Table 3.
Association between seroconversion and duration of IgG and IgM antibodies against SARS-CoV-2
| Generalized log-rank test | Proportional hazards models¶ | |||
|---|---|---|---|---|
| Time interval#, Median (IQR) |
P value | Hazard ratio (95%CI) | P value | |
| IgG seroconversion | ||||
| Abroad imported case: yes | 27 (19,35) | 0.016* | 6.331 (1.56–26.63) | 0.010* |
| No | 61 (58,82.5) | |||
| Fever: yes | 60 (53,77) | 0.075 | 0.450 (0.204–0.993) | 0.048* |
| No | 27.5 (20.5,54.5) | |||
| IgM seroconversion | ||||
| Abroad imported case: yes | 26.5 (21.5,33) | 0.001** | 5.152 (1.936–13.711) | 0.001** |
| No | 61 (58,90) | |||
| Involved in a cluster: yes | 61 (59,150) | 0.008** | 0.365 (0.180–0.743) | 0.005** |
| No | 42 (26,62) | |||
| Any symptom: yes | 59.5 (32,89) | 0.039* | 0.368 (0.161–0.842) | 0.018* |
| No | 27.5 (22,53) | |||
| Pneumonia: yes | 60 (30,90) | 0.015* | 0.477 (0.261–0.873) | 0.016* |
| No | 53 (26,62) | |||
| IgM duration# | ||||
| Age: ≥ 40 years | 89 (30,122) | 0.004** | 0.074 (0.012–0.442) | 0.004** |
| < 40 years | 6 (5,6.5) | |||
Each serological result of patients was regarded as interval censored
*P < 0.05; **P < 0.01
¶Only statistically significant results are shown in the table
#Time interval for seroconversion means the interval from illness onset to first positive test for antibody. Time interval for duration means the interval from first to last positive antibody test