In 2012, when the WHO reviewed the safety of a single 0.75mg/kg dose of primaquine for blocking falciparum malaria transmission and recommended the lower dose of 0.25mg/kg, there were few data on haemoglobin falls after treatment with the single high (0.75mg/kg) dose and the limited characterisation of the G6PD status of the subjects involved in such studies was highlighted (summarized in S2 Table) [13]. This evidence concerns the gene G6PD and Plasmodium falciparum malaria.