The interim analysis was based on 43 recorded cases of Covid-19 in the trial of 25,800 participants, conducted in partnership with the Indian government’s medical research body.
Thirty-six of the 43 cases were recorded in participants who received a placebo, compared with seven cases in people who were given the Bharat Biotech vaccine, pointing to an efficacy rate of 80.6%, the company said.
India had approved the vaccine, branded COVAXIN, in January without late-stage efficacy data, raising questions about its effectiveness.
India’s vaccination drive, currently underway, includes COVAXIN and a vaccine developed by Oxford University and AstraZeneca.
Earlier this week, Indian Prime Minister Narendra Modi was inoculated with the first dose of COVAXIN.