Pox_ An American History - Michael Willrich [20]
The history of smallpox vaccination has a special but curious relationship to this scientific revolution. Smallpox was the granddaddy of infectious diseases: the deadliest scourge in recorded history and the one upon which the field of immunology was founded. Smallpox variolation (using live variola virus) and vaccination (using the live viruses of cowpox or vaccinia) were the oldest practices of preventive immunization. In fact, they were practiced long before the germ theory took shape. Both techniques had been developed without the benefit of microscopes and laboratory smears, through experiments based upon everyday observations about the disease. Pasteur himself saluted this lineage when he proposed, in 1881, that the term “vaccination” be universalized to apply to preventive inoculation with other infectious agents.50
Variolation was practiced in China and India as early as the tenth century. It probably originated in the commonplace observation that people with pockmarks never contracted smallpox. The practice entailed introducing a small amount of material from the pustules or scabs of a smallpox patient into the body of a healthy person. In China, the common method was nasal insufflation: scabs were ground into a fine powder and then snorted. In India, the pus material was inserted into the skin. Variolation normally produced a mild attack of smallpox, followed by long-lasting immunity. The practice spread far and wide from its Asian (and perhaps African) origins. By the early eighteenth century, variolation spread into Europe from the Balkans and from Turkey into England. Called “inoculating the smallpox” or simply “inoculation” by the English, it grew increasingly common in Britain and the colonies—especially when epidemics threatened. In the terrible Boston epidemic of 1720–21, Reverend Cotton Mather and Dr. Zabdiel Boylston caused a public firestorm by promoting inoculation. In 1777, as North American smallpox epidemics took more than 100,000 lives, General George Washington ordered the compulsory variolation of all new recruits into the Continental Army. The wide adoption of variolation during the eighteenth century is perhaps all the evidence one needs of the severity of smallpox, for the practice carried serious risks. The artificially induced attack was not always mild: as many as one in fifty died. Even worse, during the infection the inoculated person could infect others with full-blown smallpox.51
Vaccination descended directly from variolation, and it came about in much the same way. In the late eighteenth century, it was a commonplace observation among the country people of smallpox-ridden parts of England and Europe that milk hands and milkmaids rarely had pockmarks. An English country doctor named Edward Jenner, who had himself suffered a harsh bout of smallpox following his childhood inoculation, had trouble persuading dairy workers to take the pox. The workers, Jenner later explained, had the “vague opinion” that they had been protected by their exposure to diseased cows. Some of the workers had pocklike ulcers on their hands, gotten by milking cows whose teats were broken out with cow-pox. From one such ulcer, on the hand of a milkmaid named Sarah Nelmes, Jenner extracted the pus that he inserted, just beneath the