Valneva voluntarily withdrew its chikungunya vaccine’s U.S. application and stopped a halted post‑marketing study after learning the FDA placed a clinical hold tied to a newly reported serious adverse event outside the U.S. Ixchiq received accelerated approval in November 2023 but has faced safety scrutiny and regulatory actions in Europe and the U.S. The company said it will continue post‑marketing activities pending discussions with regulators but removed its U.S. filings amid the ongoing safety review.