Occupational Risk Factors for SARS-CoV-2 Seropositivity in Healthcare Workers: Results of a Longitudinal Cohort.

OBJECTIVE: To evaluate COVID-19 risk factors among health care workers (HCWs) prior to vaccine-induced immunity.

METHODS: We conducted a longitudinal cohort study of HCWs (N = 1,233) with SARS-CoV-2 IgG quantification by ELISA and repeated surveys over 9 months. Risk factors were assessed by multivariable-adjusted logistic regression and Cox proportional hazards models.

RESULTS: SARS-CoV-2 IgG was associated with work in internal medicine (OR 2.77, 95% CI 1.05 - 8.26) and role of physician-in-training (OR 2.55, 95% CI 1.08 - 6.43), including interns (OR 4.22, 95% CI 1.20 - 14.00) and resident physicians (OR 3.14, 95% CI 1.24 - 8.33). Odds were lower among staff confident in N95 use (OR 0.55, 95% CI 0.31 - 0.96) and decreased over the follow-up.

CONCLUSIONS: Excess COVID-19 risk observed among physicians-in-training early in the COVID-19 pandemic was reduced with improved occupational health interventions prior to vaccinations.