Dose Study of ACAM2000 Smallpox Vaccine in Previously Vaccinated Adults

Inclusion criteria: have a history of previous smallpox vaccination greater than 10 years previous to the date of screening and presence of a vaccination scar. females must not be pregnant, lactating and must agree to use an effective form of birth control for the 30 days following vaccination or unable to bear children. agree to be available for the entire study and agree to comply with all requirements. exclusion criteria: children 1 year of age or younger in the household or be in close contact smallpox vaccination within ten years known or suspected Human immunodeficient virus (HIV) infection, primary immunodeficiency disorder, leukemia, lymphoma, or current radiation treatment or use of immunosuppressive or anti-neoplastic drugs or have a household member or intimate contact with the conditions listed above. renal disease current or past history of eczema or a household member or direct contact who has eczema. known allergy or past allergic reactions to latex gloves or to antibiotics which include neomycin, streptomycin, chlortetracycline, and polymyxin B known allergy or past allergic reaction to blood products. known allergy to cidofovir or sulfa-containing drugs. history of allergic phenomena following smallpox vaccination in the past, including urticaria, erythema multiforme, or Stevens-Johnson syndrome. transfusion of blood or treatment with any blood product. current or history of drug or alcohol abuse innoculation with any other live vaccine or participating in another drug or vaccine trial within 30 days of enrollment.