Chikungunya virus infection

Pause in use of live-attenuated chikungunya vaccine in older adults due to safety concerns

Drug regulatory agencies have recommended a pause in the use of the live-attenuated chikungunya vaccine (known commercially as Ixchiq®) in older adults, due to reports of serious adverse events during postmarketing use of the vaccine.

The Food and Drug Administration (FDA) has recommended a pause in the use of the live-attenuated vaccine in people ages ≥60 years while it investigates the issue and conducts an updated assessment of the benefits and risks in people in this age group.[46]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 ​​​​ The Centers for Disease Control and Prevention (CDC) supports this recommendation.[45]Centers for Disease Control and Prevention​. Chikungunya vaccine information for healthcare providers. May 2025 [internet publication]. https://www.cdc.gov/chikungunya/hcp/vaccine/index.html ​

The European Medicines Agency (EMA) has also suspended use of the vaccine in older adults, but with a higher age cut-off of ≥65 years. Use of the vaccine is now contraindicated in adults ages ≥65 years in affected regions. The EMA has introduced this temporary measure while it conducts a thorough safety review of the vaccine, and determines whether any changes are required to the terms of its marketing authorization.[47]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

The recommendations come after reports of serious adverse events occurring in older people who have received the vaccine. As of 7 May 2025, 17 serious adverse events, including two deaths, have been reported globally in people ages between 62 and 89 years. The fatal cases were due to encephalitis and aspiration pneumonia. Many of the people experiencing serious adverse events had pre-existing comorbidities, and it is unknown whether there is a causal relationship with the vaccine as yet.​​[46]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 [47]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

The live-attenuated vaccine may still be used in people <60 years of age (in the US) and <65 years of age (in Europe) within its license. The vaccine is contraindicated in people who are immunocompromised.

The live-attenuated vaccine 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. More recently, an adjuvanted recombinant virus-like particle vaccine (known commercially as Vimkunya®) was approved for the prevention of disease caused by chikungunya virus; this vaccine is not currently affected by the restrictions and may be used in people ages ≥60 years.

Approximately 18.7 million cases of chikungunya virus infection have been reported across 110 countries between 2011 and 2020, with most of the burden in the Latin American and Caribbean region.

See Management: prevention

Original source of update