Role of the World Health Organization in the world-wide eradication of smallpox.
D003906:Developing Countries; D006801:Humans; D007391:International Cooperation; D012041:Regional Medical Programs; D012899:Smallpox / Q000453:epidemiology / Q000517:prevention & control*; D012900:Smallpox Vaccine; D014944:World Health Organization
D012900:Smallpox Vaccine