Vaccines are biological products which stimulate the defence mechanisms of the body against specific infectious diseases to provide active immunity. The main purpose is the prevention of diseases.

Onderstepoort Biological Products (OBP) has a long history of providing animal vaccines, not only for South Africa but also for other countries. In fact, the origin of Onderstepoort Biological Products goes back to 1896, when a devastating outbreak of rinderpest threatened the country and a veterinary institute became necessary to provide vaccines. To fight stock diseases such as rinderpest, botulism, bluetongue, lumpy-skin disease and horse sickness, which made farming in Southern Africa very difficult, if not impossible in some areas, was initially the main task of Onderstepoort.

The use of vaccines for preventive immunization is based on the development of protective antibodies and cellular immunity following exposure to antigens such as micro-organisms or their products in man and animals and the fact that they are then usually immune to a particular disease after recovering. The same effect is obtained by injecting microorganisms or their products which have been altered artificially, genetically or naturally, in such ways that they no longer cause disease, but still posses the ability to stimulate immunity. The high standard of vaccines is maintained by continuous research and development.