Table I.
Proportions of SARS-CoV-2 anti-RBD IgM-, IgA-, and IgG-positive and -negative subjects
| Antibody | Result | No. (%) or n/N (%) | Antibody titer (AU/mL), median (IQR) |
|---|---|---|---|
| Anti-RBD | Positive | 277 (28.4) | NA |
| Negative | 700 (71.6) | ||
| Anti-RBD IgM | Positive | 116 (11.8) | 21.7 (14.5-568.4) |
| Negative | 864 (88.2) | 3.1 (0.0-14.4) | |
| Anti-RBD IgA | Positive | 67 (6.8) | 5.3 (2.7-429.4) |
| Negative | 913 (93.2) | 0.0 (0.0-2.6) | |
| Anti-RBD IgG | Positive | 219 (22.4) | 60.3 (25.9-1407.4) |
| Negative | 758 (77.6) | 3.7 (0.0-24.8) | |
| IgG+IgM+IgA+ | Positive/total | 24/277 (8.7) | NA |
| IgG+IgM+IgA− | Positive/total | 39/277 (14.1) | NA |
| IgG+IgM−IgA+ | Positive/total | 36/277 (13.0) | NA |
| IgG−IgM+IgA+ | Positive/total | 2/277 (0.7) | NA |
| IgG−IgM+IgA− | Positive/total | 51/277 (18.4) | NA |
| IgG−IgM−IgA+ | Positive/total | 5/277 (1.8) | NA |
| IgG+IgM−IgA− | Positive/total | 120/277 (43.3) | NA |
IQR, Interquartile range; NA, not applicable.