Levels of SARS-COV-2 anti-spike protein receptor-binding domain (S-RBD) IgG in Indonesian-vaccinated healthcare workers: experimental research

Betty A Tambunan; I Dewa G Ugrasena; Jusak Nugraha; Munawaroh Fitriah; Cynthia A Permatasari; Emmanuel J Moses; Narazah M Yusoff; Aryati

doi:10.1097/MS9.0000000000000425

Levels of SARS-COV-2 anti-spike protein receptor-binding domain (S-RBD) IgG in Indonesian-vaccinated healthcare workers: experimental research

Ann Med Surg (Lond). 2023 Apr 4;85(4):802-806. doi: 10.1097/MS9.0000000000000425. eCollection 2023 Apr.

Authors

Betty A Tambunan^{1

2

3}, I Dewa G Ugrasena^{4

3}, Jusak Nugraha^{2

3}, Munawaroh Fitriah^{2

3}, Cynthia A Permatasari^{2

3}, Emmanuel J Moses⁵, Narazah M Yusoff^{2

5}, Aryati^{2

3}

Affiliations

¹ Doctoral Program of Medical Science, Faculty of Medicine.
² Department of Clinical Pathology, Faculty of Medicine.
³ Dr. Soetomo General Academic Hospital, Surabaya, Indonesia.
⁴ Department of Pediatrics, Faculty of Medicine, Universitas Airlangga, Surabaya.
⁵ Medical and Dental Institute, Universiti Sains Malaysia (USM), Kepala Batas, Penang, Malaysia.

Abstract

Studies evaluating the levels of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) anti-spike protein receptor-binding domain (S-RBD) immunoglobulin G (IgG) antibodies in vaccinated healthcare workers in Indonesia are limited.

Objectives: Evaluating time-dependent levels of anti-IgG S-RBD antibodies and monitoring the response of healthcare workers in a tertiary hospital in Indonesia after vaccination.

Materials and methods: This prospective cohort observational study was conducted from January to December 2021. A total of 50 healthcare workers participated in the study. Blood samples were collected at five time points. Antibody levels were measured using a CL 1000i analyzer (Mindray Bio-Medical Electronics Co., Ltd., Shenzhen, China). Antibody levels between groups were analyzed using the Wilcoxon signed-rank test with P less than 0.05.

Results: The median levels of SARS-CoV-2 anti-S-RBD IgG antibody on days 14, 28, 90, and 180 were significantly higher than the levels on day 0 (P<0.001). After the second dose, peak levels were observed on day 14; the levels decreased gradually after day 28. Despite receiving two doses of the vaccine, 10 out of 50 participants (20%) were infected with COVID-19 (coronavirus disease 2019). However, symptoms were mild, and antibody levels were significantly higher than in noninfected participants (P<0.001).

Conclusion: SARS-CoV-2 anti-S-RBD IgG antibody levels increased significantly until day 14 after the second dose; the levels decreased gradually after day 28. Ten participants (20%) were infected with SARS-CoV-2, with mild symptoms.

Keywords: CoronaVac vaccine; SARS-CoV-2 anti-spike protein RBD IgG; healthcare workers; infectious disease.