According to the vaccine's maker, Valneva, the FDA based its decision to suspend the shot on four new serious adverse events that happened outside the U.S., three of which were in people ages 70 to 82 years and the other in a 55-year-old individual.

By Stephanie Brown HealthDay ReporterMONDAY, Aug. 25, 2025 (HealthDay News) -- The U.S. Food and Drug Administration is suspending the biologics license for the live-attenuated chikungunya vaccine, Ixchiq, in the United States. The move comes after reports of serious side effects in older adults similar to the symptoms of chikungunya virus.

Valneva must immediately cease U.S. shipments and sales of Ixchiq, a vaccine for chikungunya virus. The FDA recently lifted a pause on dosing of Ixchiq, but the agency’s new safety alert is based on an assessment that found the vaccine appears to be causing chikungunya-like illness in recipients.