Investigation of IgG antibody levels among healthcare workers vaccinated with inactivated COVID-19 vaccine using indirect ELISA

Document Type : Research Article


1 Bingol University, Veterinary Faculty, Microbiology Department, 12000 Bingol/TURKEY

2 2University of Health Sciences, Fethi Sekin City Hospital, Clinic of Infectious Diseases and Clinical Microbiology, Elazig, Turkey

3 Department of Microbiology, Faculty of Veterinary Medicine, University of Firat, Elazig, Turkey

4 Department of Physiology, Faculty of Veterinary Medicine, University of Bingol, 12000, Bingol-Turkey;

5 Department of Physiology, Faculty of Medicine, University of Adıyaman, Adıyaman, Turkey

6 Department of Physiology, Faculty of Medicine, University of Inonu, Malatya, Turkey

7 Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Bingol, 12000, Bingol-Turkey

8 Firat University


This study was conducted to investigate variations in SarsCoV-2-specific IgG levels over a 5-month period in healthcare workers who received two doses of CoronaVac vaccine.  Blood samples were collected from 122 participants on days 14, 56 and 150 following the second dose of the vaccination. SarsCoV-2 specific IgG antibody titres of the participants were measured using the QuantiCOR ELISA kit. Demographic data of the participants were recorded. Seropositivity on 14th, 56th and 150th days in the previously uninfected group was 44.8%, 50.7% and 32.8%, respectively. In the previously infected group, seropositivity was detected in 87.2%, 92.7% and 43.6% of the participants, respectively. While a statistically significant difference was determined between the two groups in terms of seropositivity on the 14th and 56th days, no statistical difference was found on the 150th day. The data of this study indicated that the CoronaVac vaccine provided sufficient immunity in previously infected individuals, though the duration of immunity was short. It is suggested that CoronaVac vaccine would be more appropriate to use as a booster in order to increase the effectiveness of a vaccine rather than the first vaccination, or to vaccinate people who have been infected before.