Abstract: The invention is related to a dengue virus or chimeric dengue virus that contains a mutation in the 3? untranslated region (3?-UTR) comprising a ?30 mutation that removes the TL-2 homologous structure in each of the dengue virus serotypes 1, 2, 3, and 4, and nucleotides additional to the ?30 mutation deleted from the 3?-UTR that removes sequence in the 5? direction as far as the 5? boundary of the TL-3 homologous structure in each of the dengue serotypes 1, 2, 3, and 4, or a replacement of the 3?-UTR of a dengue virus of a first serotype with the 3?-UTR of a dengue virus of a second serotype, optionally containing the ?30 mutation and nucleotides additional to the ?30 mutation deleted from the 3?-UTR; and immunogenic compositions, methods of inducing an immune response, and methods of producing a dengue virus or chimeric dengue virus.