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Vaccines

Lassa Fever Vaccine Development Gains Momentum in West Africa

Strategic Insights

— 2 min read

As the first five months of 2025 alone showed, Nigeria reported over 717 confirmed cases and 138 deaths, underscoring the urgent need for a sustained investment in research and vaccine manufacturing capacity. In West Africa, various initiatives are underway to address this gap, including the Coalition for Epidemic Preparedness Innovations (CEPI)-funded Enable study, which is generating robust epidemiological and seroprevalence data across affected communities. The Enable study is also building critical site capacity, strengthening cold-chain systems, laboratory diagnostics, and ethical review processes and data management. Additionally, a new wave of scientific progress is redefining the prospects for Lassa fever prevention, with a Lassa fever vaccine developed from a strain native to Nigeria achieving 100% protection in preclinical trials.

Key Takeaways:

  • The Enable study is generating robust epidemiological and seroprevalence data across affected communities, essential for strengthening outbreak preparedness and informing future clinical trial design.
  • The study is also building critical site capacity, strengthening cold-chain systems, laboratory diagnostics, and ethical review processes and data management, ensuring that West Africa is not only prepared to host Lassa vaccine trials but positioned to lead them.
  • A new Lassa fever vaccine developed from a strain native to Nigeria achieved 100% protection in preclinical trials, representing a critical advancement from earlier candidates based on the Sierra Leonean Josiah strain.
  • The vaccine is now ready to begin Phase 1 clinical trials, subject to manufacturing scale-up and facility upgrades to meet Good Manufacturing Practice (GMP) standards.
  • CEPI is supporting several global vaccine candidates, including the IAVI-developed rVSV-based Lassa vaccine, which is now in Phase 2a trials, enrolling over 600 participants across Nigeria, Ghana, and Liberia through the PREVAIL partnership
  • The ChAdOx1 Lassa vaccine, developed by Oxford University's Pandemic Science Institute and supported by CEPI, entered Phase 1 clinical trials in London in early 2025, using a modified adenovirus vector.
  • The Lassa Vaccine Coalition, led by the West Africa Health Organisation (WAHO), brings together governments, researchers, and regulators to ensure vaccine development is aligned with local priorities.
  • Countries including Nigeria, Sierra Leone, and Liberia have established national Lassa vaccine task forces to coordinate preparedness and accelerate readiness for clinical trials.
  • A growing talent pipeline is advancing these goals, with the Vanderbilt-Nigeria Building Research Capacity in HIV/Non-communicable Diseases (V-BRCH) programme training researchers in ethics and Good Clinical Practice (GCP).

Statistics:

  • In the first five months of 2025, Nigeria reported over 717 confirmed cases and 138 deaths due to Lassa fever.
  • The Enable study is generating robust epidemiological and seroprevalence data across affected communities.
  • The new Lassa fever vaccine developed from a strain native to Nigeria achieved 100% protection in preclinical trials.
  • CEPI is supporting several global vaccine candidates, including the IAVI-developed rVSV-based Lassa vaccine, which is now in Phase 2a trials.
  • The ChAdOx1 Lassa vaccine, developed by Oxford University's Pandemic Science Institute and supported by CEPI, entered Phase 1 clinical trials in London in early 2025.

Sources:

  • "Lassa Fever Vaccine Development Gains Momentum in West Africa" by Ibukun Oguntola and Oluoma Karen Omeje.
  • "New Lassa Fever Vaccine Shows 100% Protection in Preclinical Trials" by Nigeria Health Watch.

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