Bavarian Nordic Initiates Phase 3 Study of Chikungunya Vaccine in Children

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• First children vaccinated in clinical study seeking to expand the target population for the chikungunya vaccine.

COPENHAGEN, Denmark, June 12, 2025 – Bavarian Nordic A/S (OMX: BAVA) announced today the initiation of a Phase 3 clinical study of its single-dose, virus-like particle (VLP) chikungunya vaccine, CHIKV VLP in children 2 to 11 years of age.

This first trial of CHIKV VLP in a pediatric population aims to expand the target population for the vaccine, currently approved for persons 12 years of age and older in the US, EU and United Kingdom under the trade name VIMKUNYA. The global, randomized, double-blind, placebo-controlled study (NCT07003984), sponsored by Bavarian Nordic, will evaluate the safety and immunogenicity of CHIK VLP vaccine in 720 children 2 to 11 years of age for two years. Primary results from the study are anticipated in the first half of 2028.

Paul Chaplin, President & CEO of Bavarian Nordic, said: “Upon the successful approvals earlier this year of our chikungunya vaccine for persons aged 12 and older, we are pleased to initiate this Phase 3 study in children for whom there are currently no vaccines available to prevent against chikungunya. This study represents a significant part of our commitment to the further development of the vaccine to help ensure access for people of all ages.”

About VIMKUNYA Chikungunya vaccine (recombinant, adsorbed)
VIMKUNYA (CHIKV VLP) is the first and only virus-like particle (VLP) vaccine for the prevention of chikungunya disease in individuals aged 12 years and above. It is designed to induce a robust seroresponse, with protective immunity starting to develop as early as 1 week after vaccination. VIMKUNYA is the only single-dose vaccine against chikungunya disease available in a prefilled syringe. VIMKUNYA does not contain viral genetic material and is therefore non-infectious and unable to cause disease, ensuring a broad range of people can benefit from vaccination.

The vaccine was approved by the U.S. Food and Drug Administration (FDA) and the European Commission in February 2025^1,2 and the United Kingdom in May 2025³.

The US, EU and UK approvals of VIMKUNYA (CHIKV VLP vaccine) were all based on results from two phase 3 clinical trials which enrolled more than 3,500 healthy individuals 12 years of age and older. The studies met their primary endpoints, with results showing that 21 days after vaccination, the vaccine induced neutralizing antibodies in up to 97.8% of the vaccinated individuals, (97.8% in individuals 12 years to 64 and 87.3% in over 65-year-olds). The key secondary endpoint of seroresponse rate at day 8 post vaccination was 46.6% and 96.8% at day 15 in the 12–64-year-old population and 82.3% at day 15 for the over 65 population. The vaccine was well-tolerated and vaccine-related adverse events were mainly mild or moderate in nature. The most common side effects were pain at the injection site, fatigue, headache, and muscle pain^4,5.