CD4 and dengue disease: Our study addresses the important question of which of the globally reported dengue-specific CD4 and CD8 T cell epitopes are present among the dengue viruses, how different these are in distinct geographical regions; which of these epitopes are present in each of the vaccine candidates under consideration; which of these epitopes are shared by both the vaccine candidates and circulating dengue viruses; and how uniform these shared epitopes are when compared to distinct geographical regions of the world.