Just weeks after announcing the U.S. Food and Drug Administration (FDA) granted Fast Track designation for VLA1553, their Chikungunya vaccine candidate, Valneva announced today positive Phase 1 interim results for the vaccine.


The primary objective of VLA1553-101 Phase 1 study was to assess the overall safety and immunogenicity profile 28 days after a single vaccination across three dose levels.

The interim results showed an excellent immunogenicity profile after a single vaccination with a 100% seroconversion rate achieved at Day 28 in a pooled analysis of all vaccinated groups. Results also showed 96.5% of subjects achieved at least a 16-fold increase in antibody titres and a high geometric mean titre, fully supporting VLA1553’s differentiated target product profile.

The pooled safety profile of all groups was considered acceptable and supports further development. No serious adverse events nor adverse events of special interest were reported up to Day 28 and the local tolerability was considered excellent. Systemic adverse events included short-term fever, headache and fatigue. As with other live-attenuated vaccines, transient cases of reduced levels of neutrophils, lymphocytes or leucocytes without clinical symptoms were observed in the pooled analysis.

Wolfgang Bender, M.D., Ph.D., Chief Medical Officer of Valneva commented, “These results mark an important milestone towards our goal of developing a single-shot vaccine against Chikungunya. We are making every commitment to advance our vaccine quickly so that we can address this serious threat to public health. Phase 1 revaccination data post month six is expected by mid-year and will be key to define development acceleration options. The recent award of FDA Fast Track designation will allow us to work closely with the FDA on this development strategy.

VLA1553 is a monovalent, single dose, live-attenuated vaccine candidate for protection against Chikungunya.

The vaccine candidate is designed for prophylactic, active, single-dose immunization against Chikungunya in humans over one year old.