NEW DELHI: The chairman and managing director of Bharat Biotech, Dr Kishna Ella, said its Covid-19 vaccine, Covaxin, would be effective on mutant strains of the coronavirus, and therefore is justified to receive the emergency approval despite a lack of data on its efficacy and an incomplete Phase 3 trial.
“It’s only a hypothesis right now... Just give me one week’s time to come out with the data. I am confident it will work,” he said on Monday. The director-general of the Indian Council of Medical Research, Dr Balram Bhargava, too, had expressed confidence the vaccine would be effective against new variants of the coronavirus. ICMR and the National Institute of Virology worked with Bharat Biotech to create the vaccine.
To be clear, Pfizer, Moderna and AstraZeneca, too, have said their vaccines would be effective against the new variant of the virus first identified in the UK, since the mutations on it, including on the spike protein, have not drastically changed its characteristics.
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But there is a particular reason for Bharat Biotech’s confidence in its product: The vaccine is not relying on the production of spike protein to prompt an immune response but packs the actual virus itself, albeit inactivated, to kickstart the immune response.
Covaxin is an inactivated virus vaccine — a tried and tested science that has been used to develop vaccines against polio, rabies and hepatitis A. The NIV, alongside the ICMR, isolated samples of the coronavirus that was in circulation in the country. These viruses are then inactivated using chemicals so that they can no longer replicate thus making them incapable of causing Covid-19 — during an infection the virus replicates itself in our body after entering the cell, creating new copies.
The virus then is mixed with adjuvants to form the basic block of the vaccine, which when administered causes the immune system to wake up and begin its self-defence mechanism — summoning the B cells to create antibodies. The vaccine also prompts memory B cells, which can come to assistance once the antibody levels taper off — an expected process.
Hence, Bharat Biotech believes that by not relying solely on the spike protein, it has a better chance against new variants of the virus. For context, Pfizer’s and Moderna’s vaccines pack genetic material — messenger RNA — that instruct our cells to produce spike proteins, duping our immune system to believe the host has been infected.