GSTM1 and anemia (phenotype): Limited data from a trial comparing ACTs [42] and a trial comparing SP vs. atovaquone-proguanil [76] suggest risk factors for a blood transfusion were: (i) high parasite biomass in ACT-treated children (clinical indication was decompensated anaemia), and, for the SP-treated children (clinical indications were Hb <3 g/dL or the development of respiratory distress or extreme lethargy), (ii) pre-treatment Hb < 5 g/dL, (iii) younger age, and (iv) high parasite biomass.