Oswald WE, Kepha S, Halliday KE, et al. - Researchers here used individual-level treatment records that had been collected for the Tuangamize Minyoo Kenya Imarisha Afya (Swahili for Eradicate Worms in Kenya for Better Health [TUMIKIA]) trial, performed in coastal Kenya from 2015 to 2017, with the aim to determine the extent of and factors linked with the same individuals not being treated over multiple rounds of mass drug administration (MDA), which was termed as systematic non-treatment. In the TUMIKIA trial, the baseline population was randomly assigned to receive biannual community-wide MDA for soil-transmitted helminthiasis; data from the baseline population of this trial was linked to longitudinal records on receipt of treatment in any of the four treatment rounds of the study. This analysis was performed including 36,327 participants: 16,236 children aged 2–14 years and 20,091 adults aged 15 years or older. Among individuals missing treatment in a given round, there was a higher likelihood of missing treatment in later rounds; this was noted irrespective of the sociodemographic factors that affect reach and uptake overall. Those aged 15–30 years were noted to be at the greatest odds of non-treatment. In Kwale county, this age group has previously been noted to harbour the highest rate of hookworm infections. In this group, the substantial degree of non-treatment could have important implications for the feasibility of attaining sustained morbidity or transmission control.