Participant engagement and feedback in microbiome projects: a case of AWI-Gen 2

Returning individualized microbiome results in ways that are ethical, comprehensible, and useful remains under-explored in African settings. We nested a multi-site, mixed-methods study within the AWI-Gen Wave 2 gut microbiome sub-study of 1,801 women aged 42-86 years to engage participants and provide feedback. All (1,001) participants from Agincourt and Soweto (South Africa) and Nairobi (Kenya) were invited to feedback meetings: 496 from Agincourt, 87 from Soweto, and 195 from Nairobi responded. Engagement strategies were tailored by site (small-group and home-based sessions, visual metaphors, Foldscopes, and local-language delivery). Using semi-structured discussions and structured observations analyzed thematically in MAXQDA under COREQ, five cross-cutting themes emerged: (i) understanding of microbiome reports, (ii) emotional responses to feedback, (iii) perceived health relevance, (iv) trust in research institutions, and (v) suggestions for improving engagement. Culturally grounded explanations and local-language facilitation enhanced comprehension; English-heavy sessions were associated with more confusion. Most participants expressed satisfaction and described planned or enacted dietary and lifestyle changes, while frustration centered on delays between sampling and feedback. Trust increased with transparency and individualized return of results but was often conditional on minimizing burdensome procedures such as repeat blood sampling and ensuring timely feedback. Engagement was feasible and low cost (approximately USD 29-59 per participant) with site-specific resource needs. Limitations included constrained generalizability beyond the three study sites and the study population of women aged 42-86 years. Returning individualized microbiome findings in African community settings is acceptable, feasible, and can motivate health-promoting behaviors when delivered promptly and in culturally appropriate ways.IMPORTANCEMicrobiome studies rarely return individualized results in low-resource settings due to concerns about appropriate feedback and associated costs. This gap risks eroding trust and diminishing research impact. In three African communities, tailored feedback on gut microbiome profiles was provided to 778 women. By documenting a costed, multi-site engagement model and the themes influencing acceptance and actionability, this work offers a practical framework for ethically returning complex -omics results at scale in underrepresented populations-advancing scientific equity and strengthening community trust in microbiome research.