Taylor WRJ, et al. - Through a randomized, double-blind, placebo-controlled, non-inferiority trial in eight health-care clinics (two each in Afghanistan, Ethiopia, Indonesia, and Vietnam) with 2,336 patients (aged ≥6 months) with normal glucose-6-phosphate dehydrogenase (G6PD) and who presented with uncomplicated vivax malaria, experts evaluated the effectiveness of a shorter course (7 days) of primaquine for radical cure of vivax malaria. For 935 subjects in the 7-day primaquine group and for 937 subjects in the 14-day primaquine group, the incidence rate of symptomatic recurrent Plasmodium vivax malaria was 0.18 recurrences per person-year and 0.16, respectively. In the placebo group, the incidence rate for 464 subjects was 0.96 recurrences per person-year. In nine of 935 subjects in the 7-day group, one of 937 in the 14-day group and none of 464 in the control arm, potentially drug-related serious adverse events within 42 days of beginning treatment were recorded. A 7-day primaquine regimen was tolerated well and non-inferior to 14-day primaquine in subjects with normal G6PD. Moreover, for radical cure of P vivax malaria, the short-course regimen might increase adherence and consequently the effectiveness of primaquine.