Na-GST-1 is a protein expressed during the adult stage of the Necator americanus hookworm life cycle that is thought to play a role in the parasite's degradation of host hemoglobin for use as an energy source. Vaccination with recombinant Na-GST-1 has protected dogs and hamsters from infection in challenge studies. This study will evaluate the safety and immunogenicity of administering Na-GST-1 with or without the CpG 10104 immunostimulant to healthy Gabonese adults living in an area of endemic hookworm infection.