ABSTRACT
In ancient history, it was found that individuals who survived a disease seldom suffered from a secondary exposure towards that same disorder. This protective effect led to deliberate inoculation where smallpox scabs were first used as a vaccine more than three centuries ago in China and India. However, the birth of vaccine immunology as a science may be dated back to Edward Jenner’s successful vaccination against smallpox reported in 1798. Jenner noted that milkmaids who had pockmarks on their hands, consistent with cowpox, did not develop smallpox. He proceeded to study the protective effect of cowpox by deliberately inoculating an 8 year old boy, who was later exposed to smallpox. The boy failed to develop smallpox despite repeated inoculation with pus from smallpox lesions.
