This study specifically seeks to quantify the contribution of relapes to the burden of P. vivax infections and disease by determining on the effect of radical pre-erythrocytic and erythrocytic clearance on subsequent rates of Plasmodium spp. infection and disease in children aged 5-10 years in a treatment to re-infection study design. In order the clear liver-stage/blood-stages G6PD-normal children were randomised to receive Chloroquine (3 days, standard dose) and Coartem (3 days, standard dose) plus either i) primaquine (20 days, 0.5mg/kg) or ii) placebo (20days). These drugs were administered over a period of 4 weeks.