Ixchiq Vaccine for Chikungunya Virus Pulled Following At Least One Death

Vaccine removed from market after a number of reports of chikungunya-like side effects, which resulted in at least one fatal event.

After being granted accelerated approval by U.S. federal health regulators, the Ixchiq vaccine was pulled from the U.S. market this week, after more than 20 recipients reported experiencing serious side effects.

Following the U.S. Food and Drug Administration’s (FDA) suspension of the biologics license for the manufacturer, Valneva, in August 2025, the company issued an update on January 19, announcing its plan to pull the chikungunya vaccine from the U.S. market.

Chikungunya Health Risks

Chikungunya is a viral disease spread by bites from infected mosquitoes. The virus causes fever, severe joint and muscle pain, headache, nausea, fatigue and rash. Most people experience debilitating joint pain that lasts for weeks to years.

The disease began to spread quickly in the mid-2000s, following major outbreaks around the world. Since then, it has been identified in more than 110 countries in Asia, Africa, Europe, and North and South America.

More than 3.7 million cases of chikungunya were reported in the Americas between 2013 and 2023. The World Health Organization said chikungunya is a major public health problem.

The FDA granted Ixchiq accelerated approval in November 2023 for use among travelers to tropical and subtropical areas like Asia, Africa and the Americas. These are areas where the virus is endemic and the outbreak risk is high.

In February 2025, the FDA granted accelerated approval to a second Ixchiq vaccine, a chikungunya virus-like particle vaccine. Just months later, in August 2025, the agency suspended Ixchiq’s biologics license and placed the vaccine on clinical hold while investigating newly reported side effects. Those adverse events closely resembled symptoms of chikungunya infection itself and included severe reactions in approximately 1.6% of recipients.

The FDA’s Center for Biologics Evaluation and Research (CBER) has determined the vaccine’s benefits do not outweigh the risks under most scenarios.

Ixchiq Chikungunya-Like Side Effects

Valneva’s removal of the Ixchiq vaccine from the market comes after 20 cases of serious chikungunya-like illness were reported among people who received the vaccine as well as one death from encephalitis attributed to the vaccine.

In addition to removing the vaccine from the market, Valneva is also withdrawing the biologics license application and investigational new drug application for Ixchiq. The company said it believes the vaccine’s benefit-risk profile is still favorable for people living in endemic and outbreak settings, and is continuing to review the vaccine’s performance on the global market.

Ixchiq is currently licensed in Europe, Canada, the United Kingdom and Brazil.

Fast-Track Drug Approval Concerns

The drug’s withdrawal is one of the latest actions raising questions about drugs approved through fast-track approval processes. A study published by researchers from Harvard Medical School concluded that nearly half of all cancer drugs approved through the FDA’s accelerated approval process do not offer patients treatment benefits.

In fact, because drug makers are not required to complete the same lengthy and rigorous testing under the normal approval process, these products are often brought to market before comprehensive safety data is available and without evidence that they improve patient survival. In many cases, those shortcomings are not identified until post-marketing surveillance data is reviewed, a process critics argue effectively treats the public as unwilling test subjects.

Researchers urged physicians to inform patients when prescribing drugs approved through the FDA’s accelerated approval pathway, noting that such medications are often less effective and have not been shown to improve patient survival.

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