FDA suspends Ixchiq license over safety risks

FDA has suspended the biologics license for Ixchiq, the live attenuated chikungunya vaccine, following serious postmarketing safety concerns. Approved in late 2023 for adults at risk of chikungunya exposure, Ixchiq has been linked to 21 hospitalizations, three deaths, and multiple cases of neurologic and cardiac complications. One fatal case of vaccine-strain encephalitis was confirmed via CSF PCR.

The vaccine mimics natural infection and can cause chikungunya-like symptoms. Most adverse events occurred in older adults with chronic conditions. FDA’s benefit-risk analysis found that Ixchiq’s risks outweigh its benefits, especially given the lack of confirmatory efficacy data.

Although a temporary pause in use for adults ≥60 was lifted earlier in August, FDA has now fully suspended the license, stating that continued administration would pose a public health risk.

Sources:

(2025, August 22). FDA. FDA Update on the Safety of Ixchiq (Chikungunya Vaccine, Live). https://www.fda.gov/vaccines-blood-biologics/safety-availability-biologics/fda-update-safety-ixchiq-chikungunya-vaccine-live

(2025, August 25). Valneva. Valneva announces FDA’s decision to suspect license of chikungunya vaccine IXCHIQ in the U.S. [Press release]. https://valneva.com/press-release/valneva-announces-fdas-decision-to-suspend-license-of-chikungunya-vaccine-ixchiq-in-the-u-s/