Written and Reviewed by Team Pharmacally
Bavarian Nordic A/S, a prominent biotechnology firm focused on vaccine development, has reached a major milestone with the dual approval of its chikungunya vaccine, Vimkunya, by the European Medicines Agency (EMA) and the U.S. Food and Drug Administration (FDA). This vaccine is now authorized for use in individuals aged 12 and older, making it the first vaccine globally approved for immunization against the chikungunya virus, a mosquito-borne pathogen that is spreading to new regions. The EMA granted PRIME designation to Vimkunya in January 2020, and it was reviewed under the EMA’s accelerated assessment program. Meanwhile, the FDA has approved Vimkunya for injection, marking it as the first VLP chikungunya vaccine available in the U.S. for those aged 12 and above.
Understanding Chikungunya: A Growing Threat
Chikungunya is a viral disease transmitted by mosquitoes, first recognized in southern Tanzania in 1952. The Aedes aegypti and Aedes albopictus mosquitoes, which also spread dengue and Zika viruses, are the primary carriers of the chikungunya virus. The term “chikungunya” comes from the Kimakonde language, meaning “to become contorted,” which describes the intense joint pain that those infected often endure. This disease is found worldwide, with outbreaks noted in Africa, Asia, the Americas, and occasionally in other areas. It tends to lead to large outbreaks, with attack rates reaching as high as 75% in regions where the virus is active. Recently, chikungunya has seen resurgence, resulting in significant outbreaks across the globe. For example, from 2013 to 2015, more than 1.1 million suspected cases were documented in the Americas. India has also experienced large outbreaks, with numerous cases reported across various states.
Both adults and children can get infected with chikungunya and show symptoms. Following the outbreaks in the Americas from 2014 to 2017, over 4,000 chikungunya cases were reported among travelers from the US, along with 13 locally acquired cases in the continental United States. Additionally, the US territories of American Samoa, the US Virgin Islands, and Puerto Rico reported locally acquired cases during 2014 and 2015, with Puerto Rico continuing to report sporadic cases since 2016. From 2018 to 2020, there were 340 cases reported among US travelers, with a significant drop in 2020 due to reduced international travel during the COVID-19 pandemic.
The disease typically begins suddenly with a high fever and intense joint pain, which can be quite debilitating. Additional symptoms may consist of muscle aches, headaches, nausea, fatigue, and rashes. Although most individuals recover completely, some may suffer from lingering joint pain that lasts for months or even years.
Currently, there is no specific antiviral treatment for chikungunya. Management mainly focuses on relieving symptoms through pain and fever management, such as using paracetamol (acetaminophen). Anti-inflammatory medications, including nonsteroidal anti-inflammatory drugs (NSAIDs), can help manage acute pain and inflammation. Additionally, disease-modifying ant rheumatic drugs (DMARDs) may be considered for patients who develop chronic arthritis-like symptoms.
By 2024, there has been notable advancement in the creation and approval of vaccines aimed at fighting chikungunya. The first chikungunya vaccine, called Ixchiq, was licensed by the U.S. Food and Drug Administration (FDA) in November 2023.
Vimkunya: A Breakthrough in Prevention
Vimkunya, created by Bavarian Nordic A/S, marks a major step forward in preventing chikungunya. In February 2025, the U.S. Food and Drug Administration (FDA) approved Vimkunya for use in individuals aged 12 and older, making it the first chikungunya vaccine authorized for this age group in the United States. At the same time, the European Medicines Agency’s (EMA) Committee for Medicinal Products for Human Use (CHMP) recommended that Vimkunya be granted marketing authorization in the European Union for those aged 12 and older. This recommendation, made in January 2025, establishes Vimkunya as the first chikungunya vaccine in the EU aimed at both adolescents and adults. The vaccine is given as a single-dose injection and includes adjuvant recombinant virus-like particles (VLPs) that imitate the chikungunya virus, triggering an immune response without causing the disease. The approval of this vaccine addresses a significant unmet need, particularly for travelers heading to areas where chikungunya is common, as well as for populations in regions at risk of outbreaks. Although chikungunya is not widespread in Europe, the presence of Aedes mosquitoes, which can transmit the virus, raises concerns about possible outbreaks, especially in Southern Europe. The introduction of Vimkunya provides a proactive approach to safeguarding public health against this debilitating illness.
Clinical Trial Success
To evaluate the safety and efficacy of the vaccine, two multicenter, randomized, double-blind, placebo-controlled, parallel-group trials were carried out. The first trial focused on adults and adolescents aged 12 to 64 years, while the second trial involved older adults aged 65 years and above. Participants received either the Vimkunya vaccine or a placebo as a single intramuscular dose. The immunogenicity objectives included measuring anti-CHIKV NT80 serum neutralizing antibody (SNA) titres at specified time points.
Anti-CHIKV NT80 measures the level of antibodies that can neutralize the chikungunya virus (CHIKV) and is used to assess the immune response to the CHIKV vaccine.
