Lassa Fever is spread primarily through rodents, specifically Mastomys rats. The viral illness affects up to half a million people a year, with thousands of deaths reported each year. Despite its destructive impact on West Africa, there is still no licensed vaccine. To fight this, the Coalition for Epidemic Preparedness Innovations (CEPI) is driving forward an ambitious strategy that combines science, partnerships and capacity building. CEPI is fighting Lassa Fever, offering a blueprint for how the world can prepare for other epidemic threats.

Accelerating Clinical Trials in West Africa

A key step toward eliminating Lassa Fever lies within vaccine development and CEPI is helping to fast-track clinical trials directly in the communities that have been most affected. In 2022, CEPI supported Phase 1 trials in Liberia, marking the first test of an experimental Lassa vaccine in West Africa. This has now been followed up with Phase 2 studies across Ghana, Nigeria and Liberia, which have enrolled more than 600 participants as of 2024.

The Lassa Fever Vaccine Efficacy and Prevention for West Africa (LEAP4WA) consortium, funded by both CEPI and the European and Developing Countries Clinical Trial Partnerships (EDCTP), is now preparing for a phase 2b efficacy trial in Liberia, Nigeria and Sierra Leone. CEPI’s April 2025 LEAP4WA newsletter confirms that this trial, evaluating the ‘rVSVΔG-LASV-GPC’ vaccine candidate, will begin in 2026 with extensive preparations already underway.

Dr. Richard Hatchett, CEO of CEPI, stressed the urgency of the development of a vaccine: “Lassa Fever has been neglected far too long; through supporting trials in endemic regions, we can help those in need.” This focus on West African communities reflects one of the most important ways CEPI is fighting Lassa Fever, ensuring that science serves the people who need it most.

Understanding the Disease Through Epidemiology

Developing a vaccine is only half the challenge; understanding the virus itself is equally vital. That is why CEPI has created its ENABLE program, the largest study of its kind for Lassa Fever, which has enrolled up to 23,000 participants across Benin, Guinea, Nigeria and Sierra Leone. This ground-breaking study aims to map transmissions, symptoms and risk factors. These findings are vital for guiding future vaccination campaigns.

To ensure global data consistency, CEPI’s Enabling Science initiative, in collaboration with the World Health Organization, has developed international standards and assays for Lassa Fever. This ensures laboratories worldwide can reliably evaluate vaccines and diagnostics.

Gabrielle Breugelmans, CEPI’s Director of Epidemiology, stated, “ENABLE 1.5, running in Nigeria, Liberia, and Sierra Leone, is giving a clearer picture. Its findings will guide vaccine trial locations and help identify priority groups for vaccination.” Supporting this, CEPI’s Centralized Laboratory Network (CLN) has become the world’s largest vaccine testing network, processing more than 120,000 samples and aiding more than 60 developers. In 2025, it expanded with new members, including the Democratic Republic of Congo, which has strengthened Africa’s outbreak readiness. 

In accordance with this, CEPI’s Biospecimen Sourcing Initiative aims to reduce the time needed to collect survivor samples from months to weeks, accelerating the diagnostic process and vaccine development. Together, these innovations demonstrate the way CEPI is fighting Lassa Fever, linking local epidemiology and global lab capacity.

Strengthening Regional Partnerships and Governance

Scientific progress alone cannot subdue Lassa Fever. Strong governance and collaboration are essential to ensure vaccines are delivered fairly and effectively. CEPI has worked with the West African Health Organization (WAHO) to launch the Lassa Fever coalition. This collaboration brings together ministries of health, NGOs and civil society organizations to coordinate strategies across borders.

Oyeronke Oyebanji, the head of CEPI’s Lassa Engagement, proclaimed, “The coalition reflects growing solidarity across West Africa, strengthening health security for Lassa and other epidemic threats.” 

In parallel, CEPI supports the RegECs Project, which has harmonized regulatory and ethical approval processes across West Africa through collaboration with the African Regulatory Forum (AVAREF). This innovation has reduced delays in starting trials whilst upholding the international safety standards. Such cross-border cooperation is yet another example of how the CEPI is fighting Lassa Fever, ensuring that progress doesn’t stop at the laboratory but extends into policy and practice.

Building Clinical Trial Infrastructure

One of CEPI’s most forward-thinking strategies is investment in local infrastructure. Through the Research Preparedness Program West Africa (RPPWA), CEPI is helping establish new laboratories, train researchers and prepare trial sites capable of hosting large-scale studies. These investments are designed to outlast any single project. By strengthening scientific capacity across the region, CEPI is building resilience that will help West African countries respond not only to Lassa fever but also to future outbreaks such as Ebola or unknown diseases like “Disease X.” This commitment to sustainability is another practical way CEPI is fighting Lassa fever, leaving behind a legacy of stronger, self-reliant health systems.

A Blueprint for Future Epidemics

CEPI’s fight against Lassa fever illustrates how epidemic preparedness must go beyond developing a vaccine. Indeed, it requires embedding research with affected communities, building networks of trust and investing in long-term infrastructure. Its work shows that when science, governance and regional leadership align, neglected diseases can be confronted head-on.

Through accelerated clinical trials, pioneering epidemiological studies, regional governance initiatives and infrastructure development, CEPI is reshaping how the world approaches epidemic threats. These strategies are among the most impactful ways CEPI is fighting Lassa fever while also providing a model for addressing other emerging infectious diseases. In a region where outbreaks have too often devastated communities, CEPI’s approach offers hope not just of a vaccine but of a safer, more resilient future.

– Charlie Wood

Charlie is based in Liversedge, West Yorkshire and focuses on Global Health for The Borgen Project.

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