This is an adaptive design Phase 1 clinical trial to evaluate the safety and immunogenicity of VXCO-102 in healthy adult participants.

This first-in-human, dose-escalation Phase 1 trial evaluates the safety, tolerability, and immunogenicity of VXCO-102 in healthy young adults across multiple sites in Australia.

Part A will enroll ~45 participants aged 18-25. After sentinel safety review in each dose cohort, participants will be randomized to receive VXCO-102 or placebo, with a booster at Week 8. If Part A results are favorable, the study may expand to Part B to further assess safety, reactogenicity, and immunogenicity.

All participants will undergo ongoing safety monitoring and immune response assessments through clinical evaluations, sample collection, and participant reporting.

Inclusion Criteria:

• Aged 18 to 25 years, inclusive
• Healthy per medical assessment based on self-reported medical history, physical examination, vital signs, and laboratory assessment

Exclusion Criteria:

• Self-reported or medically-documented significant medical or psychiatric condition that per medical assessment could interfere with study participation
• Likely or confirmed myocarditis or pericarditis
• Prior receipt of an investigational EBV vaccine
• Prior receipt of a licensed vaccine within 56 days prior to Day 1
• Received more than 10 days of any systemic immunosuppressants or cytotoxic medications within 56 days prior to Day 1, any within 14 days prior to Day 1, or will need immunosuppressants at any time during the study.
• For participants of childbearing potential: pregnant, breastfeeding or planning to become pregnant during the study

Note: Other inclusion and exclusion criteria apply.