GSTM1 and anemia (phenotype): The cumulative number of children who had anaemia (Hb<7g/dL) at OPD visits during surveillance or at the end of the transmission season was 32/470 (6.8%) in the SP group and 42/477 (8.8%) in the placebo group (ratio 0.77 (0.50,1.2) P = 0.252), and of these 4/465 (0.9%) had Hb<5 in the SP group compared to 11/462 (2.3%) in the placebo group (ratio 0.37 (0.12,1.2) P = 0.074).