Homegrown healthcare and pharmaceutical major Zydus Cadila has applied for emergency use authorisation (EUA) to the office of the Drug Controller General of India for ZyCoV-D, its plasmid DNA vaccine against Covid-19. "As the first-ever plasmid DNA vaccine for human use, ZyCoV-D has proven its safety and efficacy profile in our fight against Covid-19. The vaccine, when approved, will help not only adults but also adolescents in the 12-to-18-years age group," said Dr Sharvil Patel, MD, Cadila Healthcare Ltd, the flagship of the Ahmedabad-based Zydus Cadila Group.
What is the ZyCov-D vaccine, and how does it work?
ZyCov-D is a “plasmid DNA” vaccine - or a vaccine that uses a genetically engineered, non-replicating version of a type of DNA molecule known as a ‘plasmid’. The plasmids in this case are coded with the instructions to make the spike protein of SARS-CoV-2, the coronavirus that causes Covid-19. Vaccination gives the code to cells in the recipient’s body, so they can begin making the spiky outer layer of the virus. The immune system is expected to recognize this as a threat and develop antibodies in response.
Most Covid-19 vaccines currently are given in two doses, with a couple of single-shot ones also available. ZyCov-D by contrast, will be given in three doses, with an interval of 28 days between the first, second and third shots. The other unique thing about the vaccine no needle is used - instead, a spring-powered device delivers the shot as a narrow, precise stream of fluid that penetrates the skin. ZyCov-D has been developed with the support of the central government’s Department of Biotechnology and the Indian Council of Medical Research (ICMR).
How safe and effective is the vaccine?
ZyCov-D has been tested in phase 1, 2 and 3 clinical trials involving over 28,000 participants in all. A thousand of these participants were of ages between 12 and 18 years. In December 2020, Zydus Group chairman Pankaj R Patel had said that the first two phases of the trial showed that the vaccine was “safe and immunogenic”.
According to trial data so far, the vaccine has been able to bring down symptomatic cases of Covid-19 in those who received doses by nearly 67 per cent compared with those who did not get a vaccine. This is based on 79 to 90 RT-PCR confirmed cases of Covid-19 from those vaccinated in the phase 3 trials, Dr Patel said.
Two doses of the vaccine seem to be enough to prevent people from developing severe symptoms of Covid-19 and to prevent death, while three doses keep even moderate symptoms at bay, according to trial data.
If cleared, by when will this vaccine be available, and what will it cost?
Zydus is setting up a new facility to manufacture up to 120 million doses a year. This would mean up to 40 million people can be vaccinated with three shots of ZyCov-D in a year. The new facility is expected to be ready by the end of this month, and production is expected to begin by mid-August, according to Dr Patel. The company will be producing 10 million doses every month then on, and hopes to supply 50 million doses to the country by December. The company has not yet decided on a price of the vaccine, Dr Patel said.
