India's first COVID-19 vaccine Covaxin journey: From test results to phase 3 trial, latest updates

Developed by Bharat Biotech in collaboration with the Indian Council of Medical Research (ICMR), Covaxin is currently in the phase II clinical trial in the country. Hyderabad-based Bharat Biotech earlier released the animal study results of Covaxin. "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 drugmaker said.

In the early stage of human trials, Covaxin has been tested in 12 hospitals across the country. Volunteers between the ages of 18 and 55 with no co-morbidity conditions have participated in the trial. The vaccine trial took place in Hyderabad, Rohtak, Patna, Kancheepuram, Delhi, Goa, Bhubaneswar and Lucknow among other places.

Covaxin will use adjuvant Alhydroxiquim-II to boost immune response and longer lasting immunity, the firm said last week. The technology is being used under a licensing agreement with Kansas-based ViroVax, said Bharat Biotech.

"There is critical need for development and availability of adjuvants that elucidate mechanisms of action inducing greater antibody responses to vaccine antigens, thus resulting in long-term protection against pathogens. Adjuvants also enhance the sustainability of the global vaccine supply on account of their antigen-sparing effect," Krishna Ella, chairman and managing director of Bharat Biotech said.

How does Covaxin work?

Covaxin has been derived from a strain of the novel coronavirus isolated by the National Institute of Virology in Pune. Bharat Biotech developed an “inactivated" vaccine at its high-containment facility at Genome Valley in Hyderabad.

“Once the vaccine is injected into a human, it has no potential to infect or replicate, since it is a killed virus. It just serves to the immune system as a dead virus and mounts an antibody response towards the virus," Bharat Biotech said.

For phase III trial, the drugmkaer plans to enroll 28,500 volunteers aged 18 years and above. The trial will be conducted across 10 states including Delhi, Mumbai, Patna and Lucknow. The phase III clinical trial application proposed a dose of 0.5 ml on day 0 and 28, sources told PTI.

COVID-19 vaccine candidates in India

India's coronavirus vaccine production and delivery capacity will help all humanity in fighting the pandemic, said Prime Minister Narendra Modi at the United Nations General Assembly last month. "As the largest vaccine producing country of the world, I want to give one more assurance to the global community today. India's vaccine production and delivery capacity will be used to help all humanity in fighting this crisis," he added.

Besides, Bharat Biotech, another vaccine candidate developed by Zydus Cadila Ltd is in the phase II of the human clinical trials. Serum Institute of India has partnered with AstraZeneca for manufacturing the COVID-19 vaccine candidate developed by the University of Oxford. Pune-based drugmaker is conducting Phase II and III human clinical trials of the candidate in India.