This is a summary, written by members of the CITF Secretariat, of

Watts AW, Mâsse LC, Goldfarb DM, Irvine MA, Hutchison SM, Muttucomaroe L, et al. SARS-CoV-2 cross-sectional seroprevalence study among public school staff in Metro Vancouver after the first Omicron wave in British Columbia, Canada. BMJ Open. 2023;13(6):e071228. doi:

The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.

A CITF-funded study, published in BMJ Open, found that despite frequent COVID-19 exposures, SARS-CoV-2 seroprevalence among school staff in the Vancouver area remained no greater than in the community reference group. Results are consistent with the premise that many infections among school-based employees were acquired outside the school setting, even during Omicron. Researchers do acknowledge that the school staff who participated may not have been randomly selected, potentially contributing to selection bias. The study was led by Dr. Pascal Lavoie and Louise Mâsse (University of British Columbia), in collaboration with Dr. Sheila O’Brien (Canadian Blood Services).

Key findings:

  • Of the 1850 school staff enrolled, 65.8% (1245/1854) reported close contact with a COVID-19 case outside their household. About half of these close contacts were at school, either a student (51.5%) or co-worker (54.9%).
  • In a representative sample of 1620 school staff who completed serology testing, the adjusted infection-acquired seroprevalenceAdjustments considered the sensitivity and specificity of the serology test and regional variation. was 26.5%, compared to 32.4% among 7164 blood donors.

Samples were collected from January 27 to April 8, 2022. Seroprevalence estimates were compared to data obtained from blood donors from January 1 to March 31 weighted according to a proportionally identical age, sex, sampling month, and first two postal code digits distribution as the school sample.