Development of a Recombinant VSV-Based Vaccine for Lassa Fever
Technical Report,01 Sep 2019,31 Aug 2020
University of Texas Medical Branch Galveston United States
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Lassa virus LASV can cause severe and sometimes fatal hemorrhagic fever in humans. It has been estimated that LASV infects over 300,000 individuals per year across West Africa, causing over 3,000 deaths. The case fatality rate for Lassa fever LF has historically ranged from 15 to 50 in hospitalized patients with a recent multi-year study in Sierra Leone reporting a 69 rate. Previous and recent importation of LF into Europe and the US by travelers on commercial airlines illustrates the potential for spread outside the endemic area. In addition to causing morbidity and mortality as a naturally acquired infection, LASV is also categorized as a Category A Priority Pathogen by several US Government agencies because of the concern for deliberate misuse. In addition, LASV was recently listed on the World Health Organizations WHO 2018 List of Priority Pathogens. Geographically, LASV is restricted to West Africa and has two endemic regions the Mano River Region Sierra Leone, Guinea, Liberia and Nigeria, where LASV infections are documented annually. Sequence analysis of LASV isolates from these regions show a remarkably high level of genetic diversity, with at least four lineages of LASV described that correlate with geographical regions. LASV lineages I, II, and III are localized in Nigeria and appear to be ancestral to lineage IV viruses that are found in and around Sierra Leona, Liberia, and Guinea. Two additional lineages have been proposed for isolates from Mali and Ivory Coast, representing a fifth potential lineage isolates from Togo represent a sixth potential lineage. The genetic heterogeneity within LASV raises questions about the efficacy of a potential universal LASV vaccine that could elicit a protective immune response capable of preventing infection from all strains of LASV. Currently, there are no licensed vaccines for the prevention of LF.
- Medicine and Medical Research