Prevalence of SARS-CoV-2 Antibodies in Laboratory Healthcare Workers at Assiut University Hospital, Egypt

COVID-19 is an illness caused by a novel coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Laboratory healthcare workers (LHCWs) are at highest risk for COVID-19 infection due to direct exposure to COVID-19 patients and/or infected samples.

Our primary objective in this study was to evaluate SARS-CoV-2 Ab testing as a screening tool for detecting COVID-19 infection among asymptomatic LHCWs. Our secondary aims were to establish the relationship between exposure to COVID-19 infection and subsequent asymptomatic disease and working in different areas of the laboratory.

The detection of SARS-CoV-2 antibodies was done by different methods (rapid testing, electrochemiluminescence, and chemiluminescent microparticle immunoassay). The study included 199 asymptomatic LHCWs at Assiut University Hospital, Egypt, from different laboratory areas including molecular biology, microbiology, parasitology, and outpatient clinic laboratories in addition to LHCWs involved in automation, phlebotomy, rotating physicians, and those working in the sample receiving area.

The incidence of SARS-CoV-2 antibodies by rapid testing and immunoassay among asymptomatic LHCWs was 29.6% and 24.4%. Laboratory phlebotomists (55.6%) were most likely to be exposed to positive patients and samples, followed by those working in the sample receiving area (32%), LHCWs in the automation area (29.6%), rotating doctors (28.6%), and LHCWs in the diagnostic molecular biology laboratory (15.4%). The sensitivities of the rapid test and SARS-CoV-2 total antibody were 94.1% and 92%, whereas the specificities were 92.6% and 91%.

Rapid serological testing is an effective screening method for the detection of SARS-CoV-2 infection among asymptomatic LHCWs and the identification of the groups of workers who have a significantly higher seroprevalence than the rest of the laboratory population.