Covaxin phase 2 data shows vaccine safe, induces immune response: Lancet Study

The latest study comes a week after Bharat Biotech announced that the vaccine has shown 81 per cent efficacy in the third phase of clinical trials

Bharat Biotech's Covaxin has shown better safety and enhanced immune responses in the vaccine's Phase-2 clinical trial results, medical journal Lancet said in its study

The Hyderabad-based company last week announced that its vaccine demonstrates 81 percent efficacy in preventing Covid-19. Bharat Biotech's interim projections were based on Covaxin's Phase-3 trials.

Covaxin, developed by Bharat Biotech and ICMR-National Institute of Virology, is part of the ongoing Covid-19 immunization drive in the country.

Lancet had published the Phase-1 trial results in January. The interim report then said that Covaxin affected enhanced immune responses against Covid-19.

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In the phase 1 trial, BBV152 or Covaxin induced high neutralising antibody responses that remained elevated in all participants at three months after the second vaccination.

“In the phase 2 trial, BBV152 showed better reactogenicity and safety outcomes, and enhanced humoral and cell-mediated immune responses compared with the phase 1 trial,” the report whose contributors include Bharat Biotech CMD Krishna Ella, and ICMR Director General Balram Bhargava and others said.

The phase-2 trials of the indigenously developed vaccine were conducted in September for which 921 potential participants were screened. 380 of them enrolled andrandomly assigned into two groups - 3 μg with Algel-IMDG group (n=190) or 6 μg with Algel-IMDG group (n=190).

The Lancet Infectious Diseases paper, published on Monday, said that the 6 μg with Algel-IMDG formulation has been selected for the phase 3 efficacy trial.

The report said that the proportion of participants reporting adverse events in the phase 2 trial were lower than in the phase 1 trial.

The most common adverse event in the phase 2 trial was pain at the injection site, followed by headache, fatigue, and fever. No severe or life-threatening adverse events were reported.

“Further corroboration with phase 3 safety results is required. The study enrolled a small number of participants aged 12–18 years and 55–65 years. Follow-up studies are required to establish immunogenicity in children and in those aged 65 years and older,” the Lancet publication said.