Table 3.
Positivity rate of surface and air samples according to various factors.
| Overall |
Surface samples only |
Air samples only |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Negative | Positive | Total | P value | Negative | Positive | Total | P value | Negative | Positive | Total | P value | |
| Presence of COVID-19 compatible symptoms | ||||||||||||
| No | 960 (94.8) | 53 (5.2) | 1013 (100.0) | 0.013* | 570 (92.4) | 47 (7.6) | 617 (100.0) | 0.034* | 390 (98.5) | 6 (1.5) | 396 (100.0) | 0.105 |
| Yes | 1147 (92.1) | 98 (7.9) | 1245 (100.0) | 664 (89.0) | 82 (11.0) | 746 (100.0) | 483 (96.8) | 16 (3.2) | 499 (100.0) | |||
| Fever on the day of sampling | ||||||||||||
| No | 1757 (94.1) | 110 (5.9) | 1867 (100.0) | 0.001* | 1039 (91.9) | 92 (8.1) | 1131 (100.0) | <0.001* | 718 (97.6) | 18 (2.5) | 736 (100.0) | 0.959 |
| Yes | 350 (89.5) | 41 (10.5) | 391 (100.0) | 195 (84.1) | 37 (16.0) | 232 (100.0) | 155 (97.5) | 4 (2.5) | 159 (100.0) | |||
| Cough on the day of sampling | ||||||||||||
| No | 1315 (94.6) | 75 (5.4) | 1390 (100.0) | 0.002* | 779 (92.2) | 66 (7.8) | 845 (100.0) | 0.008* | 536 (98.4) | 9 (1.7) | 545 (100.0) | 0.052 |
| Yes | 792 (91.2) | 76 (8.8) | 868 (100.0) | 455 (87.8) | 63 (12.2) | 518 (100.0) | 337 (96.3) | 13 (3.7) | 350 (100.0) | |||
| Cough in past 3 days | ||||||||||||
| No | 1008 (94.3) | 61 (5.7) | 1069 (100.0) | 0.077 | 595 (91.7) | 54 (8.3) | 649 (100.0) | 0.169 | 413 (98.3) | 7 (1.7) | 420 (100.0) | 0.150 |
| Yes | 1099 (92.4) | 90 (7.6) | 1189 (100.0) | 639 (89.5) | 75 (10.5) | 714 (100.0) | 460 (96.8) | 15 (3.2) | 475 (100.0) | |||
| Shortness of breath on the day of sampling | ||||||||||||
| No | 1986 (93.2) | 145 (6.8) | 2131 (100.0) | 0.362 | 1163 (90.4) | 123 (9.6) | 1286 (100.0) | 0.606 | 823 (97.4) | 22 (2.6) | 845 (100.0) | 0.248 |
| Yes | 121 (95.3) | 6 (4.7) | 127 (100.0) | 71 (92.2) | 6 (7.8) | 77 (100.0) | 50 (100.0) | 0 (0.0) | 50 (100.0) | |||
| Latest SARS-CoV-2 test | ||||||||||||
| Negative | 132 (97.8) | 3 (2.2) | 135 (100.0) | 0.034* | 80 (96.4) | 3 (3.6) | 83 (100.0) | 0.064 | 52 (100.0) | 0 (0.0) | 52 (100.0) | 0.234 |
| Positive | 1939 (93.1) | 144 (6.9) | 2083 (100.0) | 1134 (90.3) | 122 (9.7) | 1256 (100.0) | 805 (97.3) | 22 (2.7) | 827 (100.0) | |||
| Duration since symptom onset/first positive test (whichever is earlier) | ||||||||||||
| 0–1 day | 38 (92.7) | 3 (7.3) | 41 (100.0) | < 0.001* | 22 (91.7) | 2 (8.3) | 24 (100.0) | <0.001* | 16 (94.1) | 1 (5.9) | 17 (100.0) | 0.117 |
| 2–3 days | 138 (87.3) | 20 (12.7) | 158 (100.0) | 80 (83.3) | 16 (16.7) | 96 (100.0) | 58 (93.6) | 4 (6.5) | 62 (100.0) | |||
| 4–7 days | 502 (90.0) | 56 (10.0) | 558 (100.0) | 286 (85.1) | 50 (14.9) | 336 (100.0) | 216 (97.3) | 6 (2.7) | 222 (100.0) | |||
| 8–10 days | 485 (91.7) | 44 (8.3) | 529 (100.0) | 283 (88.4) | 37 (11.6) | 320 (100.0) | 202 (96.7) | 7 (3.4) | 209 (100.0) | |||
| 11–13 days | 505 (96.0) | 21 (4.0) | 526 (100.0) | 299 (94.6) | 17 (5.4) | 316 (100.0) | 206 (98.1) | 4 (1.9) | 210 (100.0) | |||
| 14 + days | 328 (99.1) | 3 (0.9) | 331 (100.0) | 196 (98.5) | 3 (1.5) | 199 (100.0) | 132 (100.0) | 0 (0.0) | 132 (100.0) | |||
