In November 2023 Valneva announced that the US FDA has approved its single-dose, live-attenuated vaccine for the prevention of disease caused by chikungunya virus: IXCHIQ. The vaccine has been approved for individuals aged 18 or above who are at “increased risk of exposure” to chikungunya (CHIKV). The approval was granted under accelerated approval based on anti-CHIKV neutralising antibody titers, and continued approval for the indication relies on confirmation of clinical benefit in confirmatory studies.  

What is CHIKV? 

Chikungunya is a mosquito-borne viral disease caused by chikungunya virus, a member of the Togaviridae family. It is transmitted by Aedes mosquitoes, endemic in parts of the Americas, parts of Africa, and Southeast Asia. Infection provokes symptomatic disease in up to 97% of humans after 4-7 days after a mosquito bite. These symptoms include acute onset of fever, debilitating pain, headaches, and nausea. 

“While mortality with CHIKV is low, morbidity is high.” 

The virus often causes “sudden” outbreaks with “high attack rates”, affecting between one-third and three-quarters of the population in areas where the virus is circulating. The economic effects are considered “significant”, and the medical and economic burden will grow as the primary mosquito vectors increase their geographic spread.  

“The global market for vaccines against chikungunya is estimated to exceed $500 million annually by 2032.” 

Until this approval there were no approved vaccines or effective treatments, allowing chikungunya to be a “major public health threat”.  


In the US, IXCHIQ is a live-attenuated vaccine indicated for the prevention of disease caused by CHIKV in adults aged 18 and above who are “at increased risk of exposure”. It is administered as a single dose by intramuscular injection. Valneva reports that, with this approval, the vaccine becomes the “world’s first licensed chikungunya vaccine” to address the “unmet medical need”.  

Pivotal Phase III results were shared in The Lancet in June 2023, but the company will continue to evaluate antibody persistence for “at least five years”. The FDA states that it is “requiring” Valneva to conduct a post marketing study to “assess the serious risk” of “serve chikungunya-like adverse reactions” following administration of the vaccine.  

An ongoing clinical study in adolescents between the ages of 12 and 17 is continuing in Brazil. This forms part of an agreement between Instituto Butantan and Valneva in January 2021 to ensure the vaccine is “more accessible” to low- and middle-income countries (LMICs). This study is funded by CEPI and could support future regulatory submissions in the age group and licensure in Brazil, signifying the first potential approval for use in an endemic region.  

Valneva also expects this study to support regulatory approval in Europe; initial safety data was included in a submission to the EMA last month. The vaccine was granted PRIME designation by EMA in 2020. A regulatory review is also taking place in Canada.  

Who will benefit? 

Valneva suggests that the vaccine will “initially” address the “potential needs” of US travellers, fitting “seamlessly into Valneva’s global established travel vaccines business”. The company intends to begin commercialising IXCHIQ in the US at the start of 2024, while “continuing to support the work towards an anticipated vote” from the Advisory Committee on Immunisation Practices at the end of February. FDA’s Director of the Centre for Biologics Evaluation and Research, Dr Peter Marks, is hoping that “older adults and individuals with underlying health conditions” will benefit. 

“Today’s approval addresses an unmet medical need and is an important advancement in the prevention of a potentially debilitating disease with limited treatment options.”  

The approval is a source of pride for Valneva’s CEO Thomas Lingelbach, whom we interviewed at the Congress in Washington this April about “unmet medical needs”. He described it as an “important step forward” and “personally” expressed “a huge thank you” to everyone involved. Notably, he looks forward to the ongoing trial results. 

“I would also like to recognise CEPI and Instituto Butantan for their collaboration in potentially bringing this product to low- and middle-income countries.” 

CEPI’s CEO Dr Richard Hatchett is “proud” of his organisation’s contribution and offered his congratulations to “our partner Valneva” on “this historic achievement”. 

“The first-ever licensed chikungunya vaccine will play a crucial role in preventing the suffering caused by this debilitating disease.” 

He emphasised that the partnership with Valneva and Instituto Butantan, with “support from the EU”, will ensure the vaccine is accessible to the “people most affected by the virus”. Dr Juan Carlos Jaramillo, Chief Medical Officer at Valneva, echoed this intention. 

“Our objective is to make this vaccine available to the largest number of people that will benefit from it.” 

Dr Jaramillo reflects that “more than 75%” of the global population lives in “areas at risk” due to factors like “global warming and climate change”. Will Valneva’s vaccine reach these people in time? How do you think the FDA approval might drive further progress for other areas? 

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