Edward Jenner vaccinating patients in the Smallpox and Inoculation Hospital at St. Pancras: the patients develop features of cows. Coloured etching by J. Gillray, 1802., Welcome Museum, https://wellcomecollection.org/works/dsu7wxau, Attribution-Non Commercial 4.0 International (CC BY-NC 4.0), https://creativecommons.org/licenses/by-nc/4.0/
"Thousands of years ago, variola virus (smallpox virus) emerged and began causing illness and deaths in human populations, with smallpox outbreaks occurring from time to time. Thanks to the success of vaccination, the last natural outbreak of smallpox in the United States occurred in 1949. In 1980, the World Health Assembly declared smallpox eradicated (eliminated), and no cases of naturally occurring smallpox have happened since."
---https://www.cdc.gov/smallpox/ (accessed April 5, 2021)