A new vaccine against dengue has been approved by the World Health Organization (WHO) as over 6 million cases of the mosquito-borne virus have been reported in the Americas so far this year. Dengue is transmitted to humans through the bite of an infected mosquito. It can cause flu-like symptoms and in rare cases lead to death. The vaccine was developed by Japanese pharmaceutical company Takeda and contains weakened versions of the four serotypes of dengue virus. The global health agency recommended the vaccine for children aged six to 16 years old in areas where there are high levels of the vi…