• Chikungunya vaccine candidate met all the co-primary endpoints of the Phase 3 study and was shown to be highly immunogenic in the majority of subjects 22 days post a single vaccination.
• A fast and durable response was confirmed with high levels of immunity at both 2 weeks and 6 months post a single vaccination.
• Regulatory submissions planned for 2024

A total of 3,254 participants were enrolled and randomized to receive either a single intramuscular injection of CHIKV VLP, or placebo. The results up to day 22 post vaccination showed that CHIKV VLP was highly immunogenic in healthy adolescents and adults, as demonstrated by the strong induction of chikungunya neutralizing antibodies in 98% of vaccinees in the active group. The strong neutralizing antibody titres were equal to, or exceeded the threshold agreed with authorities as a marker of seroprotection, meeting primary objectives of the study.

Importantly, CHIKV VLP induced significant neutralizing antibodies in 97% of the subjects at 2 weeks post vaccination, confirming a rapid onset of protective levels of immunity. These responses were robust and durable, as 86% of the subjects had seroprotective levels of neutralizing antibodies 6 months post vaccination.

CHIKV VLP was well-tolerated in this adolescent and adult population and adverse events were mainly mild or moderate in nature.

“We are highly encouraged by the positive topline results now demonstrated in both Phase 3 studies of our chikungunya vaccine candidate. Our focus remains to finalize the studies and prepare for regulatory submissions next year,” said Paul Chaplin, President and CEO of Bavarian Nordic. “With a fast and durable response, our vaccine has the potential to be the best in class to prevent chikungunya infections in adolescents to elderly adults. Chikungunya that can often result in a severe and incapacitating disease affects large parts of the world, and with international travel on the rise again, our CHIKV vaccine offers a significant opportunity to address this large unmet medical need.”

In June 2023, Bavarian Nordic reported positive topline data from a similar Phase 3 study in healthy adults ≥65 years of age (NCT05349617), which demonstrated that CHIKV VLP induced chikungunya neutralizing antibodies in 87% of vaccinees 22 days after a single vaccination and was well-tolerated. Results from both studies will form the basis for submission of a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) and a Marketing Authorization Application (MAA) to the European Medicines Agency (EMA) in 2024 to support potential launch of the vaccine in 2025.