In Lubbock, Texas, a scientist named Afzal Siddiqui has spent decades working on something that could help hundreds of millions of people worldwide. Siddiqui, who leads the Center for Tropical Medicine and Infectious Diseases at Texas Tech University Health Sciences Center, has developed an experimental vaccine called SchistoShield. New research published in the journal npj Vaccines shows the vaccine is working as hoped.
Schistosomiasis is a disease caused by a parasitic worm found in freshwater. The worm's tiny larvae can slip through a person's skin when they wade, swim, or gather water. Once inside, the larvae grow into adult worms that produce eggs, which cause the disease. The World Health Organization estimates 250 million people carry schistosomiasis, and another 800 million are at risk of infection. The disease is common in sub-Saharan Africa and can be found in nearly 80 countries. Among tropical parasitic diseases, it ranks second only to malaria in deadliness.
Right now, there is only one drug available to treat schistosomiasis. But that drug cannot stop someone from getting infected again. "The people we have vaccinated, in both the U.S. and in Africa, have the memory response, both B-cell- and T-cell-based," Siddiqui said. "The vaccine is doing what it is supposed to."
That memory response is key. A good vaccine must do two things: trigger the immune system to fight, and teach the body to remember the disease so it can fight it faster in the future. The new study found that SchistoShield creates both kinds of protection. Researchers tested the vaccine on small groups in the United States and Africa, totaling 50 to 100 people. Blood samples from those participants showed their immune systems had learned to recognize and fight the parasite. Siddiqui said the next step is testing the vaccine on thousands of people.
Schistosomiasis is called a "neglected disease" because it mostly affects poor communities in tropical regions where pharmaceutical companies see little profit in developing treatments. Siddiqui has built SchistoShield as a humanitarian project, supported by federal grants and international health organizations, rather than as a product for sale.
"Our purpose from the beginning has been to expand access to care," said Lori Rice-Spearman, president of Texas Tech University Health Sciences Center. "Dr. Siddiqui's work reflects that commitment through research that could help address a disease affecting millions of people around the world."
For Siddiqui, the road ahead is long but the direction is clear. "Now it has to go to thousands of people," he said. "So that's where we are moving."