The urgent vaccine imperative: Sustaining visceral leishmaniasis elimination
Abstract
In October 2023, Bangladesh became the first country validated by the World Health Organization for eliminating visceral leishmaniasis (VL) as a public health problem. This achievement rests on robust case detection, effective treatment, and sustained vector-control interventions; however, these measures are resource intensive, vulnerable to political and funding disruptions, and may be undermined by population displacement and emergent drug resistance. Post-kala-azar dermal leishmaniasis reservoirs now outnumber primary VL cases in Bangladesh, while East Africa accounts for 73% of global VL cases with zoonotic transmission and exophilic sand fly behavior complicating control. The human vaccine pipeline remains concerningly thin: no licensed human vaccine exists, no phase III VL-specific efficacy trials are underway, and correlates of immune protection remain undefined. On the balance of current evidence, vaccination offers a potentially durable strategy to interrupt transmission independently of passive case detection and to reduce reliance on programmatic activities that are operationally fragile. Several factors in 2026 create a strategic inflection point for accelerated vaccine development and deployment, including Bangladesh’s validation, East Africa’s 2023-2030 elimination framework, and advances in next generation platforms (for example, mRNA and reverse-vaccinology approaches). We recommend planning multi-country phase III trials by 2027 with VL-relevant endpoints, establishing dedicated funding mechanisms, and integrating a future vaccine into regional elimination frameworks to maximize publichealth impact. Rapid, coordinated progress toward an effective vaccine is essential to safeguard and sustain the gains achieved to date. This review synthesizes current evidence on epidemiology, vaccine development, and programmatic challenges and proposes pragmatic priorities to accelerate VL vaccine evaluation and policy translation.