|Vaccines for smallpox virus
Small pox is a very serious disease of humans in most of the countries. The vaccinia virus (the cowpox virus) can be used as the basis of the smallpox vaccine by using the recombinant DNA technology. The genome of vaccinia virus is altered by inserting the foreign genes which encodes the pathogenic antigens. When a person is immunized with a vaccine in preparations, the foreign genes enter the body cells of the patients receiving vaccinia virus and direct the synthesis of the foreign antigenic proteins. The genes replicate like vaccinia genes and induce immunity to the smallpox, However, it resemble the other types of vaccine. The vaccinia virus can be modified in such a way that a single preparation confers protection against many viral disease (Peters 1993).