Chikungunya Vaccine, Recombinant (Bavarian Nordic)

Ixchiq contributed €7.5m to Valneva’s €91m total product sales in H1 2025. Credit: Ink Drop via Shutterstock.com. The US Food and Drug Administration (FDA) has suspended the licence for Valneva’s chikungunya vaccine Ixchiq, just two weeks after lifting a partial pause on the jab’s use after investigating safety concerns. The U-turn by the FDA comes amid new reports of serious adverse events (SAEs) in individuals administered with Ixchiq. Shares in Paris-listed Valneva were trading 25.5% down compared to market open on 22 August, the day the FDA issued its decision after market close. The agency stated its verdict, made via the Center for Biologics Evaluation and Research (CBER), is “based on serious safety concerns related to the vaccine, which appears to be causing chikungunya-like illness in vaccine recipients”. The agency cited reports of 21 hospitalisations and three deaths linked to the vaccine. This includes one death from encephalitis directly attributable to the vaccine. The CBER said its benefit-risk is no longer in favour of the drug under most plausible scenarios. The FDA department said it therefore “believes this vaccine is not safe” and that “continued administration to the public would pose a danger to health”. GlobalData Strategic Intelligence US Tariffs are shifting - will you react or anticipate? Don’t let policy changes catch you off guard. Stay proactive with real-time data and expert analysis. By GlobalData Learn more about Strategic Intelligence The decision to revoke the vaccine’s licence means it can no longer be used in the US. In a statement, Valneva said it is now mandated to stop shipping and selling Ixchiq in the country. “Valneva is committed to upholding the highest safety standards and will continue to engage proactively with health authorities in all territories where Ixchiq is licensed,” the French vaccine specialist added in its statement. Adding more clarity to the safety events, Valneva highlighted that three of the four deaths – all of which occurred outside the US – occurred in elderly patients. The company stated: “Valneva believes all cases describe symptoms consistent with those previously reported during clinical trials and post-marketing experience, particularly among the elderly individuals for whom the vaccine’s Prescribing Information (PI) includes warnings and precautions.” Valneva’s CEO Thomas Lingelbach confirmed that Ixchiq will still be sold in all countries where the product is licensed. Ixchiq contributed €7.5m to Valneva’s €91m total product sales in H1 2025. The company says it is currently evaluating the financial impact of the US suspension. In an email to P harmaceutical Technology , a Valneva spokesperson said the company is “continuing to investigate these cases in detail and if warranted will pursue further steps in connection with FDA’s decision in accordance with applicable statutory procedures.” The shot’s ban in the US is the latest undulation in a rocky regulatory road Ixchiq has traversed in the past month. In May 2025, the FDA and the US Centers for Disease Control and Prevention (CDC) jointly recommended a pause in the vaccine’s use in those aged 60 and over after post-marketing reports of serious adverse events. However, this partial pause was lifted on 8 August after the FDA reevaluated the vaccine’s benefit-risk profile as part of its investigation. The FDA suspension of Ixchiq’s licence leaves Bavarian Nordic’s Vimkunya as the sole chikungunya vaccine approved in the US. Unlike Ixchiq, which was only approved for adults, Vimkunya is licensed for immunisation in those aged 12 years and above. It is unclear whether the European Medicines Agency (EMA), which has made similar decisions to the FDA in the past month regarding Ixchiq, will also, in turn, suspend marketing authorisation. Caused by its namesake virus, chikungunya is a mosquito-borne disease mainly found in tropical regions. Although cases are not prevalent in North America or Europe, there is a risk of disease transmission to travellers visiting outbreak-affected countries in Africa and South America, along with islands in the Indian and Pacific Oceans. Indeed, the CDC has issued a considerable number of chikungunya-related travel alerts amid a new wave of outbreaks in countries, including China, Kenya, and Bolivia. The CBER reversals with Ixchiq mirror similar decisions with Sarepta’s gene therapy Elevidys in July. Even the agency’s director Vinay Prasad was involved in a reversal. Prasad stepped down from his role as CBER director in late July, only to rejoin the department in the same role two weeks later. 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After clearing Valneva's chikungunya vaccine Ixchiq earlier this month, the FDA has made a U-turn, suspending its use in the United States. Less than three weeks after lifting a pause on the use of Valneva’s chikungunya vaccine Ixchiq, the FDA has done an about-face, banning the use of the shot in the United States.On Friday, the agency suspended Valneva’s license “based on serious safety concerns,” citing 21 hospitalizations and three deaths, including one from encephalitis directly attributed to the live-attenuated vaccine. With the decision, the price of the French company’s shares has plummeted by 22%.In a release, Valneva called (PDF) the FDA’s decision “sudden,” after the regulator had lifted a previous halt on the use of the vaccine in older adults on August 6. The company added that the agency’s move came after it received four reports of side effects from its Vaccine Adverse Event Reporting System (VAERS), each happening outside of the U.S. The reports included one user who was hospitalized for two days.“Valneva believes all cases describe symptoms consistent with those previously reported during clinical trials and post-marketing experience, particularly among the elderly individuals for whom the vaccine’s prescribing information includes warnings and precautions,” the company said in its statement.Valneva CEO Thomas Lingelbach added that the company “remains fully committed to maintaining access to our vaccine” in all countries where it is licensed.The FDA’s decision comes amid a new wave of chikungunya outbreaks, which has caught the attention of the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC). The CDC has issued chikungunya-related travel alerts for outbreaks in Bolivia, Kenya, Madagascar, Mauritius, Mayotte, Réunion, Somalia, Sri Lanka and the southern Chinese province of Guangdong, where more than 8,000 cases have been reported since June.The side effects of the vaccine are similar to the symptoms of chikungunya infection, including fever, joint pain, lethargy, confusion and loss of appetite. The virus is spread by a particular species of mosquitoes in tropical areas. With the grounding of Ixchiq, Bavarian Nordic’s virus-like particle vaccine Vimkunya becomes the lone shot approved for the prevention of chikungunya in the U.S. While Ixchiq was originally endorsed for adults only, Vimkunya can be used by those 12 and older. The Danish company is also testing the shot in children ages 2 to 11.The decision with Ixchiq also comes amid uncertainty about the future of vaccines in the U.S. under the watch of Health and Human Services (HHS) Secretary Robert F. Kennedy Jr., who has long professed his anti-vaccine views. Earlier this month, the HHS revealed a plan to end mRNA vaccine work funded by the Biomedical Advanced Research and Development Authority (BARDA).The FDA granted an accelerated approval to Ixchiq in November 2023. Then, in May of this year, the regulator paused its use in the U.S. for those age 60 and older. The move came in response to adverse event reports from users of the shot and followed similar decisions by France’s public health agency and the European Medicines Agency (EMA) to halt use of the shot in people age 65 and older. In July, the EMA lifted its pause on Ixchiq, while adjusting its label with additional warnings for use by older adults. A month later, the FDA followed suit, also adjusting its label.Earlier this month, Valneva said sales of Ixchiq reached 7.5 million euros ($8.8 million) in the first half of this year, while the company’s overall sales during the period jumped 38% year over year to 98 million euros ($115 million). The company added on Monday that it is evaluating the financial impact of the FDA suspension, while not yet adjusting its annual revenue projection.