The US Food and Drug Administration has suspended the licence for Valneva’s chikungunya vaccine, Ixchiq, with immediate effect, citing safety concerns. The decision triggered a sell-off in Paris, where the French vaccine maker’s shares dropped roughly 25% on Monday. Regulators acted after receiving four additional reports of serious adverse events that resembled chikungunya illness, three of them in patients aged 70-82. Valneva must halt all shipments and sales of the product in the United States while the review is under way. Ixchiq generated €7.5 million ($8.8 million) in the first half of 2025, accounting for about 8% of the company’s product revenue. Valneva said it is evaluating the financial impact of a potential permanent withdrawal but has not altered its full-year guidance.