Figure 1

SARS-CoV-2 total antibodies and ACE2 receptor blocking antibodies in individuals 4 weeks after the first dose of Gam-COVID-Vac. The SARS-CoV-2 total antibody levels (antibody index values) were measured using the WANTAI SARS-CoV-2 Antibody ELISA assay in those between 20 to 39 years (n = 71), 40 to 59 years (n = 168) and 60 years (n = 88) (A) and the antibody levels were correlated with the age of individuals (n = 327), Spearman’s r = −0.21, p = 0.0001 (B). ACE2 receptor blocking antibodies were measured by the surrogate neutralizing antibody assay in a sub-cohort of baseline uninfected individuals (n = 69, blue) at 4 weeks and in a cohort of baseline infected individuals (n = 62, red), who were found to be seropositive for SARS-CoV-2 at the time of recruitment (C). The differences in the total antibody titres between different age groups was determined by the Kruskal–Wallis test. The differences in ACE2 receptor blocking antibodies at baseline uninfected and infected individuals were assessed by the Wilcoxon matched pairs signed ranked test. All tests were two sided. The error bars indicate the median and the interquartile ranges.