Immunoprophylaxis is the prevention of disease by the pro-duction of active or passive immunity. The incidence of dis-eases, such as diphtheria, measles, mumps, pertussis (whooping cough), rubella (German measles), poliomyelitis, and tetanus, has declined dramatically as vaccination has become more common.
Vaccination is a cost-effective weapon for disease prevention. Use of vaccines has contributed solely in the eradication of small-pox, one of mankind’s long-standing and most terrible scourges. Since October 1977, not a single naturally acquired smallpox case has been reported anywhere in the world. Other diseases like diphtheria, pertussis, tetanus, measles, mumps, rubella, and poliomyelitis, also known as “vaccine preventable diseases” have been successfully brought down to negligible levels in most devel-oped nations and in some cases in the developing nations as well.
Immunity to infectious microorganisms can be achieved by active or passive immunization. In each case, immunity can be acquired either by natural processes (usually by transfer from mother to fetus or by previous infection by the organism) or by artificial means, such as injection of antibodies or vaccines. The agents used for inducing passive immunity include antibodies from humans or animals, whereas active immunization is achieved by inoculation with microbial pathogens that induce immunity but do not cause disease or with antigenic components from the pathogens.