Sample size
parasitaemia
The multiple dose stage served as safety assessment and did not have any sample size calculation, an empiric number of five participants per group was chosen. The sample size of the randomized-controlled trial stage was calculated with the assumption that 25% of participants allocated to placebo would reduce parasitaemia to 90% of the initial value within 7 days due to naturally acquired immunity, while at least 75% of ivermectin-treated participants would reduce parasitaemia by 90%. Considering a power of 90%, a single-sided α of 2.5% and a ratio of 1:1 (ivermectin vs. placebo), 17 participants per group were required.