SARS-CoV-2 Antibody Screening in Healthcare Workers in Non-Infectious Hospitals in Two Different Regions of Southern Poland (Upper Silesia and Opole Voivodeships): A Prospective Cohort Study.

Rafał Jakub Bułdak,Janusz Kasperczyk,Martyna Fronczek,Mateusz Lejawa,Ewa Gawrylak-Dryja,Zenon Brzoza,Renata Mond-Paszek,Marlena Golec,Marta Wąsik,Sławomir Kasperczyk,Adam Konka,Karina Badura-Brzoza,Elżbieta Woźniak-Grygiel,Marcin Markiel

doi:10.3390/ijerph18084376

Abstract

(1) Background: Detection of asymptomatic or subclinical human coronavirus SARS-CoV-2 infection in healthcare workers (HCWs) is crucial for understanding the overall prevalence of the new coronavirus and its infection potential in public (non-infectious) healthcare units with emergency wards. (2) Methods: We evaluated the host serologic responses, measured with semi-quantitative ELISA tests (IgA, IgG, IgM abs) in sera of 90 individuals in Hospital no. 4 in Bytom, 84 HCWs in the University Hospital in Opole and 25 in a Miasteczko Śląskie local surgery. All volunteers had negative RT-PCR test results or had not had the RT-PCR test performed within 30 days before sampling. The ELISA test was made at two different time points (July/August 2020) with a 2-weeks gap between blood collections to avoid the “serological window” period. (3) Results: The IgG seropositivity of asymptomatic HCWs varied between 1.2% to 10% (Opole vs. Bytom, p < 0.05; all without any symptoms). IgA seropositivity in HCWs was 8.8% in Opole and 7.14% in Bytom. IgM positive levels in HCWs in Opole and Bytom was 1.11% vs. 2.38%, respectively. Individuals with IgA and IgM seropositivity results were observed only in Opole (1.19%). More studies are needed to determine whether these results are generalizable to other populations and geographic as well as socio-demographic locations. (4) Conclusions: 100% of IgG(+) volunteers were free from any symptoms of infection in the 30 days before first or second blood collection and they had no awareness of SARS-CoV-2 infection. Asymptomatic HCWs could spread SARS-CoV-2 infection to other employees and patients. Only regular HCWs RT-PCR testing can reduce the risk of SARS-CoV-2 spreading in a hospital environment. The benefit of combining the detection of specific IgA with that of combined specific IgM/IgG is still uncertain.

Highlights

The rapid spread of SARS-CoV-2 coronavirus infections caused the World HealthOrganization to declare the COVID-19 pandemic on 11 March 2020
A total of 199 healthy participants were included in the study (Figure 1: 84 (42.2%) from the University Hospital in Opole, 90 (45.2% of the overall number of healthcare workers (HCWs)) from Hospital
27 (32.1%) men were recruited from the Clinical University Hospital in Opole, 10 (11.1%) men were recruited from Hospital No 4 in Bytom and 3 (12.0%) men were recruited from the Eko-Prof-Med Healthcare Unit (HCU) in Miasteczko Ślaskie

Summary

Introduction

The rapid spread of SARS-CoV-2 coronavirus infections caused the World HealthOrganization to declare the COVID-19 pandemic on 11 March 2020. The rapid spread of SARS-CoV-2 coronavirus infections caused the World Health. 2019 to early April 2021, over 130.5 million cases of COVID-19 and 2.8 million deaths caused by coronavirus SARS-CoV-2 infection have been reported globally [1]. At the beginning of September 2020, the daily number of confirmed cases of COVID-19 in Poland began to increase significantly [2]. Dominant points of infections are numerous and small, rather than isolated and big as was the case at the beginning of the pandemic. The present serological research was performed during the first wave of the rise of morbidity in Poland, where most institutions focused on genetic diagnosis of SARS-CoV-2 infection (vide RT-PCR) to eliminate infected health care workers (HCWs) from the health care system (HCS)

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