Study to Evaluate the Safety, Tolerability, and Immunogenicity of Hantaan and Puumala Virus DNA Vaccines

Inclusion Criteria: * Healthy adult male or non-pregnant, non-lactating female, ages 18-49 (inclusive) at time of screening * Have demonstrated adequate comprehension of the protocol, by achieving a score of at least 80% correct on a short multiple-choice quiz * Individuals who fail to achieve a passing score on the initial quiz will be given the opportunity to retest after a review of protocol information * Individuals who fail the comprehension assessment for the second time will not be enrolled * Have provided written informed consent before screening * Free of clinically significant health problems, as determined by pertinent medical history and clinical examination before entry into the study * Available and able to participate for all study visits and procedures * If sexually active, known to be at least 1 year post-menopausal, or willing to use an effective method of contraception (e.g., birth control pill, diaphragm, cervical cap, intrauterine device, condom, or anatomical sterility \[in self or partner\]) from the date of screening until at least 6 months after the last vaccination * Negative hantavirus IgG antibody test result at screening (ELISA) Exclusion Criteria: * History or serologic evidence of prior infection with either HTNV or PUUV virus, or prior participation in a HTNV or PUUV virus vaccine trial * History of severe local or systemic reactions to any vaccination or a history of severe allergic reactions * Any serologic evidence of hepatitis B or C infection * Ongoing participation in another clinical trial * Receipt or planned receipt of any vaccination, experimental or otherwise, within the period 30 days prior to initial injection through 60 days after the Day 70 follow-up (approximately a 6 month period in total) * Individuals in whom a skinfold measurement of the cutaneous and subcutaneous tissue for all eligible injection sites (deltoid region) exceeds 40 mm * Individuals in whom the ability to observe possible local reactions at the eligible injection sites (deltoid region) is, in the opinion of the investigator, unacceptably obscured due to a physical condition or permanent body art * Acute or chronic, clinically significant hematologic, pulmonary, cardiovascular, hepatic or renal functional abnormality as determined by the investigator based on medical history, physical examination, EKG, and/or laboratory screening test * Pregnant or lactating female, or female who intends to become pregnant during the study period * Administration of immunoglobulins and/or any blood products within the 120 days preceding study entry or planned administration during the study period * Any confirmed or suspected immunosuppressive or immunodeficient condition, including human immunodeficiency virus infection * Administration of chronic (defined as more than 14 days) immunosuppressants or other immune-modifying drugs within 6 months of study entry * For corticosteroids, this will mean prednisone, or equivalent, greater than or equal to 0.5 mg/kg/day * Inhaled and topical steroids are allowed * Any chronic or active neurologic disorder, including seizures and epilepsy, excluding a single febrile seizure as a child * Syncopal episode within 12 months of screening * Suspected or known current alcohol abuse as defined by the American Psychiatric Association in DSM IV (Diagnostic and Statistical Manual of Mental Disorders-4th edition) * Chronic or active illicit and/or intravenous drug use * Unwilling to allow storage and use of blood for future hantavirus-related research * Any other significant finding that in the opinion of the investigator would increase the risk of the individual having an adverse outcome from participating in this study