Phase 1 study

The study is designed to evaluate the safety, reactogenicity, tolerability, and immunogenicity of Four arms of healthy volunteers who receive two intramuscular doses of BBV152 vaccine formulations or a Placebo. A total number of 375 subjects will be enrolled in 4:1 ratio.

This study will be conducted in a dose escalatory manner with a two-dose regimen fourteen days apart.

Phase 2 study

The study is designed to evaluate the safety, reactogenicity, tolerability, and immunogenicity of two arms of healthy volunteers who will receive two intramuscular doses of BBV152 vaccine formulations (BBV152-A & BBV152-B) in a 1:1 ratio with dosage schedule on Day 0 and Day 28.

Results

On July 14, 2022, Scientific Reports published the results of this trial.

It is well known that neutralizing antibodies induced by COVID-19 vaccines wane within 6 months of vaccination, leading to questions on the effectiveness of two-dose vaccination against breakthrough infections.

Therefore, we assessed the persistence of immunogenicity up to 6 months after a two or three-dose with BBV152 and the safety of a booster dose in this ongoing phase 2, double-blind, randomized controlled trial. We report the persistence of humoral and cell-mediated immunity up to 12 months of vaccination, despite a decline in the magnitude of antibody titers.

Administration of a third dose of BBV152 increased neutralization titers against both homologous (D614G) and heterologous strains (Alpha, Beta, Delta, Delta Plus, and Omicron) with a slight increase in B cell memory responses. Thus, seroconversion rate remains high in boosted recipients compared to non-booster, even after 6 months post third dose against variants.

No serious adverse events were observed, except pain at the injection site, itching, and redness.

These results indicate that a booster dose of BBV152 is safe and necessary to ensure persistent immunity to minimize breakthrough infections of COVID-19 due to newly emerging variants.