Prospective voluntary SARS-CoV-2 virus and anti-COVID-19 antibody tests in asymptomatic medical and research staff who work in direct contact with cancer patients: A single center study

ABSTRACT

Background The SARS-CoV-2 pandemic has assaulted all aspects of daily life. Medical professionals in oncology face additional challenges with balancing prompt cancer diagnosis and urgent treatment against potential COVID-19 exposure risk in these high-risk patients. We designed this prospective freewill study to offer testing for SAR2-CoV-2 viral RNA and/or anti-COVID-19, respectively in asymptomatic medical and research staff who work in direct contact with cancer patients. The overall goal was to evaluate the prevalence of infection in this group of asymptomatic healthcare providers to reduce exposure of cancer patients to asymptomatic staff. Methods Asymptomatic medical and research staff who work in direct contact with cancer patients were asked to voluntarily be tested for either SARS-CoV-2 viral RNA or antibodies or both. Either NP swabs and/or blood samples (EDTA tube) were collected. Tests are performed at Sinochips Kansas LLC, Sinochips Diagnostics (CLIA number17D2176068, CAP number 8709463). The PCR test is performed with FDA authorized 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel EUA. The Elecsys® Anti-SARS-CoV-2 (Roche Diagnostics) immunoassay was used to qualitative detection of antibodies to SARS-CoV-2 in human plasma. Results From 06/18/2020 to 12/18/2020, 861 participated in the study. 1095 tests were completed for SAR2-CoV-2 virus infection, and 918 were completed for antibody. Amount participants, 530 had both virus and antibody tested. 235 were tested more than once for viral infection and 166 were tested more than once for the antibody. Median age of participants was 39 years (IQR 32-51 years). Among these 84.7% were females, 84.4% white, 6.7% African American, 4.8% Asian and 84.7% non-Hispanic. The cumulative incidence of a positive test for the virus was 2.2% (16/712), and for the antibody test was 3.8% (26/679). 5 had both viral and antibody tests positive, with an average time of 4.1 weeks from viral testing positivity to detectable antibody among 3 cases and 2 cases with both viral infection and antibody detected at same time. There were 3 cases virus was detected more than once after turning positive. 2 remained positive at 16 and 22 days after initial test and one turned negative at 36 days as of last follow up. There were 7 cases where the antibody was tested more than once after turning positive and all 7 remained positive as of last follow up (range 7-103 days). Conclusion Prospective voluntary testing in asymptomatic medical and research staff who work in direct contact with cancer patients was feasible and resulted in identification of asymptomatic carriers who then placed in quarantine, thereby limiting exposure to cancer patients. Medical and research staff who work with cancer patients are general very cautious and the frequency of infections were significantly lower than general society. In addition, it seems that 1) virus and antibody may co-exist in the same person after exposure, and 2) the antibody may last for a relatively long time.