[tex]\Large\textbf{ACTIVE AND PASSIVE IMMUNITY}[/tex]
Active Immunity, Immunity which is acquired by the own immune response of the body.
Passive Immunity, Immunity which is acquired and dependent upon the antibodies transported from another person or even an animal. A person's immune system does not acquire or make the antibodies itself. A newborn baby acquires passive immunity from its mother through the placenta.
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Vaccination is a artificial active immunity. Artificial because the antibodies are not acquired by any natural infection but it is injected into the healthy body of the person. It is Active immunity because the body does not get already made (from other animal) antibodies but it acts on the small amount of the pathogen which is injected in the body and acquires the antibodies itself. So the person acquires antibodies naturally acting on the antigen. Antigen is any foreign agent which triggers the immune system to produce antibodies against it. Vaccines contains antigen which is a harmless form of the bacteria or a virus that causes the disease you are being immunised against. The bacteria or virus are in small proportion and greatly weakened in the vaccine so they just trigger an immune response without causing any real damage. When Vaccine is injected in the body, the immune system starts to make antibodies of different forms against the antigen(Virus or bacteria in the vaccine). When the appropriate shape antibody reacts with the antigen and forms antibody-antigen complex which destroys the antigen. This means that type and shape of antibody is perfect to work against that antigen, then the immune system start forming only those kind of antibodies in great proportion and the Person gets immunised by the vaccine in a natural way.
