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. 2025 Aug;30(32):2500543.
doi: 10.2807/1560-7917.ES.2025.30.32.2500543.

Surveillance for adverse events following use of live attenuated chikungunya vaccine, United States, 2024, and the associated public health response in 2024 and 2025

Susan L Hills  1 , Rebekah A Sutter  1 , Elaine R Miller  2 , Edwin J Asturias  3 , Lin H Chen  4   5 , Beth P Bell  6 , Michael M McNeil  2 , Jeffrey Rakickas  2 , Melinda Wharton  2 , Sarah Meyer  2 , J Erin Staples  1
Affiliations

Surveillance for adverse events following use of live attenuated chikungunya vaccine, United States, 2024, and the associated public health response in 2024 and 2025

Susan L Hills et al. Euro Surveill. 2025 Aug.

Abstract

A live attenuated chikungunya vaccine (IXCHIQ) received licensure in the United States (US) for ≥ 18-year-olds in November 2023. Post-licensure safety surveillance identified 28 adverse events in 2024 among US persons, including six neurological or cardiac serious adverse events (SAEs) in males ≥ 65 years. In early 2025, providers were alerted, a precaution for older persons was issued and vaccine guidance was updated. In May, following 11 additional SAEs reported outside the US, use in older persons was temporarily paused until 6 August 2025.

Keywords: adverse event; chikungunya; immunisation; ixchiq; live attenuated; serious; vaccine.

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Conflict of interest statement

Conflict of interest: None declared.

References

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