UK Regulators Impose Major Restrictions on Chikungunya Vaccine Following Fatal Adverse Events
Key Insights
The UK's MHRA has restricted IXCHIQ chikungunya (search) vaccine use to adults aged 18-59 years only, following global reports of 28 serious adverse reactions including three fatal cases.
The vaccine is now contraindicated in individuals with hypertension (search), cardiovascular disease (search), diabetes, chronic kidney disease (search), and various immunodeficiency conditions.
Healthcare professionals must conduct comprehensive benefit-risk assessments and administer the vaccine at least 30 days before travel to ensure access to UK healthcare if serious reactions occur.
The UK's Medicines and Healthcare products Regulatory Agency (MHRA) has imposed significant new restrictions on the IXCHIQ chikungunya (search) vaccine following a comprehensive safety review that identified 28 cases of serious adverse reactions globally, including three fatal outcomes. The regulatory action, announced on February 11, 2026, follows recommendations from the Commission on Human Medicines (search) (CHM), the government's independent expert advisory committee.
New Age and Medical Restrictions
The vaccine is now limited to adults aged 18 to 59 years and is contraindicated in individuals aged 60 or over. Additionally, the vaccine should not be used in people of any age who have high blood pressure, heart disease, diabetes, or chronic kidney disease (search).
The restrictions extend to immunodeficient or immunosuppressed individuals, including those with IgA (immunoglobulin A) deficiency, and individuals with a history of thymus disorder and/or thymectomy. The CHM concluded that vaccination benefits remain favorable only for individuals at risk of chikungunya (search) infection who are aged 18-59 years and do not have these contraindicated conditions.
Enhanced Safety Protocols
Healthcare professionals must now undertake comprehensive benefit-risk assessments before offering the IXCHIQ vaccine, with particular caution advised when vaccinating individuals with two or more underlying chronic health conditions. The benefit-risk assessment and vaccine administration should only be conducted by healthcare professionals with training and experience in risk assessments for live vaccines.
As a precautionary measure, the vaccine must be administered at least 30 days before travel to ensure that if serious adverse reactions occur, the individual remains in the UK with appropriate access to healthcare and without language barriers.
Clinical Context and Disease Background
Chikungunya virus (search) is found in subtropical regions of the Americas, Africa, Southeast Asia, India, and the Pacific Region, spreading to humans through bites from infected Aedes aegypti and Aedes albopictus mosquitoes. The virus cannot be transmitted person-to-person through casual contact such as coughing, sneezing, or touching.
The majority of people infected with chikungunya virus (search) develop sudden fever and severe pain in multiple joints (arthralgia). Other symptoms may include headache, muscle pain, joint swelling, or rash. These symptoms typically resolve within 7 to 10 days, and most patients make a full recovery.
Safety Profile and Adverse Events
Because IXCHIQ contains a live, weakened strain of the chikungunya virus (search), serious side effects that resemble chikungunya (search) infection can occur, though they are very rare. These include rare neurological side effects such as encephalitis (search), which can be fatal. The risks are more likely to occur in certain groups, particularly people with weakened immune systems.
The decision to restrict vaccine use is based on global safety data analysis, with the regulatory review prompted by reports of serious adverse events in older people and individuals with underlying chronic conditions.
Regulatory Timeline
The MHRA initially approved the IXCHIQ chikungunya (search) vaccine in February 2025. In June 2025, the agency issued a temporary precautionary pause on vaccine use in people aged 65 years and over while conducting further safety data review. Following completion of this comprehensive safety review, the MHRA has now issued permanent restrictions on vaccine use, aligned with CHM recommendations.
Healthcare professionals, patients, and caregivers are encouraged to report suspected adverse reactions through the Yellow Card scheme, available via website, mobile app, or clinical IT systems. The MHRA emphasizes that comprehensive reporting should include medical history, concomitant medications, onset timing, and treatment dates.