It is hard to determine who invented vaccine. It may have been used in ancient times in China, India or Persia. But we do know that Edward Jenner was the first person which the first recorded vaccination in the western world.
In 1796, Gloucestershire physician Dr Edward Jenner conducted one of the most important, if unethical, experiments in medical history. His aim was to investigate claims that people could be protected from deadly smallpox if previously exposed to cowpox, an apparently related but harmless disease. To find out, he risked the life of an eight-year-old boy (whom he had exposed to cowpox) by deliberately exposing him to smallpox. Apart from a brief fever following the cowpox infection, the boy remained healthy. Ever since, Jenner has been hailed as the discoverer of ‘vaccination & vaccine’, a vital weapon in the fight against disease and one that led to the global elimination of smallpox in 1980.
The idea that prior infection gave ‘immunity’ against later disease had, however, been noted as early as the 10th Century by Chinese physicians. By the early 18th Century, Lady Mary Wortley Montagu, wife of a diplomat in Turkey, was advocating ‘variolation’. This involved deliberately exposing patients to smallpox-infected tissue. While often successful, the technique was risky, with around one in eight dying from smallpox.
Jenner was not even the first person to test cowpox as a way to provide immunity against smallpox. Even so, he deserves credit for studying the theory systematically, and convincing the Royal Society to publish his findings leading to inventions of various vaccine.
As a natural disease, the origin of smallpox can be traced back to the prehistoric culture when it first appeared around 10,000 BC in northeastern Africa. The mummies, including that of pharaoh Ramses V, provide the earliest most convincing evidence of the existence of smallpox 3000 years ago in the Egyptian Dynasties. Presumably, the Indians contracted the disease from the Egyptian merchants as is mentioned in the ancient Sanskrit text. Then, it appeared in China (1122 BC) and was carried to Japan in the 6th century.
In Europe, the smallpox arrived between 5th to 7th century and spread like a plague with the increase in population, during the Middle Ages and captured all of Europe by the 16th century. It was widespread and fatal all around the world during the 18th century killing 400,000 people annually in Europe alone and devastated the development of western civilization. The killer disease effected peasants and princes alike and was referred to as the speckled monster for disfiguring its survivors. Sadly enough, the infants and children were the most frequent victims of the disease everywhere.