The Drug Controller General of India has given the Emergency Use Authorization for the ZyCov-D vaccine. This is the first approved DNA needle-free vaccine against COVID-19 and the pharmaceutical company Zydus Cadila reports efficacy of 66 percent against the disease.
The vaccine will be delivered in three doses each 28 days apart. It was well-tolerated and safe. It was tested in over 28,000 volunteers including 1,000 adolescents between 12 and 18. The approval will allow for this age group to be immunized in India. The company expects to produce between 100 and 120 million doses every year.
“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 immunization drive. 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. I would like to thank all the researchers, clinical trial investigators, volunteers and the regulators who have supported this endeavour,” Mr. Pankaj R. Patel, Chairman of Cadila said in a statement.
DNA vaccine works differently from vector-based vaccines such as the AstraZeneca one, where a genetically modified and harmless virus is used to stimulate the immune response. Instead, it uses a plasmid, which is a small loop of DNA that can replicate and it can be used to stimulate the human body to produce the spike proteins of the virus.
These proteins are used by SARS-CoV-2, the virus that causes COVID-19, to attach itself to cells. When such proteins are produced by our own organism it generates an immune response. Our immune system learns that these need to be dealt with and quickly.
The advantage of DNA vaccines is the ability to make such vaccines quickly, cheaply, and safely. It also allows for the development of updated versions very rapidly. This could be particularly useful in the fight against the emerging variants, such as the Delta one which has been the most common in many countries across the world. It is stored at a regular fridge temperature and can survive at room temperature for months without degrading.
Data from Phase I of the clinical trial was recently published in the journal EClinicalMedicine, published by the Lancet. There is certainly a lot of interest in the data from the full trial as previous attempts at crafting a DNA vaccine have not worked out. In particular, several approaches showed great promise in animal models but couldn’t be translated into humans. If the approach has been cracked, this could be revolutionary.
There are hundreds of DNA vaccines being investigated, many of them hoping to use this approach to fight cancer, parasitic diseases, influenza, and HIV among many other diseases.