U.S. health authorities approved the world's first vaccine for chikungunya, a virus spread by infected mosquitoes that the Food and Drug Administration called "an emerging global health threat."

• The vaccine, developed by Europe's Valneva which will be marketed under the name Ixchiq, was approved for people 18 and over who are at increased risk of exposure, the FDA said.
• Ixchiq's green-light by the U.S. drug regulator is expected to speed the vaccine's rollout in countries where the virus is most prevalent.
• Chikungunya, which causes fever and severe joint pain, is generally seen in tropical and subtropical regions of Africa, southeast Asia and parts of the Americas.