Baseline characteristics of the study population
| Non-Severe disease No mechanical ventilation | Severe disease Mechanical Ventilation necessary | p-Value | ||
| n=92 | n=51 (55.4%) | n=41 (44.6%) | ||
| Age, mean±sd | 60.2±15.8 | 57.9±18.1 | 63.1±12.7 | 0.258 |
| Male, n (%) | 71 (77.3%) | 36 (70.6%) | 34 (82.9%) | 0.22 |
| Continuous oxygen insufflation, n (%) | 61 (66.3%) | 21 (41.2%) | 41 (100%) | <0.001 |
| Admission to ICU, n (%) | 47 (51.1%) | 9 (17.6%) | 41 (100%) | <0.001 |
| Days of mechanical ventilation±sd | n.a. | 22.6±14.1 | n.a. | |
| Days of hospitalisation±sd | 18.5±13.4 | 13.1±7.8 | 25.3±15.6 | <0.001 |
| Use of ECMO, n (%) | 5 (5.4%) | n.a. | 5 (12.2%) | n.a. |
| Days of ECMO use | n.a. | 13.6±3.8 | n.a. | |
| ECMO mortality, n (%) | n.a. | 3 (60%) | n.a. | |
| Discharge, n (%) | 66 (72.5%) | 45 (88.2%) | 21 (47.2%) | <0.001 |
| Fatal, n (%) | 7 (7.6%) | 0 (0.0%) | 7 (17.9%) | 0.003 |
| Presence of COVID-19 typical radiological changes, n (%) | 85 (92.4%) | 44 (86.3%) | 41 (100%) | 0.013 |
| Initial viral load in nose swabs (copies·mL−1)±sd | 12.8×106±41.1×106 | 12.6×106±43.1×106 | 13.0×106±39.9×106 | 0.127 |
| Initial viral load in endotracheal aspirate (copies·mL−1)±sd | n.a. | 67.2×106±273×106 | n.a. | |
| Duration of viral shedding in days (with twice confirmed negativity)±sd | 18.7±12.0 | 13.9±9.5 (n=16) | 25.8±11.8 (n=18) | 0.025 |
| Persistent viral shedding (≥17 days), n (%) | 44 (47.8%) | 14 (27.5%) | 30 (73.2%) | <0.001 |
| Time to first testing in days±sd | 7.4±4.7 | 6.5±4.0 | 8.4±5.3 | 0.12 |
| Comorbidities n (%) | ||||
| Arterial hypertension | 48 (52.2%) | 24 (47.1%) | 24 (58.5%) | 0.30 |
| Diabetes mellitus Type 2 | 18 (19.6%) | 8 (15.7%) | 10 (24.4%) | 0.43 |
| Coronary artery disease | 15 (16.3%) | 9 (17.6%) | 6 (14.6%) | 0.78 |
| COPD | 11 (12.0%) | 4 (7.8%) | 7 (17.1%) | 0.21 |
| Immunosuppression | 22 (23.9%) | 13 (25.5%) | 9 (22.0%) | 0.81 |
| Charlson comorbidity index±sd | 2.5±1.8 | 2.5±1.9 | 2.6±1.7 | 0.62 |
Data are mean (sd) or n (%). p values were calculated by Mann-Whitney U test or χ² test, as appropriate. Severe disease was defined by the need of mechanical ventilation. COVID-19 typical changes included either ground glass opacities or diffuse bilateral infiltrates. Duration of nasopharyngeal viral shedding was defined by the time between symptom begin and last positivity for viral shedding in standardized nose swabs or endotracheal aspirates.