Bharat Biotech's Covid-19 vaccine well tolerated with no serious adverse events: Phase 1 trial findings

It was a double-blind randomised controlled phase 1 clinical trial to evaluate the safety and immunogenicity of Covaxin (BBV152)

India’s first homegrown vaccine against Covid-19 has shown “robust immune responses” with barely any serious side effects, according to the first scientific study on human trials of the vaccine.

Developed jointly by Bharat Biotech, Hyderabad and Indian Council of Medical Research, the vaccine (popularly known as Covaxin) the vaccine was administered to 300 people. The results from these inoculations were then compared to results from 75 other subjects who didn’t receive any vaccine.

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The vaccine was administered in three doses and all of them were well tolerated well. The immune responses also give hints of long-term efficacy in all the three formulations, according to the study carried out by the researchers from Bharat Biotech, ICMR and All India Institute of Medical Sciences, Delhi along with doctors from other hospitals in India where the trials were carried out.

On the basis of such early promising results, the Drugs Controller General of India (DCGI) has permitted phase-3 clinical trial of the indigenous vaccine on 26,000 persons.

The Bharat Biotech vaccine is the first and only vaccine so far whose efficacy will be examined in India unlike the vaccine manufactured by Serum Institute (Covishield) and the Russian product (Sputnik V), which will have to only demonstrate safety and immune response.

“The most common adverse event was pain at the injection site, which resolved spontaneously. The overall incidence rate of local and systemic adverse events was 10%-20% in all vaccine treated arms, which is noticeably lower than the rates for other SARS-CoV-2 vaccine platform candidates,” the researchers reported.

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There was one serious adverse event when a participant who was screened on July 25, reported fever and headache, five days after the vaccination. On August 8, he tested positive for Covid-19 and was admitted to a hospital on August 15. A week later, he was found Covid-negative and was discharged from the hospital.

“The event was not causally associated with the vaccine. No other symptomatic SARS-CoV-2 infections were reported in the first 75 days,” reported the team of researchers comprising ICMR director general Balram Bhargava and AIIMS director Randeep Guleria among others.

The DCGI, India’s drug regulator, remained silent on the adverse event reported in August but allowed Bharat Biotech to continue with the trial after reviewing the data.