World's 'first' DNA vaccine against coronavirus: All you need to know

Ahmedabad-based Cadila Healthcare has applied for an emergency-use authorisation (EUA)  (EUA) to the Drug Controller General of India, for its needle-free, DNA-plasmid, 3 doses vaccine, ZyCoV-D. Plasmid is an extrachromosomal DNA molecule with an ability to self replicate. So, when a plasmid DNA vaccine is injected, it produces the spike protein of the virus and builds an immune response mediated by the cellular and humoral arms of the human immune system. This approach not only helps protect humans from infection but also in viral clearance.

If Zydus’ ZyCoV-D gets nod from the officials, it will become India's fifth vaccine authorised for use after Covishield, Covaxin, Sputnik V and Moderna. However, unlike any of these vaccines, Zydus’ ZyCoV-D is a 3 dose vaccine with a needle-free application system. The company aims to produce 1 crore vaccine doses in a month. 

The plug and play technology on which the plasmid DNA platform is based is ideally suited for dealing with Covid-19 as it can be easily adapted to deal with mutations in the virus, such as those already occurring.

The vaccine has shown 66.6 per cent efficacy in interim analysis of Phase 3 trials. It can be stored at 2-8 degrees Celsius but shows better stability at 25 degrees Celsius for at least three months.

Zydus claimed to have conducted India’s largest clinical trial with 28,000 plus volunteers across the country and included subjects of 12-18 age group. This was the very first time any Covid-19 vaccine has been tested on children in India.  Roughly, 1,000 children enrolled for the test and found the vaccine safe for use. The tolerability profile was similar to that of adults