Immunogenicity and safety of Biological E's CORBEVAX? vaccine compared to COVISHIELD? (ChAdOx1 nCoV-19) vaccine studied in a phase-3, single blind, multicentre, randomized clinical trial

Optimum formulation of Biological-E's protein subunit CORBEVAX (TM) vaccine was selected in phase-1 and -2 studies and found to be safe and immunogenic in healthy adult population. This is a phase-3 prospective, single-blinded, randomized, active controlled study conducted at 18 sites across India in 18-80 year-old subjects. This study has two groups; (i) immunogenicity-group, participants randomized either to CORBEVAX (TM) (n = 319) or COVISHIELD (TM) arms (n = 320). (ii) Safety-group containing single CORBEVAX (TM) arm (n = 1500) and randomization is not applicable. Healthy adults without a history of COVID-19 vaccination or SARS-CoV-2 infection were enrolled into immunogenicity arm and subjects seronegative to SARS-CoV-2 infection were enrolled into the safety arm. The safety profile of CORBEVAX (TM) vaccine was comparable to the comparator vaccine COVISHIELD (TM). Majority of reported AEs were mild in nature in both arms. The CORBEVAX (TM) to COVISHIELD (TM) GMT-ratios at day-42 time-point were 1 center dot 15 and 1 center dot 56 and the lower limit of the 95% confidence interval for the GMT-ratios was determined as 1 center dot 02 and 1 center dot 27 against Ancestral and Delta strains of SARS-COV-2 respectively. Both COVISHIELD (TM) and CORBEVAX (TM) vaccines showed comparable seroconversion post-vaccination against anti-RBD-IgG response. The subjects in CORBEVAX (TM) cohort also exhibited higher interferon-gamma secreting PBMC's post-stimulation with SARS-COV-2 RBD-peptides than subjects in COVISHIELD (TM) cohort.