Characteristics of the residence and household practices: univariable analysis between two family groups
| Residence and household practices | Total (n (%)) (n=121) | Families without transmission (n (%)) (n=81) | Families with transmission (n (%)) (n=40) | P value | Unadjusted OR (95% CI) |
| Residential area per capita (m2) (median (IQR)) | 25.0 (17.3–35.0) | 28.0 (18.0–35.8) | 20.0 (16.9–31.8) | – | – |
| ≤20 | 50 (41.3) | 30 (37.1) | 20 (50.0) | – | Ref |
| 20–40 | 49 (40.5) | 36 (44.4) | 13 (32.5) | 0.16 | 0.54 (0.23 to 1.27) |
| ≥40 | 22 (18.2) | 15 (18.5) | 7 (17.5) | 0.51 | 0.70 (0.24 to 2.02) |
| No of bedrooms per person (median (IQR)) | 0.7 (0.5–1.0) | 0.7 (0.5–1.0) | 0.7 (0.5–1.0) | – | – |
| ≥1 | 39 (32.2) | 28 (34.6) | 11 (27.5) | – | Ref |
| <1 | 82 (67.8) | 53 (65.4) | 29 (72.5) | 0.49 | 1.34 (0.59 to 3.08) |
| No of washrooms (median (IQR)) | 1 (1–2) | 1 (1–2) | 1 (1–2) | – | – |
| 2 or more | 34 (28.1) | 23 (28.4) | 11 (27.5) | – | Ref |
| 1 | 87 (71.9) | 58 (71.6) | 29 (72.5) | 0.87 | 1.07 (0.46 to 2.49) |
| Frequency of room cleaning (wet type) | – | – | – | – | |
| Once in 1–2 days | 83 (68.6) | 59 (72.8) | 24 (60.0) | – | Ref |
| Once in >2 days | 38 (31.4) | 22 (27.2) | 16 (40.0) | 0.11 | 1.90 (0.86 to 4.19) |
| Frequency of chlorine or ethanol based disinfectant use for house cleaning* | – | – | – | – | – |
| Once in 2 or more days | 86 (71.1) | 50 (61.7) | 36 (90.0) | – | Ref |
| Once a day or more | 35 (28.9) | 31 (38.3) | 4 (10.0) | 0.003 | 0.18 (0.06 to 0.55) |
| Ventilation duration per day (hours) (median (IQR))† | 2.0 (1.0–6.0) | 3.0 (1.5–8.0) | 1.8 (1.0–4.0) | – | – |
| >1 | 85 (70.2) | 62 (76.5) | 23 (57.5) | – | Ref |
| ≤1 | 36 (29.8) | 19 (23.5) | 17 (42.5) | 0.02 | 2.55 (1.14 to 5.70) |
*When cleaning the house, disinfectant which contains chlorine or ethanol is used to disinfect the floor, door and window handles, indoor air, tables and toilets.
†Ventilation means the practice of opening the window to allow convection of indoor air.