WASHINGTON, D.C. – The United States has suspended the license for Ixchiq, a French-made vaccine against chikungunya, following reports of severe side effects among elderly recipients.
Valneva, the biotech company that developed Ixchiq, confirmed on Monday that the US Food and Drug Administration (FDA) issued the suspension last Friday after four new cases of serious adverse reactions, three of which involved patients aged 70 to 82.
“The suspension of the licence is effective immediately,” the company said in a statement, adding that it was working with regulators to determine next steps.
Ixchiq is one of only two vaccines approved by the FDA to protect against chikungunya, a mosquito-borne virus spreading rapidly beyond tropical and subtropical regions.
Valneva obtained US approval in 2023, but safety concerns—particularly among older patients—had already prompted reviews by the European Medicines Agency earlier this year.
Despite the setback, Valneva’s CEO Thomas Lingelbach said the firm remained committed to making the vaccine available globally.
“As the clear threat of chikungunya continues to escalate, Valneva remains fully committed to maintaining access to our vaccine as a global health tool,” he said.
The suspension triggered a sharp sell-off of Valneva shares, which dropped more than 26 per cent on the Paris stock exchange.
Ixchiq generated €7.5 million ($8.8m) in sales in the first half of 2025, but the company said it would not alter its revenue guidance until the financial impact of the FDA move is fully assessed.
According to US regulators, the newly reported cases mirror symptoms previously observed in clinical trials and post-marketing surveillance, including fever, severe joint pain and fatigue.
One 82-year-old patient was hospitalised for two days before being discharged.
Chikungunya, transmitted by Aedes mosquitoes, is rarely fatal but poses higher risks for infants and the elderly.
Experts warn that climate change is expanding mosquito habitats, raising the likelihood of large-scale outbreaks.
In July, the World Health Organization cautioned that chikungunya could spark a major epidemic, noting early warning signs reminiscent of the 2004 Indian Ocean outbreak that infected nearly half a million people.
This year alone, Europe has recorded 27 chikungunya clusters—a record number—according to the European Centre for Disease Prevention and Control.
Kenya has also confirmed outbreaks, with the Kenya Medical Research Institute (KEMRI) reporting that 25 of 45 suspected cases in Mombasa tested positive.
Valneva said it is investigating the reported adverse cases and pledged to uphold “the highest safety standards” while ensuring vaccine access in countries where it remains licensed.
