Components of a smallpox vaccination kit including the diluent, a vial of Dryvax® smallpox vaccine, and a bifurcated needle. Vaccinia (smallpox) vaccine, derived from calf lymph, and currently licensed in the United States, is a lyophilized, live-virus preparation of infectious vaccinia virus. It does not contain smallpox (variola) virus. Photo Credit: James Gathany Content Providers(s): CDC. Public domain.