The 77.8% vaccine efficacy was based on 130 confirmed cases, where 24 cases were observed in the vaccine group and 106 in the placebo group


Bharat Biotech’s Covaxin vial. (Credit: Srikanth Ramakrishnan/BESTpedia/Wikipedia.)

Covaxin, the Covid-19 vaccine developed by India’s Bharat Biotech International, is 77.8% effective against symptomatic Covid-19, according to an analysis published in the UK medical journal The Lancet.

The analysis, based on Phase 3 clinical study in 25 Indian hospitals, is funded by Bharat Biotech and the Indian Council of Medical Research (ICMR).

In the Phase 3 study, 25,798 participants aged 18 years and above were enrolled, who were randomised to receive either Covaxin or placebo.

The 77.8% vaccine efficacy was based on the evaluation of 130 confirmed cases, wherein 24 cases were observed in the vaccine group compared to 106 in the placebo group.

In the study, the Covid-19 vaccine was effective against symptomatic Covid-19 and was well tolerated with no safety concerns reported.

Covaxin is a 2-dose vaccination regimen developed by Bharat Biotech in collaboration with the Indian Council of Medical Research (ICMR) – National Institute of Virology (NIV).

The company developed the inactivated vaccine candidate using the Whole-Virion Inactivated Vero Cell derived platform technology.

Bharat Biotech said that inactivated vaccines contain dead virus, and are incapable of infecting people as they cannot replicate, but can still trigger the immune system to act against infection.

It does not require sub-zero storage, hence ready to use liquid presentation in multi-dose vials, eliminating the need for supply chain restructuring, the company said.

The vaccine showed tolerability, immune responses, and protective efficacy in preclinical studies, and has received DCGI approval for clinical trials in humans.

Also, it has shown neutralising activity against the B.1.1.7 (Alpha), P.1- B.1.1.28 (Gamma) and P.2 – B.1.1.28 (Zeta), B.1.617 (Kappa), B.1.351 (Beta) and B.1.617.2 (Delta) variants.

Earlier this year, Covaxin has secured India’s Central Drugs Standards Control Organisation (CDSCO) approval for restricted emergency use in India.

Recently, the Covid-19 vaccine has received the World Health Organization (WHO) emergency use listing (EUL) for active immunisation in people aged 18 and above.