What are passive and active immunization? According to the duration of the protection how do these types of immunization differ?
Active immunization is that in which an antigen penetrates the body triggering the primary immune response and the manufacture of memory lymphocytes and antibodies that give faster and more effective immune defense in future infections by the similar antigen. Passive immunization is that in which immunoglobulins against an antigen are inoculated in the body to give protection in case the body becomes infected by the antigen.
Active immunization tends to be longer lasting than passive immunization as in the active type as well as antibodies, exact memory lymphocytes remain in the circulation. In the passive immunization the duration of the protection is that of the duration of the antibodies in the circulation.