MHRA withdraws UK licence for IXCHIQ chikungunya vaccine after safety review

The MHRA withdrew the UK marketing authorisation for IXCHIQ, a live attenuated chikungunya vaccine for adults travelling to high-risk areas, on 20 October 2026. The regulator acted on advice from the Commission on Human Medicines (CHM) and concluded that the vaccine's benefit-risk balance is no longer favourable ¹.

What the regulator decided

The decision followed a review of post-authorisation safety data. Since IXCHIQ was authorised, serious adverse reactions have been reported, among them chikungunya-like symptoms and rare neurological events such as encephalitis ¹. Most cases were in older adults and in people with underlying medical conditions, but the MHRA says some were in people with no known health conditions. Some cases ended in hospitalisation or death ¹.

The MHRA has told healthcare professionals to stop prescribing, supplying and administering the vaccine and to dispose of remaining stock under local policies. The product is being taken off the UK market ¹. Clinicians are also asked to update any materials, systems or communications that list UK vaccination options so that IXCHIQ no longer appears, and to keep reporting suspected reactions through the Yellow Card scheme ¹.

For people already vaccinated, the agency says there is no need for another dose or any other treatment because of the withdrawal. Anyone who had a suspected side effect should seek medical advice and file a Yellow Card report ¹. Travellers to areas with chikungunya transmission are to be pointed towards other options: a different chikungunya vaccine, protection against mosquito bites with netting or repellent, and current travel health advice ¹.

What it means for the market

The decision removes one licensed product from the UK travel vaccine market and leaves prescribers relying on alternatives. The MHRA refers to other available chikungunya vaccines without naming them ¹. Travel clinics, pharmacies and GP practices that stock or list the vaccine will have to change stock, patient materials and clinical systems, a point the guidance makes explicit ¹.

For vaccine developers and safety teams, the case shows how post-authorisation reporting can reverse a licence. Signals concentrated in older and medically vulnerable people were enough for the CHM to judge that benefits no longer outweighed risks for UK travellers as a whole ¹. That puts weight on the quality of post-marketing surveillance for live attenuated products used in healthy travellers, where the tolerance for serious harm is low.

The notice does not give the number of reported cases, the number of doses given in the UK or any figure on remaining stock. It also says nothing about the vaccine's status outside the UK ¹.

Caveats

The MHRA's notice is a summary of its conclusions rather than the underlying analysis, so the size of the risk cannot be judged from it ¹. Reporting continues: the agency has asked healthcare professionals, patients and carers to keep submitting Yellow Card reports linked to IXCHIQ, including details of medical history, other medicines and the timing of onset ¹.