Fièvre de Lassa

Vendredi 2 juillet 2021 - Mis à jour le Vendredi 2 juillet 2021

Enable Lassa

Since the isolation of the Lassa mammarenavirus (LASV) in 1969, the disease has continued to cause seasonal morbidity and mortality. 300'000 annual infections are estimated in West Africa, making LASV a primary cause of haemorrhagic fever worldwide. A crucial step to assess the feasibility and prepare for potential future Lassa vaccine efficacy trials is to gather epidemiological data on the background rates of infection and disease due to LASV in endemic areas, because incidence & spatial distribution of Lassa Fever (LF) is likely to be significantly underestimated based on existing data, due to gaps in diagnostics, surveillance and access to health services. The aim of this project, "Prospective Multi-site cohort study to estimate the incidence of infection and disease due to Lassa Fever Virus in westafrican countries", is to conduct epidemiological cohort study that will assess LF disease and LASV incidence to determine the feasibility of future Phase IIb or III clinical trials for assessing the efficacy of LF vaccine or therapeutic candidates. Strategic aims are to (1) provide information on prevalence and incidence and to inform the design of future studies, (2) Identify sites and (3) Assess and strengthen the site and investigator capability and capacity.



For each Lassa-endemic country participating in the study, separately, : (1) to assess the incidence rate of symptomatic confirmed LF ; (2) to estimate the incidence rate of LASV infection.


A prospective multisite cohort study: (1) LF disease cohort: data on LF cases, signs & symptoms will be collected in a standardized manner (2) LASV infection cohort: data on study participant LASV serostatus will be collected

Who's Involved Besides MSF?

CEPI, BNITM, P95, Nigeria, Benin, Sierra Leone, Liberia, Guinea, Tulane University, NCDC, and Others



Nigeria, Benin, Sierra Leone, Liberia, Guinea

Tentative End date

March 2023

Our Role

Scientific Oversight, Data Management, Statistics


For more information contact: Boni-Maxime Ale