Mason L, Tribolet L, Simon A, von Gnielinski N, Nienaber L, Taylor P, et al. Centers for Disease Control and Prevention. Global Health, Division of Parasitic Diseases and Malaria. Unfortunately, this vaccine produced urticarial reactions among previously infected recipients, and its development was halted. The 3-dimensional structure of Na-ASP-2 has recently been reported and identified as a conserved tandem histidine motif necessary for catalytic or proteolytic activity.

Another antigen, Ancylostoma -secreted protein 2 (ASP-2), appears necessary for chemokine receptor binding and invasion and has shown some promise in animal vaccine trials. Phase I clinical trials conducted in Gabon for this vaccine showed no difference in adverse effects between the vaccine and placebo groups as well as production of IgG antibodies, indicating a safe and potentially effective vaccine, as of September 2020. The Sabin Vaccine Institute has developed a 2 antigen human hookworm vaccine comprising recombinant Necator antigens Na- GST-1 and Na- APR-1, each of which is required for hookworm use of host blood. In the search for possible vaccine targets, investigators have focused on hookworm molecular inhibitors of coagulation factors Xa and VIIa-TF and metalloproteases that degrade hemoglobin and intestinal mucosal cells.

Hook worms