Indigenously-developed Covaxin shot is overall 77.8 per cent effective against symptomatic Covid-19, said the Hyderabad-based Bharat Biotech on Saturday in its publicised much-awaited results of the Phase-3 trial that involved nearly 25,800 volunteers spanning 25 hospitals across the country.
This is higher than the overall 70.4 per cent efficacy reported from the Phase-3 trial results of the AstraZeneca (Covishield) vaccine published in Lancet in January. Covaxin is a whole virus inactivated vaccine against SARS-CoV2, developed by Bharat Biotech in partnership with ICMR and NIV Pune.
The data is yet to be peer-reviewed and has appeared on a pre-print server.
In addition to the overall efficacy, Bharat Biotech said that the two-dose Covaxin provides 65.2 per cent protection against the B.1.617.2 (Delta) variant, which is currently dominant in India and linked to a rising number of cases in Europe as well as the United States. Further, the vaccine has shown 93.4 per cent efficacy against severe infections.
The preprint reveals that in those 60 years and older, the vaccine was 67.8 per cent effective and 79.4 per cent effective in younger people.
“Safety analysis demonstrates adverse events reported were similar to placebo (or those who got a dummy dose), with 12 per cent of subjects experiencing commonly known side-effects and less than 0.5 per cent of subjects feeling serious adverse events,” the company said in a statement.
“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.
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 authorization 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 of authorisation 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.”
“We are proud to put India on the global map with scientific conviction, competence and commitment. Covaxin scores 10 world-class publications endorsing Innovation, clinical research, data, safety, efficacy. Thank collaborators & Positive BB teamwork enduring a pandemic (sic),” Bharat Biotech co-founder Suchitra Ella said in a late-night tweet.
“The successful development of Covaxin has consolidated the position of Indian academia and Industry in the global arena,” added Prof (Dr) Balram Bhargava, Secretary Department of Health Research & Director General Indian Council of Medical Research.