Lassa Fever: A Global Pandemic Threat in Hiding
A major six-year study has warned that Lassa fever is being dangerously underdiagnosed, with a “substantial number” of infections slipping through routine clinical screening. The PREPARE study, led by the University of North Carolina and published in The Lancet Infectious Diseases, found that 11% of patients admitted with general fevers in Liberia actually had Lassa virus, despite having no typical clinical symptoms. This diagnostic “blind spot” means the virus is far more prevalent than official tallies suggest, posing a silent risk of person-to-person transmission in hospitals.
The timing of the report is critical for Nigeria, which is currently battling a worsening seasonal surge. As of March 2026, the Nigeria Centre for Disease Control (NCDC) has recorded 82 confirmed cases and 75 deaths this year alone. This puts the current Case Fatality Rate (CFR) at a staggering 23%, significantly higher than the 19.7% recorded during the same period in 2025. Bauchi, Taraba, Ondo, and Edo states remain the primary hotspots, accounting for 84% of all infections.
The study’s findings highlight a narrow window for medical intervention. Mortality is closely linked to high viral loads and weak antibody responses, particularly in children, who made up 43% of the confirmed cases in the PREPARE cohort. Because severe complications typically emerge in the second week, early detection is the only way to effectively use antiviral treatments like ribavirin. However, without a high “clinical suspicion” from doctors, many patients are simply treated for malaria or typhoid while the virus replicates unchecked.
Nigeria’s frontline health workers are bearing the brunt of these diagnostic gaps. The NCDC reported that five more healthcare workers were newly infected last week, bringing the seasonal total to 28 infections and three deaths among medical staff. When Lassa fever is not suspected, basic outpatient and maternity settings become accidental epicentres for human-to-human spread. The NCDC has pointed to “suboptimal adherence” to infection control and late patient presentation, often due to financial barriers, as the primary drivers of this year’s high death toll.
The threat is no longer confined to West Africa. With over 32 imported cases reported globally, including in the United States, the study warns that a lack of point-of-care diagnostics makes Lassa a legitimate “quiescent” pandemic threat. One-third of those imported cases were fatal. Dr. William Fischer II, the study’s lead, argues that widening the “diagnostic aperture” is not just a regional priority but a global security necessity.
The NCDC has now activated its Incident Management System in several states, including Kebbi and Gombe, to strengthen contact tracing and early detection. However, officials admit that the current dry season peak (November–April) continues to test the limits of the national response. For Nigeria to break the cycle of annual outbreaks, the transition from “suspected case” to “confirmed lab result” must become a matter of hours, not days.
To report suspected Lassa fever cases in Nigeria, call the NCDC toll-free number 6232. Other contact methods include WhatsApp (+234 708 711 0839), SMS (0809 955 5577), or by contacting your local government area disease surveillance and notification officer (DSNO).