GS Question

The basic principle behind vaccine development is to stimulate the immune system to recognize and fight off specific pathogens, such as viruses or bacteria. Vaccines work by presenting a weakened or inactivated form of the pathogen or a piece of the pathogen (such as a protein) to the immune system. This triggers an immune response and the production of antibodies, which are specialized proteins that can recognize and neutralize the pathogen. This immune response creates a memory, so that if the person is later exposed to the actual pathogen, their immune system can quickly recognize and mount a defense against it, preventing or lessening the severity of the infection.

In India, several vaccine manufacturers adopted different approaches to produce COVID-19 vaccines:

1. Covishield by Serum Institute of India: This vaccine is developed in collaboration with Oxford University/AstraZeneca. It uses a viral vector approach where a weakened chimpanzee adenovirus, carrying the gene for the COVID-19 spike protein, is used. When the vaccine is administered, the immune system recognizes the spike protein and mounts a defense.

2. Covaxin by Bharat Biotech: Covaxin is a whole-virion inactivated vaccine. It is made by growing the SARS-CoV-2 virus in the laboratory and then killing it using chemicals or heat. The inactivated virus stimulates an immune response without causing the disease.

3. ZyCoV-D by Zydus Cadila: ZyCoV-D is a DNA-based vaccine. It uses a small, circular piece of DNA known as a plasmid, which contains the gene for the spike protein of SARS-CoV-2. Once injected, the plasmid enters the body's cells, and the spike protein is produced, triggering an immune response.

These vaccine approaches have undergone rigorous testing and have been authorized for emergency use by regulatory authorities in India.