SARS-CoV-2 IgG Antibody Levels After Inactivated Vaccine (CoronaVac) among Elderly

Harika Öykü Dinç; İlker İnanç Balkan; Beyhan Budak; Mehmet Demirci; Doğukan Özbey; Rıdvan Karaali; Bilgül Mete; Günay Can; Sevgi Ergin; Bekir Kocazeybek; Neşe Saltoğlu

doi:10.36519/idcm.2022.115

SARS-CoV-2 IgG Antibody Levels After Inactivated Vaccine (CoronaVac) among Elderly

Infect Dis Clin Microbiol. 2022 Jun 13;4(2):129-132. doi: 10.36519/idcm.2022.115. eCollection 2022 Jun.

Authors

Affiliations

¹ Department of Pharmaceutical Microbiology, Bezmialem Vakıf University School of Pharmacy, İstanbul, Turkey.
² Department of Infectious Diseases, İstanbul University-Cerrahpaşa Cerrahpaşa School of Medicine, İstanbul, Turkey.
³ Department of Medical Microbiology, Kırklareli University School of Medicine, Kırklareli, Turkey.
⁴ Department of Medical Microbiology, İstanbul University-Cerrahpaşa Cerrahpaşa School of Medicine, İstanbul, Turkey.
⁵ Department of Public Health, İstanbul University-Cerrahpaşa Cerrahpaşa School of Medicine, İstanbul, Turkey.

Abstract

We aimed to describe the antibody response against SARS-CoV-2 after inactivated COVID-19 vaccine in elderly individuals. SARS-CoV-2 IgG levels were measured in the blood samples of 126 volunteers over the age of 60. The antibody positivity rate was 42.8% after the first dose and 96.8% after the second dose of the vaccine. The median antibody titers after two vaccine doses were 561.3AU/mL and 43AU/mL, respectively(p<0.001). After vaccination, 22.2% of the participants had antibodies equivalent to 1:80 dilutions in plaque reduction neutralization test (PNRT). We believe that the booster dose is needed to continue the protective immune response in especially elderly groups.

Keywords: COVID-19; CoronaVac; SARS-CoV-2; antibody; inactivated vaccine.