Table 1.
Characteristics of study participants by baseline cohort allocation and follow-up.
| All participant (N = 1644) | Baseline | Follow-up | |||
|---|---|---|---|---|---|
| Negative cohort (N = 1080) | Positive cohort (N = 750) | Negative cohorta (N = 277) | Positive cohortb (N = 38) | ||
| Gender | |||||
| Male | 940 (57.2%) | 609 (56.4%) | 446 (59.4%) | 167 (60.3%) | 27 (71.1%) |
| Female | 704 (42.8%) | 471 (43.6%) | 304 (40.6%) | 110 (39.7%) | 11 (28.9%) |
| Age (year) | |||||
| Mean | 38.4 | 38.3 | 39.1 | 40.5 | 40.2 |
| Median (Std. deviation) | 37.0 (10.2) | 37.0 (10.4) | 38.0 (9.9) | 40.0 (9.9) | 38.0 (10.7) |
| IQR | 30.0–45.8 | 30.0–45.0 | 31.0–46.7 | 32.0–48.0 | 30.7–50.3 |
| Cause for testing | |||||
| Influenza like illness | 587 (54.4%) | 607 (80.8%) | 203 (73.3%) | 32 (84.2%) | |
| Contact with COVID-19 case | 112 (10.4%) | 79 (10.7%) | 38 (13.7%) | 6 (15.8%) | |
| Asymptomatic periodic test | 381 (35.2%) | 64 (8.5%) | 36 (13.0%) | – | |
| Symptomsc | |||||
| Fever | 358 (33.1%) | 466 (62.1%) | 180 (64.9%) | 29 (76.3%) | |
| Cough | 383 (35.4%) | 328 (43.7%) | 130 (46.9%) | 21 (55.3%) | |
| Short of breath | 44 (4.1%) | 25 (3.3%) | 13 (4.7%) | 2 (5.3%) | |
| Sore throat | 77 (7.1%) | 39 (5.2%) | 11 (4.0%) | 3 (7.9%) | |
| Other symptom | 44 (4.1%) | 49 (6.5%) | 22 (7.9%) | 5 (13.2%) | |
| Day intervalsd | |||||
| Mean (Std. error of mean) | 173.6 (7.7) | 195.6 (19.4) | |||
| Median (Std. deviation) | 138.0 (128.0) | 156.5 (119.5) | |||
| IQR | 68–257 | 93.5–287.8 | |||
| Minimum | 1 | 47 | |||
| Maximum | 566 | 460 | |||
aFirst infections.
bReinfections.
cSymptomatic case.
dDuring follow-up.