Clarke, NaomiDoi, SuhailClements, ArchieGray, DarrenCampbell, SuzyWang, DongxuVaz Nery, Susana2020-12-202020-12-200140-6736http://hdl.handle.net/1885/218472We thank Gang Qin and Xun Zhuang for their letter regarding our systematic review and meta-analysis published in The Lancet. Qin and Zhuang raise concerns about the heterogeneity of the included studies, reflecting low study quality. However, the heterogeneity in our meta-analysis in terms of prevalence reduction cannot be solely attributed to low study quality. The effect of soiltransmitted helminth (STH) control programmes varies significantly, because of a variety of factors, including environmental conditions, water, sanitation, and hygiene, and underlying transmission intensityapplication/pdfen-AU201710.1016/S0140-6736(17)31343-02020-11-23