Valneva must immediately cease U.S. shipments and sales of Ixchiq, a vaccine for chikungunya virus. The FDA recently lifted a pause on dosing of Ixchiq, but the agency’s new safety alert is based on an assessment that found the vaccine appears to be causing chikungunya-like illness in recipients.

According to the vaccine's maker, Valneva, the FDA based its decision to suspend the shot on four new serious adverse events that happened outside the U.S., three of which were in people ages 70 to 82 years and the other in a 55-year-old individual.

The US Food and Drug Administration (FDA) announced late last week that it has suspended the license for French drugmaker Valneva's chikungunya vaccine, saying that continued administration of the vaccine to the public would pose a danger to health.