Ending Lassa neglect: the urgent case for a licensed vaccine.

Lassa fever is an endemic viral hemorrhagic disease in West Africa with significant morbidity and mortality, yet it remains inadequately addressed in global health priorities. First identified in Nigeria in 1969, the disease continues to affect an estimated 100 000-300 000 individuals annually, with high case fatality rates among hospitalized patients and vulnerable populations. Despite its substantial burden and recurrent seasonal outbreaks, particularly in Nigeria, major gaps persist in both prevention and treatment strategies. Notably, there is no licensed vaccine available more than five decades after its discovery, and current therapeutic practices rely heavily on ribavirin, a drug supported by limited and methodologically weak evidence. Recent years have witnessed encouraging developments, including early-phase vaccine trials and large-scale epidemiological initiatives such as the ENABLE study, alongside coordinated efforts to establish adaptive clinical trial platforms. However, these advancements remain insufficient without sustained funding, robust clinical trial infrastructure, and policy-level commitment. This letter highlights the urgent need to accelerate vaccine development, reassess existing treatment guidelines, and strengthen outbreak preparedness in endemic regions. Addressing these gaps is critical to transitioning from reactive outbreak response to proactive and evidence-based disease control, ultimately reducing the burden of Lassa fever and improving global health equity.