This is a phase 1, multisite clinical trial to evaluate the safety and immunogenicity of 3 dose levels of VXCO-100 in healthy adult volunteers.~Participants will be vaccinated with 1 dose of VXCO-100 on Day 1. All participants will be offered an additional booster at month 12.~Safety will be evaluated 1) before proceeding to a higher dose level and 2) prior to enrollment of participants aged 56 years and older at a particular dose level.
The purpose of this study is to evaluate the safety and immunogenicity of ascending dose levels of VXCO-100 in healthy adults.