Table 2.

Current schistosomiasis vaccine candidates in clinical trials

Vaccine Candidate	Function	Targeted species	Experimental models	Vaccine efficacy	Resulting immune response	Clinical trial	Status of the vaccine	References
Sm-TSP-2/Alhydrogel®	Tegument stability and parasite development	S. mansoni	Mice	Reduction of 25%-58% worm burden and 27%-56% reduction in tissue eggs	Vaccinated individuals generated sufficient IgG antibodies	Phases 1a & 1b completed	Phase 1 trials to determine the toxicity and immunogenicity of the vaccine in healthy adults.	[91,119]
Sm14/GLA-SE	Absorption and transportation of fatty acids from the host	S. mansoni	Mice and rabbits	A 65.9% and 93.2% decrease in worm burden in rabbits and mice respectively	Triggered the Th1 and Th2 cytokines and produced a substantial amount of Sm14-specific IgG, with no IgE detected	Phases 1 and 2a completed	The vaccine produced durable immunogenicity, which led to the planning of Phase 2b and Phase 3 trials.	[94,96]
Sh28GST/Alhydrogel (Bilharvax®)	Fatty acid metabolism and prostaglandin D2 production; might aid in parasite immune evasion in immunized people	S. haematobium	Rodents, primates, and cattle	A 40-60% reduction of the worm burden and a significant decrease in female worms	Highly immunogenic in adults, however, immunized children lacked IgG3 and IgA antibodies, which are linked to acquired immunity	Phases 1, 2 & 3 completed	Failed to achieve protection against urinary schistosomiasis.	[111,120]
Sm-p80/GLA-SE	Surface membrane biogenesis and renewal to escape the host immune response	S. mansoni	Mice and baboons	A 93.45% reduction in adult female worms and an 89.95% decrease in tissue egg load	Produced Sm-p80-specific total IgG and IgG subtypes with an increase in Th1 cytokines IFN-γ, IL-2, and TNF-α	Phase 1 initiated	Clinical trials are still ongoing.	[114,117,118]