Human Immune Responses Smallpox

Inclusion Criteria: * Hematocrit greater than 34% for women, greater than 38% for men, white blood cells between 2500 and 11000/mm3 with normal differential, and platelet count equal to or greater than 150000/mm3 * Availability for followup for the planned duration of the study * Negative urine or serum pregnancy test on day of vaccination for women * If the subject is female, she agrees to use acceptable contraception and not become pregnant for at least seven months after vaccination * Negative ELISA for HIV or negative Western Blot for subject who have a positive ELISA and participated in an HIV vaccine trial * Meets the criteria for assignment into one of the three study groups * Willing to sign informed consent * ALT greater than 1.5 times institutional upper limit of normal * Negative hepatitis B surface antigen and negative antibody to hepatitis C virus * Negative urine glucose by dipstick * Adequate renal function defined as a serum creatinine greater than 1.5 mg/dL, urine protein greater than 100 mg/dL or less than 2+ proteinuria, and a calculated creatinine clearance greater than 55 mL/min * Acceptable medical history by screening evaluation and brief clinical assessment Exclusion Criteria: * History of immunodeficiency * Known or suspected impairment of immunologic function including but not limited to clinically significant liver disease, diabetes mellitus, moderate to severe kidney impairment * Malignancy other than squamous cell or basal cell skin cancer * Autoimmune disease * Live attenuated vaccines within 60 days of study * Known allergies to any component of the vaccine (e.g. polymyxin B sulfate, dihydrostreptomycin sulfate, chlortetracycline hydrochloride, neomycin sulfate) * Known allergies to any known component of VIG i.e. thimerosal or previous allergic reaction to immunoglobulins * Acute febrile illness on the day of vaccination * Eczema of any degree or history of eczema * Use of immunosuppressive medication. Corticosteriod nasal sprays are permissible * Medical or psychiatric condition or occupational responsibilities that preclude subject compliance with the protocol * History of "illegal" injection drug use * Inactivated vaccine 14 days prior to vaccination * Use of experimental agents within 30 days prior to study * Receipt of blood products or immunoglobulin in the past 6 months * Pregnant or lactating women * History of chronic exfoliative skin disorders/conditions * Any acute skin disorders of large magnitude e.g. laceration requiring sutures, burn greater than 2 x 2 cm * Any condition that, in the opinion of the investigator, might interfere with study objectives * Known allergies to any known component of the diluent (i.e. glycerin and phenol) * Known allergies to cidofovir or probenecid * Household contacts/sexual contacts with, or occupational exposure to (other than minimal contact), any of the following: 1) pregnant women, 2) children less than 12 months of age, 3) people with a history of eczema, 4) people with chronic exfoliative skin disorders/conditions or any acute skin disorders of large magnitude e.g. laceration requiring sutures, burn greater than 2 x 2 cm, or 5) people with immunodeficiency disease or use of immunosuppressive medications