Natural and artificial active immunization

Question

What do you mean by the natural active immunization and artificial active immunization?

Answer 1

Natural active immunization refers to that where a previous natural infection induces a primary immune response, specific memory cells are generated and individual becomes immune to the new infections with antigen. This is what occurs in the diseases which affect people only once in the life, such as chickenpox and mumps. Artificial active immunization is that where the primary immune response is caused due to the inoculation into an individual of the specially prepared antigens. This is the case with the vaccines.