Zydus Cadila Gets Emergency Use Nod: How is It Different From Others?

Zydus Cadila's COVID-19 vaccine has reported an efficacy of 66.6 percent against symptomatic cases.

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Zydus Cadila's three-dose COVID-19 vaccine, ZyCoV-D, has received emergency use authorisation (EUA) from the Drugs Controller General of India (DGCI), the Centre announced on Friday, 20 August. ZyCoV-D has been dubbed as the first plasmid DNA vaccine globally against COVID-19.

What is different about this vaccine? How safe is it? Here's all you need to know.

What type of vaccine is ZyCoV-D?

ZyCoV-D is a Plasmid DNA vaccine.

The DNA (and RNA) vaccines – a relatively new technology developed for the first time only in the 1990s – don't introduce a weakened form of the pathogen like traditional vaccines.

How does it work?

This type of vaccine works by carrying the genetic code of the virus. The plasmid vector is taken up into cells and transcribed in the nucleus. This is transferred to another mRNA molecule, which induces a cell-mediated immune response.

The Zydus vaccine is the first DNA vaccine to be produced in India.

In theory, DNA vaccines produce the same results as mRNA vaccines, and so the efficacy of the Zydus vaccine too is likely to be in the realm of the other mRNA vaccines already in the market, including Moderna, Pfizer, and Johnson & Johnson.

How different is it from Covishield and Covaxin?

Zydus vaccine has the same goal, and is likely to have the same results as the two existing vaccines manufactured in India, but where it differs is in the way it works.

Covaxin is a whole inactive virus type vaccine, and Covishield is a non-replicating viral vector type vaccine.

Both of which are relatively traditional, well established types of vaccine technology that work by introducing a part (in the Oxford vaccine it is the gene protein spikes found on the virus’ surface) or whole of the virus in a ‘harmless’ form to trigger the immune system into producing a large number of antigens to fight the actual virus.

How safe is it?

While Phases I and II of the trials showed no side effects after the vaccine.

Phase III trials have been completed for the vaccine, and it has reported an efficacy of 66.6 percent against symptomatic cases in the interim analysis, Moneycontrol reported.

When will it be available? What will be the price per dose?

ZyCoV-D is the sixth vaccine approved for use in India after Serum Institute's Covishield, Bharat Biotech's Covaxin, Russia's Sputnik V, and the US-made Moderna and Johnson & Johnson. It is likely to be available from September.