History of Vaccination
Edward Jenner coined the word vaccination in or around 1796, to describe the practice he had developed of inoculating individuals with a small amount of live cowpox virus. Exposure to cowpox would then provide protection against the more virulent and deadly smallpox (due to antigenic similarities between the two virus species). The word vaccination is derived from the Latin word for cowpox: vaccinia (which itself is derived from vacca, the Latin word for cow).
However, while Jenner’s discovery was made at the end of the eighteenth century the practice has been around much longer – a form of vaccination is thought to have been practiced as early as 200 BC in China (although the first recorded instances of the practice are much more recent).
The earliest recorded incidences of vaccination are described as inoculation, which simply refers to the practice of introducing a living organism into a medium within which it can grow (in this case, the introduction of a virus into a human recipient).
Variolation
The most common form of inoculation throughout history is variolation – the practice of inducing immunity to smallpox. This deadly disease ran rampant through the ancient world, killing up to a third of everyone it infected, and leaving the living severely scarred.
Via the practice of variolation, a small amount of smallpox virus was introduced to a recipient in a controlled fashion, to reduce the severity of symptoms, and to protect against further infection by inducing immunity in the recipient.
The risk was controlled in two ways.
First, care was taken to use the weaker of the two smallpox strains in existence. This was typically achieved by taking virus specimens (usually scabs, blister fluid, or pus) from someone who was only mildly ill with a natural smallpox infection.
Second, the virus was introduced via a particular route. The natural route of smallpox infection is via the lungs, but for inoculation, often the inoculum was typically introduced via a scratch on the hand (in ancient China, the inoculation process involved taking a smallpox scab from a patient, and inserting it into the nostril of the person being inoculated).
Early Records of Inoculation in Humans
The earliest record of this practice is thought to exist in a book called the Nidana, written in the eighth century by an Indian physician named Madhav. In the book, a chapter on smallpox referred to the practice of inoculation to protect against a lethal infection. This is a controversial piece of information, however – it has been argued that no such reference exists, and that the reference was invented in the nineteenth century by British vaccination proponents.
Records of inoculation also exist in China, dating to the tenth century. One indicates that the practice began during the tenth century, apparently initiated by Wang Dan (957-1017) a Chancellor of the country whose eldest son contracted smallpox and died. Following the death, the Chancellor summoned physicians from across the country to discuss how to prevent or cure the disease. During the meeting, it is said, a wise woman introduced the concept of variolation.
Regardless of the veracity of this particular story, in China the practice was not widely used until the mid sixteenth century, and the first clear records of inoculation date back only as far as 1643.
Inoculation in the Western World
Inoculation was introduced into the Western world by a woman named Lady Mary Wortley Montagu. Her husband, Edward Wortley Montagu, served as the British ambassador to the Ottoman Empire from 1716 to 1717.
Lady Mary, while living in Constantinople, witnessed several instances of inoculation being practiced. Having lost a brother to smallpox, she was concerned about the safety of her children, and had her five year old son inoculated. Upon returning to England, she had her young daughter inoculated too.
Charles Maitland, the physician who had inoculated Lady Mary’s son, gained permission to test the procedure at Newgate Prison in England. In exchange for their freedom, six men who had been condemned to hang agreed to be inoculated with smallpox.
After all six men survived (and were presumably released), the practice slowly gained favor among English and European royalty. From there, inoculation eventually became a common practice amongst the general public.
In 1796, Edward Jenner’s development of a safer method of inducing immunity to smallpox—via the use of the cowpox virus—ensured that vaccination was around to stay.