FDA Recommends Pause on Chikungunya Vaccine for Over 60s Following Adverse Event Reports

Federal drug safety officials are urging a temporary halt to the administration of the Ixchiq vaccine, designed to prevent the mosquito-borne disease chikungunya, specifically for individuals over the age of 60. This recommendation follows the emergence of reports detailing serious adverse events experienced by vaccine recipients in this age group.

The U.S. Food and Drug Administration (FDA) revealed that a total of 17 serious adverse events, including two fatalities, have been reported globally among individuals over 60 who received the Ixchiq vaccine. Within the United States, six of these adverse events were documented, prompting the FDA to issue a safety communication on Monday, May 12.

The adverse events were reported through the Vaccine Adverse Event Reporting System (VAERS), a collaborative program managed by the FDA and the U.S. Centers for Disease Control and Prevention (CDC). VAERS serves as a critical tool for monitoring and identifying potential safety concerns associated with vaccines.

The FDA emphasized that the reported cases involved individuals with pre-existing chronic medical conditions, suggesting that the adverse events may not necessarily be directly caused by the vaccination. The agency underscored the need for further investigation to determine the precise relationship between the vaccine and the reported health issues.

Valneva, the manufacturer of the Ixchiq vaccine, released a statement reaffirming its commitment to upholding the highest safety standards. The company highlighted the potential influence of underlying health conditions and other medications as contributing factors to the adverse events. Valneva emphasized the importance of a thorough evaluation of each case to ensure the safe and appropriate use of Ixchiq.

Concerns regarding the safety of Ixchiq in older adults have also been raised by regulatory bodies in other countries. French drug regulators updated their recommendations for Ixchiq in April, while the European Medicines Agency (EMA) announced earlier this month that its safety committee had initiated a review of the vaccine. As a precautionary measure, the EMA has prohibited the use of Ixchiq in individuals aged 65 and older. This information was reported by the Center for Infectious Disease Research and Policy at the University of Minnesota.

Chikungunya is a viral illness transmitted to humans through the bites of infected mosquitoes. The disease is characterized by joint pain, a symptom from which its name is derived. The Cleveland Clinic states that most individuals infected with chikungunya recover within approximately one week. However, some individuals experience persistent joint pain that can last for an extended period. There is currently no specific cure for chikungunya, and treatment primarily focuses on alleviating symptoms.

The FDA approved Ixchiq for the prevention of chikungunya in adults aged 18 and older in November 2023. The vaccine utilizes a live, attenuated (weakened) version of the chikungunya virus. As a result, some individuals may experience symptoms similar to those associated with the disease following vaccination.

The FDA acknowledged that some of the reported adverse events were consistent with severe complications of chikungunya disease itself. This further complicates the assessment of causality and underscores the need for a comprehensive investigation.

The FDA announced that it will conduct an updated benefit-risk assessment specifically for the use of Ixchiq in individuals aged 60 and older. This assessment will carefully weigh the potential benefits of the vaccine against the risks identified in the adverse event reports. Both the FDA and the CDC will continue to closely monitor safety reports related to the vaccine to detect any emerging patterns or trends.

The recommendation to pause the use of Ixchiq in individuals over 60 reflects a cautious approach to vaccine safety. The FDA is prioritizing the health and well-being of this vulnerable population while gathering additional information to determine the appropriate course of action. The ongoing investigation will involve a detailed review of the adverse event reports, an analysis of the underlying health conditions of the affected individuals, and an assessment of the overall risk-benefit profile of the vaccine.

The outcome of the FDA’s updated benefit-risk assessment will determine whether the recommendation to pause the use of Ixchiq in individuals over 60 will be lifted, modified, or extended. The agency is committed to providing timely and transparent communication to healthcare providers and the public regarding its findings and recommendations.

In the meantime, individuals over 60 who are considering vaccination against chikungunya should consult with their healthcare providers to discuss the potential risks and benefits of Ixchiq, as well as alternative preventive measures, such as mosquito bite avoidance. It is crucial for healthcare providers to report any suspected adverse events following vaccination to VAERS to contribute to the ongoing safety monitoring efforts. The FDA, CDC, and other regulatory bodies will continue to work collaboratively to ensure the safety and effectiveness of vaccines and to protect public health.