Study to Evaluate Safety and Immunogenicity of a Prime-Boost Regimen of rVSV-Nipah Virus Vaccine Candidate PHV02 in Healthy Adult Subjects

The goal of this clinical trial is to test the safety and immunogenicity of PHV02 live, attenuated recombinant vesicular stomatitis virus vaccine expressing the Nipah Virus glycoprotein in healthy adult subjects. The main questions it aims to answer are: * which doses of PHV02 are safe to administer to and well-tolerated by healthy adult subjects as a 2 dose regimen given 1 month apart? * what is the immunologic response (Nipah-specific IgG ELISA antibody and neutralizing antibodies) to each dose level after a 2-dose regimen given 1 month apart? Participants will receive 2 intramuscular injections of PHV02 (2x105, 2x106, and 2x107 plaque-forming units \[pfu\]) or placebo on Day 1 and Day 29 and will be followed for 197 days.