Covaxin phase-3 trial to end today; avg efficacy 60-70%

Covaxin phase-3 trials to end today, average efficacy 60-70%

Recipients to be monitored for 1 year for reactions

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Bharat Biotech’s Covaxin is set to end its phase-3 trials on Tuesday, a research firm involved in monitoring the trials in Karnataka confirmed.

Dr Rajesh Naidu, managing director of Clintrac International Private Limited, a research company monitoring the clinical trials, told DH that the trials had so far seen 23,000 volunteers across India getting vaccinated.

This number is about 3,000 people short of the target number of volunteers set by the Indian Council of Medical Research (ICMR) with sources pointing to a consistent shortage in attracting volunteers to join the trials.

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In Bengaluru, out of 800 registered participants, just 540 individuals had been included in the trials, half of which were the control group. 

“The results in Karnataka have been positive. The phase-3 trials showed that the vaccine has an average efficacy of 60% to 70%. In a few subjects, the efficacy is as high as 85 to 90%. No side-effects were seen,” Dr Naidu said.

An informed second source said the recipients would be monitored for up to one year for adverse reactions to the vaccine. 

When asked how this would be done if the vaccine was potentially deployed in a backup capacity as had been stated by ICMR, the source said: “this post-vaccine monitoring was routine across the industry and the Pfizer vaccine required a post-observation period of up to three years. By that measure, we are relatively better.”

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The emergency-use approval for the vaccine has triggered furore over a lack of transparency of its proposed deployment even before its phase-3 clinical data has been made public.  

Dr Srinivas S, spokesperson for the Karnataka chapter of the Indian Medical Association (IMA), suggested that the backup status of the vaccine means that it will likely not be deployed on a large scale until it is formally approved as a registered vaccine.

“From the information we have, the vaccine will only be administered within government circles. It will not be supplied to the private sector and it will not be sold to consumers until it is fully approved,” Srinivas said.

He said if Covaxin secured full approval, IMA would follow the Centre’s lead on deployment and administration.

Dr Chirag Trivedi, president, Indian Society for Clinical Research (ISCR), suggested that the DCGI’s approval had likely been made using trial data which has not yet been made public.