The variable was log transformed for the multivariate analysis.
‡‘Number of patients had contact with’ variable was created by taking average of the number of patients in contact with a HCW over the trial period. Median and range is presented in the table.