The present invention is directed to virus-like particles (VLPs) which display immunogenic peptides of Flavivirus non-structural Protein 1 (NS1) derived from Dengue Virus (DENY), immunogenic compositions and vaccines against Flavivirus infection and related methods of immunizing and/or vaccinating subjects against Flavivirus, especially Dengue infections. The VLPs according to the present invention comprise polypeptide subunits of Dengue NS 1 protein which has been conjugated to the surface of a VLP as described herein, often a VLP derived from a Qbeta (P?) or AP205 bacteriophage.