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.