SARS-CoV-2 exposures of healthcare workers from primary care, long-term care facilities and hospitals: a nationwide matched case-control study

OBJECTIVES: This study assessed the roles of various exposures and personal protective equipment (PPE) use on healthcare workers' (HCWs) risk of COVID-19 working in primary care, long-term-care facilities or hospitals. METHODS: We conducted a matched case-control (1:1) study (10 April through 9 July 2021). Cases (HCWs with confirmed COVID-19) and controls (HCWs without any COVID-19-positive test or symptoms) were invited by E-mail to complete an online questionnaire on their exposures and PPE use over the 10-day period preceding inclusion. Risk factors were analysed using multivariable conditional logistic regression. RESULTS: A total of 2076 cases and 2076 matched controls were included. The analysis retained exposure to an infected person outside work (adjusted OR 19.9 (95% CI, 12.4–31.9)), an infected colleague (OR 2.26 (95% CI, 1.53–3.33)) or COVID-19 patients (OR 2.37 (95% CI, 1.66–3.40)), as independent predictors of COVID-19 in HCWs, while partial (OR 0.30 (95% CI, 0.22–0.40)) or complete (OR 0.19 (95% CI, 0.14–0.27)) immunisation was protective. Eye protection (OR 0.57 (95% CI, 0.37–0.87)) and wearing a gown (OR 0.58 (95% CI, 0.34–0.97)) for COVID-19 patient care were protective, while wearing an apron slightly increased the risk of infection (OR 1.47 (95% CI, 1.00–2.18)). Protection of N95 respirators and surgical face masks did not differ. Compared to medical professions, being a nurse (OR 3.79 (95% CI, 2.50–5.76)) or a nurse's aide (OR 9.08 (95% CI, 5.30–15.5)) was associated with COVID-19. Results were consistent across all healthcare settings. DISCUSSION: HCWs were more likely to get COVID-19 in their personal sphere than during occupational activities. Our results suggest that eye protection for HCWs during patient care should be actively promoted.