SARS-CoV-2 infection following home, community and work-related exposures: a prospective cohort of teachers and education workers in Ontario, Canada, 2021–2023
Bibliographic record
Abstract
OBJECTIVES: To determine the association between rates of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection following home, community and work-related exposures, to assess real-world relative vaccine effectiveness, and to determine whether anti-receptor-binding domain (RBD) IgG levels were associated with the rates of subsequent infection. DESIGN: Prospective cohort of 34 months' duration (February 2021 to December 2023). SETTING: Teachers and education workers working ≥8 hours per week in the Canadian province of Ontario. PARTICIPANTS: 3155 education workers were eligible for the risk factor analysis; 2977 for the serological analysis. OUTCOME MEASURE: Rate of SARS-CoV-2 infection. RESULTS: 1909 SARS-CoV-2 infections were reported (0.93 per 1000 participant-days); the highest incidence occurred during the period dominated by the Omicron BA.2 variant (2.01 per 1000 participant-days). Rates of infection were significantly higher following the repeal of the mask mandate. Compared with participants without known contact with an infected person, those in close contact with infected adult or child household members (adjusted HR (aHR) 1.43; 95% CI 1.24 to 1.65 and 1.39; 95% CI 1.17 to 1.65, respectively), coworkers (aHR 1.28; 95% CI 1.10 to 1.50), or individuals from more than one setting (aHR 1.44; 95% CI 1.27 to 1.64) had higher rates of infection. Participants with three or more doses of vaccine were 79%-87% less likely to develop SARS-CoV-2 than participants who had two or fewer vaccine doses. Blood samples with anti-RBD antibody levels in the highest quintile (≥5850 binding antibody unit/mL) were associated with a lower rate of subsequent infection (aHR 0.40; 95% CI 0.23 to 0.72) compared with samples with RBD levels below the threshold of detection. CONCLUSIONS: Risk of SARS-CoV-2 infection in education workers occurred at home as well as the workplace, indicating the need to practise multiple intervention strategies whenever the potential for transmission of respiratory diseases is high. COVID-19 vaccines provided protection through December 2023.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".