Dengue is a mosquito-borne viral disease of humans that is a major public health concern in tropical and subtropical regions of the world. The increasing mortality and morbidity rates caused by infection in recent years are attributable partly to a lack of availability of effective antiviral therapies and vaccines. In a concerted attempt to arrest this global expansion, several dengue vaccine candidates have progressed from pre-clinical testing into clinical trials. However, the advancement of vaccine development has manifest challenges to be overcome. A principal tenet underpinning dengue vaccine design is balanced immunity to all five recognised virus serotypes, but difficulties in achieving optimal attenuation of each virus and interference between individual attenuated viruses are significant hurdles to successful implementation. Currently, the most advanced vaccine candidate, the recombinant, live-attenuated ChimeriVax-DEN1-4 preparation developed by Sanofi Pasteur, is likely to achieve licensure at the completion of phase III trials and undergo population safety surveillance. Subunit and DNA vaccines are also in various stages of clinical evaluation. The intrinsic rationale is to produce a safe, efficacious and cost-effective vaccine. While this remains an achievable goal, progress is limited by an incomplete understanding of dengue viral pathogenesis, together with a lack of suitable animal models for fundamental pre-clinical development. This editorial highlights current approaches and future directions for vaccine strategies to combat the global expansion of this infectious disease
