1. A tetravalent dengue virus composition comprising:live, attenuated dengue viruses comprising a dengue-2/4 chimera, wherein the dengue-2/4 chimera comprises a live, attenuated dengue-2 virus backbone having one or more structural proteins from a dengue-4 virus, and wherein a nucleic acid construct encoding the live, attenuated dengue-2/4 chimera further comprises one or more mutations, the one or more mutations comprising:
a mutation in an envelope (E) protein at an amino acid position synonymous to amino acid 417 of dengue-4 when the E protein is from dengue-4, wherein the mutation in the E protein at the position synonymous to amino acid 417 changes glutamic acid to a positively charged amino acid residue;
a mutation in the capsid (C) protein at an amino acid position synonymous to amino acid 107 in the live, attenuated dengue-2 virus backbone, wherein the mutation in the C protein at the position synonymous to amino acid 107 changes cysteine to an aromatic amino acid residue in dengue-2 virus backbone; and
a mutation in nonstructural protein 4A (NS4A) at an amino acid position synonymous to amino acid 17 in the dengue-2 virus backbone; and
one or more live, attenuated flaviviruses or one or more flavivirus chimeras, wherein the composition comprises all four dengue virus serotypes, dengue-1, dengue-2, dengue-3 and dengue-4, wherein the dengue-4 virus is present in the composition in an amount that is at least one log greater than the amount of dengue-2 virus.