Explainer: All you need to know about ZyCoV-D, needle free painless COVID vaccine

Cadila Healthcare (Zydus Cadila) on August 20 received Emergency Use Authorization (EUA) from the Drug Controller General of India (DCGI) for ZyCoV-D, the world's first and India's indigenously developed DNA-based vaccine for COVID-19 to be administered in humans including children above 12 years of age and adults.

Earlier, the Subject Experts Committee (SEC) of the Central Drugs Standard Control Organisation (CDSCO) has recommended ZyCoV-D vaccine, clearing a major hurdle for the vaccine's emergency use.

ZyCoV-D is the world's first plasmid DNA COVID-19 vaccine to be approved and the second indigenous vaccine to be rolled out.

Here is an explainer on its safety, efficacy, delivery, and capacities.

Zydus said ZyCoV-D exhibited a robust immunogenicity and tolerability and safety profile in the adaptive Phase I/II clinical trials. The three doses (2mg per dose) of the vaccine were found to have an efficacy of 66.6 percent for symptomatic RT-PCR positive cases in the interim analysis.

Needle-less vaccine

The vaccine is delivered through a needle-free applicator called the PharmaJet to ensure painless intradermal vaccine delivery.

Zydus Cadila has taken a novel approach for its potential COVID-19 vaccine. Called plasmid DNA, the vaccine consists of genetic material of SARS-CoV-2 proteins, which instruct human cells to make the SARS-CoV2 antigen, eliciting an immune response.

Challenges

Firstly, the platform is novel. Not a single human vaccine using this platform has been approved anywhere in the world. The other big challenge is that the vaccine has to be administered in three doses – the first dose, and the other doses after 28 and 56 days.

Being a three-dose vaccine adds an additional layer of distribution and administration complexity, possibly raising the cost of the vaccine. While the company has promised to ensure that the vaccine is affordable, it has also sought approval for a two-dose vaccine.