Lassa Fever Outbreak in Nigeria Worsens, Fatalities Rise

Strategic Insights -

The Nigeria Centre for Disease Control and Prevention (NCDC) has reported a significant increase in the case fatality rate (CFR) of Lassa fever infections, surpassing the rate recorded in the same period in 2024. As of epidemiological week 23 in 2025, a total of 143 deaths have been reported, with a CFR of 18.9 per cent higher than the 17.8 per cent CFR recorded for the same period in 2024. The outbreak has affected 18 states, with the highest concentration of cases in Ondo, Bauchi, Edo, Taraba, and Ebonyi states. The virus continues to affect health workers, with one new healthcare worker infected in the reporting week.

Key Takeaways:

  • The NCDC has reported a significant increase in the case fatality rate (CFR) of Lassa fever infections, with a CFR of 18.9 per cent in 2025 compared to 17.8 per cent in 2024.
  • A total of 143 deaths have been reported as of epidemiological week 23 in 2025.
  • The outbreak has affected 18 states, with the highest concentration of cases in Ondo (31%), Bauchi (25%), Edo (16%), Taraba (15%), and Ebonyi (3%).
  • The most affected age group is 20-30 years, with a median age of 30.
  • The gender distribution of cases shows a male-to-female ratio of 1:0.8.
  • The virus continues to affect health workers, with one new healthcare worker infected in the reporting week.
  • The NCDC has activated its multi-partner, multi-sectoral Incident Management System (IMS) to coordinate control efforts at the national level.
  • Several activities have been implemented across states and communities to control the outbreak, including sensitisation of clinicians, national Lassa fever risk assessment, and integration of key messages on Lassa into broader viral haemorrhagic fever (VHF) communication strategies.
  • The NCDC has distributed essential response commodities, including personal protective equipment (PPE), Ribavirin, hand sanitizers, thermometers, and health education materials, to treatment centers and state health facilities.
  • Community sensitization campaigns were implemented in Ondo State through radio outreach, town hall engagements, and environmental response activities.

Statistics:

  • The CFR of Lassa fever infections in 2025 is 18.9 per cent.
  • A total of 143 deaths have been reported as of epidemiological week 23 in 2025.
  • The number of confirmed cases rose to 11 in week 23, up from eight reported in the preceding week.
  • The highest concentration of cases is in Ondo (31%), Bauchi (25%), Edo (16%), Taraba (15%), and Ebonyi (3%).
  • The most affected age group is 20-30 years.
  • The gender distribution of cases shows a male-to-female ratio of 1:0.8.

Sources:

  • Nigeria Centre for Disease Control and Prevention (NCDC)
  • World Health Organisation (WHO)
  • Georgetown University
  • Breakthrough Action Nigeria (BA-N)
  • Global Fund
  • Dr. Ameyo Stella Adadevoh (DRASA)