The NT80 value represents the reciprocal of the serum dilution that decreases viral activity by 80%.
The seroresponse rate (SRR) indicates the percentage of participants who reached an NT80 SNA titer of 100 or higher.
Safety outcomes were monitored by tracking adverse events (AEs) up to Day 183.
In the adult/adolescent trial, 3,254 participants were enrolled, with 2,790 receiving the CHIKV VLP vaccine and 464 receiving a placebo. The primary endpoints were successfully achieved, showing a Day 22 seroresponse rate (SRR) of 98% (2,503 out of 2,559) for the vaccine group compared to just 1% for the placebo. Additionally, the study demonstrated lot consistency and superiority to placebo in terms of geometric mean titer (GMT). A quick antibody response was noted in the CHIKV VLP vaccine group, with a Day 8 SRR of 47% (1,169 out of 2,510) and a Day 15 SRR of 97% (2,355 out of 2,434). The responses remained durable through Day 183, with an SRR of 86% (1,967 out of 2,301).
In the older adult trial, 413 participants were enrolled, with 206 receiving the CHIKV VLP vaccine and 207 receiving a placebo. The primary endpoints were achieved, showing a Day 22 seroconversion rate (SRR) of 87% (167 out of 191) for the vaccine group compared to just 1% (2 out of 183) for the placebo group (p< 0.0001). Additionally, a rapid antibody response was noted in the CHIKV VLP vaccine group at Day 15, with an SRR of 82% (150 out of 182).
The CHIKV VLP vaccine showed a good safety profile, with most adverse events being mild to moderate in severity. The most frequently reported adverse events included myalgia, fatigue, and headache.
Regulatory and Public Health Impact
The dual EMA-FDA approval allows Bavarian Nordic to sell Vimkunya in the U.S., EU, and regions that acknowledge these agencies’ decisions. This achievement meets a long-standing need, as there have been no specific treatments or preventive options available aside from mosquito control. “Vimkunya is a groundbreaking step in the fight against chikungunya,” stated Paul Chaplin, President and CEO of Bavarian Nordic. “This vaccine not only safeguards travelers and residents in affected areas but also enhances global readiness for emerging arboviruses.”
Strategic Distribution and Future Plans
Bavarian Nordic intends to focus on distributing its products in high-risk areas, particularly in the Americas and South Asia. The company is working alongside organizations such as WHO and Gavi to guarantee fair access. Additionally, they are looking into pediatric trials to make their treatments available for younger children and are considering booster dose regimens for extended protection.
Broader Implications
Vimkunya’s endorsement highlights the increasing significance of vaccines in the fight against diseases influenced by climate change. With Aedes mosquitoes spreading to new areas, proactive vaccination could help reduce the incidence of outbreaks related to dengue and Zika. Public health experts stress the need to incorporate Vimkunya into national immunization initiatives in regions where these diseases are common, as well as in travel health recommendations.
Conclusion
The approval of Vimkunya marks a significant milestone in the battle against chikungunya, bringing hope to millions at risk of this debilitating disease. Bavarian Nordic’s success underscores the essential role of innovation in addressing neglected tropical diseases and emphasizes the need for global cooperation in public health efforts. With regulatory challenges now behind us, the next priority is to guarantee quick and fair access to the vaccine—an essential move to combat the growing threat of chikungunya.
References:
- Jason S Richardson, Debbie Anderson, Jason Mendy, et al., Safety and Immunogenicity of an Adjuvant Chikungunya Virus (CHIKV) Virus-like Particle (VLP) Based Vaccine in Two Pivotal Phase 3 Trials, ≥12 Years of Age, Open Forum Infectious Diseases, Volume 10, Issue Supplement_2, December 2023, ofad500.2471, https://doi.org/10.1093/ofid/ofad500.2471
- Bavarian Nordic receives US FDA approval of chikungunya vaccine for persons aged 12 and older, Bavaria Nordic, 14 February 2025 https://www.bavarian-nordic.com/media/media/news.aspx?news=7053
- New Chikungunya vaccine for adolescents from 12 and adults European Medicine Agency, 31 January 2025
- Bavarian Nordic receives EMA filing acceptance and validation of the MAA for its chikungunya vaccine, Bavaria Nordic, 18 July 2024
- Chikungunya Fact Sheet, World Health Organization, 08 December 2022, available from https://www.who.int/news-room/fact-sheets/detail/chikungunya
- J. Erin Staples, Susan Hills, Ann Powers, Chikungunya, CDC Yellow Book 2024, Travel-Associated Infections & Diseases, CDC Travellers Health, U.S. Department of Health & Human Services https://wwwnc.cdc.gov/travel/yellowbook/2024/infections-diseases/chikungunya
- Cunha RVD, Trinta KS. Chikungunya virus: clinical aspects and treatment – A Review. Mem Inst Oswaldo Cruz. 2017 Aug; 112(8):523-531. Doi: 10.1590/0074-02760170044. PMID: 28767976; PMCID: PMC5530543.
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