Vaccine manufacturer Bharat Biotech, has said Covaxin has demonstrated ‘persistence of immunity’ and impact of third dose of inactivated Covid‐19 vaccine against emerging variants.
Published in Nature Scientific Reports, the study demonstrated multiple benefits of the vaccine such as long-term immune response, cell mediated immunity, safety of booster dose, immunogenicity against spike protein and neutralising antibody responses against Alpha, Beta, Delta, Delta Plus and Omicron variants.
“Administration of a third dose, after six months of two-dose vaccination, dramatically increased neutralising antibody responses against both homologous and heterologous strains (Alpha, Beta, Delta, Delta Plus and Omicron) and showed increased memory B cell response,” the study said. It said that the vaccine has induced robust T cell responses and persisted till six months, even after the decline of antibodies.
Immune responses
“Immune responses declined at six months, but increased by 40 fold in subjects who received a booster dose. Immune responses when assessed against variants of concern and persisted up to 12 months,” a Bharat Biotech statement, quoting the study said.
It said that there were no serious adverse events observed, except pain at the injection site, itching and redness. There were no cases of myocarditis, pericarditis, blood clots, or thrombocytopenia detected.
“Our team has now demonstrated that Covaxin is a multi epitope vaccine with antibodies against spike, RBD and N proteins. Post booster dose, it has proven neutralising antibody responses against variants of concern,” Krishna Ella, Chairman and Managing Director, Bharat Biotech, said.
“We have now achieved our goal of developing a safe and efficacious vaccine with long term protection against a spectrum of variants,” he said. The company has a stockpile of more than 50 million doses of Covaxin ready to be distributed as required, he added.