An estimated 50-100,000,000 dengue infections are caused each year by four antigenically distinct serotypes of Dengue virus (Den-1 to –4) resulting in widespread dengue fever (DF).  Approximately 250,000 cases of dengue hemorrhagic fever/dengue shock syndrome (DHF) are seen in the infected individuals.  The viruses are transmitted primarily by the mosquito Aedes aegypti and are endemic throughout the tropical and subtropical regions.  Dengue has expanded throughout the tropical Americas and the expansion is expected to accelerate due to climate warming.  Despite the health importance of DF and DHF, vector control is the only available control measure.  Treatment of DF and DHF consists largely of supportive care only.

Although vaccines are available against two related flaviviruses, yellow fever and Japanese encephalitis. dengue vaccine development has been complicated by antibody mediated enhancement of infection and by strain-specific immunity to vaccine candidates.  BMI and its collaborators are designing immune refocused dengue vaccines with the aim of producing a single vaccine that protects against multiple variants that are encountered in endemic areas.