Covaxin-maker Bharat Biotech early on Saturday confirmed that the coronavirus vaccine shows 77.8% efficacy against the infection. The company published the pre-print data of the third phase of the vaccine trials in the medical journal medRxiv.

On June 23, reports citing unidentified officials had suggested that a Subject Expert Committee of the Central Drugs Standard Control Organisation had accepted trial data of the vaccine. This came after Bharat Biotech submitted the data to the Drug Controller General of India.

In the data published on Saturday, Bharat Biotech claimed that Covaxin shows 65.2% efficacy against the Delta variant of coronavirus. The strain, first detected in India, has been classified as a “variant of concern” by the World Health Organization. It is likely to become the dominant strain of the virus in the coming months, the health body warned recently.

The indigenously developed Covaxin shot was granted emergency use authorisation in India in January though data of phase 3 trials were not available at that time. The company had then said it would submit efficacy results by March. On June 9, it said that the data will be made public in July.

In April, an interim analysis of Covaxin’s phase three data had shown that it was 78% effective against Covid-19. This was slightly lower than the 81% efficacy reported by the company in March.

Elaborating on the efficacy of the vaccine, Bharat Biotech claimed that Covaxin shows 93.4% effectiveness against severe symptomatic Covid-19 cases, and 63.6% in preventing asymptomatic infections.

The third phase trial was conducted among 25,798 participants, of whom 24,419 received two doses of the vaccine or a placebo in an interval of four weeks, the medRxiv report said.

According to Bharat Biotech data, 130 cases of symptomatic infections were reported in a case-driven analysis of 16,973 participants, who were followed up at least two weeks after the second dose. Of these 130 cases, 24 occurred in the vaccine group and 106 among placebo recipients, resulting in an overall vaccine efficacy of 77.8%.

So far, three coronavirus vaccines are in use in India – Covaxin, the Oxford-AstraZeneca jab developed in India under the brand name Covishield, and the Sputnik V shot developed by Russia’s Gamaleya Research Institute.

On June 29, the Centre granted permission to import Moderna’s Covid-19 vaccine for restricted emergency use, but it is still not available.