The Central Drugs Standard Control Organisation (CDSCO), the national regulator of pharmaceutical products in India created history on August 20th, by approving a DNA-based vaccine against COVID-19. This is the first instance when a DNA-based vaccine has been approved for use in humans ever. Previously, DNA-based vaccines were first tried out in the 1990s and were approved for veterinary use. So, what was stopping them from being used in humans?

How Does a DNA Vaccine Work?
Conventional vaccines use live attenuated organisms or a part of them as an antigen to induce an antibody response. DNA-based vaccines carry this information in plasmids and rely on host cell machinery to express them. To do this, the plasmid first needs to enter the host cell nucleus. Depending on the host, a specific promoter sequence is used to ensure the plasmid DNA transcription. The cellular protein-making mechanism then follows up to make up the antigen and express it.