Arenaviruses, the largest family of haemorrhagic fever causing viruses, represent an important but often overlooked family of zoonotic pathogens, with increasing global presence and pandemic potential. Due to a lack of licenced vaccines and antiviral therapeutics, methods to alleviate the global arenavirus disease burden are currently limited. Attenuated vaccine designs have utilised the structured intergenomic regions (IGRs) of arenavirus genomes to create recombinant vaccine candidates for Lassa and LCMV, however the exact mechanisms of attenuation remain unknown. Experimentally validated structures of these IGRs remain missing from the literature, along with limited characterisation of their functions. This project utilises the orbiSIMS system to enable residue-level structural characterisation of key arenavirus IGRs. Accurately determining the functional regions within these IGR structures will provide potential new targets for vaccine design and anti-viral therapeutics. We have generated four of these key IGR structures which have undergone orthogonal validation using optical tweezers and are using cryoEM for further structural validation. RNA-protein pull-downs combined with proteomics-based approaches have identified a range of host-IGR interactions that may be responsible for the attenuated phenotype seen in recombinant IGR viruses. Future work involving using targeted mutations to validate these regions of interaction. This project attempts to address a gap in the current scientific literature by providing insight into the molecular functions of these IGRs within the life cycle an important group of pathogens and thus enable rational design of new arenavirus vaccines and therapeutics.