Table II.
Characteristics associated with baseline severe acute respiratory syndrome coronavirus-2 immunoglobulin G (IgG) seropositivity
| Characteristic (N of responses) | IgG index (S/C) | Pa,b | ||
|---|---|---|---|---|
| <1.4 (N=6430, 93.7%) |
≥1.4 (N=433, 6.3%) |
|||
| Age, years (mean ± SD) (6649) |
43.2 ± 12.9 |
43.3 ± 12.8 |
42.0 ± 13.5 |
0.06 |
| All (%) |
N (%) |
N (%) |
||
| Gender (6811) | ||||
| Female | 5387 (79.1) | 5033 (93.4) | 354 (6.6) | 0.11 |
| Male | 1424 (20.9) | 1347 (94.6) | 77 (5.4) | |
| Race (6481) | <0.001 | |||
| African American | 351 (5.4) | 310 (88.3) | 41 (11.7) | |
| Asian | 365 (5.6) | 340 (93.2) | 25 (6.8) | |
| Caucasian | 5661 (87.3) | 5347 (94.5) | 314 (5.5) | |
| Hawaiian/Pacific Islander | 10 (0.2) | 7 (70.0) | 3 (30.0) | |
| Native American | 15 (0.2) | 12 (80.0) | 3 (20.0) | |
| Multi-racial | 79 (1.2) | 71 (89.9) | 8 (10.1) | |
| Ethnicity (6521) | <0.001 | |||
| Hispanic | 616 (9.4) | 553 (89.8) | 63 (10.2) | |
| Non-Hispanic | 5905 (90.6) | 5557 (94.1) | 348 (5.9) | |
| Prior PCR test (1317) | <0.001 | |||
| Positive | 223 (16.9) | 25 (11.2) | 198 (88.8) | |
| Negative | 1094 (83.1) | 1028 (94.0) | 66 (6.0) | |
| Exposure to patients with COVID-19 (6820) | <0.001 | |||
| Daily or almost daily contact | 2466 (36.2) | 2271 (92.1) | 195 (7.9) | |
| Occasional contact | 2887 (42.3) | 2712 (93.9) | 175 (6.1) | |
| No known contact | 1467 (21.5) | 1407 (95.9) | 60 (4.1) | |
| At least one symptom of COVID-19 (6863) | <0.001 | |||
| Yes | 2614 (38.0) | 2286 (87.5) | 328 (12.5) | |
| No | 4249 (62.0) | 4144 (97.5) | 105 (2.5) | |
| High-risk exposure to a COVID-19-positive patient (6821) | <0.001 | |||
| Yes | 880 (12.9) | 767 (87.2) | 113 (12.8) | |
| No | 5941 (87.1) | 5623 (94.6) | 318 (5.4) | |
| Exposure outside work (6819) | <0.001 | |||
| Yes | 439 (6.4) | 369 (84.1) | 70 (15.9) | |
| No | 6380 (93.6) | 6020 (94.4) | 360 (5.6) | |
| Prior quarantine (6822) | <0.001 | |||
| Yes | 791 (11.6) | 525 (66.4) | 266 (33.6) | |
| No | 6031 (88.4) | 5866 (97.3) | 165 (2.7) | |
| Medical conditions (responses) | condition present | |||
| Obesity (6777) | 1411 (20.8) | 1308 (92.7) | 103 (7.3) | 0.09 |
| Cancer (6749) | 107 (1.6) | 101 (94.4) | 6 (5.6) | 0.74 |
| Diabetes (6758) | 254 (3.8) | 234 (92.1) | 20 (7.9) | 0.31 |
| Pregnancy (women only; 5332) | 134 (2.5) | 126 (94.0) | 8 (6.0) | 0.77 |
| Immunodeficiency (6747) | 61 (0.9) | 59 (96.7) | 2 (3.3) | – |
| Heart disease (6747) | 171 (2.5) | 160 (93.6) | 11 (6.4) | 0.97 |
| Asthma requiring medication (6755) | 592 (8.8) | 557 (94.1) | 35 (5.9) | 0.65 |
| Chronic lung disease (6741) | 35 (0.5) | 34 (97.1) | 1 (2.9) | – |
| Liver disease (6748) | 18 (0.3) | 18 (100.0) | 0 (0.0) | – |
| Haematological disorder (6744) | 60 (0.9) | 58 (96.7) | 2 (3.3) | – |
| Chronic kidney disease (6743) | 21 (0.3) | 20 (95.2) | 1 (4.8) | – |
| Neurological disorder (6732) | 40 (0.6) | 40 (100.0) | 0 (0.0) | – |
| Organ/bone marrow recipient (6717) | 14 (0.2) | 14 (100.0) | 0 (0.0) | – |
| At least one medical condition (6799) | ||||
| Yes | 2242 (33.0) | 2095 (93.4) | 147 (6.6) | 0.61 |
| No | 4557 (67.0) | 4273 (93.8) | 284 (6.2) | |
PCR, polymerase chain reaction; COVID-19, coronavirus disease 2019; S/C, signal/cut-off; SD, standard deviation; –, too few cases for meaningful evaluation.
a
Values in bold denote statistical significance (P<0.05).
b
Age: Student's t-test; all others, Pearson's Chi-squared test.