Safety and immunogenicity of the live-attenuated chikungunya virus vaccine candidate VLA1553

A recent study suggests that VLA1553 batches are both safe and immunogenic. This study’s findings were published in the Journal of travel medicine.

This was a phase 3, randomized, double-blinded, and focused on lot-to-lot consistency trial that included 408 healthy adults (aged 18-45 years). The primary endpoint of the study was to compare the geometric mean titre (GMT) ratios of chikungunya virus (CHIKV)-specific neutralizing antibodies between three different batches of VLA1553, 28 days after the administration of the vaccine. Additionally, secondary endpoints included assessing the immunogenicity and safety of the vaccine over a period of 6 months post-vaccination.

GMTs were similar among the batches that met the criteria for equivalence. The average GMT (measured by fifty percentage CHIKV micro plaque neutralization test; μPRNT50) reached 2643 at 28 days post-vaccination and dropped to 709 at 6 months post-vaccination. At 28 days post-vaccination, a high seroresponse rate (μPRNT50 titre ≥ 150 considered protective) was seen in 97.8% of participants, maintained at 96% at 6 months post vaccination. Following the administration of VLA1553 immunization, adverse events (AEs) were reported by 72.5% of the participants with no significant variations observed between the different batches. Generally, AEs were mild or moderate and resolved without any sequela, typically within 3 days.

Thus, it can be concluded that all three batches of VLA1553 were found to be safe and immunogenic. These findings emphasize the potential of VLA1553 as a vaccine for effectively preventing CHIKV disease in individuals residing in or visiting areas where the disease is prevalent.