Lassavirus vaccines

A polynucleotide comprising a sequence of a live, infectious, attenuated Flavivirus, the polynucleotide comprising:

• a nucleotide sequence encoding at least a part of an arenavirus glycoprotein, the arenavirus glycoprotein comprising a GP1 domain and a GP2 domain, the arenavirus glycoprotein lacking an N terminal signal peptide and a GP2 transmembrane domain,
• wherein:
• the nucleotide sequence is located at an intergenic region between an E gene of the Flavivirus and an NS1 gene of the Flavivirus, the E gene encoding an E protein, the NS1 gene encoding an NS1 protein, the NS1 protein comprising a signal peptide, such that a chimeric virus is expressed;
• and
• the nucleotide sequence is translatable such that the nucleotide sequence encodes a chimeric viral peptide, the chimeric viral peptide comprising:
• (a) a further signal peptide, positioned C terminally of the E protein, wherein the further signal peptide has the same sequence as the signal peptide of the NS1 protein;
• (b) the arenavirus glycoprotein, positioned C terminally of the further signal peptide;
• and
• (c) a TM1 and a TM2 domain of a further flaviviral E protein, positioned C terminally of the arenavirus glycoprotein;
• and
• the chimeric viral peptide is positioned N terminally of the NS1 protein of the Flavivirus.