Lassa Fever

Lassa fever is an acute viral disease belonging to the category of viral hemorrhagic fevers. It is endemic in West Africa. Outbreaks occur every year, and it is estimated that between 100 000 and 300 000 individuals are infected each year, with a fatality rate for symptomatic cases that ranges between 15 and 30%. There is no efficient treatment against the disease, as ribavirin, the only licensed therapy, is at best poorly efficient. MOPEVAC-Las is a live-attenuated vaccine candidate targeting Lassa virus. The objective of this phase 1 clinical trial is to evaluate the safety of the MOPEVAC-Las vaccine candidate on healthy volunteers. It will also evaluate the immunogenicity and optimal dose of the vaccine candidate. The main questions it aims to answer are: * What are the safety and tolerability of the MOPEVAC-Las vaccine candidate following two intramuscular injections in healthy volunteers ? * Are cell-mediated immunity and humoral immunity induced by the MOPEVAC-Las vaccine ? * What is the optimal dose of MOPEVAC-Las vaccine regarding safety, tolerability and immunogenicity ? Researchers will compare the MOPEVAC-Las vaccine candidate to a placebo (a look-alike substance that contains no drug).

Lassa fever (LF) is a viral haemorrhagic fever responsible of 5000 deaths per year in West Africa, with in-hospital mortality at 12%. Transmission to humans occurs mainly via direct or indirect exposure to excreta from the rodent reservoir, mainly made up of Mastomys natalensis . Less frequently, LASV may also be transmitted from human to human and cause nosocomial outbreaks. Ribavirin is the only treatment available with worrying toxicity, questionable efficacy and low access because of its high cost. Consequently, there is an urgent need for new drugs to treat LF patients. The Research and Development (R\&D) Blueprint of the World Health Organization (WHO) has included LF in the list of priority diseases for urgent research and development. The INTEGRATE consortium is an unprecedented international collaboration on Lassa fever of 15 partners from 10 countries across West Africa, Europe and North America and across several disciplines (epidemiological researchers, social scientists, medical health facility professionals, humanitarian actors, etc.).

A Phase 2 Randomized, Double-Blinded, Placebo-Controlled Clinical Trial to Evaluate the Safety, Tolerability, and Immunogenicity of rVSV∆G-LASV-GPC Vaccine in Adults and Children Residing in West Africa

Dexamethasone is a corticosteroid which can modulate inflammatory-mediated tissue damage associated with a wide range of infectious diseases. Dexamethasone is routinely used for treatment of tuberculous meningitis and for pneumococcal meningitis in adults. In Coronavirus Disease 2019 (COVID-19) dexamethasone is also effectively preventing immune mediated damage of the lungs. There is also indication that dexamethasone may be promising in severe LF.