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 FDA suspended Valneva’s U.S. license for its chikungunya vaccine Ixchiq due to serious safety concerns, multiple hospitalizations, and deaths linked to chikungunya-like illness.

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,