ZyCoV-D, an indigenously developed product may well be on its way to becoming the world's first licenced DNA COVID vaccine. Once approved, this vaccine could be a game-changer especially because of the way it has been developed and its safety.

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Introduction

Zydus Cadila of Gujarat has informed the Indian government that it would submit an application for emergency usage authorisation within the next 10-12 days. A DNA vaccination introduces the genetic code for the portion of a virus that activates the body's immune system into the body. The message is decoded by the host cell's own machinery, which causes the antigen to be produced and the immune system to be stimulated. This guarantees that when an infection does occur and the SARS-CoV-2 enters the body, the immune system is already prepared to recognise it and understands how to fight it most effectively.

How are the antibodies generated with DNA vaccines?

DNA vaccines are made up of bacterial plasmids containing the desired protein's gene, as well as a transcription promoter and terminator. The plasmid is able to replicate in a variety of cells, including myocytes, keratinocytes, and antigen-presenting cells (APCs). It reaches the nucleus as an episome, not integrating with the host cell's DNA. The inserted gene is translated into antigen using the host cell's transcription and translation machinery. A protein produced by plasmid-transfected cells is likely to be folded in its natural form within the cell. APCs detect the antigen, which further generates antibodies and cellular response.

ZyCov-D will be the first vaccination with a three-dose regimen. The second and third dosages should be taken on days 28 and 56, respectively. Zydus Cadila has enrolled over 28,000 volunteers in its phase three research and has completed the majority of the study's objectives.

How safe is it to administer ZyCoV-D?

The vaccine was proven to be safe in phase I and phase II clinical studies. The phase 2 study enrolled 1,000 adult volunteers and was done as part of an adaptive phase I/II dose-escalation, multi-centric, randomised, double-blind, placebo-controlled trial.

Both ZyCoV-D and the vaccines produced by American firms Pfizer and Moderna are classified as "nucleic acid vaccines." The sole distinction is that the latter two employ messenger RNA to deliver identical information to the body.

A senior government official who has been at the forefront of talks and meetings with vaccine makers explained, “Zydus Cadila has informed us that they would submit an emergency use authorisation application within the next 10-12 days, which means we might see another indigenous vaccine very soon. However, there has been no discussion about the vaccine's cost because the firm is currently determining it. We must bear in mind that this is a novel technology.”

However, authorities stated that even if Zydus receives approval from India's Drug Controller General, the company's production capability is insufficient to add significantly to the country's COVID-19 immunisation programme, at least in terms of volume. The government believes that the organisation may produce around 5 crore doses between August and December 2021. As ZyCoV-D is an indigenous vaccine, in contrast to Sputnik, which was imported in its first few million doses it may be acquired by the Government of India immediately upon obtaining required permissions and stocks. “Because it is an indigenous vaccine, the Government of India will purchase 75% of the supply when it becomes available. We are willing to do it even for Sputnik, but the vaccine must be manufactured locally,” the official stressed.

ZyCov-D vaccination-A game changer

1. ZyCoV-D is the world's first DNA coronavirus vaccine. The vaccine is composed of genetic material that instructs human cells to produce the SARS-CoV-2 antigen.

2. Children were also involved in the experiment. Thus, if the vaccine is approved by the DCGI, it will be India's first vaccination for children under the age of 18.

3. Additionally, this is the first vaccination to include three doses. The second and third dosages should be taken on days 28 and 56, respectively.

Dr VK Paul, a member of the Niti Aayog (health), stated,

"We hope they will apply in the near future. The majority of their research is complete. Their phase 3 research has enlisted almost 28,000 people. We anticipate they will submit the results shortly. We are hoping about this vaccination since it would be the first of its kind on the globe. We are really pleased with their accomplishments."

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.

The author is a practising super specialist from New Delhi.