It's the fastest-growing tropical disease, killing an estimated 20,000 people a year.
Nearly half the world's population is at risk of contracting dengue fever.
100 million people each year are infected according to the World Health Organisation.
France's Sanofi has been developing a dengue vaccine for the past 20 years.
Now a large clinical study in five Asian countries showed the three-dose vaccine provides moderate protection against the disease.
Nicholas Jackson is head of dengue research and development at Sanofi's vaccines unit, Sanofi Pasteur.
SOUNDBITE: Dr. Nicholas Jackson, Head of Dengue Research and Development, Sanofi Pasteur, saying (English):
"In addition to reducing just over half of all disease, we've also shown that we can reduce disease by 88 percent in the severe form, and this is critically important when you think about the gravity of a severe infection."
The trial showed the vaccine offered poor protection to young c