Vaccination and Immunization

Vaccination and Immunization:

• The principle of immunization or vaccination is based on the property of ‘memory’ of the immune system.
• “Vaccination is the process of administrating a vaccine into the body or the act of introducing a vaccine into the body to produce immunity to a specific disease.” The antibodies produced in the body against these antigens would neutralize the pathogenic agents during actual infection.
• Immunization is the process of the body building up immunity to a particular disease.
• Immunization describes the actual changes in the body after receiving a vaccine.
• Vaccines work by fighting the pathogen and then recording it in their memory system to ensure that the next time this pathogen enters the body, it is eliminated far quickly.
• Once, the body is able to fight against the disease, it is believed to have built immunity for it, also known as the body being immunized against the disease.
• The vaccines also generate memory. The B and T-cells recognize the pathogen quickly on subsequent exposure and synthesize a large amount of antibodies to kill the invaders.
• If a person is infected with some deadly microbes to which a quick immune response is required as in tetanus, we need to directly inject the preformed antibodies, or antitoxin (a preparation containing antibodies to the toxin). Even in cases of snakebites, the injection which is given to the patients contains preformed antibodies against the snake venom. This type of immunization is called passive immunization.
• Recombinant DNA technology has allowed the production of antigenic polypeptides of pathogens in bacteria or yeast.
• Vaccines produced using this approach allow large-scale production and hence greater availability for immunization, e.g., hepatitis B vaccine produced from yeast.