Valneva SE announced the successful completion of the lot-to-lot Phase 3 trial of its single-shot chikungunya vaccine candidate, VLA1553. The final analysis included six-month follow-up data and confirmed the topline results reported in December 2021. The VLA1553-302 trial met its primary endpoint, demonstrating that three consecutively manufactured vaccine lots elicited equivalent immune responses measured by neutralizing antibody titer GMT ratios on Day 29 after vaccination.

The trial included 408 participants aged 18 to 45 years. The safety profile shown in study VLA1553-302 was similar to the Phase 3 trial, VLA1553-301. With a 96.0% seroprotection rate at Day 180, the immunogenicity profile from study VLA1553-301 was also confirmed.