Infectious Diseases: Modelling, Immunity
It has been observed for centuries that a patient who survives an episode of certain infectious diseases such as smallpox or measles becomes immune for life against a further infection. For smallpox, the idea therefore arose to infect persons artificially by a “mild” form of the disease. This practice seems to have originated very early in China where dried smallpox scabs were blown into the nose of an individual who then contracted a mild form of the disease and was immune upon recovery. Starting in the eighteenth century, a modified procedure named “variolation” was used in Europe. Here the dried scabs were injected under the skin.