Four of the 16 secondary outcomes examined were related to haemoglobin (Hb); all showed trends towards a negative impact of vaccination with AMA1 relative to the comparator group, with two of these statistically significant at the 0.05 level (mean Hb during clinical malaria, unadjusted p = 0.004, and number of episodes with Hb < 8.5 g/dL, unadjusted p = 0.029), although differences were no longer significant after correction for multiple tests. This evidence concerns the gene GSTM1 and malaria.