Sample size determination
ADVERSE EVENT
A minimum sample size of 188 children in each treatment group was calculated to provide a probability of 95% or higher of observing at least one severe adverse event in the SMC plus anthelminthic groups, if the true incidence of the severe adverse event was 5% or higher in each treatment group. Haemoglobin (Hb) concentration was also taken into account for calculating the sample size. Given that the mean Hb concentration in the SMC alone group in a previous study [