Nigeria, Lassa fever death toll climbs as outbreak declines

The Nigeria Centre for Disease Control and Prevention (NCDC) has reported a decline in confirmed cases of Lassa fever during the fourth epidemiological week of 2025, while the mortality rate continues to rise, with 53 reported deaths across the country. NCDC documented 76 confirmed cases between the 20th and 26th of January, representing a slight decrease from the 71 cases reported in the previous week. Cumulative data for 2025 shows 290 confirmed cases and 1,171 suspected cases in 10 states, with a case fatality rate (CFR) of 18.3%. Three-quarters of all confirmed cases were concentrated in Ondo (37%), Edo (21%) and Bauchi (17%) states. The age group most affected is between 21 and 30, with a gender ratio of almost 1:1. Despite the general decline in new cases, the NCDC has expressed concern about the increasing number of deaths attributed to late submission of cases, high treatment costs and inadequate environmental hygiene in high-risk communities. The disease is fatal in 20% of cases when treatment is delayed. The mortality rate is 1%, but this has seen an upward trend amongst pregnant women and healthcare workers. At present, there are no approved vaccines in use, although approximately 20 are in the development phase, with the most advanced in Phase IIa clinical trials, as reported by The Guardian.