PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-1 Life expectancy: At least 6 months Hematopoietic: Not specified Hepatic: Bilirubin no greater than 3 times upper limit of normal (ULN) SGOT no greater than 3 times ULN Alkaline phosphatase no greater than 3 times ULN Renal: Creatinine no greater than 3 times ULN Immunologic: Clinical evidence of immune response required within 4 days of smallpox vaccination At least 1 positive cutaneous delayed-type hypersensitivity response to 1 of the following: Microbial recall antigens Dinitrofluorobenzene after sensitization Purified protein derivative of tuberculin following BCG vaccination No altered immunocompetence (e.g., immune deficiency disease or immunosuppressive therapy) in patient or household contacts No allergy to any of the following: Polymyxin B sulfate Streptomycin sulfate Chlortetracycline hydrochloride Neomycin sulfate No history of eczema or other exfoliative skin conditions in patient or household contacts HIV negative Other: No other malignancy within the past 3 years except superficial squamous cell or basal cell skin cancer or carcinoma in situ of the cervix or prostate Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception