Overall, Treg frequencies (FoxP3+CD25+CD127dim) were higher in children from the high transmission district compared to the lower transmission district across all age groups (Wilcoxon ranksum p<0.0001, Fig 3A), and this difference was most marked in the youngest age group (Fig 3B), possibly reflecting an earlier expansion of Tregs in response to initial infections during early childhood or even in utero [27–30]. This evidence concerns the gene FOXP3 and infection.