Smallpox vaccination.
D000349:Africa; D001208:Asia; D049671:History, 18th Century; D049673:History, 20th Century; D006801:Humans; D012899:Smallpox / Q000517:prevention & control*; D012900:Smallpox Vaccine / Q000266:history; D013020:South America; D014611:Vaccination / Q000266:history
D012900:Smallpox Vaccine