Vaccination disease people tried to prevent by inoculation and was the first disease for which a vaccine was produced. The smallpox vaccine was invented in 1796 by English physician Edward Jenner and although at least six people had used the same principles years earlier he was the first to publish evidence that it was effective and to provide advice on its production. Louis Pasteur furthered the concept through his work in microbiology. The immunization was called "vaccination" because it was derived from a virus affecting cows ( 'cow'). Smallpox was a contagious and deadly disease, causing the deaths of 20–60% of
1837 Great Plains smallpox epidemic experienced a major smallpox epidemic in 1780-81 which severely reduced their numbers down to less than a few thousand. Many other bands along the Missouri river suffered smallpox epidemics during 1801-02 and 1831. Sporadic efforts were made to promote vaccination among the Indigenous peoples since the turn of the nineteenth century. Later, the Indian Removal Act the U.S. Congress took its first step in 1832 to generate public support for vaccination of the Native Americans. But shortly after passage of this congressional act to extend vaccinations to Indians, Secretary Cass stated that no effort would be made "under any circumstances"