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. 2022 Apr 29;3:211–217. doi: 10.1016/j.ijregi.2022.04.006

Fig. 4.

Figure 4

Covishield-induced severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) immunoglobulin (IgG) antibodies in prior coronavirus disease 2019 (COVID-19)-positive and -negative participants from older and younger age groups. Receptor-binding-domain-specific serum IgG antibody responses were measured in four different groups: (1) <40 years and prior COVID negative (n=6–29), (2) ≥40 years and prior COVID negative (n=10–93), (3) <40 years and prior COVID positive (n=6–27) and (4) ≥40 years and prior COVID positive (n=7–28) before vaccination and every month until 6 months after the first dose of vaccine. A second dose was given 2 months after the first dose. Bars indicate the geometric mean (GM) concentration of IgG with 95% confidence interval (CI). The dashed line indicates the cut-off concentration of IgG antibodies (500 ng/mL) for seropositivity. *P<0.05, ⁎⁎P<0.01.