Dengue fever is among the top 10 threats to global health as 40% of the world’s population reside in the areas at risk of dengue infection, the WHO said. The disease leads to about 20,000 deaths worldwide each year. So far this year, Vietnam has recorded more than 90,000 dengue fever cases, including 26 deaths, said the Ministry of Health.

Some countries used to test and license some dengue vaccines, but the vaccines’ efficacy has yet to meet expectations, according to Nguyen Van Kinh, Vice Chairman of the Vietnam Medical Association.

Recently, Japan has developed a new vaccine which initially showed efficacy for all dangue virus types. The single-dose vaccine can be used for both adults and children.