TABLE 3.
Comparison of clinical characteristics and laboratory results between patients >50 and ≤50 years old.
| Age > 50 (n = 71) | Age ≤ 50 (n = 109) | P-value | |
| Male, n (%) | 47 (66.2) | 66 (60.6) | 0.528 |
| With underlying disease, n (%) | 35 (49.3) | 18 (16.5) | <0.001 |
| Symptomatic at initial onset, n (%) | 42 (59.2) | 76 (69.7) | 0.152 |
| Symptomatic at re-positive, n (%) | 28 (39.4) | 36 (33) | 0.427 |
| Total disease duration (days) | 35 (31, 42) | 35 (28, 43) | 0.735 |
| Vaccinated, n (%) | 49 (69) | 94 (86.2) | 0.008 |
| COVNAT negative to re-positive duration, IQR (days) | 11 (8, 18) | 13 (9, 18) | 0.412 |
| Initial onset to COVNAT negative duration, IQR (days) | 13 (7, 17) | 11 (8, 16) | 0.986 |
| Re-positive to COVNAT negative duration, IQR (days) | 7 (3, 12) | 5 (3, 10) | 0.107 |
| CoV O gene levels at re-positive time, mean ± SD (Ct) | 32.3 ± 4.7 | 32.5 ± 4.5 | 0.796 |
| CoV N gene levels at re-positive time, mean ± SD (Ct) | 31.2 ± 4.7 | 31.4 ± 4.3 | 0.841 |
| Lowest CoV O gene levels during re-positive period, mean ± SD (Ct) | 27.6 ± 5.4 | 29.7 ± 5.3 | 0.015 |
| Lowest CoV N gene levels during re-positive period, mean ± SD (Ct) | 26.2 ± 4.9 | 28.5 ± 5.2 | 0.004 |
| Anti-CoV IgG levels at re-positive time, IQR (AU/ml) | 30.6 (1.15, 98) | 78 (26, 158) | <0.001 |
| Patient with elevated anti-CoV IgG, n (%) | 56 (78.9) | 104 (95.4) | 0.001 |
| Anti-CoV IgM levels at re-positive time, IQR (AU/ml) | 0 (0, 0.43) | 0 (0, 0.45) | 0.984 |
| Patient with elevated anti-CoV IgM, n (%) | 9 (12.7) | 15 (13.8) | 1 |
CoV, coronavirus; COVID-19, coronavirus disease 2019; COVNAT, coronavirus nucleic acid test. Differences in continuous variables were analyzed using independent sample T-test or Mann–Whitney U test. Differences in categorical variables were calculated using Fisher’s exact or the Chi-square test as appropriate. P-values indicate differences between mild case and asymptomatic case groups. P < 0.05 was considered statistically significant.