SARS-CoV-2 seroprevalence among Vancouver public school staff in British Columbia, Canada: a cross-sectional study. Issue 4 (5th April 2022)

• Record Type: Journal Article
• Authors: Goldfarb, David M; Mâsse, Louise C; Watts, Allison W; Hutchison, Sarah M; Muttucomaroe, Lauren; Bosman, Else S; Barakauskas, Vilte E; Choi, Alexandra; Dhillon, Nalin; Irvine, Michael A; Reicherz, Frederic; O'Reilly, Collette; Sediqi, Sadaf; Xu, Rui Yang; Razzaghian, Hamid R; Sadarangani, Manish; Coombs, Daniel; O'Brien, Sheila F; Lavoie, Pascal M
• Is Part Of: BMJ open. Volume 12:Issue 4(2022)
• Publication Date: 2022-04-05
• Subjects: COVID-19 -- public health -- paediatrics -- epidemiology; Medicine -- Research -- Periodicals; 610.72
• DOI: 10.1136/bmjopen-2021-057846
• Languages: English
• ISSNs: 2044-6055

Abstract

Abstract : Objectives: Few studies reported COVID-19 cases in schools during the 2020/21 academic year in a setting of uninterrupted in-person schooling. The main objective was to determine the SARS-CoV-2 seroprevalence among school staff in Vancouver public schools. Design: Cumulative incident COVID-19 cases among all students and school staff based on public health data, with an embedded cross-sectional serosurvey among a school staff sample that was compared to period, age, sex and geographical location-weighted data from blood donors. Setting: Vancouver School District (British Columbia, Canada) from kindergarten to grade 12. Participants: Active school staff enrolled from 3 February to 23 April 2021 with serology testing from 10 February to 15 May 2021. Main outcome measures: SARS-CoV-2 seroprevalence among school staff, based on spike (S)-based (unvaccinated staff) or N-based serology testing (vaccinated staff). Results: Public health data showed the cumulative incidence of COVID-19 among students attending in-person was 9.8 per 1000 students (n=47 280), and 13 per 1000 among school staff (n=7071). In a representative sample of 1689 school staff, 78.2% had classroom responsibilities, and spent a median of 17.6 hours in class per week (IQR: 5.0–25 hours). Although 21.5% (363/1686) of surveyed staff self-reported close contact with a COVID-19 case outside of their household (16.5% contacts were school-based), 5 cases likely acquired the infection at school based on viral testing. Sensitivity/Specificity-adjusted seroprevalence in 1556/1689 staff (92.1%) was 2.3% (95% CI: 1.6% to 3.2%), comparable to a sex, age, date and residency area-weighted seroprevalence of 2.6% (95% CI: 2.2% to 3.1%) among 5417 blood donors. Conclusion: Seroprevalence among staff was comparable to a reference group of blood donors from the same community. These data show that in-person schooling could be safely maintained during the 2020/21 school year with mitigation measures, in a large school district in Vancouver, Canada.