Figure 2.
Anti-Spike RBD IgG titres by age group and vaccine plus booster
(A) Mean (SE) anti-spike RBD IgG titres in individuals younger than 60 years (left) or 60 years or older (right) at 1 and 3 months after the second CoronaVac vaccination dose, followed by 1 month after a BNT162b2 or CoronaVac booster shot given at 6 months after the initial CoronaVac vaccination. For the 60 years and older age group, the geometric mean fold rise in antibody titres from 1 month after baseline to after the booster was approximately 8-fold in the BNT162b2 boost group versus approximately 3-fold in the CoronaVac group (7·9 [95% CI 5·8–10·8] in the BNT162b2 boost group vs 2·8 [95% CI 1·6–5·0] in the CoronaVac boost group). p values comparing the two groups in the right panel are from the Wilcoxon two-sample test. (B) Individual anti-spike RBD IgG titres over time in individuals younger than 60 years (left) or 60 years or older (right) at 1 and 3 months after the second CoronaVac vaccination dose, followed by 1 month after a single BNT162b2 booster shot given at 6 months after the initial CoronaVac vaccination. (C) Individual anti-spike RBD IgG titres in individuals younger than 60 years (left) or 60 years or older (right) at 1 and 3 months after the second CoronaVac vaccination dose, followed by 1 month after a single CoronaVac booster shot given at 6 months after the initial CoronaVac vaccination. Only one individual younger than 60 years of age received CoronaVac as a booster shot, and thus has been omitted from the mean plot in panel A. RBD=receptor binding domain.