Table 1.
Sample description and prevalence of anti-SARS-CoV-2 IgG antibodies, SEROCoV-WORK + study, May–September 2020, Geneva, Switzerland.
| N (%) | Seropositive | Relative risk (95% CrI) | |
|---|---|---|---|
| Total | 10513 | 1026 (9.8) | – |
| Women | 5848 (55.6) | 598 (10.2) | 1.00 (ref.) |
| Men | 4665 (44.4) | 428 (9.2) | 0.88 (0.76–1.01) |
| Age group, years | |||
| 18–34 | 2678 (25.5) | 291 (10.9) | 1.00 (ref.) |
| 35–49 | 4524 (43.0) | 467 (10.3) | 0.94 (0.80–1.10) |
| 50–65 | 3311 (31.5) | 268 (8.1) | 0.71 (0.57–0.85) |
| Educational levela | |||
| Mandatory education | 867 (8.3) | 87 (10.0) | 0.75 (0.50–1.07) |
| Apprenticeship | 2216 (21.1) | 175 (9.7) | 0.54 (0.35–0.76) |
| Secondary education | 2098 (20.0) | 194 (9.3) | 0.65 (0.45–0.90) |
| University | 4626 (44.0) | 491 (10.6) | 0.77 (0.56–1.04) |
| Doctorate | 413 (3.9) | 52 (12.6) | 1.00 (ref.) |
| Other | 289 (2.7) | 27 (9.3) | – |
| Activity sectorb | |||
| Healthcare | 1668 (15.9) | 185 (11.1) | 1.00 (ref.) |
| Transportation | 1185 (11.3) | 99 (8.4) | 0.66 (0.31–1.18) |
| Nursing homes | 1102 (10.5) | 157 (14.3) | 1.24 (0.67–2.07) |
| Public administration | 1056 (10.0) | 94 (8.9) | 0.91 (0.41–1.74) |
| Public security | 1055 (10.0) | 83 (7.9) | 0.53 (0.22–0.93) |
| Food industry | 755 (7.2) | 76 (10.1) | 0.92 (0.46–1.67) |
| Homecare | 753 (7.2) | 91 (12.1) | 0.99 (0.33–2.06) |
| Social work | 734 (7.0) | 62 (8.5) | 0.68 (0.27–1.33) |
| Financial services | 528 (5.0) | 65 (12.3) | 1.00 (0.42–1.93) |
| International organizations | 425 (4.0) | 24 (5.7) | 0.47 (0.10–1.40) |
| Early childhood education | 259 (2.5) | 15 (5.8) | 0.37 (0.09–0.84) |
| Pharmacy | 254 (2.4) | 28 (11.0) | 0.86 (0.37–1.58) |
| Construction | 182 (1.7) | 11 (6.0) | 0.53 (0.10–1.52) |
| Media | 166 (1.6) | 7 (4.2) | 0.55 (0.07–2.02) |
| Agriculture | 97 (0.9) | 8 (8.3) | 0.65 (0.13–1.70) |
| Other | 294 (2.8) | 21 (7.1) | 0.54 (0.17–1.08) |
| Confinement statusc | |||
| Mobilized/partially confined | 9430 (89.9) | 899 (9.5) | 1.00 (ref.) |
| Fully confined | 1065 (10.1) | 125 (11.7) | 1.27 (1.03–1.56) |
| Out-of-work exposured | |||
| 0 | 9129 (87.0) | 775 (8.5) | 1.00 (ref.) |
| ≥1 | 1365 (13.0) | 248 (18.2) | 2.29 (1.93–2.74) |
| Smoking | |||
| Non-smoker | 6122 (58.3) | 709 (11.6) | 1.00 (ref.) |
| Ex-smoker | 1664 (15.8) | 143 (8.6) | 0.72 (0.55–0.88) |
| Smoker | 2718 (25.9) | 172 (6.3) | 0.45 (0.30–0.57) |
| BMI group | |||
| 18–24.9 | 5747 (56.1) | 585 (10.2) | 1.00 (ref.) |
| 25–29.9 | 3278 (32.0) | 306 (9.3) | 0.96 (0.81–1.13) |
| ≥30 | 1227 (12.0) | 115 (9.4) | 0.96 (0.75–1.19) |
| Chronic conditionse | |||
| None | 9282 (88.3) | 903 (9.7) | 1.00 (ref.) |
| 1 | 1062 (10.1) | 106 (10.0) | 1.11 (0.87–1.38) |
| ≥2 | 167 (1.6) | 17 (10.2) | 1.19 (0.62–1.89) |
Results are N (%), or as stated. Relative risks (95% credible interval) are from Bayesian logistic regression models, and are adjusted for test performance, age and sex. These pertain to the reference individual (Female, 18–34). 69 participants were excluded due to missing serology or sociodemographic data, or due to being outside target age range of 18–65 years. All data beside serology are self-reported.
aEach category indicates the highest level of education attained by participant; mandatory education indicates 15 years of primary education as the highest obtained degree.
bSee Supplementary Table 1 for details.
cFully confined at home between March and May 2020; otherwise partially confined or fully mobilized at work.
dOut-of-work exposure to confirmed COVID-19 cases.
eChronic conditions: hypertension, diabetes, cardiovascular disease, respiratory disease, cancer.