Vital Signs is a monthly program bringing viewers health stories from around the world.

(CNN) Dengue fever infects 390 million people each year, and kills as many as 25,000, according to the World Health Organization.

The disease could soon see these numbers decline as the Philippines start administering the world's first dengue vaccine to high-risk children.

The historic drug took 20 years and $1.8 billion to develop. The Philippines' Department of Health launched a school-based immunization program in highly affected areas, making it the first country where the vaccine is commercially available.

Around 70% of dengue fever cases occur in Asia, with the Philippines reporting 200,000 cases in 2013, according to Sanofi.

It's one of the world's most common mosquito-borne viruses, with severe symptoms including headaches, rashes and leaking blood vessels.

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