US health regulators have suspended the license for the Ixchiq vaccine, used against the mosquito-borne chikungunya virus, following fresh reports of severe adverse reactions.
The French pharmaceutical company Valneva, which developed the vaccine, confirmed the suspension in a statement on Monday, August 25, 2025.
According to the company, the US Food and Drug Administration (FDA) issued the order last Friday after four new cases of serious side effects were reported.
Three of the patients were elderly, aged between 70 and 82.
Ixchiq, approved in 2023, is one of only two vaccines authorized by the FDA to protect against chikungunya, a disease that causes high fever and painful, often debilitating joint inflammation.
While rarely fatal, the illness poses the greatest risk to newborns and older adults.
Valneva said the suspension takes effect immediately, but insisted the company remains committed to addressing safety concerns.
“As we determine next steps, and as the threat of chikungunya continues to escalate globally, we remain fully committed to maintaining access to our vaccine as a public health tool,” Valneva’s CEO Thomas Lingelbach said.
Health experts have long warned that chikungunya could become a major pandemic threat.
Climate change has been driving mosquito populations into new regions, increasing the likelihood of outbreaks in areas where the disease was previously unknown.
Earlier this year, the European Medicines Agency also reviewed Ixchiq’s safety, especially in elderly populations.
In July, the World Health Organization (WHO) sounded the alarm over the risk of a global chikungunya epidemic, pointing to warning signs similar to those that preceded a massive outbreak two decades ago.
That earlier crisis spread across the Indian Ocean region and eventually infected nearly half a million people worldwide.
The European Centre for Disease Prevention and Control (ECDC) reported that Europe has already recorded 27 chikungunya outbreaks in 2025 alone the highest number ever documented on the continent.
The symptoms of chikungunya are often mistaken for dengue or Zika virus, with fever, severe joint pain, and fatigue among the most common.
While most patients recover, the joint pain can last weeks or months, making the disease a growing public health challenge.