 Children in CI or CP classes of public schools in St Louis Region Senegal A male or female between, and including, 6 and 9 years of age at the time of the first vaccination Free of obvious health problems excepted schistosomiasis as established by clinical examination W8-W1 Found positive for S. haematobium infection during the selection period W12 à W9 : microhaematuria 2 et Urinary Filtration, UF 50 eggs of Sh10ml urine Written inform consent obtained from the parent or guardian of the subject W9 and child acceptance Pretreated with 2 doses of 40mgkg PZQ at W9 and W8 Absence of heavy lesions of the urinary tract under echotomography W8 et W1 