The US Food and Drug Administration (USFDA) has given the green light to Ixchiq, the inaugural vaccine designed to prevent diseases caused by the chikungunya virus. This approval applies to individuals aged 18 and above who face an elevated risk of chikungunya virus exposure.

Chikungunya is chiefly transmitted through mosquito bites and poses a growing global health threat, with over 5 million reported cases in the past 15 years. While the primary risk occurs in tropical and subtropical regions of Africa, Southeast Asia, and parts of the Americas where virus-carrying mosquitos are endemic, the virus has extended its reach to new areas, contributing to a surge in global prevalence.

Common symptoms of chikungunya encompass fever and joint pain, often accompanied by a rash, headache, and muscle pain. Some individuals may endure prolonged joint pain lasting months or even years. Treatment typically involves rest, fluids, and over-the-counter medications for pain and fever.

Director of the FDA's Center for Biologics Evaluation and Research, Peter Marks, highlighted the severity of chikungunya-related health problems, particularly for older adults and those with underlying medical conditions. The approval of Ixchiq addresses an unmet medical need and represents a significant advancement in preventing this debilitating disease.

Ixchiq, administered as a single dose via muscle injection, contains a live, weakened version of the chikungunya virus, potentially causing symptoms resembling those experienced by individuals with the disease. Safety evaluations involved two North American clinical studies with approximately 3,500 participants, where the most common side effects included headache, fatigue, muscle and joint pain, fever, nausea, and tenderness at the injection site.

Although severe chikungunya-like adverse reactions occurred in 1.6% of Ixchiq recipients, none were reported in the placebo group. Two recipients with severe reactions were hospitalized, and some experienced prolonged adverse reactions lasting at least 30 days. The FDA requires the manufacturer to conduct a postmarketing study assessing the risk of severe chikungunya-like adverse reactions.

While chikungunya virus transmission to newborns from pregnant individuals has been reported, the vaccine's blood detection within the first week after vaccination diminishes after 14 days. The Prescribing Information includes warnings regarding the unknown transmission risk to newborns and potential adverse effects.

Ixchiq's effectiveness is based on immune response data from a US clinical study in individuals aged 18 and older. Almost all vaccine study participants achieved the antibody level considered protective based on non-human primate studies. The Accelerated Approval pathway was used, allowing approval for serious or life-threatening conditions based on evidence reasonably predicting clinical benefit.

Ixchiq received Fast Track and Breakthrough Therapy designations, Priority Review, and a tropical disease priority review voucher from the FDA. The approval was granted to Valneva Austria GmbH.