There is increasing evidence that P. vivax results in significant morbidity and associated mortality. A significant proportion of this morbidity is attributable to severe anaemia from recurrent P. vivax infections, where each relapse results in an increased cumulative risk of anaemia. Malaria-associated anaemia is a complex phenomenon, related to increased red cell destruction and haemopoeitic suppression, compounded by nutritional status, helminth carriage and drug induced haemolysis. The degree of anaemia caused by vivax malaria and its risk factors has not been evaluated widely. 
Control and ultimate elimination of P. vivax requires the safe and effective prevention of recurrent infections and this requires radical cure targeting both blood and liver stages of the parasite. However, the only widely available drug which is active against the liver stages is primaquine which can cause drug-induced haemolysis in glucose-6-phosphate dehydrogenase (G6PD) deficient patients. In order to quantify the risks and benefits of P. vivax radical cure, it is crucial to determine the normal haematological response following P. vivax infection and treatment.