Risk and protective factors for SARS-CoV-2 infection among healthcare workers: a test-negative case-control study in Quebec, Canada

OBJECTIVES: In Quebec, Canada, we evaluated the risk of SARS-CoV-2 infection associated with: 1) the demographic and employment characteristics among healthcare workers (HCWs); and 2) the workplace and household exposures and the infection prevention and control (IPC) measures among patient-facing HCWs. DESIGN: Test-negative case-control study. SETTING: Provincial health system. PARTICIPANTS: HCWs with PCR-confirmed COVID-19 diagnosed between November 15, 2020 and May 29, 2021 (cases) were compared to HCWs with compatible symptoms but testing negative during the same period (controls). METHODS: Adjusted odds ratios (aOR) of infection were estimated using regression logistic models evaluating demographic and employment characteristics (all 4919 cases and 4803 controls) or household and workplace exposures and IPC measures (2046 patient-facing cases and 1362 controls). RESULTS: COVID-19 risk was associated with working as housekeeping staff (aOR=3.6), patient support assistants (aOR=1.9) and nursing staff (aOR=1.4) (compared to administrative staff), being unexperienced (aOR=1.5) and working in private seniors' homes (aOR=2.1) and long-term care (aOR=1.5) facilities (compared to acute-care hospitals). Among patient-facing HCWs, exposure to a household contact was reported by 9% of cases and was associated with the highest risk of infection (aOR=7.8). Most infections were likely attributable to the more frequent exposure to infected patients (aOR=2.7) and coworkers (aOR=2.2). Wearing a N95 respirator during contacts with COVID-19 patients (aOR=0.7) and vaccination (aOR=0.2) were the measures associated with a risk reduction. CONCLUSION: In the context of the ever-changing SARS-CoV-2 virus with increasing transmissibility, measures to ensure HCWs' protection, including vaccination and respiratory protection, and patients' safety will need ongoing evaluation.
Auteurs (Zotero)
Carazo, Sara; Villeneuve, Jasmin; Laliberté, Denis; Longtin, Yves; Talbot, Denis; Martin, Richard; Denis, Geoffroy; Ducharme, Francine; Paquet-Bolduc, Bianka; Anctil, Geneviève; Hegg-Deloye, Sandrine; De Serres, Gaston
Date de publication (Zotero)
septembre, 2022