Less than three weeks after lifting a pause on the use of Valneva’s chikungunya vaccine Ixchiq, the FDA has done an about-face, banning the use of the shot in the United States.
On Friday, the agency suspended Valneva’s license “based on serious safety concerns,” citing 21 hospitalizations and three deaths, including one from encephalitis directly attributed to the live-attenuated vaccine. With the decision, the price of the French company’s shares has plummeted by 22%.
In a release, Valneva called (PDF) the FDA’s decision “sudden,” after the regulator had lifted a previous halt on the use of the vaccine in older adults on August 6. The company added that the agency’s move came after it received four reports of side effects from its Vaccine Adverse Event Reporting System (VAERS), each happening outside of the U.S. The reports included one user who was hospitalized for two days.
“Valneva believes all cases describe symptoms consistent with those previously reported during clinical trials and post-marketing experience, particularly among the elderly individuals for whom the vaccine’s prescribing information includes warnings and precautions,” the company said in its statement.
Valneva CEO Thomas Lingelbach added that the company “remains fully committed to maintaining access to our vaccine” in all countries where it is licensed.
The FDA’s decision comes amid a new wave of chikungunya outbreaks, which has caught the attention of the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC).
The CDC has issued chikungunya-related travel alerts for outbreaks in Bolivia, Kenya, Madagascar, Mauritius, Mayotte, Réunion, Somalia, Sri Lanka and the southern Chinese province of Guangdong, where more than 8,000 cases have been reported since June.
The side effects of the vaccine are similar to the symptoms of chikungunya infection, including fever, joint pain, lethargy, confusion and loss of appetite. The virus is spread by a particular species of mosquitoes in tropical areas.
With the grounding of Ixchiq, Bavarian Nordic’s virus-like particle vaccine Vimkunya becomes the lone shot approved for the prevention of chikungunya in the U.S. While Ixchiq was originally endorsed for adults only, Vimkunya can be used by those 12 and older. The Danish company is also testing the shot in children ages 2 to 11.
The decision with Ixchiq also comes amid uncertainty about the future of vaccines in the U.S. under the watch of Health and Human Services (HHS) Secretary Robert F. Kennedy Jr., who has long professed his anti-vaccine views. Earlier this month, the HHS revealed a plan to end mRNA vaccine work funded by the Biomedical Advanced Research and Development Authority (BARDA).
The FDA granted an accelerated approval to Ixchiq in November 2023. Then, in May of this year, the regulator paused its use in the U.S. for those age 60 and older. The move came in response to adverse event reports from users of the shot and followed similar decisions by France’s public health agency and the European Medicines Agency (EMA) to halt use of the shot in people age 65 and older.
In July, the EMA lifted its pause on Ixchiq, while adjusting its label with additional warnings for use by older adults. A month later, the FDA followed suit, also adjusting its label.
Earlier this month, Valneva said sales of Ixchiq reached 7.5 million euros ($8.8 million) in the first half of this year, while the company’s overall sales during the period jumped 38% year over year to 98 million euros ($115 million). The company added on Monday that it is evaluating the financial impact of the FDA suspension, while not yet adjusting its annual revenue projection.