Zydus Cadila on Friday announced that it has received Emergency Use Authorisation from the Drug Controller General of India for ZyCoV-D - the world's first plasmid DNA vaccine for Covid-19.ZyCoV-D is a three-dose vaccine which will be administered first on day zero, the 28th and then on the 56th day.With this approval, India now has its first Covid-19 vaccine for the adolescents in the 12-18 age group, besides the adult population, the company said in a statement."This is a historic milestone with ZyCoV-D, a product of Indian innovation becoming the world's first DNA vaccine being offered for human use and supporting the world's largest immunisation drive," Cadila Healthcare Chairman Pankaj R. Patel said in a statement."We are particularly happy that our vaccine will contribute to this fight against Covid-19 and enable the country to vaccinate a larger population, especially in the age group of 12-18 years," he added.ZyCoV-D is a needle-free vaccine administered using the PharmaJet -- a needle free applicator, which ensures painless intra-dermal vaccine delivery.The company plans to manufacture 10-12 crore doses of ZyCoV-D annually.It also plans to seek approval for the two-dose regimen of the vaccine.ZyCoV-D is a Plasmid DNA vaccine which, when administered, 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.The Covid-19 vaccine was also tested in the adolescent population in the 12-18 years age group in India and was found to be safe and very well tolerated.ZyCoV-D had already exhibited a robust immunogenicity and tolerability and safety profile in the adaptive Phase 1/2 clinical trials carried out earlier. Both the Phase 1/2 and Phase 3 clinical trials have been monitored by an independent Data Safety Monitoring Board.The vaccine is stored at 2-8 degrees Celsius but has shown good stability at temperatures of 25 degrees Celsius for at least three months.