The European Medicines Agency (EMA)’s Pharmacovigilance Risk Assessment Committee (PRAC) has issued a safety update on the chikungunya vaccine after review of the Ixchiq live-attenuated jab. It said that it would now lift the temporary restriction put in place in May on vaccinating people aged 65 years and above as a result of reports of serious side effects.
However, the committee emphasized that the vaccine should only be used after careful consideration of risks and benefits when there is significant risk of chikungunya infection.
Chikungunya is a viral disease that is most common in Africa, Asia, the Caribbean, and South and Central America, with a few cases also reported in Europe and the US. It is carried by mosquitoes, most often Aedes aegypti and Aedes albopictus, that may also transmit dengue and Zika viruses. Person-to-person transmission does not occur, though rarely the infection may be passed on via blood.
Crippling Joint Pain
The incubation period is 3-7 days. Common symptoms are fever, rash, muscle pain, and severe arthralgia. The name chikungunya comes from a Tanzanian word to describe the way severely affected patients often assume a stooped appearance due to crippling pain. Most infections are mild, with only about 2% leading to severe symptoms. There may be a risk of encephalitis, but this is rare and unclear.
Most of those affected recover within a week to 10 days of the start of symptoms. But 30%-40% of those affected develop ongoing chronic joint pain and chronic arthritis that can last for months or even years. Treatment is largely symptomatic.
Side Effect Risk Groups
Ixchiq was authorized in the EU in June 2024. When the recent PRAC review began, around 36,000 doses of the vaccine had been used worldwide. Safety data recorded 28 cases of serious side effects, mainly in people aged 65 years and older and those with multiple underlying comorbidities, particularly chronic or uncontrolled medical conditions such as cardiovascular diseases, diabetes mellitus, or chronic kidney disease. There had been three deaths.
Although serious vaccine side effects most often affected this group, these were also the people at highest risk of severe chikungunya infection, the PRAC noted. Many of the serious side effects reported were similar to symptoms of chikungunya infection itself, the committee said. These could include fever, malaise, anorexia, and confusion, which can lead to falls. In some cases, vaccine side effects had worsened patients’ medical conditions or caused deterioration in their general health, in some instances resulting in hospitalization.
Avoid Vaccinating Immunocompromised People
The committee also reminded healthcare professionals that Ixchiq must not be given to people whose immune system is weakened because of disease or medical treatment, as they are at greater risk of having complications from vaccines containing live-attenuated viruses. This contraindication remains in place following the review.
The product information for Ixchiq will be updated with the latest recommendations following the review. A direct healthcare professional communication will be sent to healthcare professionals prescribing, dispensing, or administering Ixchiq and will be published on a dedicated page on the EMA website.
The PRAC recommendations will now be sent to the Committee for Medicinal Products for Human Use, which will adopt the agency’s opinion before adoption by the European Commission of a legally binding decision applicable in all EU Member States.