TWiP 279: Tolling for hookworms

This Week in Parasitism episode 279 dives into a landmark phase two randomized, double-blind, placebo-controlled trial of a hookworm vaccine candidate, NAGST1 absorbed on L-hydrogel and co-administered with Toll-like receptor agonists. The study, published in The Lancet Infectious Disease, used a controlled human infection model to evaluate vaccine efficacy in hookworm-naive adults in the U.S. The most promising results came from the group receiving NAGST1 with the TLR9 agonist CPG10104, which showed significantly reduced fecal egg counts, lower eosinophil levels (indicating reduced tissue migration), and robust anti-NAGST1 IgG antibody responses. This suggests the vaccine may block infection at an early stage. The episode explores the broader challenges of helminth vaccine development—economic disincentives, immune evasion by parasites, and lack of natural immunity—while highlighting the scientific rigor of the human challenge model. The team also discusses the potential for future deployment alongside existing interventions like mass drug administration and improved sanitation, and notes a parallel phase two trial for a schistosomiasis vaccine in West Africa, signaling growing momentum in the field of parasitic vaccine research.