J Korean Med Sci.  2021 Nov;36(43):e294. 10.3346/jkms.2021.36.e294.

Prevalence of SARS-CoV-2 Antibody in 2,935 Healthcare Workers at 6 Major Hospitals, Daegu, Korea

• Kim YK
• Minn D
• Song DY
• Lee CH
• Ryoo NH
• Jeon CH
• Song KE
• Suh JS
• Chang SH

• KMID: 2522284
• DOI: http://doi.org/10.3346/jkms.2021.36.e294

Abstract

Background
In Korea, the first community outbreak of coronavirus disease 2019 (COVID-19) occurred in Daegu on February 18, 2020. This study was performed to investigate the prevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antibodies in healthcare workers (HCWs) at 6 major hospitals in Daegu.
Methods
Blood specimens of 2,935 HCWs at 6 major hospitals in Daegu from January 2021 to February 2021 were collected. Every specimen was tested for antibody against SARS-CoV-2 using both Elecsys Anti-SARS-CoV-2 electrochemiluminescence immunoassay (Roche Diagnostics, Rotkreuz, Switzerland) and R-FIND COVID-19 IgG/M/A enzyme-linked immunosorbent assay kit (SG medical Inc., Seoul, Korea) as screening tests. If 1 or more of these screening test results was positive, 2 additional antibody tests were performed using Abbott Anti-SARS-CoV-2 IgG assay (Abbott, Abbott Park, IL, USA) and cPass SARS-CoV-2 Neutralization Antibody Detection Kit (GenScript USA Inc., Piscataway, NJ, USA). If 2 or more of the total 4 test results were positive, it was determined as positive for the antibody against SARS-CoV-2.
Results
According to the criteria of SARS-CoV-2 antibody positivity determination, 12 subjects were determined as positive. The overall positive rate of the SARS-CoV-2 antibody was 0.41% (12/2,935). Of the 12 subjects determined as positive, 7 were diagnosed with COVID-19, and the remaining 5 were nondiagnosed cases of COVID-19.
Conclusion
In early 2021, the overall seroprevalence of SARS-CoV-2 antibody among HCW located in Daegu was 0.41%, and 0.17% excluding COVID-19 confirmed subjects. These results were not particularly high compared with the general public and were much lower than HCWs in other countries.

Keyword

COVID-19; SARS-CoV-2 Antibody; Healthcare Worker; Neutralizing Antibody

Figure

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  Fig. 1 Criteria of SARS-CoV-2 antibody positivity determination. Total 2,935 blood samples of HCWs were tested using 2 antibody assays simultaneously as screening tests. If 1 of these screening results was positive, 2 additional antibody tests were performed. If 2 or more of the total 4 test results were positive, it was determined as positive for the antibody against SARS-CoV-2.HCW = healthcare worker, SARS-CoV-2 = severe acute respiratory syndrome coronavirus-2, ELISA = enzyme-linked immunosorbent assay.

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  Fig. 2 Trend of COVID-19 confirmed cases in Daegu.COVID-19 = coronavirus disease 2019.aCOVID-19 incidence rate in Daegu area in February 2021 ().

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