US suspends license to sell chikungunya vaccine due to serious side effects

U.S. health authorities have suspended the license for the chikungunya vaccine Ixchiq after reports of “serious adverse effects,” the drug’s manufacturer announced Monday.

Ixchiq is one of only two vaccines approved by the U.S. Food and Drug Administration (FDA) for the mosquito-borne virus, which is endemic in tropical and subtropical regions worldwide.

French drugmaker Valneva received FDA approval for the vaccine in 2023, but reports of side effects led to revisions of the license, including by the European Medicines Agency, particularly concerning its use in older patients.

"The license suspension is effective immediately," Valneva announced regarding the FDA order issued Friday, citing four additional cases of serious side effects, three of which involved people aged 70 to 82.

"As we determine potential next steps, and as the clear threat of chikungunya continues to increase globally, Valneva remains fully committed to maintaining access to our vaccine as a global health tool," the company's CEO, Thomas Lingelbach, said in a statement.

The drugmaker added that it is evaluating the financial impact of the suspension.

Potential pandemic threat

Public health experts warn that chikungunya could pose a future pandemic threat as climate change expands the range of the mosquitoes that transmit the virus.

Europe has recorded 27 chikungunya outbreaks this year, setting a new continental record, according to data from the European Centre for Disease Prevention and Control (ECDC).

Chikungunya is rarely fatal, though infants and the elderly face a higher risk of death.