Vaccine maker Bharat Biotech on Friday announced that the animal trials of its Covid-19 vaccine candidate Covaxin were successful.
It said the results demonstrated the protective efficacy of the vaccine in a live viral challenge model.
"Bharat Biotech proudly announces the animal study results of COVAXIN - These results demonstrate the protective efficacy in a live viral challenge model," tweeted the Hyderabad-based firm.
It said the data from the study on primates substantiate the immunogenicity of the vaccine candidate.
According to a detailed statement attached to the tweet, Bharat Biotech developed and assessed the protective efficacy and immunogenicity of an inactivated SARS-CoV-2 vaccine (BBV152) or Covaxin in rhesus macaques (Macaca mulata). Twenty macaques were divided into four groups of five animals each.
"One group was administered a placebo while three groups were immunised with three different vaccine candidates at 0 and 14 days. All the macaques were challenged with SARS-CoV-2 14 days after the second dose. The protective response was observed with increasing SARS-CoV-2 specific IgG and neutralising antibody titres from third week post-immunisation," it said.
"Viral clearance was observed from bronchoalveolar lavage fluid, nasal swab, throat swab, and lung tissues at 7 days post-infection in the vaccinated groups. No evidence of pneumonia was observed by histopathological examination in vaccinated groups, unlike the placebo group which showed features of interstitial pneumonia and localisation of viral antigen in the alveolar epithelium and macrophages by immunohistochemistry."
"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," it added.
The vaccine is being evaluated in Phase-I clinical trials in India.
The vaccine maker early this month received approval from the Central Drugs Standard Control Organisation to conduct the Phase-II trials.
Bharat Biotech had announced on June 29 that it successfully developed Covaxin in collaboration with the Indian Council of Medical Research (ICMR) and the National Institute of Virology (NIV).
The SARS-CoV-2 strain was isolated in NIV, Pune and transferred to Bharat Biotech. The indigenous, inactivated vaccine candidate has been developed and manufactured in Bharat Biotech's high containment facility located in Genome Valley, Hyderabad.