Ixchiq FDA Approval History
FDA Approved: Yes (Discontinued) (First approved November 9, 2023)
Brand name: Ixchiq
Generic name: chikungunya vaccine, live
Dosage form: Injection
Previous Name: VLA1553
Company: Valneva USA, Inc.
Treatment for: Chikungunya Disease Prevention
Last updated by Judith Stewart, BPharm on Aug 26, 2025.
Ixchiq (chikungunya vaccine, live) is a live-attenuated, single dose vaccine indicated for the prevention of disease caused by chikungunya virus (CHIKV) in individuals 18 years of age and older who are at increased risk of exposure to CHIKV.
On August 22, 2025, the U.S. Food and Drug Administration's Center for Biologics Evaluation and Research (CBER) announced the suspension of the biologics license for Valneva’s live-attenuated Ixchiq vaccine. This vaccine was initially approved by the FDA under the accelerated approval pathway in November of 2023 for the prevention of disease caused by the chikungunya virus (CHIKV) in individuals 18 years of age and older who are at increased risk of exposure to CHIKV.
The decision was based on serious safety concerns related to the vaccine, which appeared to be causing chikungunya-like illness in vaccine recipients. There had been one death from encephalitis directly attributable to the vaccine (CSF PCR was + for the vaccine strain of the virus) and over 20 reported serious adverse events that were consistent with chikungunya-like illness. Reported serious adverse events have included 21 hospitalizations and 3 deaths. Furthermore, the clinical benefit of the vaccine has not yet been verified in confirmatory clinical studies.
CBER’s benefit-risk analysis broadly shows the vaccine does not have benefits outweighing risks, under most plausible scenarios. For these reasons, CBER believes this vaccine is not safe and that continued administration to the public would pose a danger to health.
The decision was based on serious safety concerns related to the vaccine, which appeared to be causing chikungunya-like illness in vaccine recipients. There had been one death from encephalitis directly attributable to the vaccine (CSF PCR was + for the vaccine strain of the virus) and over 20 reported serious adverse events that were consistent with chikungunya-like illness. Reported serious adverse events have included 21 hospitalizations and 3 deaths. Furthermore, the clinical benefit of the vaccine has not yet been verified in confirmatory clinical studies.
CBER’s benefit-risk analysis broadly shows the vaccine does not have benefits outweighing risks, under most plausible scenarios. For these reasons, CBER believes this vaccine is not safe and that continued administration to the public would pose a danger to health.
- Chikungunya is a mosquito-borne viral disease caused by the chikungunya virus (CHIKV), a Togaviridae virus, transmitted by Aedes mosquitoes. Symptoms include acute onset of fever, debilitating joint and muscle pain, headache, nausea, rash and chronic arthralgia.
- Ixchiq is a live-attenuated vaccine that has been designed by deleting a part of the chikungunya virus genome. The exact mechanism of protection has not been determined. Ixchiq elicits CHIKV-specific immune responses.
- Pivotal Phase 3 data for Ixchiq published in the Lancet in June 2023 showed a 98.9% seroresponse rate at 28 days with a single vaccination. Ixchiq-induced seroresponse was sustained over time with a 96.3% seroresponse rate six months post-vaccination. Valneva will continue to evaluate antibody persistence for at least five years.
- Ixchiq is administered by intramuscular injection.
- Warnings and precautions associated with Ixchiq include severe or prolonged chikungunya-like adverse reactions, vertical transmission of wild-type CHIKV from pregnant individuals with viremia at delivery causing potentially fatal CHIKV disease in neonates, and syncope associated with the administration of the vaccine.
- Common systemic adverse reactions include headache, fatigue, myalgia, arthralgia, fever, and nausea. Common local adverse reactions include injection site tenderness.
Development timeline for Ixchiq
Further information
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