Chikungunya vaccine, IXCHIQ, approved in the UK
Today, the Medicines and Healthcare products Regulatory Agency (MHRA) approved Valneva’s chikungunya vaccine, IXCHIQ, to protect adults against chikungunya disease, caused by the chikungunya virus (CHIKV).
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 defenses) to recognize CHIKV and it is then able to produce specific antibodies which attack the virus.
The recommended dose of chikungunya vaccine (live) can only be obtained via a prescription.
According to MHRA:
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.
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.