The Medicines and Healthcare products Regulatory Agency (MHRA) has today, 4 February 2025, approved the vaccine chikungunya vaccine (live) (brand name IXCHIQ) to protect adults against chikungunya disease, caused by the chikungunya virus (CHIKV).
CHIKV is found in the subtropical regions of the Americas, Africa, Southeast Asia, India, and the Pacific Region, and is spread to humans by the bite of an infected mosquito (Aedes aegypti and Aedes albopictus). It cannot be passed from human to human.
The majority of people infected with CHIKV develop a sudden fever and severe pain in multiple joints. 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. However, in some cases joint pain and arthritis may persist for several months or even years. Occasional cases of eye, neurological and heart complications have been reported, as well as gastrointestinal complaints.
Chikungunya vaccine has been approved for use as a prophylaxis against chikungunya disease. The vaccine contains a form of the virus that has been weakened in the laboratory so it cannot multiply. The vaccine works by training the immune system (the body's natural defences) to recognise CHIKV and it is then able to produce specific antibodies which attack the virus.
Julian Beach, MHRA Interim Executive Director of Healthcare Quality and Access, said:
Patient safety is our top priority, which is why I am pleased to confirm approval of the first vaccine in the UK to protect adults 18 years and older against Chikungunya disease. It is given as a single dose.
While mostly endemic to tropical and subtropical regions of Africa, Southeast Asia, and parts of the Americas, the virus has been detected in small numbers in new geographical areas including parts of Europe. It is therefore important we are prepared for potential further spread.
This approval is another demonstration of our commitment to supporting the UK in its efforts toward global pandemic preparedness.
As with all products, we will keep its safety under close review.
The recommended dose of chikungunya vaccine (live) can only be obtained via a prescription.
The benefits of chikungunya vaccine (live) were assessed in two main studies involving around 4,500 adults. In one main study, over 4,000 people were given the vaccine or a placebo (a dummy treatment).
The aim of the study was to determine whether the vaccine would trigger the immune system to produce a level of antibodies that, based on pre-clinical studies and information from people previously exposed to the virus who had developed immunity, is expected to provide protection.
Results showed that 99% of participants who received chikungunya vaccine (live) had the required level of antibodies after one month, compared with none of those who received placebo. Follow-up data showed that two years after vaccination, this target level was maintained in 97% of people who received the vaccine.
During clinical studies, the most common side effects with chikungunya vaccine (live) (which may affect more than 1 in 10 people) include leucopenia, neutropenia and lymphopenia (low levels of white blood cells, including neutrophils and lymphocytes, as seen in blood tests), headache, fatigue, myalgia (muscle pain), joint pain (arthralgia), elevated liver enzymes as seen in blood tests, fever, nausea (feeling sick), and tenderness, pain, erythema (redness), induration (hardening) or swelling at the site of injection.
As with any medicine, the MHRA will keep the safety and effectiveness of the vaccine under close review.
Anyone who suspects they are having a side effect from this vaccine are encouraged to talk to their doctor, pharmacist or nurse and report it directly to the Yellow Card scheme, either through the website ( https://yellowcard.mhra.gov.uk/ ) or by searching the Google Play or Apple App stores for MHRA Yellow Card.
