COVAXIN booster increases 19-97 fold rise in antibody levels against Covid-19 variants of concern. Results from the highly anticipated trial study on the immunogenicity and safety of Bharat Biotech’s COVAXIN® (BBV152) a whole- virion inactivated COVID-19 vaccine as a booster dose was published in medRxiv on Saturday which showed promising results.
COVAXIN Booster: Highlights of the Study, published on preprint online journal medRxiv Saturday
- The phase 2, double-blind, randomised controlled COVAXIN® trial demonstrated long-term safety with no serious adverse events.
6 months after receipt of the second COVAXIN® dose:
- Durable neutralising, T and B cell responses detected, which 90% of recipients had a detectable neutralising antibody response against the wild – type strain (6 months after the second dose).
- 6 months after receipt of the second COVAXIN® dose, participants received a third booster dose of COVAXIN®: Neutralisation titers against wild – type and Delta variants were 5 times higher than after a two-dose schedule. Similar increases in neutralising antibodies against Alpha, Beta, Delta plus were observed.
- The booster dose led to a pronounced increase in CD4+ T- and CD8+ Tcell response. This may allow COVAXIN® to confer long term protective efficacy against severe SARS-CoV-2.
- The frequency of adverse events was lower than vaccines from other manufacturing platforms.
This analysis re-emphasises Bharat Biotech’s continued efforts to stay ahead of COVID-19, and this update provides a comprehensive vaccine booster strategy. COVAXIN® is the first vaccine (in India) to report safety and immunogenicity results from a booster clinical trial.
The analysis showed, six months after a two-dose BBV152 vaccination series cell-mediated immunity and neutralising antibodies to both homologous (D614G) and heterologous strains (Alpha, Beta, Delta, and Delta plus) persisted above baseline, although the magnitude of the responses had declined.
Furthermore, Neutralising antibodies against homologous and heterologous SARS-CoV-2 variants increased 19 to 265 fold after a third vaccination. Booster BBV152 vaccination is safe and may be necessary to ensure persistent immunity to prevent breakthrough infections.
We found the vaccine induces both memory B and T cells with a distinct CD4 and CD8 phenotype suggests good immune memory responses and long-term protection from severe disease.
Further, reactogenicity after vaccine and placebo was minimal and comparable, and no serious adverse events were reported.
While protection against the severe disease remains high across the full 6 months, a decline in efficacy against symptomatic disease over time and the continued emergence of variants are expected. Based on emerging data, Bharat Biotech believes that a third dose may be beneficial to maintain the highest levels of protection.
COVAXIN® is formulated uniquely such that the same dosage can be administered to adults and children alike. COVAXIN® is ready-to-use a liquid vaccine, stored at 2- 8C, with 12 months shelf life and multi-dose vial policy. The same vaccine can also be used for 2 dose primary immunization and for booster dose vaccinations, making it truly an universal vaccine.