The Centers for Disease Control and Prevention (CDC) is currently investigating five hospitalizations among individuals aged 65 and older who recently received IXCHIQ, the only U.S.-licensed vaccine to prevent chikungunya virus. The patients were hospitalized due to cardiac or neurologic events following their vaccination.
IXCHIQ, approved by the U.S. Food and Drug Administration (FDA) in November 2023, is designed to prevent chikungunya virus infection. The CDC’s investigation into these adverse events highlights the agency’s ongoing efforts to monitor vaccine safety and detect rare reactions.
Chikungunya virus, primarily spread by infected mosquitoes, is a tropical and subtropical disease. While most adults do not receive the vaccine, it is sometimes recommended for travelers at high risk of exposure, particularly to regions experiencing outbreaks.
CDC Investigation and Vaccine Safety Monitoring
The CDC’s announcement, posted on Tuesday, emphasized that the hospitalizations involved individuals who had received IXCHIQ, which is a live, weakened version of the chikungunya virus. The investigation is ongoing, and the CDC has cautioned against drawing conclusions prematurely. Experts, including Dr. William Schaffner, an infectious disease expert, stressed that the investigation is crucial to understanding whether the reported incidents were directly caused by the vaccine or are coincidental.
“While we await further details, it is important not to make conclusions yet,” Dr. Schaffner explained. “This investigation is part of the CDC’s rigorous vaccine surveillance system.”
Vaccine Administration and Risks
The IXCHIQ vaccine is administered as a single-dose shot into the muscle and is approved for individuals aged 18 and older who are at an increased risk of chikungunya exposure. This includes travelers heading to countries with current or recent outbreaks, as well as laboratory personnel working with the chikungunya virus.
While the vaccine is recommended in limited cases, the CDC has highlighted that healthcare providers should assess the benefits and risks of vaccination based on factors like age, destination, and trip duration.
Common Side Effects and Severe Reactions
Clinical trials for IXCHIQ found that common side effects in more than 10% of vaccinated individuals included fever, headache, fatigue, muscle pain, joint pain, nausea, and tenderness at the injection site. Some participants also experienced “severe or prolonged chikungunya-like reactions,” including fever, joint pain, and headaches. In rare cases, these reactions have included serious cardiac and neurologic conditions.
Healthcare providers are encouraged to report any adverse events to the CDC’s Vaccine Adverse Events Reporting System (VAERS) to ensure continued monitoring of vaccine safety.
Chikungunya Virus and Global Concerns
Chikungunya virus is a significant health concern in tropical and subtropical areas. Although there have been no locally acquired cases in the U.S. since 2019, outbreaks continue to affect over 100 countries across the Americas, Africa, Asia, Europe, and the Pacific. Symptoms of chikungunya include fever, joint pain, rash, and muscle pain. As of now, there is no specific treatment for the virus, but supportive care, such as rest and over-the-counter medications for pain and fever, can help alleviate symptoms.
Final Thoughts
The CDC’s proactive investigation into these hospitalizations underlines the importance of vaccine safety surveillance. As this investigation unfolds, healthcare professionals will continue to monitor for potential risks and ensure that the benefits of vaccination outweigh any potential adverse effects.
For more information on the IXCHIQ vaccine and to report any adverse events, visit the CDC’s website or use the VAERS system.
