The origins of vaccination: myths and reality.

In 1796, 75 years after Lady Mary Wortley Montague and Charles Maitland introduced inoculation into England, Edward Jenner performed an experiment that would eventually lead to the eradication of smallpox and the end of inoculation. (NB: in this article, inoculation refers to immunization with smallpox virus and vaccination refers to immunization with cowpox virus.) He inoculated a child with material from a cowpox pustule just as he would have done from a smallpox pustule. About six weeks later, he performed a conventional inoculation on the same child using smallpox material. When there was no reaction to the inoculation, Jenner believed that he had demonstrated that cowpox could produce immunity to smallpox just like the real smallpox virus. His experiment had worked. But how did Edward Jenner get to this point, where had the ideas come from, and what lay behind his seemingly audacious practice on a defenceless child? History texts and children’s stories all focus on the supposed role of milkmaids in guiding Jenner to cowpox. Even the most recent histories of smallpox eradication say that he learned of cowpox’s benefits from a milkmaid. In many cases, the milkmaid is beautiful because she cannot catch smallpox. In some versions of this story, the fabled beauty of the unscarred milkmaids is widely known and gives Jenner his first clue. Occasionally, other names pop up but are quickly dispatched as not really significant and home in on Jenner as the man who realized why the milkmaids were so beautiful. Sadly the milkmaid story is a lie invented by John Baron, Jenner’s friend and first biographer. Jenner himself never claimed to have discovered the value of cowpox, nor did he ever say, despite a huge volume of correspondence, how he first came across the idea. The myths of the milkmaids are just that, myths. To modern eyes, Jenner is revered for eradicating smallpox by using cowpox; in his lifetime, however, Edward Jenner faced severe criticism from jealous competitors and from many ordinary doctors who did not trust his method because, unlike inoculation, it did not give permanent immunity to smallpox. John Baron invented the milkmaid story to counteract these criticisms. What really happened is more prosaic although no less fascinating. The Suttons’ improved method of inoculating spread rapidly through England. By 1768, a country surgeon, John Fewster, and his colleague, Mr. Grove, had become partners with them. Years later, in response to the renowned chemist George Pearson’s inquiries, Fewster wrote: