Schistosoma Vaccine Development: A Comprehensive Review of Progress, Challenges, and Future Directions

Schistosomiasis is a neglected tropical disease caused by parasitic trematodes of the genus Schistosoma, affecting millions of people globally. It poses a substantial public health challenge, particularly in low- and middle-income countries, most of which are in sub-Saharan Africa, where defaecating and urinating in or near freshwater bodies is prevalent. Despite decades of control efforts, including mass drug administration, reinfection by the parasites remains a common occurrence, with a vaccine being viewed as a crucial tool for sustainable control and ultimate elimination of the disease. Recent advancements in vaccine developments, particularly through the Vaccine Against Schistosomiasis in Africa initiative, therefore, offer hope of getting an anti-schistosomiasis vaccine soon. Several vaccine candidates, including Glutathione S-transferase, Sm-TSP-2, Sm14, and Sm-p80, are thus being explored currently, with Sm-p80, S. mansoni calcium-activated neutral protease, calpain, involved in tegmental maintenance, promising safety and immunogenicity results in Phase 1b trials conducted in a couple of African countries that pave the way for Phase 2a trials. These efforts, supported by global regulatory engagement and partnerships, aim to streamline the approval of the anti-schistosomiasis vaccine and ensure equitable access, but are not without challenges. This review, therefore, explores the current state of schistosomiasis vaccine development, highlighting key scientific, regulatory, and logistical gains made toward a viable and impactful vaccine solution against the disease.