A Study to Evaluate the Safety and Immunogenicity of Ad5-105K in Adults Aged 18 to 49 Years

This is a randomized, observer-blind, positive-controlled study. There will be 2 treatment groups (Group A and B). In each treatment group, 18 participants will be randomly assigned to receive either the investigational vaccine (Dose A or Dose B of Ad5-105K) or a placebo in a ratio of 2:1. The distribution of participant's gender and age should be balanced in each group.