The U.S. Food and Drug Administration (FDA) has approved Vimkunya (Chikungunya Vaccine, Recombinant) developed by Bavarian Nordic A/S, marking it as the first virus-like particle (VLP) single-dose chikungunya vaccine available in the U.S. for individuals 12 years of age and older. This approval, granted under Priority Review, signifies a crucial advancement in preventing the mosquito-borne disease caused by the chikungunya virus (CHIKV).
The FDA's decision was based on data from two Phase 3 clinical trials involving over 3,500 healthy participants aged 12 and older. The trials demonstrated that Vimkunya induced neutralizing antibodies in up to 97.8% of vaccinated individuals 21 days post-vaccination, with a rapid immune response observed within one week. The vaccine was well-tolerated, with mainly mild to moderate adverse events reported.
Clinical Efficacy and Safety
The Phase 3 trials showcased strong immunogenicity data, with the vaccine eliciting a rapid immune response. In one trial (NCT05072080), neutralizing antibodies were found in 98% of vaccinated patients. Another study (NCT05349617) showed that 87% of persons aged 65 and over exhibited neutralizing antibodies 22 days after immunization. These results highlight Vimkunya's potential to provide rapid and effective protection against chikungunya.
Addressing an Unmet Need
Chikungunya, transmitted by mosquitoes, has spread across Asia, Africa, and the Americas, impacting popular travel destinations. In 2024, there were 620,000 cases of chikungunya and over 200 deaths reported worldwide. Symptoms include fever, rash, fatigue, headache, and severe joint pain, with 30-40% of those affected potentially developing chronic symptoms.
Paul Chaplin, President and CEO of Bavarian Nordic, stated, "The approval of our chikungunya vaccine is a testament to our unwavering commitment to addressing unmet medical needs and protecting communities worldwide. As climate change continues to expand the reach of mosquito-borne illnesses like chikungunya, this milestone underscores the importance of cutting-edge solutions to safeguard travelers and vulnerable populations."
Mechanism of Action and Availability
Vimkunya is a VLP vaccine, meaning it uses virus-like particles to mimic the chikungunya virus without the ability to infect cells, replicate, or cause disease. It is supplied as a single-dose 1-mL glass pre-filled syringe with 0.8 mL dose volume.
Bavarian Nordic anticipates commercial availability in the U.S. in the first half of 2025. The vaccine has also received a positive opinion from the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA), suggesting a launch in key European markets in the first half of 2025, pending final authorization.
Important Safety Information
Vimkunya is contraindicated in individuals with a known allergy to any of the vaccine's ingredients or those who have experienced an allergic reaction following a previous dose. Individuals with a compromised immune system may have a diminished response to the vaccine. Common side effects include pain at the injection site, fatigue, headache, and muscle pain.
With this approval, Bavarian Nordic received a Priority Review Voucher (PRV) under the Tropical Disease PRV program, which the company intends to monetize. This voucher can be used to expedite the review of another drug.
Implications for Public Health
The FDA approval of Vimkunya marks a significant step forward in global public health, providing a crucial preventive tool against chikungunya. As outbreaks continue to emerge, particularly in regions frequented by travelers, this vaccine offers a vital layer of protection. It is also the first chikungunya vaccine approved for use in adolescents, addressing a key gap in available preventative measures.
