Covid-19 vaccine: Bharat Biotech completes recruitment for phase 3 trials

More than 5,000 people have been given both shots of the vaccine; efficacy data around March

Amidst a heated debate surrounding the approval of Covaxin, Bharat Biotech's Covid-19 vaccine candidate, the Hyderabad based firm on Thursday said that it has completed recruitment of 25,800 people for its phase 3 efficacy trial.

The last leg of enrolment for the trials happened in the last week of December, with the company saying it was half-way through for its recruitment target. On January 2 the company had informed that it has recruited 23,000 volunteers.  The efficacy data is expected around March and over 5000 people have already received both the shots of the vaccine.

The subject expert committee (SEC) had recommended for the restricted use approval of Covaxin in clinical trial mode on January 2 and eventually the country's drug regulator announced an approval the next day. The SEC that was reviewing Bharat Biotech's application for approval had noted on January 1 that the firm should try to expedite the recruitment and perform interim efficacy analysis.

 

This is so far India's largest efficacy trial of any vaccine. Efficacy trials typically check if the vaccine works to prevent disease. About 50 percent of volunteers are given placebo shots and the remaining are given vaccine shots. This data is kept blinded. Once a statistical number of disease cases emerge in the sample, the data is unblinded to analyse the efficacy.

Covaxin is yet to generate any efficacy data and has not submitted any interim analysis data to the SEC. It has proven safety in phase 1 and 2 trials and has also shown efficacy in animal challenge trials (on non-human primates). Its approval in clinical trial mode led to a public debate as the vaccine did not have a proven efficacy. Now when given to any person, one needs to give informed consent, and also would be monitored regularly by the firm.

Covaxin, India's indigenous Covid-19 vaccine by Bharat Biotech is developed in collaboration with the Indian Council of Medical Research (ICMR) - National Institute of Virology (NIV). Covaxin is a highly purified and inactivated 2 dose SARS-CoV2 vaccine, manufactured in a vero cell manufacturing platform with an excellent safety track record of more than 300 million doses.