U.S. halts Valneva's promotion of the chikungunya vaccine due to safety issues

In a significant development, the U.S. Food and Drug Administration (FDA) has suspended the marketing application for Valneva's chikungunya vaccine, Ixchiq. The decision, announced on August 25, 2025, follows reports of over 20 serious adverse events and one vaccine-attributable death.

Ixchiq, a live-attenuated vaccine developed by French biotech Valneva, was initially cleared by the FDA in November 2023 for preventing chikungunya in individuals aged 18 and older at increased risk. However, the FDA's biologics division has determined that Ixchiq's benefits do not outweigh its risks based on a benefit-risk analysis.

The FDA's suspension of Ixchiq's application has caused Valneva to stop shipment and sales in the U.S. The FDA's concerns centre around the vaccine causing chikungunya-like illness in recipients. The FDA and Centers for Disease Control and Prevention (CDC) believe that continued administration of Ixchiq poses a danger to health.

Notably, the FDA had previously paused and then lifted a pause on the use of Ixchiq especially in people aged 60 and older, with a recommendation to restrict the vaccine to individuals at high risk of exposure. However, the FDA's recent decision to suspend the vaccine's application is not related to the removal of the pause in the use of Ixchiq in the elderly.

The FDA and CDC's decision regarding Ixchiq's safety concerns the vaccine's continued administration to the public. The FDA has recorded 21 hospitalizations and three deaths associated with Ixchiq. The agency is currently investigating these serious adverse events.

In the U.S. chikungunya vaccine market, other operators include Danish biotech Bavarian Nordic. Bavarian Nordic is traded on OTC under the ticker symbols BVNRY and BVNKF.

Valneva has reported its 1H results and reaffirmed its FY outlook. However, there are no new facts about Valneva's earnings call presentations or transcripts. Similarly, there are no new facts about Seeking Alpha's Quant Rating on Valneva.

Ixchiq is traded on NASDAQ under the ticker symbol VALN. The company's stock price has seen a significant drop following the FDA's decision. Investors are advised to closely monitor the situation and seek professional financial advice before making any investment decisions.