Impact of adverse events during community-wide mass drug administration for soil-transmitted helminths on subsequent participation-a Theory of Planned Behaviour analysis

Background Experiencing adverse events (AEs) during mass drug administration (MDA) could affect participation in future MDAs. This study aims to understand the potential influence of AEs during a community-wide MDA (cMDA) trial for soil-transmitted helminths (STH) in India on intention to participate in future cMDAs.Methods This study was conducted using a multi-method quantitative and qualitative approach among 74 participants who experienced an AE during STH cMDA and the 12 participants who subsequently refused cMDA treatment of the ongoing DeWorm3 trial. Path analysis and thematic analysis guided by the Theory of Planned Behaviour, was used.Principal findings Among 74 individuals who reported an AE, 12% refused treatment in the cMDA immediately subsequent to their AE and 4% refused in all subsequent cMDAs. Of these 74 individuals, 59 (80%) completed a survey and eight participated in in-depth interviews. A positive attitude towards deworming and perceived ability to participate in cMDA (perceived behavioural control) were significant predictors of intention to participate in cMDA (p < 0.05). A positive attitude towards cMDA was associated with caste (chi(2) = 3.83, P = 0.05), particularly among the scheduled caste/scheduled tribe (SC/ST) (62%). Perceived behavioural control in cMDA participation was associated with occupation (chi(2) = 5.02, P < 0.05), with higher perceived control among those engaged in skilled occupations (78%). Intention to participate in subsequent cMDAs was associated with caste and family type (chi(2) = 3.83, P = 0.05 and chi(2) = 7.50, P < 0.05 respectively) and was higher among SC/ST (62%) and those with extended families (67%). In-depth interviews demonstrated that perceived severe AEs may lead to treatment refusal in future, particularly if children were affected.Conclusions Intention to participate in future STH cMDAs was associated with caste (SC/ST) and family type (extended families). Therefore, community mobilization messages about potential AEs and their management may need to intentionally target non-SC/ST households, nuclear families, and those engaged in unskilled occupations to increase cMDA participation given the possibility of AEs occurring.