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Vaccination is defined as the administration of some agents that mimic the microbe in the form of a vaccine. The agent can be a suspension of killed or attenuated microbes, or a substance that mimics the disease-causing microbes.  It provides protection to the body against communicable diseases.

When people or children are vaccinated, antigens (a weakened form of the microbe) are given to the person in the form of a vaccine. The immune system of the vaccinated person starts to make antibodies against the introduced antigen. These antibodies remain in the body for a longer time and in some cases even for a lifetime. So, when that person encounters the same pathogen again or is infected by the same microbe, our body recognises the pathogen easily and the antibodies fight against the infection resulting in the prevention of that disease. In this way, it produces immunity against the diseases and keeps us safe from that particular disease. For example, the polio vaccine.  

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