Kinepox
Kinepox is an alternate term for the smallpox vaccine used in early 19th century America. Popularized by Jenner in the late 1790s, kinepox was a far safer method for inoculating people against smallpox than the previous method, variolation, which had a 3% fatality rate.
In a famous letter to Meriwether Lewis in 1803, Thomas Jefferson instructed the Lewis and Clark expedition to "carry with you some matter of the kine-pox; inform those of them with whom you may be, of its efficacy as a preservative from the smallpox; & encourage them in the use of it..." Jefferson had developed an interest in protecting Native Americans from smallpox having been aware of epidemics along the Missouri River during the previous century. One year prior to his special instructions to Lewis, Jefferson had persuaded a visiting delegation of North American Indian Chieftains to be vaccinated with kinepox during the winter of 1801-2. Unfortunately, Lewis never got the opportunity to use kinepox during the pair's expedition as it had become inadvertently inactive — a common occurrence in a time before vaccines were stabilized with preservatives like glycerol or kept at refrigeration temperatures.
Read more about this topic: Cowpox