Figure 2.

(a) GMCs of anti-RBD IgG concentrations for all four formulation groups on Day 0 (pre-vaccination), Day 28 (post-first dose), and Days 42 and 56 (post second dose). GMCs (top of each column) with a 95% confidence interval (two-sided bars) are included in the figure.

RBD, receptor-binding domain; GMC, geometric mean concentration; IgG, immunoglobulin G.

(b) nAb titres determined by the PNA method for all four formulation groups on Day 0 (pre-vaccination), Day 28 (post-first dose), and Days 42 and 56 (post second dose). GMT was determined from 273 serum samples (human convalescent serum panel; HCS) collected from COVID-19 patients (determined by RT-PCR) with a range of disease severity. GMCTs (top of each column) with 95% confidence intervals (two-sided bars) are shown in the figure.

nAb: neutralising antibody titres; PNA: pseudovirus neutralisation assay;; GMT: geometric mean titre.

(c) nAb titres determined by the MNA method for all four formulation groups on Day 0 (pre-vaccination) and Day 56 (post second dose). The GMT for human convalescent serum panel was determined using serum samples from 32 subjects. The GMTs (top of each column) with 95% confidence intervals (two-sided bars) are included in the figure.

nAb, neutralising antibody; MNA, microneutralisation assay; GMT, geometric mean titre.

(d) Direct comparison of nAb titres by the PNA method against PSV mimicking the ancestral Wuhan and beta strains of SARS-COV-2 for a subset of subjects from all four formulation groups on Day 56 (post second dose). A direct comparison of neutralising antibodies was performed in a randomly selected subset of subjects from all four formulation groups on Day 56 (post second dose). The geometric mean reduction in nAb titres of the ancestral Wuhan to those of the beta strain was 2.25-fold.

PSV: pseudovirus neutralization assay; GMT: geometric mean titre, PvSNT: pseudovirus neutralisation titres.