Seroprevalence among school staff in the EnCORE Study in March–October 2021, by participant characteristics
| Number seropositive per group | Seroprevalence 95% CI (%) | ||
| Overall | 30/362 | 8.3 (5.8 to 11.6) | |
| School level | Daycare | 10/109 | 9.2 (4.9 to 16.2) |
| Elementary school | 16/130 | 12.3 (7.6 to 19.2) | |
| High school | 4/123 | 3.3 (1.0 to 8.3) | |
| Age group | <40 years | 9/130 | 6.9 (3.5 to 12.8) |
| 40–50 years | 9/105 | 8.6 (4.4 to 15.7) | |
| 50+years | 12/125 | 9.6 (5.4 to 16.2) | |
| Sex at birth | Male | 3/40 | 7.5 (1.9 to 20.6) |
| Female | 27/322 | 8.4 (5.8 to 12.0) | |
| Ethnic or racial minority | White | 27/346 | 7.8 (5.4 to 11.2) |
| Other | 3/14 | 21.4 (6.8 to 48.3) | |
| Number classes taught | 1–2 | 11/126 | 8.7 (4.8 to 15.1) |
| 3–4 | 10/120 | 8.3 (4.4 to 14.8) | |
| Not applicable | 9/116 | 7.8 (4.0,14.3) | |
| Bedroom density | <1 persons per bedroom | 11/110 | 10.0 (5.5 to 17.2) |
| ≥1 persons per bedroom | 19/252 | 7.5 (4.8 to 11.5) | |
| Household income | <100 000$ CAD* | 16/158 | 10.1 (6.2 to 15.9) |
| ≥100 000$ CAD | 9/161 | 5.6 (2.8 to 10.4) | |
| Education level | No university | 10/112 | 8.9 (4.8 to 15.8) |
| University degree | 20/248 | 8.1 (5.2 to 12.2) | |
| Vaccinated with at least one dose | No | 10/105 | 9.5 (5.1 to 16.8) |
| Yes | 20/257 | 7.8 (5.0 to 11.8) | |
| School area | HOMA | 2/38 | 5.3 (0.5 to 18.2) |
| Montreal North | 14/176 | 8.0 (4.7 to 13.0) | |
| Plateau Mont Royal | 7/53 | 13.2 (6.2 to 25.2) | |
| West Island | 7/95 | 7.4 (3.4 to 14.7) | |
| Contact with students that do not usually physically distance | Yes | 28/271 | 10.3 (7.2 to 14.6) |
| No | 2/91 | 2.2 (0.1 to 8.1) | |
| Contact with students that do not usually wear a mask | Yes | 10/124 | 8.1 (4.3 to 14.4) |
| No | 20/238 | 8.4 (5.4 to 12.7) | |
| DBS collected before 23 May 2021 | Yes | 14/179 | 7.8 (4.6 to 12.8) |
| No | 16/183 | 8.7 (5.4 to 13.8) |
*$ CAD: Canadian dollars
DBS, dried blood spot.