IgG-RBD Response Due to Inactivated SARS-CoV-2 Vaccine: Alteration in D-Dimer and Fibrinogen Concentrations, Association with Comorbidities and Adverse Effects

Abstract Objective To examine the immunoglobulin G-receptor-binding domain (IgG-RBD) response and changes in fibrinogen and D-dimer concentrations in individuals with a past coronavirus infection and followed by CoronaVac. Methods The study consisted of a total of 116 participants. Blood samples were drawn from subjects 21–25 days after they received first and second doses of CoronaVac as well as from individuals with a past infection. Fibrinogen, D-dimer, and IgG-RBD concentrations were measured. Results The IgG concentrations of the vaccinated subjects were significantly higher (P < .001), fibrinogen levels were lower (P < .001), and D-dimer levels increased following the second vaccination compared with the first vaccination (P = .083). No difference was obtained in IgG-RBD between vaccinated and previously infected individuals (P = .063). The differences in fibrinogen and D-dimer were statistically nonsignificant between both groups. Conclusion The CoronaVac vaccine appears to be safe and effective. It is essential for individuals to take personal protective measures, such as using masks and distancing.