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.

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. | Less than three weeks after lifting a pause on the use of Valneva’s chikungunya vaccine Ixchiq,