Following World Health Organization approval last week, interim data from a phase 3 trial of BBV152, a COVID-19 vaccine developed in India, reports 77.8% efficacy against symptomatic COVID-19. 

The study, published in The Lancet, indicated that BBV152 induced a robust antibody response, with the majority of adverse events, including headache, fatigue, fever, and pain at the injection site, were mild and occurred within seven days of vaccination. 

BBV152, also known as Covaxin, is an inactivated whole virion vaccine developed by India-based Bharat Biotech. The vaccine has recently received emergency use approval (EUL) from WHO for people aged 18 and older, and is administered in a two-dose regimen, 28 days apart. 

The trial conducted an efficacy analysis of 24,419 randomly-assigned participants across 25 hospitals in India who received either two doses of the vaccine or a placebo between 16 Nov 2020 – 17 May 2021.

Vaccine cold-chain requirements make it suitable for low- and middle-income countries

Covaxin’s ability to be stored and transported between 2-8 degrees Celsius has made it suitable for  low- and middle-income countries.

Jing-Xin Li and Feng-Cai Zhu of the Jiangsu Provincial Center for Disease Control and Prevention in China, who were not involved with the study, say “the roll-out of BBV152 might ease the ultra-cold chain requirements of other SARS-CoV-2 vaccine platforms, increase the finite global manufacturing capacity, and improve insufficient supply of vaccines which disproportionately affects low-income and middle-income countries.” 

Bharat Biotech said the WHO EUL approval will help countries “expedite their regulatory approval processes to import and administer Covaxin.” 

“It allows procurement by UNICEF, the Pan-American Health Organization (PAHO), and the GAVI COVAX for distribution to countries in need,” a company press release said. 

The Gavi managed COVAX global vaccine facility has not  yet  signed an agreement with Bharat Biotech, with India delaying committing supplies to the COVAX global sharing effort, sources told Reuters.  

The world’s biggest vaccine maker resumed exports of COVID-19 doses in October, for the first time since April. It has sent about 4 million doses to countries such as neighboring Bangladesh and Iran, but none to COVAX.  

The vaccine has, however, been distributed widely already in India, with 121 million doses administered since the beginning of the country’s big COVID surge in the spring of 2021. 

Covaxin gears up for major distribution abroad 

Following the WHO approval and publication of its Phase 3 results, Covaxin is gearing up for major distribution abroad.

Airfinity’s COVID-19 Vaccine Market Forecast 2021 – 2022, which covers global demand scenarios, supply and production, and revenue of COVID vaccine, has predicted 545 million Covaxin doses will be sold to low-middle-income countries in 2022.

As many as 96 countries have already recognized Covaxin, with Hong Kong the latest to approve the vaccine for international travelers. 

Canada, the US, Australia, Spain, the United Kingdom, France, Germany, Belgium, Russia, and Switzerland, are among the 96 nations to recognize both Covaxin and Covishield, another India-manufactured vaccine. 

Further research needed against COVID-19 variants 

The next step for studies of BBV152, noted Li and Zhu, should be long-term monitoring of vaccine efficacy against COVID-19 and its efficacy against variants. 

This is to “identify whether the vaccine provides ongoing protection when any variation of concern replacement (other than the variants of concern investigated in the study) has occurred,” they said. 

Preliminary analysis of efficacy found Covaxin to be 65% effective against symptomatic COVID-19 from the delta variant. 

Additionally, there was no decrease in efficacy against the alpha variant (B.1.1.7) and marginal reductions in efficacy against other variants of concern, including delta and gamma variants.

Image Credits: Mohammed Naseeruddin/Twitter, Airfinity.