Covid-19 vaccine: Covaxin shows interim clinical efficacy of 81% in phase-3 results, says Bharat Biotech

Covaxin, country’s first indigenous Covid-19 vaccine candidate, has shown 81 per cent interim clinical efficacy in phase-3 results.

This was announced by its manufacturer, Bharat Biotech International Ltd, on Wednesday.

“The whole virion inactivated Covid-19 vaccine candidate demonstrated an interim vaccine efficacy of 81 pc in its Phase-3 clinical trial,’’ the Hyderabad-based company said.

The trials involved 25,800 subjects, the largest-ever conducted in India, in partnership with the Indian Council of Medical Research.

“With today’s results from our Phase 3 clinical trials, we have now reported data on our COVID-19 vaccine from Phase 1, 2, and 3 trials involving around 27,000 participants,’’ Krishna Ella, Chairman and Managing Director, Bharat Biotech, said.

The results assume significance as Covaxin is now being administered for emergency use in the country along with Serum Institute’s Covisheild.

“Covaxin demonstrates a high clinical efficacy trend against Covid-19 but also significant immunogenicity against the rapidly emerging variants,” Ella added.

Also read: Bharat Biotech welcomes PM’s gesture for taking Covaxin

The Phase-3 study enrolled 25,800 participants between 18-98 years of age, including 2,433 over the age of 60 and 4,500 with comorbidities.

The primary endpoint of Phase-3 clinical trial is based on the first occurrence of PCR-confirmed symptomatic (mild, moderate, or severe) Covid-19 with onset at least 14 days after the second study vaccination in serologically negative (to SARS-CoV-2) adult participants at baseline.

Interim analysis

The first interim analysis is based on 43 cases, of which 36 cases of Covid-19 were observed in the placebo group versus 7 cases observed in the BBV152 (Covaxin) group, resulting in a point estimate of vaccine efficacy of 80.6 pc.

The interim analysis included a preliminary review of the safety database, which showed that severe, serious, and medically attended adverse events occurred at low levels and were balanced between vaccine and placebo groups. The trial’s conduct and monitoring are as per Good Clinical Practice guidelines and have been outsourced to IQVIA, the company said.

Analysis from the National Institute of Virology indicates that vaccine-induced antibodies can neutralize the UK variant strains and other heterologous strains.

Hydeabad-based Bharat Biotech expects to share further details of the trial results as additional data become available. An additional interim analysis is planned for 87 cases, and the final analysis is planned for 130 cases.

All data from the second interim and final analyses will be shared via pre-publication servers and submitted to a peer-reviewed journal for publication.

More than 40 countries globally have expressed their interest in COVAXIN®. These countries are highly satisfied with the safe, inactivated vaccine technology and robust data package for safety and immunogenicity.

Covaxin (BBV152) contains a whole virion inactivated SARS-CoV-2 vaccine, which is produced in Vero cells.

It is stable at 2 to 8°C (refrigerated) and is shipped in a ready-to-use liquid formulation that permits distribution using existing vaccine supply chain channels, the company said.

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