COVID-19: Animal trials prove efficacy of COVAXIN

Animal trials of Bharat Biotech International Limited’s Covid-19 vaccine candidate, Covaxin, have been successful and the results showed the shot’s “remarkable immunogenicity and protective efficacy” in the Phase I clinical trials in India, the drugmaker has said.

Covaxin, the indigenously developed Covid-19 vaccine, developed by the ICMR and Bharat Biotech International, is being tested at 12 institutes across India.

The Hyderabad-based firm said the data from the study on primates substantiate the immunogenicity of the vaccine candidate.

“Bharat Biotech proudly announces the animal study results of COVAXIN – These results demonstrate the protective efficacy in a live viral challenge model,” Bharat Biotech tweeted September 11.

Bharat Biotech has said in a release that it developed and assessed the protective efficacy and immunogenicity of an inactivated Sar-CoV-2 vaccine (BBV152) or Covaxin in rhesus macaques. Twenty macaques were divided into four groups of five animals each, it said.

One group was administered with placebo, while three groups were immunized with 3 different vaccine candidates at 0 and 14 days. All the macaques were exposed to viral challenge 14 days after the 2nd dose.

The results showed protective efficacy, increasing coronavirus specific IgG and neutralizing antibodies, reducing replication of the virus in the nasal cavity, throat, and lung tissues of monkey.

No evidence of pneumonia was observed by histopathological examination in vaccinated groups, unlike the placebo group.

Adverse events were not seen in animals immunized with a two-dose vaccination regimen.

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 coronavirus.

Covaxin is one of the frontrunners in the race for a covid-19 vaccine in India. It is an “inactivated” vaccine – it works by injecting doses of the virus that have been killed aiming to prompt the body to build antibodies against it without the virus a posing a threat.

Each stage of a vaccine’s clinical trial tests its safety and ability to develop an effective immune response. Phase 1 focuses on determining safety and dosage in a small group of healthy participants, while Phase 2 looks at the vaccine’s effectiveness. Phase 3 looks into these aspects in a much larger population that would represent a wider demographic.