| Duration since admission to the ward | ||||||||||||
| 0–1 day | 134 (93.7) | 9 (6.3) | 143 (100.0) | 0.001* | 77 (91.7) | 7 (8.3) | 84 (100.0) | 0.002* | 57 (96.6) | 2 (3.4) | 59 (100.0) | 0.113 |
| 2–3 days | 292 (91.3) | 28 (8.8) | 320 (100.0) | 171 (89.1) | 21 (10.9) | 192 (100.0) | 121 (94.5) | 7 (5.5) | 128 (100.0) | |||
| 4–7 days | 795 (91.3) | 76 (8.7) | 871 (100.0) | 455 (87.2) | 67 (12.8) | 522 (100.0) | 340 (97.4) | 9 (2.6) | 349 (100.0) | |||
| 8–10 days | 467 (94.7) | 26 (5.3) | 493 (100.0) | 276 (91.7) | 25 (8.3) | 301 (100.0) | 191 (99.5) | 1 (0.5) | 192 (100.0) | |||
| 11–13 days | 329 (96.8) | 11 (3.2) | 340 (100.0) | 201 (96.2) | 8 (3.8) | 209 (100.0) | 128 (97.7) | 3 (2.3) | 131 (100.0) | |||
| 14+ days | 83 (98.8) | 1 (1.2) | 84 (100.0) | 50 (98.0) | 1 (2.0) | 51 (100.0) | 33 (100.0) | 0 (0.0) | 33 (100.0) | |||
| Wearing mask during sampling | ||||||||||||
| Not always | 1685 (93.4) | 120 (6.7) | 1805 (100.0) | 0.819 | 974 (90.4) | 103 (9.6) | 1077 (100.0) | 0.861 | 711 (97.7) | 17 (2.3) | 728 (100.0) | 0.595 |
| Always | 415 (93.1) | 31 (7.0) | 446 (100.0) | 256 (90.8) | 26 (9.2) | 282 (100.0) | 159 (97.0) | 5 (3.1) | 164 (100.0) | |||
| Time since last disinfection | ||||||||||||
| <1h | 264 (93.6) | 18 (6.4) | 282 (100.0) | < 0.001* | 150 (90.9) | 15 (9.1) | 165 (100.0) | 0.055 | 114 (97.4) | 3 (2.6) | 117 (100.0) | < 0.001* |
| 1–3 h | 1115 (94.7) | 62 (5.3) | 1177 (100.0) | 651 (92.0) | 57 (8.1) | 708 (100.0) | 464 (98.9) | 5 (1.1) | 469 (100.0) | |||
| 3–6 h | 478 (91.2) | 46 (8.8) | 524 (100.0) | 276 (87.1) | 41 (12.9) | 317 (100.0) | 202 (97.6) | 5 (2.4) | 207 (100.0) | |||
| 6–12 h | 136 (85.5) | 23 (14.5) | 159 (100.0) | 86 (86.0) | 14 (14.0) | 100 (100.0) | 50 (84.8) | 9 (15.3) | 59 (100.0) | |||
| >12 h | 62 (96.9) | 2 (3.1) | 64 (100.0) | 39 (95.1) | 2 (4.9) | 41 (100.0) | 23 (100.0) | 0 (0.0) | 23 (100.0) | |||
| Number of COVID-19 patients in the same isolation room | ||||||||||||
| 1–2 patients | 384 (95.8) | 17 (4.2) | 401 (100.0) | 0.080 | 230 (94.3) | 14 (5.7) | 244 (100.0) | 0.031* | 154 (98.1) | 3 (1.9) | 157 (100.0) | 0.422 |
| 3 patients | 712 (93.3) | 51 (6.7) | 763 (100.0) | 424 (91.4) | 40 (8.6) | 464 (100.0) | 288 (96.3) | 11 (3.7) | 299 (100.0) | |||
| 4 patients | 995 (92.6) | 80 (7.4) | 1075 (100.0) | 571 (88.8) | 72 (11.2) | 643 (100.0) | 424 (98.2) | 8 (1.9) | 432 (100.0) | |||
| 5 patients | 10 (83.3) | 2 (16.7) | 12 (100.0) | 6 (75.0) | 2 (25.0) | 8 (100.0) | 4 (100.0) | 0 (0.0) | 4 (100.0) | |||
| Number of COVID-19 patients in the same ward | ||||||||||||
| <=10 | 62 (88.6) | 8 (11.4) | 70 (100.0) | 0.153 | 40 (88.9) | 5 (11.1) | 45 (100.0) | 0.772 | 22 (88.0) | 3 (12.0) | 25 (100.0) | 0.005* |
| 11–20 | 1576 (93.8) | 104 (6.2) | 1680 (100.0) | 911 (90.9) | 91 (9.1) | 1002 (100.0) | 665 (98.1) | 13 (1.9) | 678 (100.0) | |||
| 21–30 | 351 (92.4) | 29 (7.6) | 380 (100.0) | 208 (89.7) | 24 (10.3) | 232 (100.0) | 143 (96.6) | 5 (3.4) | 148 (100.0) | |||
| Total | 2107 (93.3) | 151 (6.7) | 2258 (100.0) | 1234 (90.5) | 129 (9.5) | 1363 (100.0) | 873 (97.5) | 22 (2.5) | 895 (100.0) | |||
*
P < 0.05.