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

Research Authors
Moza Alishaq, Andrew Jeremijenko, Zeina Al-Kanaani, Hanaa Nafady-Hego, Diana H Jboor, Rosaline Saba, Jameela Al-Ajmi, Nasser Asad Alansari, Anil George Thomas, Sameera Bihi Fareh, Suni Vinoy, Maryam Nooh, Nadya Alanzi, Abdul-Badi Abou-Samra, Adeel Ajwad B
Research Date
Research Journal
Plos one
Research Publisher
Public Library of Science
Research Year
2021
Research Abstract

Background 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 upon 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 a NPS (11.8% positive). Among outsourced staff, 94.4% had a NPS (31.1% positive). Antibody testing was performed on 33.9% 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 risk of infection. Clinical staff are at a lower risk likely due to increased awareness and infection prevention measures. Risk is higher for those in the lower socioeconomic strata. Infection is more likely to occur in non-healthcare setting than