Table 2.
Distribution and strength of association as odds ratios (OR) with 95% confidence interval (95% CI) of various variables with detectable SARS-CoV-2 IgG antibodies.
| Variables | Serological Test | OR (95% CI) | p Value | |
|---|---|---|---|---|
| Positive Ab (n = 433) | Negative Ab (n = 1460) | |||
| Age, mean (std) | 45 (11) | 44 (11) | 0.013 c | |
| Female, n (%) | 330 (76.2) | 1129 (77.3) | 0,9 (0.7;1.2) | 0.6 d |
| Working in a COVID-19 unit/ER, n (%) | 234 (54) | 774 (53) | 1.04 (0.8; 1.3) | 0.7 d |
| Comorbidities, n (%) | 141 (32.6) | 472 (32.3) | 1 (0.8; 1.3) | 0.9 d |
| Pregnancy, n (%) | 7 (1.6) | 15 (1) | 1.6 (0.6; 3.9) | 0.3 d |
| Underlying immunosuppression, n (%) | 12 (2.8) | 33 (2.3) | 1.2 (0.6; 2.4) | 0.6 d |
| Chronic steroid therapy, n (%) | 4 (0.9) | 18 (1.2) | 0.7 (0.2; 2.2) | 0.8 d |
| Other immunosuppressive therapy, n (%) | 7 (1.6) | 14 (1) | 1.7 (0.7; 4.2) | 0.3 d |
| COVID-19 compatible signs/symptoms, n (%) | 377 (87) | 545 (37.3) | 11.3 (8.4; 15.2) | <0.0001 d |
| Duration of signs and symptoms (in days), mean (std) | 25 (24) | 20 (21) | 0.001 c | |
| Delay time between signs and symptoms onset and serology test (in days), mean (std) | 48 (14) | 49 (18) | 0.3 c | |
| Previously diagnosed with positive SARS-CoV-2 RT-PCR a, n (%) | 248 (61) | 42 (4.7) | 10.1 (6.7; 15.2) | <0.0001 d |
| Radiologic evidence of viral pneumonia b, n (%) | 46 (12.2) | 2 (0.37) | 37.7 (9; 156.4) | <0.0001 d |
| Oxygen therapy b, n (%) | 17 (4.5) | 1 (0.2) | 25 (3.4; 193) | <0.0001 d |
| Hydroxychloroquine treatment, n (%) | 63 (14.5) | 23 (1.6) | 10.6 (6.5; 17.4) | <0.0001 d |
| Close contact with confirmed COVID-19 case, n (%) | 284 (65.6) | 814 (55.7) | 1.5 (1.2; 1.9) | <0.0001 d |
| Close contact with suspected COVID-19 case, n (%) | 231 (53.4) | 505 (34.6) | 2.2 (1.7; 2.7) | <0.0001 d |
a 1294 SARS-CoV-2 rt-PCR performed: 887 IgG negative, 407 IgG positive b among the 922 symptomatic subjects (545 IgG negative, 377 IgG positive). c Mann–Whitney test. d Chi-squared test.