ZyCoV-D, Zydus Cadila's needle-free COVID-19 vaccine gets DCGI nod; all you need to know

ZyCoV-D, a needle-free three-dose COVID-19 vaccine developed by Indian pharmaceutical firm Zydus Cadila received an emergency use license in India on Friday, after a government panel recommended the same to India's central drug authority.The Ahmedabad-based pharma major had on 1 July applied for emergency use authorisation (EUA) with the Drug Controller General of India (DCGI) for the vaccine. The company said it has conducted the largest clinical trial for the vaccine in India in over 50 centres so far.Why is this relevant?ZyCoV-D is the world's first DNA vaccine against the SARS-Cov-2 virus infection, developed by an Indian company and become the sixth vaccine that has been approved for use in the country after Serum Institute's Covishield, Bharat Biotech's Covaxin, Russia's Sputnik V and the US-made Moderna and Johnson and Johnson.It is also the first vaccine candidate in India that has been found safe for use in children above the age of 12. Countries like US, France and Germany are already at various stages of providing vaccines for minors. In India, apart from ZyCoV-D, Bharat biotech's Covaxin is also under trial for use among the 2 to 18-year-old population.Zydus Cadila, that already has anti-COVID treatments available in the market claimed to have conducted the largest clinical trial in India so far at over 50 centers and the participants included people between age group 12 and 18 years. The Covaxin trial includes 525 minor volunteers.How is it different from other vaccines?

•  ZyCoV-D is a three-dose vaccine, unlike Bharat Biotech's Covaxin and Serum Institute of India-manufactured Covishield jabs.

However, the company said it has also evaluated a two-dose regimen for ZyCoV-D vaccine using a 3-milligram dose per visit and the immunogenicity results had been found to be equivalent to the current three-dose regimen.This will further help in reducing the full course duration of vaccination while maintaining the high safety profile of the vaccine in the future, the company added.

• ZyCoV-D is touted to be a 'needle-free' vaccine.

It is an intradermal vaccine, which is applied using The PharmaJet needle-free system.  Needle-free injectors deliver the vaccine using a narrow stream of fluid to penetrate the skin and deliver the vaccine to the proper tissue depth. The company says this methodology can eliminate chances of needlestick injury and will also lead to a significant reduction in any kind of side effects. It will also help people suffering from trypanophobia, a common condition marked by an irrational fear of blood or needles. It's estimated that fear of needles affects up to 25 percent of adults.

• ZyCoV-D is not very sensitive to temperature, unlike its competitors. The prescribed storage temperature is between 2 to 8 degrees centigrade but has shown good stability at temperatures of 25 degrees centigrade as well for at least three months.

The thermostability of the vaccine will help in easy transportation and storage of the vaccine and reduce any cold chain breakdown challenges leading to vaccine wastage.

• The plasmid DNA platform provides ease of manufacturing with minimal biosafety requirements.

It can be manufactured at a BSL-1 grade lab which brings down the cost of production and ensures that the cost of expanding production units. In comparison, Covaxin needs a Bio-Safety Level 3 lab to manufacture the jab.

• The Plasmid DNA platform also allows generating new constructs quickly to deal with mutations in the virus, such as those already occurring

The science behind the jab: How does it work?ZyCoV-D is a plasmid DNA vaccine which when injected produces the spike protein of the SARS-CoV-2 virus and elicits an immune response mediated by the cellular and humoral arms of the human immune system, which play a vital role in protection from disease as well as viral clearance.In simpler words, it means that the vaccine is manufactured by creating a close enough copy of the virus' DNA sequence so that no harm or disease is caused, but the immune system response is triggered when the body encounters the real virus the next time.Interim efficacy resultsThe vaccine has shown a primary efficacy of 66.6 percent for symptomatic RT-PCR positive cases in the interim analysis. Whereas, no moderate case of COVID-19 disease was observed in the vaccine beneficiaries post administration of the third dose suggesting 100% efficacy for moderate disease.No severe cases or deaths due to COVID-19 occurred in the vaccine recipients after administration of the second dose of the vaccine.

However, its phase three trial data is not yet peer-reviewed.

The vaccine manufacturers also claimed that the vaccine's efficacy data were collected through India's largest clinical trial for a coronavirus vaccine so far. A study carried out in more than 50 clinical sites spread across the country and during the peak of the second wave of COVID-19 reaffirming the vaccine's efficacy against the new mutant strains especially the delta variant, Cadila Healthcare managing director Dr Patel said.He also emphasised that the plasmid DNA platform is ideally suited for dealing with COVID-19 as it can be easily adapted to deal with mutations in the virus. Moreover, the DNA vaccines offer a number of potential advantages over traditional approaches that include stimulation of both B and T cell responses, improving the vaccine stability, says WHO.Availability and pricingThe company said that it can be ready for rollout within 45 to 60 days of getting approval. The company plans to manufacture 10 to 12 crore doses annually in the early stages. However, the company did not give any hint on the expected price of the vaccine jab. It clarified that the price of the vaccine will be charged separately and the needle-free applicator will come at a separate cost. The company has, however, not yet decided if it will roll out the final product by clubbing the prices of the jab and the applicator."It is too early to comment on the pricing. That discussion is yet to happen. We will announce the price before the commercial launch of ZyCoV-D," Patel told a press conference. He said that so far up to Rs 500 crore has been invested in the development of the Zydus vaccine.