501. Serum IgG Antibody Testing Against Severe Acute Respiratory Syndrome Coronavirus 2 in Healthcare Workers

BACKGROUND: With the COVID-19 pandemic, many changes were made in healthcare institutions including but not limited to canceling elective surgeries, limiting face-to-face clinic visits, and implementing visitor restrictions. Phased reopening began at West Virginia University (WVU) Medicine on May 25, 2020. While preparing for transition, concern was raised regarding potential for more employee exposures to persons with SARS-CoV-2 infection. In West Virginia (WV), we did not get the predicted surge of SARS-CoV-2. Current cumulative percent positivity for SARS-CoV-2 PCR in WV is 2332 positives of 133,142 tests (1.75%). We provided appropriate personal protective equipment (PPE), including controlled air purifying respirators for all healthcare workers (HCW) caring for persons with suspected or confirmed COVID-19 from the beginning. Policies requiring masks for all HCW and patients took effect on March 27, 2020 and April 29, 2020, respectively. We hypothesized that due to appropriate PPE use there would be no difference in SARS-CoV-2 antibody positivity in HCW working in high versus low risk areas. METHODS: Serum samples from 1042 randomly selected HCW across 4 WVU Medicine hospitals, ranging from 170 to 690 beds with 121 cumulative SARS-CoV-2 PCR positive patients at the time of the study, were tested for SARS-CoV-2 IgG between May 26, 2020 and June 5, 2020. Physicians, nurses, and respiratory therapists were characterized as high or low risk based on work location. Environmental services (EVS) workers were included but not risk-stratified. A questionnaire was used to obtain information on demographics, chronic medical conditions, symptoms, and exposures. RESULTS: SARS-CoV-2 IgG was positive in 9 of 1042 (0.86%) randomly selected HCW. Seroprevalence was lower in high risk 5/835 (0.60%) versus low risk 4/176 (2.27%) group. This was not statistically significant. No EVS workers tested positive 0/31 (0%). Of 9 HCW who tested positive, 2 had previously tested positive for SARS-CoV-2 PCR. CONCLUSION: SARS-CoV-2 IgG seroprevalence in a large sample of HCW across 4 WVU Medicine hospitals was low (0.86%). Low seroprevalence among HCW in high risk areas may be related to appropriate PPE use. Seroprevalence in HCW not caring for patients with COVID-19 could be from community or other inadvertent exposure. DISCLOSURES: All Authors: No reported disclosures