Table 1.
Association of demographic, community, and occupational risk factors with seropositivity in unadjusted and adjusted analyses (n=9,610).
| Factor | Total sample N (%) | Seropositive N (%) | Unadjusted OR (95% CI) | Adjusted (unweighted)a OR (95% CI) | Adjusted (weighted, to adjust for participation)b OR (95% CI) |
|---|---|---|---|---|---|
| Demographic and community factors | |||||
| Age group | |||||
| 60+ | 1153 (12.0) | 57 (4.9) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) |
| 50–59 | 1805 (18.8) | 93 (5.2) | 1.0 (0.7, 1.5) | 0.9 (0.7, 1.3) | 1.0 (0.7, 1.4) |
| 40–49 | 2118 (22.0) | 125 (5.9) | 1.2 (0.9, 1.7) | 1.1 (0.8, 1.5) | 1.0 (0.7, 1.4) |
| 30–39 | 2953 (30.7) | 171 (5.8) | 1.2 (0.9, 1.6) | 1.1 (0.8, 1.6) | 1.1 (0.8, 1.5) |
| <30 | 1581 (16.5) | 109 (6.9) | 1.4 (1.0, 2.0) | 1.4 (1.0, 2.0) | 1.3 (0.9, 1.8) |
| Race | |||||
| White | 5263 (54.8) | 226 (4.3) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) |
| Black | 2860 (29.8) | 238 (8.3) | 2.0 (1.7, 2.4) | 2.0 (1.6, 2.5) | 2.0 (1.6, 2.4) |
| Asian | 1133 (11.8) | 60 (5.3) | 1.2 (0.9, 1.7) | 1.2 (0.9, 1.6) | 1.1 (0.8, 1.5) |
| Multiracial | 132 (1.4) | 10 (7.6) | 1.8 (0.9, 3.4) | 1.8 (0.9, 3.3) | 1.7 (0.8, 3.4) |
| American Indian/Alaska Native | 33 (0.3) | --d | 1.4 (0.2, 4.8) | 1.6 (0.3, 5.5) | 1.1 (0.3, 4.9) |
| Native Hawaiian/Pacific Islander | 16 (0.2) | --d | --e | --e | --e |
| Not specified | 173 (1.8) | 19 (11.0) | 2.7 (1.6, 4.4) | 2.8 (1.6, 4.7) | 3.0 (1.8, 5.2) |
| Ethnicity | |||||
| Non-Hispanic | 9206 (95.8) | 534 (5.8) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) |
| Hispanic | 404 (4.2) | 21 (5.2) | 0.9 (0.6, 1.4) | 0.8 (0.5, 1.2) | 0.7 (0.4, 1.1) |
| Community contact with confirmed/suspected positive individual(s) | |||||
| No | 8862 (92.2) | 478 (5.4) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) |
| Yes | 748 (7.8) | 77 (10.3) | 2.0 (1.6, 2.6) | 1.7 (1.3, 2.2) | 1.9 (1.4, 2.5) |
| Residential COVID-19 incidencec | 1.70 (mean) | 1.72 (mean) | 1.4 (1.0, 1.9) | 1.2 (0.9, 1.7) | 1.4 (1.0, 2.0) |
| Occupational factors | |||||
| Caring for COVID-19 positive patient(s) | |||||
| No | 6049 (62.9) | 332 (5.5) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) |
| Yes | 3561 (37.1) | 223 (6.3) | 1.2 (1.0, 1.4) | 0.9 (0.7, 1.2) | 0.9 (0.7, 1.3) |
| Caring for patient(s) found to be COVID-19 positive while not on isolation precautions | |||||
| No | 7893 (82.1) | 437 (5.5) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) |
| Yes | 1717 (17.9) | 118 (6.9) | 1.3 (1.0, 1.5) | 1.1 (0.8, 1.4) | 1.1 (0.8, 1.5) |
| Contact with other healthcare worker found to be COVID-19 positive | |||||
| No | 7878 (82.0) | 421 (5.3) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) |
| Yes | 1732 (18.0) | 134 (7.7) | 1.5 (1.2, 1.8) | 1.4 (1.1, 1.7) | 1.2 (1.0, 1.6) |
