Bharat Biotech’s Covaxin has shown an overall efficacy of 78 per cent against Covid-19 and 100 per cent efficacy against a severe form of the disease, the vaccine maker said on Wednesday.
The vaccine has also shown 70 per cent efficacy against asymptomatic infections, suggesting that it prevents transmission. The second interim analysis of Covaxin’s Phase 3 clinical trials is based on accruing 87 symptomatic cases of the virus.
Trials are double-blinded and the investigator and volunteer do not know if they have received a placebo or a vaccine shot. After a certain statistical number of cases of the disease are reported in the sample, the data is un-blinded to see whether those in the vaccinated arm got the disease.
“Due to the recent surge in cases, 127 symptomatic cases were recorded, resulting in a point estimate of vaccine efficacy of 78 per cent against mild, moderate, and severe Covid-19 disease. The efficacy against severe Covid-19 disease was 100 per cent, with an impact on reduction in hospitalisations. The efficacy against asymptomatic Covid-19 infection was 70 per cent, suggesting decreased transmission in recipients,” the Hyderabad based firm said.
In the first interim analysis, the whole virion (virus) inactivated Covid-19 vaccine candidate had shown an efficacy of 80.6 per cent. This included 2,433 people over the age of 60 and 4,500 people with co-morbidities.
The first interim analysis was based on 43 cases, of which 36 cases of Covid-19 were observed in the placebo group versus 7 cases observed in the BBV152 (Covaxin) group, resulting in a point estimate of vaccine efficacy of 80.6 per cent.
The company is in process of ramping up its vaccine production capacity to 700 million doses annually and is also pursuing approval for it in 60 countries. In Mexico, the Philippines, and Iran, it is already fetching $15-20 per shot.
The safety and efficacy results from the final analysis will be available in June and Bharat Biotech will submit the final report to a peer-reviewed publication. Further, based on the achievement of the success criteria, placebo recipients have now become eligible to receive two doses of Covaxin.
The Phase 3 study enrolled 25,800 participants between 18-98 years of age, including 10 per cent over the age of 60, with analysis conducted 14 days after the second dose.
“Efficacy against SARS-Cov-2 has been established. Covaxin has demonstrated an excellent safety record in human clinical trials and in usage under emergency use. Covaxin is now a global innovator vaccine derived from research and development from India. The efficacy data against severe Covid-19 and asymptomatic infections is highly significant, as this helps reduce hospitalizations and disease transmission, respectively,” said Bharat Biotech CMD Krishna Ella.
Commenting on the results, Balram Bhargava, secretary, Department of Health Research and Director General of the Indian Council of Medical Research (which has collaborated with Bharat Biotech to develop the vaccine) said he was pleased with the results.
“The first indigenous vaccine has shown the efficacy of 78 per cent in the second interim analysis. I am also happy to note that Covaxin works well against most variants of SARS-CoV-2. These findings together consolidate the position of our indigenous vaccine in the global vaccine landscape,” said Bhargava.