Title: Prevalence and risk factors for SARS-CoV-2 infection and seroprevalence among staff in a national healthcare system

Biography:

Abstract

Introduction:
While many studies have reported the rate and risk of SARS-CoV-2 infection among healthcare workers (HCWs), there are scant data regarding the impact of employment type and job grades on such risk.

Methods:
We determined the rate of SARS-CoV-2 infection based on a positive nasopharyngeal swab (NPS) PCR among employees of a large national healthcare system. Antibody testing was performed on those who agreed to provide a blood sample. Using logistic regression analysis, we determined the risk of infection (PCR+) associated with demographic characteristics, job family and job grade.

Results:
We identified 35,075 staff (30,849 full-time, 4,226 outsourced) between March 1-October 31, 2020. Among full-time employees, 78.0% had an NPS (11.8% positive). Among outsourced staff, 94.4% had an NPS (31.1% positive). Antibody testing was performed on 33.9% of full-time employees (13.0% reactive), and on 39.1% of the outsourced staff (47.0% reactive). PCR-positivity was higher among outsourced staff (31.0% vs. 18.3% in non-clinical and 9.0% in clinical full-time employees) and those in the low-grade vs. mid-grade and high-grade job categories. Male sex (OR 1.88), non-clinical job family (OR 1.21), low-grade job category (OR 3.71), and being an outsourced staff (OR 2.09) were associated with a higher risk of infection.

Conclusion:
HCWs are a diverse population with varying risks of infection. Clinical staff is at a lower risk likely due to increased awareness and infection prevention measures. The risk is higher for those in the lower socioeconomic strata. Infection is more likely to occur in non-healthcare settings than within healthcare facilities.