Zydus Cadila's India-developed anti-Covid jab ZyCoV-D secured regulatory approval on Friday for emergency use, becoming the world's first DNA-based vaccine for the novel coronavirus that will be administered to children above 12 years and adults.

The company has indicated a supply of around five crore doses by December, a senior official said. The delivery of vaccines is likely to begin by next month-end. The DNA-based vaccine is the sixth shot to receive approval in India.

While the government is yet to sign a final agreement with Cadila, supplies to the national programme are set to be augmented.

To start with, the company will supply around one crore doses in a month. Pankaj R Patel, chairman, Cadila Healthcare, told that the vaccine showed 66% efficacy against moderate Covid infection and 100% against severe Covid, preventing serious disease and hospitalisation. The clinical trials were conducted on over 28,000 subjects, including kids, and were done when the Delta variant was prevalent across the country. This has been the largest vaccine trial so far in India for Covid-19.

According to the WHO, DNA technology is a radically new approach to vaccination that involves direct introduction of a plasmid containing the DNA sequence encoding the antigen (in this case the Covid virus) against which an immune response is sought. "This approach offers a number of potential advantages over traditional approaches, including stimulation of both B and T-cell responses, improved vaccine stability, absence of any infectious agent and the relative ease of large-scale manufacture," says the WHO.

(With inputs from agencies)