The Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) have advised a temporary halt in administering the chikungunya vaccine Valneva SE’s (NASDAQ:VALN) Ixchiq to adults aged 60 and older as they investigate reports of serious adverse events, including neurological and cardiac complications, following vaccination.
As of May 7, 2025, 17 serious adverse events, including two deaths, have been reported globally among recipients aged 62 to 89.
Six of those reports originated from the United States, the agencies said in a recommendation on Friday.
Many affected individuals had underlying chronic medical conditions, though it remains unclear whether the vaccine directly caused the adverse reactions.
About 80,000 doses of Ixchiq have been distributed worldwide.
Also Read: Valneva’s Chikungunya Shot Shows Strong, Long-Lasting Antibody Persistence At Three Years, Comparable In Older And Younger Adults
The vaccine, approved by the Food and Drug Administration (FDA) in November 2023, contains a live, weakened version of the chikungunya virus and is intended for adults 18 and older at risk of exposure.
During clinical trials involving roughly 3,500 participants in North America, the most commonly reported side effects were headache, fatigue, joint and muscle pain, fever, nausea, and injection site tenderness.
Although rare in the trials, severe reactions resembling chikungunya disease occurred in 1.6% of vaccinated participants, with two individuals requiring hospitalization.
The Vaccine Adverse Event Reporting System (VAERS), jointly managed by the FDA and the Centers for Disease Control and Prevention (CDC), is gathering and analyzing these cases.
In response to these concerns, the FDA is conducting a new benefit-risk assessment specifically for individuals 60 years and older.
In the first quarter of 2025, Ixchiq sales increased to 3 million euros from 0.2 million euros a year ago.
- Sales include a very small number of the 40,000 doses Valneva supplied to La Réunion to respond to the chikungunya outbreak, as the large majority were only shipped in April 2025.
In April, France’s national health agency updated its advice on using Ixchiq after reports of serious side effects in older people with other health conditions during a vaccination campaign in La Réunion and Mayotte, where there is currently a major chikungunya outbreak with around 40,000 confirmed cases so far in 2025.
Initially, French health officials focused on vaccinating people aged 65 and older, especially those with existing health problems. But they paused the use of Ixchiq for this age group after three people over 80 were hospitalized with serious side effects following vaccination, one of whom died. All three had other health conditions.
In April, the Brazilian Health Regulatory Agency approved Ixchiq for individuals 18 and older.
In January, Valneva reported Phase 3 data in adolescents for its single-shot chikungunya virus vaccine.
The vaccine showed a 98.3% sero-response rate one year after the single vaccination.
Price Action: VALN stock is down 0.08% at $6.47 at the last check on Monday.
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