The invention relates to a protein comprising a plurality of conserved peptide sequences, or variants thereof, wherein at least one of the conserved sequences is conserved across all four dengue virus serotypes DENV-1, DENV-2, DENV-3 and DENV-4, and wherein the conserved sequences comprise at least part of a sequence of one or more non-structural proteins of the dengue virus serotypes. The invention further relates to associated peptides, compositions,nucleic acids, viral vectors, virus- like particles, use,prime boost vaccination kits, agents and methods.