The tools to combat mosquito-linked illnesses received a shot in the arm with the United States Food and Drug Administration approving Ixchiq, the first chikungunya vaccine.

Ixchiq from French specialty vaccine company Valneva is approved for individuals 18 years and older, at increased risk of exposure to the chikungunya virus, the US regulator said.

The approval makes Ixchiq the world’s first licensed chikungunya vaccine, said Valneva. “This indication is approved under accelerated approval based on anti-CHIKV neutralising antibody titers. Continued approval for this indication is contingent upon verification of clinical benefit in confirmatory studies,” it added.

Geographical spread

The virus is primarily transmitted through the bite of an infected mosquito, and the infection is being reported from new geographical areas causing a global increase in prevalence, the USFDA said. Presently, the highest risk of infection is in the tropical and subtropical regions of Africa, Southeast Asia, and parts of the Americas where chikungunya virus-carrying mosquitos are endemic, it said.

Dr Richard Hatchett, CEO, the Coalition for Epidemic Preparedness Innovations (CEPI) says, in the Valneva statement, “Climate change is intensifying the threat posed by chikungunya, which means safe and effective vaccines are needed now more than ever before. Through our partnership with Valneva and Instituto Butantan, CEPI – with support from the EU – will help to make this vaccine accessible to the people most affected by the virus in low- and middle-income countries (LMIC).” Details on access to the vaccine in LMICs were not outlined.

“Infection with chikungunya virus can lead to severe diseases and prolonged health problems, particularly for older adults and individuals with underlying medical conditions,” said Peter Marks, Director, FDA Center for Biologics Evaluation and Research. Symptoms of chikungunya include fever and joint pain, sometimes debilitating joint pain that persists for months or years. And treatment included rest, fluids, and over-the-counter medications for pain and fever.

Ixchiq is a single dose injection, given in the muscle. “It contains a live, weakened version of the chikungunya virus and may cause symptoms in the vaccine recipient similar to those experienced by people who have chikungunya disease,” the FDA said.

Clinical studies

The safety of Ixchiq was evaluated in two clinical studies conducted in North America in which about 3,500 participants aged 18 years and older received a dose of the vaccine with one study including about 1,000 participants who received a placebo, the USFDA note explained. The commonly reported side effects by vaccine recipients were headache, fatigue, muscle pain, joint pain, fever, nausea and tenderness at the injection site.

The FDA has asked the company to undertake a post-marketing study to assess the serious risk of severe chikungunya-like adverse reactions following administration of Ixchiq. Valneva said it has plans to begin commercialising the vaccine in the US, early next year.