Chikungunya virus infection

FDA suspends biologics license of live-attenuated chikungunya vaccine (Ixchiq®) in the US

The US Food and Drug Administration (FDA) has suspended the biologics license of the live-attenuated chikungunya vaccine (known commercially as Ixchiq®) in the US. The suspension is effective immediately (as of 22 August 2025) and requires the manufacturer to stop shipping and selling the vaccine in the US. The FDA believes that the vaccine is not safe as it appears to be causing chikungunya-like illness in recipients, and continued administration would pose a danger to public health.[49]Food and Drug Administration. FDA update on the safety of Ixchiq (chikungunya vaccine, live). FDA suspends biologics license: FDA safety communication. Aug 2025 [internet publication]. https://www.fda.gov/safety/medical-product-safety-information/fda-update-safety-ixchiq-chikungunya-vaccine-live-fda-suspends-biologics-license-fda-safety

​The suspension follows the FDA’s decision on 6 August 2025 to remove a pause in the use of the vaccine in people aged ≥60 years. At the time, the agency approved updates to the prescribing information including revising the indication, adding limitations of use, and adding enhanced warnings and precautions to reflect serious adverse events picked up during postmarketing surveillance.[50]Food and Drug Administration. ​FDA update on the safety of Ixchiq (chikungunya vaccine, live). Aug 2025 [internet publication]. https://www.fda.gov/vaccines-blood-biologics/safety-availability-biologics/fda-update-safety-ixchiq-chikungunya-vaccine-live ​ However, since then, four new cases of serious adverse events have been reported in the Vaccine Adverse Event Reporting System (VAERS), prompting the FDA to suspend the vaccine’s license.[51]Valneva. Valneva announces FDA’s decision to suspend license of chikungunya vaccine IXCHIQ® in the U.S. Aug 2025 [internet publication]. https://valneva.com/press-release/valneva-announces-fdas-decision-to-suspend-license-of-chikungunya-vaccine-ixchiq-in-the-u-s

In May 2025, use of the live-attenuated vaccine was paused in older patients (aged ≥60 years in the US and ages ≥65 years in Europe) due to post-marketing reports of serious adverse events, including cardiac and neurological events, in people who received the vaccine.[52]Food and Drug Administration. ​FDA and CDC recommend pause in use of Ixchiq (chikungunya vaccine, live) in individuals 60 years of age and older while postmarketing safety reports are investigated. May 2025 [internet publication]. https://www.fda.gov/vaccines-blood-biologics/safety-availability-biologics/fda-and-cdc-recommend-pause-use-ixchiq-chikungunya-vaccine-live-individuals-60-years-age-and-older [53]​European Medicines Agency. ​EMA starts review of Ixchiq (live attenuated chikungunya vaccine). May 2025 [internet publication]. https://www.ema.europa.eu/en/news/ema-starts-review-ixchiq-live-attenuated-chikungunya-vaccine ​​​ At the time, a review of the safety data revealed 28 cases of serious adverse effects, including encephalitis and chikungunya-like symptoms, and three deaths. The serious adverse effects were mainly reported in people aged ≥65 years and those with multiple or uncontrolled medical conditions. The adverse effects led to a worsening of the patients’ medical conditions or a deterioration in their general health, sometimes leading to hospitalisation and death. Cases of encephalitis were rare.​[54]European Medicines Agency. Ixchiq: temporary restriction on vaccinating people 65 years and older to be lifted. Jul 2025 [internet publication]. https://www.ema.europa.eu/en/news/ixchiq-temporary-restriction-vaccinating-people-65-years-older-be-lifted

The live-attenuated vaccine continues to be available in countries where it is still licensed.[51]Valneva. Valneva announces FDA’s decision to suspend license of chikungunya vaccine IXCHIQ® in the U.S. Aug 2025 [internet publication]. https://valneva.com/press-release/valneva-announces-fdas-decision-to-suspend-license-of-chikungunya-vaccine-ixchiq-in-the-u-s

• In Europe, the European Medicines Agency (EMA) also paused use of the vaccine in people ages ≥65 years in May 2025, but lifted the restriction in July 2025. The EMA currently recommends that, in people of all ages, the live-attenuated vaccine should only be given when there is a significant risk of chikungunya virus infection, and only after careful consideration of the risks and benefits of vaccination.[54]European Medicines Agency. Ixchiq: temporary restriction on vaccinating people 65 years and older to be lifted. Jul 2025 [internet publication]. https://www.ema.europa.eu/en/news/ixchiq-temporary-restriction-vaccinating-people-65-years-older-be-lifted

• In the UK, the Medicines and Healthcare products Regulatory Agency (MHRA) has temporarily restricted use of the vaccine in people ages ≥65 years while it reviews the data.[55]Medicines and Healthcare products Regulatory Agency. IXCHIQ chikungunya vaccine: temporary suspension in people aged 65 years or older. Jun 2025 [internet publication]. https://www.gov.uk/drug-safety-update/ixchiq-chikungunya-vaccine-temporary-suspension-in-people-aged-65-years-or-older

The live-attenuated vaccine was initially approved by the FDA under the accelerated approval pathway in November 2023. The clinical benefit of the vaccine has not yet been confirmed in clinical studies. It was the first vaccine to be approved for the prevention of disease caused by chikungunya virus. Over 80,000 doses have been used worldwide since its approval.

An adjuvanted recombinant virus-like particle vaccine (known commercially as Vimkunya®) was recently approved in the US and Europe for the prevention of disease caused by chikungunya virus for people aged ≥12 years. There have been no safety issues reported with this vaccine as yet.

See Management: prevention

Original source of update