Dynamics of humoral response to coronavirus antigens among employees of COVID-dedicated hospital: an observational study.

Abstract

INTRODUCTION\nA high priority for study during the pandemic of SARS-CoV-2 is the safety at work of hospital staff taking care of COVID-19 patients. The authors decided to analyze the results of opportunistic screening for anti-SARS-CoV-2 antibodies among employees of a COVID-19-dedicated centre.\xa0 Objectives: The authors aimed to investigate if potential exposition to SARS-CoV-2 antigens is reflected in the results of serological studies.\n\n\nPATIENTS AND METHODS\nEvery employee who took at least one test between 21st April and 20th July was included in the study. Every test\xa0assessed levels of immunoglobulin G (IgG) and immunoglobulin M+A (IgM+IgA). Employees were divided in terms of having contact with COVID-19 patients and participating in aerosol-generating procedures.\n\n\nRESULTS\nResults of 2455 tests taken by 1572 persons were analyzed. 357 (22.7%) participants had at least one positive or equivocal result during the observation period. Linear mixed models revealed gradual increases in mean levels of both IgG and IgM+IgA antibodies among employees with all negative results. The rate of change was higher among persons having direct contact with COVID-19 patients and the highest rate of change was observed among person participating in aerosol-generating procedures.\n\n\nCONCLUSIONS\nWe detected developing humoral immune response to a new set of antigens of coronavirus among studied group. It is possible that employees of COVID-19-dedicated centres have regular contact with non-infectious amounts of SARS-CoV-2 or its antigens.