Covaxin 50% effective when delta was dominant, shows Lancet study

In January this year, Covaxin was approved for emergency use in India for people aged 18 years and above.

New Delhi:

According to the first real-world assessment of India’s indigenous COVID-19 vaccine published in The Lancet Infectious Disease journal, two doses of Covaxin are 50 per cent effective against the symptomatic disease.

Results from an interim study recently published in The Lancet showed that two doses of Covaxin, also known as BBV152, had 77.8 percent efficacy against symptomatic disease and no serious safety concerns.

The latest study assessed 2,714 hospital workers at the All India Institute of Medical Sciences (AIIMS) in Delhi from April 15 to May 15, who were symptomatic and underwent RT-PCR test for detection of COVID-19.

The researchers noted that the delta variant was the dominant strain in India during the study period, accounting for nearly 80 per cent of all confirmed COVID-19 cases.

Covaxin, developed by Hyderabad-based Bharat Biotech in collaboration with National Institute of Virology, Indian Council of Medical Research (NIV-ICMR), Pune, is an inactivated whole virus vaccine administered in a two-dose regimen 28 days apart .

In January this year, Covaxin was approved for emergency use in India for people aged 18 years and above. The World Health Organization (WHO) added the vaccine to its list of approved emergency use COVID-19 vaccines earlier this month.

The latest study was conducted during India’s second COVID-19 surge and in healthcare workers who were primarily offered Covaxin.

Manish Soneja said, “Our study presents a complete picture of how BBV152 (Covaxin) performs in the region and should be considered in the context of the growth situation of COVID-19 in India, which is likely to be the delta variant.” Combined with immunity,” Manish Soneja said. Additional Professor of Medicine at AIIMS New Delhi.

“Our findings add to a growing body of evidence that a rapid vaccine rollout program is the most promising route to epidemic control, while public health policies should include additional protective measures, such as mask-wearing and social distancing,” Soneja said in a statement. error.” ,

The COVID-19 Vaccination Center at AIIMS New Delhi exclusively offered Covaxin to all its 23,000 employees from January 16 this year.

The researchers evaluated the vaccine’s effectiveness against symptomatic RT-PCR confirmed SARS-CoV-2 infection.

Of the 2,714 employees in the study population, 1,617 people tested positive for SARS-CoV-2 infection, the virus that causes COVID-19, and 1,097 tested negative.

Positive cases were matched with negative RT-PCR tests (controls).

The odds of vaccination with Covaxin were compared between cases and controls and adjusted for occupational exposure to COVID-19, previous SARS-CoV-2 infection, and infection dates.

The study found that the vaccine’s effectiveness against symptomatic COVID-19 was 50 percent after two doses of Covaxin with a second dose 14 or more days before the RT-PCR test.

The effectiveness of the two vaccine doses remained stable over a seven-week follow-up period, the researchers said.

He said the adjusted vaccine effectiveness of the first dose estimated after seven and 21 days was low, which is in line with the performance of other preventives against the delta variant.

Parul Kodan, Assistant Professor of Medicine at AIIMS, New Delhi, said, “The findings from the study confirm previous research that two doses of BBV 152 are necessary to achieve maximum protection and that all vaccine roll-out plans should be implemented following the recommended dosing schedule. should do.”

Kodan said, “More research is needed to better understand how these findings translate to the effectiveness of BBV 152 against delta and other forms of anxiety, particularly severe COVID-19.” Infections, hospitalizations and deaths are related.”

The authors acknowledge that the vaccine effectiveness of Covaxin estimated in this study is lower than the efficacy reported by a recently published Phase 3 trial. He noted that several factors may have been responsible for the vaccine’s reduced effectiveness in the latest study.

The researchers said that this study population includes only hospital workers, who may be at higher risk of exposure to COVID-19 infection than the general population.

He said the research was conducted during the peak of the second wave of COVID-19 in India, which had high test positivity rates for both hospital staff and residents of Delhi.

According to the researchers, the prevalence of circulating forms of anxiety, especially delta, may also have contributed to the vaccine’s low effectiveness.

The authors acknowledge several limitations to their study.

The study does not estimate the vaccine’s effectiveness against hospitalization, serious illness and death, which requires further evaluation, they noted.

In addition, the study was not designed to estimate vaccine effectiveness for different time intervals after vaccination or to determine whether vaccine effectiveness changed over time, the researchers said. PTI Saree


(Except for the title, this story has not been edited by NDTV staff and is published from a syndicated feed.)


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