The US Food and Drug Administration (FDA) has suspended the license for Valneva’s chikungunya vaccine, IXCHIQ, effective immediately, following the emergence of four new reports of serious adverse events (SAEs) consistent with chikungunya-like illness. The suspension, announced by Valneva on August 25, 2025, means the company must halt all shipments and sales of the vaccine within the United States.
The decision marks a significant setback for IXCHIQ, which had been granted FDA approval in late 2023 as the first licensed vaccine to protect against chikungunya virus. The move also comes just weeks after the FDA lifted a temporary pause on use of IXCHIQ in adults aged 60 and older. That earlier pause was introduced after safety concerns were raised in May 2025 but was lifted on August 6 when regulators concluded that the benefits of vaccination outweighed the risks in older adults with underlying health conditions, provided new warnings were added to the label.
The latest development was triggered by post-marketing safety surveillance data, which identified four new SAEs reported outside the United States. According to information submitted to the Vaccine Adverse Event Reporting System (VAERS), three of the cases occurred in adults aged 70 to 82 years, one of whom required hospitalization before recovering within two days. The fourth case involved a 55-year-old recipient. Valneva stated that these events resembled patterns already documented during clinical trials and in prior post-marketing observations, particularly among elderly vaccine recipients. The prescribing information for IXCHIQ already included warnings about potential risks in older adults.
Despite the suspension, Valneva’s chief executive officer, Thomas Lingelbach, emphasized the company’s commitment to maintaining vaccine access in countries where IXCHIQ remains licensed. He noted that Valneva is prioritizing distribution in low- and middle-income regions where chikungunya is endemic and vaccination is most urgently needed. The company has also confirmed that it is investigating the new reports in detail and may pursue additional regulatory steps under FDA procedures.
Financially, IXCHIQ has represented a modest but important contributor to Valneva’s revenue stream. In the first half of 2025, the vaccine generated €7.5 million in sales, largely driven by one-time shipments to La Réunion, which was grappling with a chikungunya outbreak. By comparison, Valneva reported total product sales of €91 million for the same period. While the company acknowledged that the US suspension could impact future growth, it has not yet revised its revenue guidance for the year.
Timeline of Regulatory Actions on IXCHIQ
The FDA’s latest suspension is the culmination of several months of heightened regulatory scrutiny. On April 16, 2025, the Advisory Committee on Immunization Practices (ACIP) recommended the vaccine for travelers heading to outbreak zones and for laboratory workers at risk of exposure, but also flagged uncertainty around risks for older adults with comorbidities after reviewing six SAEs from clinical trials. On May 12, 2025, the FDA and Centers for Disease Control and Prevention (CDC) jointly advised pausing vaccination in adults aged 65 and older, citing VAERS reports of SAEs, including one death, during a campaign in La Réunion. Although no causal relationship was established, the precaution was deemed necessary. On August 6, 2025, following a three-month review in collaboration with the European Medicines Agency, the FDA lifted that restriction, reinstating access for older adults but with updated warnings. Less than three weeks later, on August 25, 2025, the FDA reversed course, suspending IXCHIQ’s US license altogether.
Broader Implications
The FDA’s suspension underscores the challenges of balancing urgent public health needs with vaccine safety, particularly in vulnerable populations. While chikungunya poses significant risks in endemic regions and can lead to debilitating long-term illness, concerns about adverse events may hinder confidence in new preventive tools. For Valneva, the decision represents both a regulatory and commercial setback, but the company maintains that its broader global strategy—focused on endemic regions—remains intact.
