Encouragingly, the presence of pre-existing antibody responses to the Sm-TSP-2 antigen did not appear to interfere with the humoral response to vaccination, since significant fold-increases in IgG were observed particularly in those vaccinated with 30 or 100 μg of antigen, to a degree equivalent to or exceeding that previously reported in schistosomiasis-naïve individuals [17]. Here, THBS2 is linked to schistosomiasis.