Prevalence of SARS-CoV-2 Infection Among Health Care Workers in a Tertiary Community Hospital

New York City and its surrounding metro area have emerged as an epicenter of the coronavirus disease 2019 (COVID-19) outbreak worldwide. A recent population survey¹ for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies among those in New York state shows a prevalence of 21.2% in New York City and 16.7% in Long Island. Across the US, up to 11% of reported COVID-19 cases were found to be in health care professionals,² but the true prevalence of COVID-19 among health care workers is unknown. The aim of the present study is to establish the rate of COVID-19 among health care workers by widespread screening for SARS-CoV-2 exposure.

Employees were tested with a reverse transcriptase–polymerase chain reaction (RT-PCR) test and an antibody test from March 1 to April 30, 2020, at a large tertiary community hospital in Roslyn, New York. The health system began offering antibody testing (Anti-SARS-CoV-2 ELISA [IgG] [EUROIMMUN US]; SARS-CoV2-IgG [Abbott]) on April 16, 2020, and encouraged all employees to be tested. Antibody testing was performed in workers who were asymptomatic or were previously symptomatic with no symptoms for at least 14 days. Hospital employees who had symptoms of COVID-19 were offered the RT-PCR test (cobas SARS-CoV-2 [Roche] and Xpert Xpress SARS-CoV-2 [Cepheid]). All testing was on a voluntary basis. Personal protective equipment (PPE) policy was based on US Centers for Disease Control and Prevention guidelines³ and was dependent on risk of exposure. All employees caring for patients with COVID-19 were required to wear an N95 mask, isolation gown, and gloves. Health care workers involved with procedures that could generate aerosolized virus dispersal, such as mechanical intubation, required additional eye protection. Both χ² and t tests were used to generate P values and 95% CIs to analyze categorical variables. All statistical analyses were performed using SAS version 9.4 (SAS Institute). The Institutional Review Board at St Francis Hospital approved the study and waived the need for informed consent due to its retrospective nature and anonymization of all employee data.

Among 3046 employees, 1699 (56%) underwent antibody testing, 617 (20%) underwent RT-PCR testing, and 359 (12%) underwent both. The average (SD) age among all employees was 42.8 (13.8) years and 2137 (70%) were women (Table). When comparing employees who elected to undergo either form of testing vs those who did not, there were no meaningful differences with respect to age, job title, or work area.

There were 167 employees (9.8%) who tested positive for antibodies. There was no significant difference in antibody positive rates across job titles or work areas (Figure). When comparing the prevalence of antibodies among hospital employees with the rate reported by the State of New York for the general public on Long Island, hospital employees had a significantly lower positive rate (9.9% vs 16.7%, P < .001).

Employees with positive antibody test results were similar in age (41.5 [SD, 13.5] vs 43.4 [SD, 13.7] years, P = .09) and sex (women 9.4% vs men 11.1%, P = .31). There was no significant difference between race as a whole (Table). There was no significant difference in infection rates among those working in high vs low exposure areas (10.9% vs 10.9%, P = .99).

The findings of the present study indicate that the rate of SARS-CoV-2 infection among health care workers is lower than what has been reported for the general public in the surrounding region. Given that health care workers in hospitals are exposed to a much higher density of the virus, this is strong evidence that current PPE practices are protective, easing health care workers’ concern and psychological distress.⁴

Limitations of this study are that it is a single-center analysis from a large community hospital that has the capability to adequately supply PPE to all health care workers. The present results may therefore not be applicable to all health care settings. Testing for COVID-19 was offered on a voluntary basis, with most employees complying. While no differences were observed between those tested and those not tested, a potential selection bias cannot be completely excluded.

In conclusion, PPE, when available and properly used, confers protection and lower infection rates of COVID-19 among health care workers when compared with reported infection rates in the general public.

Corresponding Author: Allen Jeremias, MD, MSc, Division of Cardiology, Department of Medicine, St Francis Hospital, The Heart Center, 100 Port Washington Blvd, #105, Roslyn, NY 11576 (allen.jeremias@chsli.org).

Published Online: August 11, 2020. doi:10.1001/jamainternmed.2020.4214

Author Contributions: Drs Nguyen and Pollack had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Jeremias, Levine, Thakore.

Acquisition, analysis, or interpretation of data: Jeremias, Nguyen, Pollack, Engellenner, Thakore, Lucore.

Drafting of the manuscript: Jeremias, Nguyen.

Critical revision of the manuscript for important intellectual content: Levine, Pollack, Engellenner, Thakore, Lucore.

Statistical analysis: Nguyen, Pollack.

Administrative, technical, or material support: Nguyen, Levine, Engellenner, Thakore, Lucore.

Supervision: Jeremias.

Conflict of Interest Disclosures: None reported.

Additional Contributions: Guy Aristide, MD (St Francis Hospital, The Heart Center); J. Jane Cao, MD, MPH (St Francis Hospital, The Heart Center); Gary Gecelter, MD; Ronald J. Gulotta, MD (St Francis Hospital, The Heart Center); Maya A. Jeremias (St Francis Hospital, The Heart Center); Stefan M. Muehlbauer, MD, PhD; Patrick O’Shaughnessy, MD (St Francis Hospital, The Heart Center); Newell Robinson, MD; Richard Shlofmitz, MD (St Francis Hospital, The Heart Center). None of the contributors was compensated and none reported any conflicts or disclosures.