For immune system, vaccines are the training course which prepares the body to fight against disease. When foreign invaders enter the body, antibodies are produced by lymphocytes-the immune cells of the body.
What is vaccination?
A vaccine is a substance that boosts immunity against a specific disease. It is a biologically prepared product that contains typical agents that resemble a disease-causing microorganism, created from weakened or dead microbes, one of their surface proteins, or their toxins.
It helps in the stimulation of the immune system and to identify the invaded microbes as the foreign agent and destroy it so that the immune system can be recognized and to destroy any microorganism encountered later.