First real-world study shows 50 per cent effectiveness of India’s homegrown Covid vaccine

·2-min read
 (AFP via Getty Images)
(AFP via Getty Images)

The first real-world assessment of Covaxin, a Covid-19 vaccine developed in India, shows it has just a 50 per cent effectiveness rate against symptomatic Covid-19 after two doses, according to a study.

Covaxin, also known by its scientific name BBV152, is a vaccine based on the virion – the complete, ineffective form of the coronavirus strain. In January 2021, it was approved for emergency use in India for adults.

More than 130 million doses of Covaxin, developed by pharmaceutical company Bharat Biotech, have been administered in India.

Published in The Lancet, the study assessed over 2,000 hospital staff from the All India Institute of Medical Sciences (AIMMS) in New Delhi, India from 15 April-15 May 2021 – when the country was hit by its second surge of virus infections.

All the health workers who participated in the study had been offered the vaccine, giving researchers the opportunity to evaluate its effectiveness.

Dr Manish Soneja, the Additional Professor of Medicine at AIMMS says the study “offers a more complete picture of how BBV152 performs in the field and should be considered in the context of Covid-19 surge conditions in India.”

Of the 2,714 participants, 1,617 tested positive for the virus, approximately 80 per cent of which could be attributed to the delta variant. The odds of vaccination with BBV152 were compared between cases and adjusted for occupational exposure to Covid-19, previous infection, and infection dates.

The data shows that the effectiveness against symptomatic Covid-19 after two doses – spaced by a minimum of 14 days before being tested was 50 per cent, with the effectiveness remaining over the seven-week follow-up period.

High infection rates and virus exposure among the hospital’s employees may have contributed to Covaxin’s weaker efficacy than had previously been reported, along with the possibility that the delta variant diminished the shot’s protection, the researchers said.

Dr Parul Kodan from AIIMS says “more research is needed to better understand how these findings translate to BBV152’s effectiveness against delta and other variants of concern, especially related to severe Covid-19 infection, hospitalisation and deaths.”

This month, the World Health Organisation (WHO) added BBV152 to the approved list of emergency Covid-19 vaccines.

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