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The use of Valneva’s chikungunya vaccine, known under the brand name Ixchiq, has been paused in elderly individuals after reports of serious adverse events (AEs)
The US Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) recommended the suspension of the vaccine in individuals aged 60 years and over on 9 May while they investigate the safety concerns.
The decision follows a similar one by the European Medicines Agency (EMA) on 7 May, which also paused the vaccine’s use in adults aged 65 years and older and those with weakened immune systems as part of an ongoing review.
Shares in the French vaccine maker have sequentially dropped over the past few days in the wake of the news. Share price was down 6.8% at market open on 12 May compared to 6 May, a day before the EMA safety notice.
The FDA stated there have been 17 serious AEs in people aged between 62 and 89 years as of 7 May, two of which have resulted in death. Reported cases have been in patients with underlying chronic medical conditions, with the agency saying the adverse events “may not be causally related to vaccination”.
The two fatal cases occurred in the French overseas department of La Réunion. Valneva sent 40,000 doses to the territory in March 2025 as part of a national vaccination drive to prioritise older adults with co-morbidities. According to the EMA, one of the fatal cases was an 84-year-old man who developed encephalitis while the other was a 77-year-old man with Parkinson's disease whose swallowing difficulties may have caused aspiration pneumonia.
“FDA will conduct an updated benefit-risk assessment for the use of Ixchiq in individuals 60 years of age and older. In addition, FDA and CDC will continue the evaluation of post-marketing safety reports for Ixchiq,” the FDA said in a statement.
Licensed to prevent the disease caused by the chikungunya virus in adults, Ixchiq was approved by the FDA and EMA in November 2023 and June 2024, respectively.
Chikungunya, caused by its namesake virus, is a mosquito-borne disease mainly found in tropical regions. Although cases are not prevalent in North America or Europe, there is a risk of disease transmission to travellers visiting outbreak-affected countries in Africa and South America, along with islands in the Indian and Pacific Oceans.
Symptoms include fever and severe joint pain, which are similar to Dengue and Zika infections, making it difficult to diagnose.
Ixchiq is a live, attenuated version of the virus administered as a single dose by injection. The vaccine may cause symptoms like those experienced by people who have chikungunya disease.