FDA, CDC issue precautionary pause on Ixchiq vaccine for those aged 60+

USA— The U.S. Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) have jointly recommended pausing of the use of Valneva’s chikungunya vaccine, Ixchiq, in individuals aged 60 and older.

This precautionary measure follows reports of serious adverse events (AEs) in this age group on May 9,  prompting a thorough safety investigation.

This decision aligns with a similar move by the European Medicines Agency (EMA) on May 7, which suspended the vaccine’s use in adults aged 65 and above, as well as in those with weakened immune systems, while conducting an ongoing safety review.

The EMA’s action came shortly after French health authorities had already restricted the vaccine for older adults.

Valneva’s Ixchiq vaccine had recently received marketing authorization from Brazil’s Health Regulatory Agency (ANVISA) for use in adults aged 18 and older, just days before these safety concerns arose.

 The vaccine was initially approved by the FDA in November 2023 and by the EMA in June 2024 for adults at risk of chikungunya virus exposure.

As of early May 2025, about 80,000 doses of Ixchiq have been distributed worldwide, with approximately 43,400 doses administered globally.

The vaccine is a single-dose, live attenuated injection designed to protect against chikungunya, a mosquito-borne viral disease prevalent in tropical regions.

 Symptoms of chikungunya include fever and severe joint pain, which can resemble other infections like dengue and Zika, complicating diagnosis.

The safety concerns emerged after 17 serious adverse events were reported globally in vaccine recipients aged 62 to 89, including two deaths.

 Six of these serious cases occurred in the United States.

 The two fatal cases were reported in La Réunion, a French overseas territory, where Valneva had supplied 40,000 doses as part of a national vaccination campaign targeting older adults with co-morbidities.

One fatality involved an 84-year-old man who developed encephalitis, while the other was a 77-year-old man with Parkinson’s disease, whose swallowing difficulties likely led to aspiration pneumonia5.

The FDA emphasized that these adverse events “may not be causally related to vaccination,” noting that most affected individuals had underlying chronic health conditions.

The agency will conduct an updated risk-benefit assessment for vaccine use in older adults and continue monitoring post-marketing safety data alongside the CDC2.

Clinical trials conducted in North America involving about 3,500 vaccine recipients aged 18 and older showed common side effects such as headache, fatigue, and muscle pain.

Severe adverse events were rare, occurring in 1.6% of vaccine recipients and none in the placebo group.

Two participants experienced severe chikungunya-like symptoms requiring hospitalization during the trials.

In response to the pause, Valneva reaffirmed its commitment to safety and cooperation with health authorities.

The company stated it still sees a positive risk-benefit profile for most people at risk of chikungunya exposure and will continue to monitor all serious adverse events closely.

Valneva’s Chief Medical Officer, Juan Carlos Jaramillo, expressed support for the precautionary steps and pledged ongoing engagement with global regulators during the investigation.

Ixchiq was the first licensed vaccine for chikungunya virus prevention until February 2025, when Bavarian Nordic’s Vimkunya entered the market.

Both vaccines have been approved for adolescents in Europe, with Ixchiq’s label expanded in April 2025.

In the U.S., only Vimkunya is currently approved for use in adolescents and adults.

Chikungunya remains a concern primarily in tropical and subtropical areas, with potential risks to travelers visiting affected regions in Africa, South America, and various islands in the Indian and Pacific Oceans.

The pause on Ixchiq for older adults reflects a cautious approach to ensure vaccine safety while continuing efforts to protect vulnerable populations from this debilitating disease.

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