ABSTRACT
The concept of vaccination was introduced in the late 18th century by Edward Jenner when he used cowpox virus as a vaccine to protect humans against smallpox virus infections. Inactivated pathogenic organisms can be used in vaccines. This is the simplest way to produce vaccines, provided the organisms can be cultured easily. Mostly attenuated organisms are being used as live virus vaccines; however, in some instances, even virulent organisms could be used, provided they are not administered via the natural route of infection. Another approach to provide protective immune response is the use of anti-idiotype antibodies as vaccines. Immunization of mammalian hosts with a plasmid DNA containing a gene under control of a heterologous promoter has introduced a new approach in the area of recombinant vaccine design. The primary advantage of the dual-chamber syringe is that it reduces the cost of vaccine delivery and, at the same time, increases the vaccine acceptability and coverage rate of vaccines.
