Covaxin booster dose study shows promising results

Bharat Biotech recently announced the results from the highly anticipated trial studying the immunogenicity and safety of the Covaxin vaccine as a booster dose.

In a statement, the company said that 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, added the statement.

Dr Krishna Ella, Chairman and Managing Director of Bharat Biotech, said, “….Our goals of developing a global vaccine against COVID-19 have been achieved. Covaxin is now indicated for adults, children, two-dose primary and booster doses. This enables the use of Covaxin as a universal vaccine.”

It was found that the vaccine induces both memory B and T cells with a distinct CD4 and CD8 phenotype, the statement further said.

In addition, 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 six 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, the statement mentioned.