| Workplace location | |||||
| No patient contact | 941 (9.8) | 43 (4.6) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) |
| Work from home | 267 (2.8) | 13 (4.9) | 1.1 (0.5, 2.0) | 1.0 (0.5, 1.9) | 1.0 (0.5, 1.9) |
| Other hospital area | 926 (9.6) | 52 (5.6) | 1.2 (0.8, 1.9) | 1.2 (0.8, 1.8) | 1.2 (0.8, 1.9) |
| OR/procedure | 672 (7.0) | 38 (5.7) | 1.3 (0.8, 2.0) | 1.2 (0.7, 1.9) | 1.0 (0.6, 1.7) |
| Outpatient clinical | 1675 (17.4) | 90 (5.4) | 1.2 (0.8, 1.7) | 1.2 (0.8, 1.8) | 1.3 (0.8, 2.0) |
| Inpatient not COVID-19 focused | 1594 (16.6) | 93 (5.8) | 1.3 (0.9, 1.9) | 1.4 (0.9, 2.1) | 1.3 (0.8, 2.1) |
| COVID-19 focused | 1750 (18.2) | 117 (6.7) | 1.5 (1.1, 2.2) | 1.5 (1.0, 2.2) | 1.5 (0.9, 2.4) |
| Emergency department | 1007 (10.5) | 67 (6.7) | 1.5 (1.0, 2.2) | 1.4 (0.9, 2.2) | 1.4 (0.9, 2.4) |
| Not specified | 778 (8.1) | 42 (5.4) | 1.2 (0.8, 1.8) | 1.2 (0.8, 1.9) | 1.1 (0.7, 1.9) |
| Workplace role | |||||
| Other with no patient contact | 1812 (18.9) | 100 (5.5) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) |
| Nurse | 2976 (31.0) | 177 (5.9) | 1.1 (0.8, 1.4) | 1.0 (0.7, 1.3) | 1.0 (0.7, 1.4) |
| Physician | 1753 (18.2) | 87 (5.0) | 0.9 (0.7, 1.2) | 1.0 (0.7, 1.4) | 1.1 (0.7, 1.6) |
| Other direct care provider | 1423 (14.8) | 88 (6.2) | 1.1 (0.8, 1.5) | 1.0 (0.7, 1.4) | 1.0 (0.7, 1.4) |
| Advanced practice provider | 698 (7.3) | 36 (5.2) | 0.9 (0.6, 1.4) | 0.9 (0.6, 1.4) | 0.9 (0.5, 1.4) |
| Nurse technician | 346 (3.6) | 28 (8.1) | 1.5 (1.0, 2.3) | 0.9 (0.6, 1.5) | 0.9 (0.6, 1.6) |
| Radiology technician | 302 (3.1) | 21 (7.0) | 1.3 (0.8, 2.0) | 1.1 (0.7, 1.9) | 1.2 (0.7, 2.2) |
| Respiratory therapist | 114 (1.2) | --d | 1.0 (0.4, 2.0) | 0.7 (0.3, 1.6) | 0.9 (0.3, 2.4) |
| Environmental services | 35 (0.4) | --d | 1.6 (0.4, 4.6) | 1.1 (0.3, 3.3) | 0.9 (0.3, 3.2) |
| Not specified | 151 (1.6) | --d | 1.1 (0.5, 2.1) | 0.9 (0.4, 1.8) | 1.0 (0.5, 2.3) |
| Personal protective equipment use | |||||
| As recommended | 6320 (65.8) | 370 (5.9) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) |
| Not as recommended | 221 (2.3) | 14 (6.3) | 1.1 (0.6, 1.8) | 0.9 (0.5, 1.6) | 1.1 (0.6, 2.0) |
| Unsure | 546 (5.7) | 22 (4.0) | 0.7 (0.4, 1.0) | 0.6 (0.4, 1.0) | 0.7 (0.4, 1.2) |
| Not specified | 2523 (26.3) | 149 (5.9) | 1.0 (0.8, 1.2) | 1.1 (0.9, 1.4) | 1.1 (0.9, 1.5) |
a
Adjusted for all other factors shown in table.
b
Adjusted for all other factors shown in table and accounting for participation bias using inverse probability of participation weighting for age group, race, and sex.
c
The base-10 logarithm of cumulative COVID-19 incidence in a participant’s zip code two weeks prior to the date they were tested.
OR: odds ratio; CI: confidence interval, ref: reference group
d
Data suppressed because N < 10
e
Odds ratio suppressed due to small sample size