Phase 1 Trial to Assess the Safety and Immunogenicity of an Inactivated, Adjuvanted Whole Zika Virus Vaccine Candidate (VLA1601) in Healthy Adults

This phase 1 clinical trial consists of an initial open-label sentinel run-in (n=25) and a randomized, double-blind, dose-finding (n=125) investigating three antigen dose levels (low, medium and high) of VLA1601 and bedside mixing of the low-dose formulation with one of the two additional adjuvants (CpG1018®, 3M-052-AF/AP 60-702). VLA1601 will be administered according to a two-dose regimen (i.e., on Day 1 and Day 29). The primary objective of this trial is to assess the safety and tolerability of the vaccine candidate up to 7 days after each vaccination; and to assess the immune response induced by the vaccine candidate 28 days after the second vaccination. Additionally, safety and immune response of the vaccine candidate will be monitored throughout the trial.