The UK MHRA has revoked IXCHIQ’s marketing authorization after a benefit-risk review, citing previous safety data without a new safety signal.
Written By: Mayuresh Salvi, PharmD
Reviewed By: Pharmacally Editorial Team
Valneva’s IXCHIQ live-attenuated chikungunya vaccine has lost its UK marketing authorization after the Medicines and Healthcare products Regulatory Agency (MHRA), following a further benefit-risk assessment by the Commission on Human Medicines (CHM), revoked the authorization. The decision was based on previously available safety data and was not associated with a newly identified safety signal.
UK Safety Restrictions Preceded the Revocation
The UK decision follows a series of progressively tighter safety measures introduced after post-marketing reports of serious adverse reactions.
In February 2026, the MHRA had already restricted IXCHIQ use in the UK. The vaccine was no longer indicated for adults aged 60 years and older and became contraindicated in people with hypertension, cardiovascular disease, diabetes or chronic kidney disease. The restrictions followed reports of very rare fatal reactions and other serious adverse events globally. The MHRA also required vaccination to occur no later than 30 days before travel and recommended a formal benefit-risk assessment by a healthcare professional experienced with live vaccines.
IXCHIQ first became available in the UK on June 18, 2025. By the time of the latest regulatory action, Valneva had already stopped active UK distribution because of low demand among travelers. No product remains on the UK market, limiting the financial impact of the revocation.
Global Safety Reviews Have Taken Different Paths
Regulatory responses in the US and European Union have also evolved as post-marketing evidence accumulated.
The US FDA initially recommended a pause in IXCHIQ vaccination for people aged 60 years and older in May 2025 after reports of serious neurologic and cardiac events. In August 2025, the agency suspended the vaccine’s biologics license after reviewing serious adverse-event reports, including hospitalizations, encephalitis and deaths, and concluded that the vaccine’s benefits did not outweigh its risks under most plausible scenarios.
The US license was subsequently voluntarily revoked at Valneva’s request on January 29, 2026. The FDA also released the company from its outstanding postmarketing requirements.
The European Union has taken a different approach. In June 2026, the European Medicines Agency’s Pharmacovigilance Risk Assessment Committee (PRAC) recommended restricting IXCHIQ to people aged 12 years and older who face a high risk of chikungunya infection. The review considered serious adverse events including aseptic meningitis, encephalitis, encephalopathy and prolonged chikungunya-like illness, with some cases resulting in hospitalization or death. The events occurred mainly in people aged 65 years and older and those with multiple chronic conditions, although younger healthy adults were also affected.
Live Vaccine Requires Careful Patient Selection
IXCHIQ contains a weakened strain of chikungunya virus. Its live-virus platform can produce chikungunya-like reactions, making patient selection particularly important. The UK safety review emphasized that serious reactions can include neurologic complications such as encephalitis and may rarely be fatal.
The regulatory concern is therefore not simply vaccine reactogenicity but the possibility of severe disease-like reactions in susceptible recipients. This has pushed regulators toward narrower indications, stronger contraindications and greater emphasis on individual benefit-risk assessment.
Regulatory Divergence Shapes IXCHIQ’s Future
Valneva maintains that IXCHIQ retains a favorable benefit-risk profile when used according to approved restrictions and has decided not to appeal the UK revocation because of its limited commercial impact. The company is instead prioritizing markets where chikungunya transmission presents a greater public health need.
The regulatory trajectory now presents a clear contrast: the US license has been revoked, the UK has withdrawn authorization, while European regulators have retained the vaccine under substantially narrower conditions. With approximately 187,000 doses administered globally, continued post-marketing surveillance will remain central to determining how the benefit-risk profile of IXCHIQ is viewed across remaining markets.
Reference
Valneva Provides Update on IXCHIQ® in the United Kingdom, Valneva, 07 October 2026
About the Writer
Mayuresh Sunil Salvi (Linkedin) is a PharmD professional and healthcare writer with a strong interest in pharmacovigilance, drug safety, and emerging medical research. He is passionate about exploring new drug discoveries, clinical research, and advances in evidence-based medicine. His interests also include ward rounds, prescription audits, and treatment analysis to support rational pharmacotherapy and improved patient care.