Safety/Immunogenicity Hantaan Virus DNA Vaccine and Puumala Virus DNA Vaccine, For Prevention of HFRS

The study will enroll 4 randomized groups of 33 subjects each for a total of 132 subjects. Every subject will receive a total of 4 vaccinations. Subjects and study personnel will be blinded to the group that they are randomized to (double-blind). The study is intended to substantiate the Phase 1 results with the 2 mg dose and to also determine if immunogenicity can be retained with a 1 mg dose (for HTNV DNA vaccine). For the 2 mg dose, each vaccination consists of 2 administrations of 1 mg (left and right deltoid) for a total of 2 mg/vaccination. For the 1 mg dose, each vaccination consists of 2 administrations of 0.5 mg (left and right deltoid) for a total of 1 mg/vaccination. Group 1 will be vaccinated with the HTNV DNA vaccine, pWRG/HTN-M(co) at the 2 mg/vaccination dose. Group 2 will be vaccinated with the HTNV DNA vaccine, pWRG/HTN-M(co) at the 1 mg/vaccination dose. Group 3 will be vaccinated with the PUUV DNA vaccine, pWRG/PUU-M(s2) at the 2 mg/vaccination dose. Group 4 will be vaccinated with the PUUV DNA vaccine, pWRG/PUU-M(s2) at the 1 mg/vaccination dose. Each group will be vaccinated on Days 1, 29, 57 and 169. All doses will be administered with the PharmaJet Stratis device, which is FDA cleared for IM administration of vaccines. All subjects will be followed until 6 months (month defined as 28 days) after the last vaccination with Day 337 being the final study visit. Subjects will complete post-injection memory aids for 7 days after each vaccination.