Covid-19 vaccine: Promising results seen in monkeys given Bharat Biotech's COVAXIN

This is a confidence boosting advancement in the trials towards confirming Covaxin's safe human utility, Dr Rakesh Mishra, director of CSIR-Center for Cellular and Molecular Biology tells DH

COVAXIN, India’s first vaccine candidate for Covid-19, has shown protective efficacy and immunogenicity in non-human primates, Bharat Biotech announced on Friday.

The development comes as a strong morale booster for the researchers testing the vaccine on humans at 12 medical centres across the country including AIIMS, New Delhi.

The BBV152, popularly known as Covaxin, was developed by the Hyderabad based BBIL in collaboration with the Indian Council of Medical Research (ICMR) and the National Institute of Virology (NIV) and is at present in Phase-II human trials.

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According to Bharat Biotech International Limited, which cited a collaborative study by researchers from the ICMR-NIV, BBIL, Armed Forces Medical College etc. institutions, a two-dose vaccination regimen of inactivated SARS-CoV-2 vaccine candidates was administered in 20 rhesus macaques, divided into four groups equally.

One group was administered with placebo, while three groups were immunized with three different vaccine candidates at 0 and 14 days. All the macaques were exposed to viral challenge 14 days after the second dose.

The results showed protective efficacy, increasing SARS-CoV-2 specific IgG and neutralizing antibodies, reducing the replication of the virus in the nasal cavity, throat, and lung tissues of monkeys.

No evidence of pneumonia was observed by histopathological examination in vaccinated groups, unlike the placebo group. Adverse events were (also) not seen in animals immunized with a two-dose vaccination regimen.

“To summarize, the vaccine candidate was found to generate robust immune responses. Thus, preventing infection and disease in the primates upon high amounts of exposure to live SARS-CoV-2 virus,” the biotech firm stated.

Dr Rakesh Mishra, director of the premier CSIR-Center for Cellular and Molecular Biology views this outcome on monkeys, with close link to humans, as a confidence-boosting advancement in the trials to confirm COVAXIN's safe human utility.

“These results are definitely a very good indication that the Covaxin could show positive effects in humans too,” Dr Mishra told DH.

While the Phase I safety of the vaccine is yet to be revealed, the DCGI had earlier this month accorded permission to BBIL to proceed with Phase-II trials which maps the efficacy of the vaccine.

“The stage-3 trials, where the safety and efficacy of the vaccine is tested on a large scale on humans, would be the crucial test for Covaxin,” Dr Mishra says.

The BBIL announcement through twitter comes at a time when the advanced human trials of the most promising Covid-19 vaccine candidate developed by the Oxford University and AstraZeneca had to be suspended following the detection of illness in a female volunteer.