Smallpox vaccination.
D006801:Humans; D007391:International Cooperation; D012899:Smallpox / Q000453:epidemiology / Q000517:prevention & control*; D012900:Smallpox Vaccine / Q000008:administration & dosage* / Q000009:adverse effects; D014481:United States; D014611:Vaccination; D014944:World Health Organization
D012900:Smallpox Vaccine