[On the problem of determination of smallpox vaccine virulence].
D006801:Humans; D012899:Smallpox / Q000276:immunology*; D012900:Smallpox Vaccine; D014612:Vaccines; D012901:Variola virus; D014774:Virulence
D012900:Smallpox Vaccine; D014612:Vaccines
SMALLPOX/immunology; VACCINES