School settings where transmission may have occurred for 55 cases of school-acquired SARS-CoV-2 infection*
| Exposure setting | No. of cases | No. (%) of cases | ||
|---|---|---|---|---|
| Grades K–7 n = 35 exposure settings | Grades 8–12 n = 17 exposure settings | Staff only n = 7 exposure settings | All grades n = 59 exposure settings | |
| Class | 28 (26 students, 2 staff) | 11 (10 students, 1 staff) | 2 (2 staff) | 41 (69.5) |
| Office, meeting or staff room | 2 (2 staff) | 1 (1 staff) | 3 (3 staff) | 6 (10.2) |
| Socializing at school | 3 (3 students) | 2 (2 students) | 0 | 5 (8.5) |
| Unspecified interaction | 0 | 1 (1 student) | 2 (2 staff) | 3 (5.1) |
| Field trip | 0 | 2 (1 student, 1 staff) | 0 | 2 (3.4) |
| Cohort† | 2 (2 students) | 0 | 0 | 2 (3.4) |
Note: K = kindergarten.
↵* There were multiple potential exposure settings for some cases; an assessment of which within-school exposure setting was most likely responsible for transmission was not included as part of this study.
↵† A cohort is a group of students and staff who remain together throughout a school term, the composition of which is consistent for all activities that occur in schools.