Serologic Evaluation of Healthcare Workers Caring for COVID-19 Patients in the Republic of Korea

Jae-Hoon Ko; Ji Yeon Lee; Hyun Ah Kim; Seung-Ji Kang; Jin Yang Baek; Su-Jin Park; Miri Hyun; Ik Joon Jo; Chi Ryang Chung; Yae-Jean Kim; Eun-Suk Kang; Young Ki Choi; Hyun-Ha Chang; Sook In Jung; Kyong Ran Peck

doi:10.3389/fmicb.2020.587613

Serologic Evaluation of Healthcare Workers Caring for COVID-19 Patients in the Republic of Korea

Front Microbiol. 2020 Nov 20:11:587613. doi: 10.3389/fmicb.2020.587613. eCollection 2020.

Authors

Jae-Hoon Ko¹, Ji Yeon Lee², Hyun Ah Kim², Seung-Ji Kang³, Jin Yang Baek⁴, Su-Jin Park⁵, Miri Hyun², Ik Joon Jo⁶, Chi Ryang Chung⁷, Yae-Jean Kim⁸, Eun-Suk Kang⁹, Young Ki Choi⁵, Hyun-Ha Chang¹⁰, Sook In Jung³, Kyong Ran Peck¹

Affiliations

¹ Division of Infectious Diseases, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
² Division of Infectious Diseases, Department of Medicine, Keimyung University Dongsan Hospital, Keimyung University School of Medicine, Daegu, South Korea.
³ Division of Infectious Diseases, Department of Internal Medicine, Chonnam National University Medical School, Gwangju, South Korea.
⁴ Asia Pacific Foundation for Infectious Diseases, Seoul, South Korea.
⁵ College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, South Korea.
⁶ Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
⁷ Department of Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
⁸ Division of Infectious Diseases and Immunodeficiency, Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University, School of Medicine, Seoul, South Korea.
⁹ Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
¹⁰ Division of Infectious Diseases, Department of Internal Medicine, School of Medicine, Kyungpook National University, Daegu, South Korea.

Abstract

The safety of healthcare workers (HCWs) against severe acute respiratory syndrome virus 2 (SARS-CoV-2) transmission is an important aspect of managing the coronavirus disease 2019 (COVID-19) pandemic. In the South Korea, highly stringent infection prevention and control (IPC) guidelines are implemented, and reports of healthcare-associated SARS-CoV-2 transmission among HCWs are limited. However, subclinical infections may have been missed by the current symptom-based screening strategy. To evaluate the risk of undetected SARS-CoV-2 transmissions from COVID-19 patients to HCWs, we conducted a multicenter seroprevalence study after the first surge of the COVID-19 outbreak. A total of 432 HCWs were evaluated, comprising 309 HCWs designated to laboratory-confirmed COVID-19 patient care and 123 non-designated HCWs. Designated HCWs wore personal protective equipment including an N95 respirator, eye protection, hooded overalls, shoe covers, and inner and outer gloves. Use of a powered air-purifying respirator was recommended for aerosol-generating procedures or long-duration care activities. A high-sensitivity (99.1%) fluorescence immunoassay immunoglobulin G (IgG) kit was used as the initial screening test, and two enzyme-linked immunosorbent assay kits for total and IgG antibodies were used to confirm the test results. A microneutralization test was additionally performed to evaluate the neutralizing activity of positive specimens. Among the evaluated HCWs, none of the non-designated HCWs had a positive result, while one of the HCWs designated for COVID-19 patient care (1/309, 0.3%) was seropositive for SARS-CoV-2 with confirmed neutralizing activity (1:40). This finding suggests that subclinical seroconversion may occur among HCWs caring for COVID-19 patients, although the risk is low under strict IPC guidance.

Keywords: COVID-19; SARS-CoV-2; antibody; healthcare worker; serology.