GSTM1 and anemia (phenotype): The transfusion trial results, published in two linked manuscripts in 2019 [18, 19], demonstrated that an immediate transfusion is not required in children with uncomplicated severe anaemia (Hb 4-6 g/dL without severity features), as long as children are monitored for progression to the development of severe and/or complicated anaemia during their initial hospital stay; such progression occurred in 49% of participants in the control arm, who then received a transfusion triggered by the development of new signs of clinical severity or a drop in haemoglobin level to less than 4 g/dL [18].