Smallpox vaccine Smallpox vaccine Smallpox vaccine, the first successful vaccine to be developed, was introduced by Edward Jenner in 1796. He followed up his observation that milkmaids who had previously caught cowpox did not later catch smallpox by showing that inoculated cowpox protected against inoculated smallpox. Dryvax is a freeze-dried calf lymph smallpox vaccine. It is the world's oldest smallpox vaccine, created in the late 19th century by American Home Products, a predecessor of Wyeth. By the 1940s, Wyeth was the leading US manufacturer of the vaccine and the only manufacturer by the 1960s. After world health authorities declared smallpox had been
Smallpox the United States and South Africa a much milder form of smallpox, "variola minor", was recognized just before the close of the 19th century. By the mid-20th century "variola minor" occurred along with "variola major", in varying proportions, in many parts of Africa. Patients with "variola minor" experience only a mild systemic illness, are often ambulant throughout the course of the disease, and are therefore able to more easily spread disease. Infection with "v. minor" induces immunity against the more deadly "variola major" form. Thus as "v. minor" spread all over the USA, into Canada, the South American countries and