Figure 2

Antibodies to the RBD of SARS-CoV-2 Ancestral Wuhan (WT) virus and the variants of concern by the haemagglutination test (HAT). Antibodies to the RBD were measured by HAT in previously uninfected individuals at 4 weeks following a single dose of Gam-COVID-Vac (n = 69) for the WT, B.1.1.7, B.351.1 and B.1.617.2 (A) and in previously infected individuals (n = 62), at 4 weeks to WT, B.1.1.7, B.1.351 and B.1.617.2 (B). The age was correlated with the HAT titres for the WT (Spearman’s r = −0.26, p = 0.03). Wilcoxon matched pairs signed ranked test was used to find out the differences in HAT titres in baseline uninfected and infected individuals for WT and the VOCs. All tests were two sided. The error bars indicate the median and the interquartile ranges.