Best age for smallpox vaccination.
D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D012899:Smallpox / Q000517:prevention & control*; D012900:Smallpox Vaccine / Q000009:adverse effects; D014611:Vaccination
D012900:Smallpox Vaccine