The FDA and CDC have also recommended pausing the use of Ixchiq in seniors 60 years and older while safety investigations are ongoing.
Health regulators in the U.S. and Europe have identified serious neurologic and cardiac safety events in older adults given Valneva’s chikungunya vaccine Ixchiq, according to their respective notices posted last week.
The FDA said 17 serious events have been documented in global post-marketing reports so far, two of which have led to death. Six of these cases occurred in the U.S. These vaccine toxicities, reported to the FDA’s and CDC’s Vaccine Adverse Event Reporting System, were detected in older adults aged 62 through 89 years. So far, around 80,000 Ixchiq doses have been distributed worldwide, according to the FDA.
In light of these safety concerns, the FDA and the CDC recommend a “pause” in the use of Ixchiq in adults 60 years and up while they conduct a review of the post-marketing data.
The European Medicines Agency, which reviews medicines approved for use in the European Union, is restricting the use of the vaccine in older adults: “As a temporary measure while an in-depth review is ongoing, Ixchiq must not be used in adults aged 65 years and above,” the regulator wrote last week. Patients below this age threshold can continue receiving the vaccine.
Ixchiq, approved by the FDA in November 2023, is indicated for the prevention of chikungunya virus in patients aged 18 years and up who are at risk of exposure to the virus. Data released in December 2024 indicated the long-term durability of the shot’s protection, with 96% of inoculated participants maintaining antibody titers above the protective threshold even 3 years after dosing.
According to its label, common side effects of Ixchiq include injection site reactions such as tenderness. Systemic toxicities include headaches, fatigue, myalgia and fever.
In its announcement last week, however, the FDA noted that there have been documented cases of “severe chikungunya-like adverse reactions that prevented daily activity and/or required medical intervention,” though these were “not commonly reported during the clinical studies.” In particular, two patients who developed these side effects had to be hospitalized, while some cases lasted for 30 days.
The Vaccine Adverse Event Reporting System (VAERS), which detected the safety signals for Ixchiq, has recently come under attack by Health and Human Services Secretary Robert F. Kennedy Jr. “It’s outrageous that we don’t have a surveillance system that functions,” Kennedy said last month, speaking at a Make America Healthy Again event, revealing that he is planning a host of changes to the system.
