The Nigeria Centre for Disease Control and Prevention (NCDC) says Lassa fever claimed 195 lives across 21 states by Epidemiological Week 49 of 2025, representing a case fatality rate of 18.2 per cent.
The agency disclosed this in its latest Lassa Fever Situation Report for Epi Week 49, covering December 1 to 7, 2025, released on its official website on Sunday.
It was reported that 33 new confirmed cases and eight deaths were recorded during the reporting week, rising from the 24 reported in Epidemiological Week 48 across affected states nationwide.
The new confirmed cases were reported from Bauchi, Ondo, Edo, and Taraba States during the epidemiological reporting period as part of ongoing national surveillance efforts coordinated by health authorities nationwide daily.
Cumulatively, as of week 49 of 2025, Nigeria recorded 9,041 suspected cases, 1,069 confirmed cases, seven probable ones, and 195 deaths, the NCDC stated in its official situation report.
The NCDC noted that the CFR of 18.2 per cent in 2025 was higher than the 16.5 per cent recorded during the same period in 2024, when 190 deaths were reported nationwide.
The report showed that 89 per cent of confirmed Lassa fever cases in 2025 came from four states: Ondo (36 percent), Edo (24 per cent), Bauchi (12 per cent), and Taraba (12 per cent), combined.
Overall, 21 states and 103 local government areas (LGAs) recorded at least one confirmed Lassa fever case in 2025, compared with 28 states and 137 LGAs during the same period in 2024.
The NCDC noted that although suspected and confirmed cases declined compared to 2024, fatalities remained high, largely due to late presentation of cases and poor health-seeking behaviour nationwide among affected communities.
It is identified that adults aged 21–30 are the most affected group, with cases ranging from one to 96 years, a median age of 30, and a male-to-female ratio of 1:0.8.
The report stated that no healthcare workers were infected during the reporting week, although 24 had been affected nationwide in 2025 so far, as officially recorded.
The NCDC said the National Lassa Fever Multi-sectoral Technical Working Group continued coordinating nationwide response efforts, supported by partners including WHO, UNICEF, US CDC, CEPI, and other key public health stakeholders.
Response activities during the week included deploying national rapid response teams to 10 states, strengthening infection prevention and control measures, training clinicians, conducting after-action reviews, and commencing the INTEGRATE trial.
Other interventions included community risk communication, distribution of ribavirin, personal protective equipment and IEC materials, environmental sanitation campaigns, and the nationwide launch of the NCDC infection prevention and control e-learning platform for workers.
The NCDC urged states to intensify year-round community engagement in Lassa fever prevention, while advising healthcare workers to maintain heightened suspicion and ensure timely referral and treatment of suspected cases.
It also called on partners to strengthen state capacity for early detection and rapid response systems to better curb transmission and reduce Lassa fever mortality nationwide, sustainably, going forward.
Lassa fever, first discovered in Nigeria in the late 1960s, remains endemic across West Africa and continues causing recurring outbreaks with high morbidity and mortality rates regionally today.
