RNA sequence data show that the dengue viruses are developing and separating. The molecular basis of violence and pathogenesis of DHF/DSS must be better understood, to approve that dengue vaccine development stays ahead of dengue virus evolution. The mechanisms of vaccine-induced protection need to be clarified in future. The agreement immunologic target of a neutralizing immunity reaction to all 4 serotypes in at least 80% of volunteers may not be convenient in all community and clinical settings.