Bharat Biotech releases Covaxin Phase-3 trial data, claims 77.8% efficacy

Vaccine also offers 65% protection against Delta variant, according to firm

A health worker administers a dose of Covaxin. File

Hyderabad-based Bharat Biotech India Ltd (BBIL) on July 3 publicised the long-awaited results of the Phase-3 trial of Covaxin that involved nearly 25,800 volunteers spanning 25 hospitals across the country.

Along with partner scientists at the Indian Council of Medical Research, the company said the vaccine had an overall efficacy of 77.8% against symptomatic COVID.

This is higher than the overall 70.4% efficacy reported from the Phase-3 trial results of the AstraZeneca (Covishield) vaccine published in Lancet in January.

The latest Covaxin study is yet to be peer-reviewed and appears on a pre-print server. While Covishield is the most widely administered vaccine in India, data from a bridging trial on Indians (extrapolating the vaccine’s potency into Indians from international recipients) has not been published.

The two-dose vaccine was also 93.4% effective against severe disease and 63% protective against asymptomatic COVID. Moreover, it was 65% protective against the Delta variant . of the coronavirus, the most widespread in India and linked to a rising number of cases in Europe as well as the United States.

The preprint reveals that in those 60 years and older, the vaccine was 67.8% effective and 79.4% effective in younger people.

“Safety analysis demonstrates adverse events reported were similar to placebo (or those who got a dummy dose), with 12% of subjects experiencing commonly known side-effects and less than 0.5% of subjects feeling serious adverse events,” the company said in a statement.

‘Excellent option’

Medical professionals welcomed the results.

“These results give all of us a lot of reassurance that Covaxin is an excellent option to prevent COVID in India,” tweeted Vincent Rajkumar, Professor, Mayo Clinic.

S.P. Kalantri, Director, Professor of Medicine, Mahatma Gandhi Institute of Medical Sciences, Wardha told The Hindu that the pre-print was rich in detail and, on preliminary reading, revealed a trial that was “well-conducted” and presented people with an informed choice on the vaccine’s efficacy.

“The true test of a vaccine is whether it protects from hospitalisation and death. The reported 93.5% is very good, and protection in those over 60 as well as against the Delta variant too are encouraging,” Dr. Kalantri added.

He cautioned, however, that it would be unwise to speculate if Covishield or Covaxin was superior to the other as there were variations in the conduct of the trial.

Priya Abraham, Director, ICMR-National Institute of Virology said in a statement, “The overall efficacy is wonderful news. ICMR-NIV and BBIL have had very fruitful interactions during this exhilarating journey. Sera (from blood samples) have also been evaluated against viral variants detected in India i.e., the Alpha, Beta, Zeta, Kappa and Delta. The making of this vaccine entirely on Indian soil is a matter of great pride to every Indian.”

NIV was among the partner labs involved in the manufacture of Covaxin and cultured the strain of the virus that was used to design the vaccine.

Bharat Biotech began recruiting volunteers in November 2020 and completed the exercise in January. Though it got emergency use authorisation in that month, there was criticism that the efficacy data was much delayed when several other vaccines — AstraZeneca, Pfizer-BioNTech, Moderna, Novavax — had reported similar data.

Bharat Biotech has also applied to the World Health Organisation, for which the submission of Phase-3 data is a necessary requirement, for a chance at obtaining an Emergency Use Licence that would aid in getting the vaccine approved in more countries. So far, less than 4 crore doses of Covaxin have been administered to Indians since January. The company has claimed it can produce over six crore doses per month and scale up to 10 crore by September.

Covaxin has now received emergency use authorisation in 16 countries, including Brazil, India, Philippines, Iran, Mexico, and is in process in 50 countries worldwide.

Krishna Ella, Chairman & Managing Director, Bharat Biotech, said in a statement, “The successful safety and efficacy readouts of Covaxin, as a result of conducting the largest-ever COVID vaccine trials in India, establishes the ability of India and developing world countries to focus towards innovation and novel product development. We are proud to state that innovation from India will now be available to protect global populations.”