Abstract: The invention relates to a recombinant measles virus expressing a heterologous amino acid sequence derived from an antigen of a determined RNA virus, said recombinant measles virus being capable of eliciting a humoral and/or cellular immune response against measles virus or against said RNA virus or against both measles virus and against said RNA virus. It also relates to the use of said recombinant measles virus for the preparation of immunogenic composition.

Abstract: 2? and/or 3? prodrugs of 1?, 2?, 3? or 4?-branched nucleosides, and their pharmaceutically acceptable salts and derivatives are described. These prodrugs are useful in the prevention and treatment of Flaviviridae infections, including HCV infection, and other related conditions. Compounds and compositions of the prodrugs of the present invention are described. Methods and uses are also provided that include the administration of an effective amount of the prodrugs of the present invention, or their pharmaceutically acceptable salts or derivatives. These drugs may optionally be administered in combination or alteration with further anti-viral agents to prevent or treat Flaviviridae infections and other related conditions.