New Delhi: Bharat Biotech on Wednesday said its COVID-19 vaccine, Covaxin, has proved an interim vaccine efficacy of 81 percent in Phase 3 clinical trials. The largest ever conducted in India, in partnership with the Indian Council of Medical Research, trials involved 25,800 subjects, said the Hyderabad-based company.

“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,” Bharat Biotech Chairman and Managing Director Krishna Ella said.

Covaxin demonstrates a high clinical efficacy trend against COVID-19 but also significant immunogenicity against the rapidly emerging variants, he added. Covaxin has been indigenously developed by Bharat Biotech in collaboration with the Indian Council of Medical Research (ICMR). Covaxin and Oxford-AstraZeneca’s Covishield are the two vaccines that are being administered in the country.

In November 2020, Covaxin received the approval to conduct Phase III human trials after the completion of Phase I and II. The trial involves a randomized, double-blinded, placebo-controlled study among volunteers of age group 18 and above and started on 25 November. The Phase III trials involved volunteers from across India. The phase III trials covered a total of 22 sites consisting of several states in the country, including Delhi, Karnataka, and West Bengal.

As of March 2021, the interim efficacy rate for the phase III trial is 81%. All data from the second interim and final analyses are yet to be made available.