progressive vaccinia: a severe or even fatal form of vaccinia that occurs mainly in persons with an immunological deficiency; characterized by progressive enlargement of the initial lesion
entity: that which is perceived or known or inferred to have its own distinct existence (living or nonliving)
anaphylactic shock: a severe and rapid and sometimes fatal hypersensitivity reaction to a substance (especially a vaccine or penicillin or shellfish or insect venom) to which the organism has become sensitized by previous exposure