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.

US health authorities have suspended the license for the Ixchiq vaccine against the chikungunya virus following reports of "serious adverse events."