U.S. health authorities have 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 [1] which will be marketed under the name [2], was approved for people who are at increased risk of exposure. [1] 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. The vaccine is injected in one dose and contains a live, weakened version of the chikungunya virus, as is standard with other vaccines. Two clinical trials were carried out in North America on 3,500 people. Headache, fatigue, muscle and joint pain, fever and nausea were commonly reported side effects. Chikungunya can be passed from a pregnant person to their unborn child, and the virus can be fatal to newborns. Since chikungunya was first identified in 1952, it has been recorded in more than 110 countries, according to the World Health Organization.