Bharat Biotech claims 81% clinical efficacy in Covaxin Phase 3 trial

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

Prime Minister Narendra Modi being administered his first dose of the COVID-19 vaccine at AIIMS, Delhi. Photo: Twitter/Narendra Modi

Vaccine maker Bharat Biotech announced the first interim analysis of its BBV152 (Covaxin) in Hyderabad on Wednesday. The whole-virion inactivated COVID-19 vaccine candidate demonstrated an interim vaccine efficacy of 81 per cent in its Phase 3 clinical trial. The trial involved 25,800 subjects, the largest ever conducted in India, in partnership with the Indian Council of Medical Research.

Announcing the results, Bharat Biotech chairman and managing director Dr Krishna Ella said: “Today is an important milestone in vaccine discovery, for science and our fight against coronavirus. 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. Covaxin demonstrates high clinical efficacy trend against COVID-19 and also significant immunogenicity against the rapidly emerging variants.”

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 co-morbidities. 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.

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

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.

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. BBV152 has a 28-day open vial policy as a unique product characteristic, thus reducing vaccine wastage by approximately 10-30 per cent, Dr Ella added.

BBV152 is based on an established manufacturing platform with a better safety profile when compared to other vaccine platforms. The inclusion of the Algel-IMDG adjuvant enhances T-cell immune responses to COVID-19, leading to long-term protection.

Also read: Second leg of COVID-19 vaccination today; PM takes Covaxin jab

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.

More than 40 countries globally have expressed their interest in Covaxin, said to be safe, inactivated vaccine technology and robust data package for safety and immunogenicity.

Ministers and officials opt for Covaxin

Meanwhile, government ministers and officials were following Prime Minister Narendra Modi’s lead by opting for Covaxin, instead of the AstraZeneca one. Health, external affairs and law ministers and governors all flocked to Twitter to express support for Covaxin, after it was administered to Modi on Monday.

“Made-in-India vaccines are 100% safe,” Health Minister Harsh Vardhan said after being inoculated with COVAXIN.

Also read: ‘Hesitancy should be buried’: Harsh Vardhan after PM gets Covaxin jab

Many state officials and doctors have refused to take COVAXIN before its effectiveness could be proved.

Bharat Biotech said the endorsement by Modi and other ministers would set an example for others and reduce “vaccine hesitancy”. The company is seeking to sell COVAXIN to other countries including Brazil and the Philippines.