Challenges, Progress, and Pathways to Equitable ACCESS in Lassa Fever Vaccine Development

Lassa fever is a viral haemorrhagic fever that remains a significant public health challenge in West Africa, particularly affecting countries such as Nigeria, Sierra Leone, Guinea, and Liberia. With over 1,300 confirmed cases and more than 200 deaths reported in 2024, the disease continues to strain healthcare systems and pose a risk to vulnerable populations, including healthcare workers. Current treatment options, such as ribavirin, have limitations in efficacy and accessibility, underscoring the urgent need for an effective vaccine. Recent outbreaks of viruses such as mpox, Marburg, Zika, and dengue highlight how ecological disruptions and fragile health systems can rapidly turn localized events into global threats. These lessons reinforce the urgency of genomic surveillance, regional collaboration, and accelerated vaccine development for Lassa fever. This review explores recent advancements in Lassa fever vaccine development, highlighting the challenges and progress in this critical field.Over 30 vaccine candidates are currently in preclinical or clinical evaluation, including inactivated, live-attenuated, viral vector, and mRNA-based approaches. The most promising candidates, such as the recombinant vesicular stomatitis virus vaccine and INO-4500 DNA vaccine have entered early-phase clinical trials, demonstrating safety and immunogenicity. However, challenges such as genetic variability, long-term efficacy, and accessibility must be addressed. International initiatives, including efforts by the Coalition for Epidemic Preparedness Innovations, are accelerating vaccine development. A successful Lassa fever vaccine must ensure robust immunogenicity, long-lasting protection, and adaptability to different at-risk populations. With continued research and investment, an effective Lassa fever vaccine may soon become a reality, significantly reducing disease burden in endemic regions and mitigating future outbreaks.