ZyCoV-D is a DNA plasmid-based

COVID-19 vaccine A COVID19 vaccine is a vaccine intended to provide acquired immunity against severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2), the virus that causes coronavirus disease 2019 ( COVID19). Prior to the COVID19 pandemic, an es ...

developed by Indian pharmaceutical company

Cadila Healthcare Zydus Lifesciences Limited, formerly known as Cadila Healthcare Limited, is an Indian multinational pharmaceutical company headquartered in Ahmedabad, which is primarily engaged in the manufacture of generic drugs. It ranked 100th in the Fortu ...

, with support from the

Biotechnology Industry Research Assistance Council The Department of Biotechnology (DBT) is an Indian government department, under the Ministry of Science and Technology responsible for administrating development and commercialisation in the field of modern biology and biotechnology in India. It ...

. It is approved for emergency use in India.

Technology

The vaccine contains a DNA plasmid vector that carries the gene encoding the spike protein of SARS-CoV-2. As with other

DNA vaccine A DNA vaccine is a type of vaccine that transfects a specific antigen-coding DNA sequence into the cells of an organism as a mechanism to induce an immune response. DNA vaccines work by injecting genetically engineered plasmid containing the D ...

s, the recipient's cells then produce the spike protein, eliciting a protective immune response. The plasmid also contains unmethylated CpG motifs to enhance its immunostimulatory properties. The plasmid is produced using ''E. coli'' cells. The vaccine is given as an

intradermal injection Intradermal injection, often abbreviated ID, is a shallow or superficial injection of a substance into the dermis, which is located between the epidermis and the hypodermis. For certain substances, administration via an ID route can result in a ...

using a spring-powered

jet injector A jet injector is a type of medical injecting syringe device used for a method of drug delivery known as jet injection, in which a narrow, high-pressure stream of liquid penetrates the outermost layer of the skin (stratum corneum) to deliver med ...

. This is because successful transfection of DNA vaccines requires traveling across both the cell plasma membrane and the nuclear membrane, and using a conventional needle gives poor results and leads to low immunogenicity.

Clinical trials

Pre-clinical trials

In February 2020,

decided to develop a DNA plasmid based

at their Vaccine Technology Centre (VTC) in Ahmedabad. The vaccine candidate was able to pass the pre-clinical trials on animal models successfully. A report of the study was made available via ''

bioRxiv bioRxiv (pronounced "bio-archive") is an open access preprint repository for the biological sciences co-founded by John Inglis and Richard Sever in November 2013. It is hosted by the Cold Spring Harbor Laboratory (CSHL). As preprints, papers ...

'' and later published in the journal '' Vaccine''. Thereafter, human trials for Phase I and II were approved by the regulator.

Phase I and II trials

Phase I trials of the vaccine candidate started on 15 July 2020 and continued until October 2020. The vaccine candidate was tested on 48 healthy individuals in the 18–55 age range, with 28 days between each of the three doses. The trial found the vaccine to be "safe, well-tolerated and immunogenic". Cadila Healthcare began phase II trials of the vaccine candidate from 6 August 2021 with over 1,000 volunteers as part of the adaptive Phase I/II multi-centric, dose escalation, randomised, double-blind placebo controlled method. The company reported that phase II trials were completed by November 2020.

Phase III trials

In November 2020, the company announced it would test the vaccine candidate on about 30,000 patients in Phase III trials. In January 2021, the

Drugs Controller General of India Drugs Controller General of India (DCGI) is the head of department of the Central Drugs Standard Control Organization of the Government of India responsible for approval of licences of specified categories of drugs such as blood and blood pr ...

(DCGI) granted permission to conduct the Phase III clinical trials for 28,216 Indian participants in the 12–99 age group. Of this, about 1,000 individuals were in the 12–18 age group. Interim results from the phase III trials were made available in July 2021. On 1 July 2021, Cadila Healthcare reported the efficacy to be 66.6% against symptomatic COVID-19 and 100% against moderate or severe disease in its interim analysis of its phase 3 trial data.

Authorizations

On 1 July 2021,

applied to the

(DCGI), seeking approval for Restricted Use in Emergency Situation for the vaccine. On 20 August 2021, the Subject Expert Committee of the

Central Drugs Standard Control Organisation The Central Drugs Standard Control Organisation (CDSCO) is India's national regulatory body for cosmetics , pharmaceuticals and medical devices. It serves a similar function to the European Medicines Agency of the European Union, the PMDA of Jap ...

(CDSCO) recommended that the DCGI grant the approval, which the DCGI then granted on the same day.

Deployment

On 23 April 2021, production of the ZyCoV-D vaccine was started, with a yearly capacity of 240 million doses.

References

External links

* * {{DEFAULTSORT:ZyCoV-D Products introduced in 2020 Clinical trials Indian COVID-19 vaccines DNA vaccines