Table 4.
Association between demographic characteristics and anti-SARS-CoV-2 seroprevalence test results, based on a univariate logistic regression model
| Demographic characteristics | Values | Number of individuals (%) | Unadjusted analysis | Age- and sex-adjusted analysis | |||
|---|---|---|---|---|---|---|---|
| Antibody-positive (n = 161) |
Negative controls (n = 162) |
OR | 95% CI | OR | 95% CI | ||
| Sex | Female | 88 (54.7) | 72 (44.4) | 1.51 | 0.97–2.34 | 1.32 | 0.84–2.08 |
| Male | 73 (45.3) | 90 (55.6) | |||||
| Age range† (years) | 18–24 | 26 (16.2) | 17 (10.5) | 2.49 | 1.15–5.42 | 2.29 | 1.04–5.04 |
| 25–39 | 46 (28.6) | 36 (22.2) | 2.08 | 1.09–3.98 | 1.89 | 0.97–3.68 | |
| 40–59 | 62 (38.5) | 65 (40.1) | 1.55 | 0.86–2.81 | 1.46 | 0.80–2.66 | |
| 60+ | 27 (16.8) | 44 (27.2) | Ref. | Ref. | Ref. | Ref. | |
| Close contact‡ with a person diagnosed with COVID-19 | Yes | 34 (21.1) | 6 (3.7) | 6.96 | 2.83–17.09 | 6.12 | 2.46–15.21 |
| No | 127 (78.9) | 156 (96.3) | |||||
| Close contact with a person not diagnosed with COVID-19, but who has had cough or fever | Yes | 42 (26.1) | 16 (9.9) | 3.22 | 1.73–6.02 | 2.84 | 1.51–5.37 |
| No | 119 (73.9) | 146 (90.1) | |||||
| Healthcare worker§ | Yes | 22 (13.7) | 6 (3.7) | 4.12 | 1.62–10.44 | 3.22 | 1.24–8.37 |
| No | 139 (86.7) | 156 (96.3) | |||||
| Area of residence | Montréal-Laval | 87 (54.0) | 59 (36.4) | 2.59 | 1.51–4.45 | 2.2 | 1.25–3.86 |
| Surrounding Montréal-Laval urban areas | 41 (25.5) | 45 (27.8) | 1.6 | 0.88–2.92 | 1.5 | 0.82–2.76 | |
| Other regions | 33 (20.5) | 58 (35.8) | Ref. | Ref. | Ref. | Ref. | |
OR, odds ratio; Ref., reference values
† Only 3 donors were more than 69 years old and all were seronegative
‡ Defined as a contact of more than 15 min within 2 m with no safety protections
§ Defined as any person who works close to ill persons in acute care and chronic care institutions, and first responders; this includes nurses, assistant nurses, physicians, orderlies, and cleaning staff