Schistosomiasis vaccine shows immune memory in early trials

Texas Tech University Health Sciences Center researcher Afzal Siddiqui says SchistoShield, the only vaccine being tested to both prevent and treat schistosomiasis, has triggered immune memory in small trial groups in the U.S. and Africa. The findings, published in NPJ Vaccines, could move the long-shot effort toward larger studies for a disease that affects hundreds of millions of people.

Why it matters: - Schistosomiasis affects nearly 80 countries and is common in sub-Saharan Africa. - The World Health Organization estimates 250 million people carry the disease, and another 800 million are at risk. - The disease is second only to malaria among the world’s deadliest tropical parasitic diseases. - A vaccine that can both trigger immunity and create lasting immune memory could fill a major gap in treatment for a disease tied to poverty and repeated infection.

What happened: - Texas Tech University Health Sciences Center researcher Afzal Siddiqui said trial samples from people vaccinated in the United States and Africa show the vaccine can produce immune memory. - The vaccine, SchistoShield, is being studied to prevent and treat schistosomiasis. - The research was published in NPJ Vaccines under the title “Schistosomiasis vaccine SchistoShield® induces functional immune memory responses in US and African populations.” - Siddiqui is director of the TTUHSC Center for Tropical Medicine and Infectious Diseases and chair of the Department of Immunology and Molecular Microbiology at the TTUHSC School of Medicine.

The details: - Schistosomiasis begins when worm larvae in contaminated fresh water penetrate the skin and mature into adult worms. - Adult worms produce eggs that cause the disease. - The published study concludes that the SchistoShield vaccine induced “robust cell-mediated effector and memory responses,” which the paper describes as hallmarks of a potentially effective vaccine against schistosome and helminth parasites. - Siddiqui said vaccinated people in both the U.S. and Africa showed B-cell and T-cell memory responses. - Siddiqui said the trials remain small, with about 50 to 100 people, and the work now needs to expand to thousands. - There is only one drug available to treat schistosomiasis, and it does not prevent reinfection. - Siddiqui developed SchistoShield with support from TTUHSC, federal grants, and national and international charitable and nonprofit groups. - Siddiqui framed the effort as a humanitarian project rather than a for-profit product.

Between the lines: - The early immune-memory data are encouraging, but they do not yet prove the vaccine will work at population scale. - SchistoShield’s progress matters because schistosomiasis has long been underfunded despite its heavy burden in low-income regions. - A successful vaccine could reduce reliance on a single treatment drug and help interrupt repeat infections. - TTUHSC President Lori Rice-Spearman said the work aligns with the university’s goal of expanding access to care and could help address a disease affecting millions worldwide.

What's next: - SchistoShield will need larger trials involving thousands of people before researchers can determine whether the vaccine can reliably prevent or treat disease. - Further testing will need to confirm whether the immune responses translate into real-world protection. - Continued support from research funders and partner groups will likely be needed as the program advances.

The bottom line: - SchistoShield has crossed an early scientific milestone by showing immune memory in small human studies, but the vaccine still has a long road before it can be considered a proven tool against schistosomiasis.