From COVAXIN to Zydus Cadila, Indian coronavirus vaccines in human trials: Explained

Where do Indian vaccine candidates stand in the global race?


The coronavirus vaccine development process is speeding up globally, with UK's Oxford-AstraZeneca candidate the clear frontrunner. It is currently in large-scale, late-stage trials. Another candidate by US National Institutes of Health (NIH) and Moderna Inc is not far behind, and experimental trials on a vaccine under preparation by American pharmaceutical giant Pfizer and European biotechnology company BioNTech SE have shown great promise (as per non peer-reviewed studies).

So, where does India figure in all this? At least seven Indian companies—Zydus Cadila, Serum Institute, Biological E, Bharat Biotech, Indian Immunologicals, Mynvax and Panacea Biotec—are working on a vaccine.

In the latest development, indigenously developed Bharat Biotech's COVAXIN and another candidate developed by Ahmedabad-based Zydus Cadila Healthcare Ltd have both received nods from Drugs Controller General of India (DCGI) for human clinical trials.

What does this mean?

Generally, the vaccine development is done in different phases. There is a pre-clinical stage, where the vaccines are tested in animals to check its safety and its immune response—whether antibodies are being produced. Once it gets approval for human testing (which is where COVAXIN and Zydus Cadila have reached), there are three phases. 

There will be small-scale safety trials in Phase I, to check its effects on humans. Phase II is a mid-scale trial with over 100 volunteers, where dosage, frequency and the effects of its variations are checked. In Phase III, there will be large-scale trials— randomised testing where thousands will be tested in placebo and vaccine groups. 

Where do the Indian candidates figure in the global vaccine race?

They are doing quite well, given a couple are about to enter Phase I human trials (globally, among more than 200 candidates, only 15 have entered clinical trials). However, they are far behind the frontrunners Oxford-AstraZeneca and Moderna Inc. The Phase I and Phase II human trials of the Indian vaccine candidates are expected to take around four months to complete. Speaking to THE WEEK at the end of May, Professor K. VijayRaghavan, principal scientific adviser to the government, had said that 30 groups, including academic and industry players in India, are working on a vaccine against COVID-19. About 20 of them are keeping good pace. Vaccine efforts in India were divided into four categories—mRNA (one component of the genetic material of the virus is injected), attenuated (a weak version of the virus), vector backbone and adjuvant vaccines. 

COVAXIN: Developed by Bharat Biotech in collaboration with ICMR and NIV, this has received the nod for human clinical trials from the DGCI. The Phase I and Phase II clinical trials, which were approved after pre-clinical studies demonstrated safety and immune response, will start across the country next month. The indigenous and inactivated vaccine has been developed at Bharat Biotechs BSL-3 (Bio-Safety Level 3) high containment facility located in the Genome Valley.

Zydus Cadila: Ahmedabad-based Zydus Cadila Healthcare Ltd was also approved by the DGCI; the process was fast-tracked following recommendation by the subject expert committee on COVID-19, considering the emergency and unmet medical need during the pandemic, reports emerged on Friday. The assent for human trials was given after the company submitted data of clinical trial on animals to the DCGI, in which the vaccine candidate was found to be successful with respect to safety and immunogenicity.

The global vaccine race

According to WHO chief scientist Soumya Swaminathan, Oxford-AstraZeneca vaccine candidate is the leading contender, already in large-scale trials. US's Moderna Inc is close on the heels, set to go into Phase III trials by the end of July.

The Oxford-AstraZeneca vaccine is being tested in Brazil. Some 2,000 Brazilians will be selected to participate in Sao Paulo and Rio de Janeiro, in a project coordinated by the Federal University of Sao Paulo. British drugs giant AstraZeneca had struck up a "landmark partnership" with the Oxford University team and said that 100 million doses could be made by the end of the year if the trials prove successful.

The vaccine made by the NIH and Moderna contains no actual, attenuated virus; rather, it is an mRNA vaccine. Those shots contain the genetic code for the aptly named spike protein that coats the surface of the coronavirus and gives it the signature shape. That is, Moderna's mRNA-1273 candidate is encoded with the mRNA (messenger RNA, which consists a genetic code) instructions for the coronavirus’s signature spike protein. Thus, human cells create the foreign protein, alerting the immune system, and help the body recognise the entry of the virus in all its forms. The mRNA vaccine is easier to make, but it is a new and unproven technology.

-Inputs from PTI