The basic principle behind vaccine development is to expose the body to a weakened or inactivated form of a pathogen, such as a virus or bacteria, in order to stimulate the immune system to produce antibodies against it. When the body is exposed to the actual pathogen at a later time, the immune system is already prepared to fight it and can provide protection from illness.

 

There are several different approaches to vaccine development, depending on the type of pathogen and the desired immune response. Some vaccines use a live, attenuated form of the pathogen, which has been modified to be less virulent but still capable of replicating and stimulating the immune system. Others use an inactivated form of the pathogen, which has been killed or otherwise rendered incapable of causing disease. Some vaccines also use pieces of the pathogen, such as proteins or genetic material, to stimulate the immune system.

 

In the case of COVID-19, several approaches were taken by Indian vaccine manufacturers. The vaccines developed by Bharat Biotech use an inactivated form of the SARS-CoV-2 virus, the virus that causes COVID-19. The vaccine developed by Serum Institute of India uses a live, attenuated form of the virus that has been genetically modified to be less virulent. All three vaccines have undergone clinical trials and have been shown to be safe and effective at providing protection against COVID-19.