"My friends would believe my word": appropriateness and acceptability of respondent-driven sampling in recruiting young tertiary student men who have sex with men for HIV/STI research in Nairobi, Kenya

Background: Tertiary student men who have sex with men (TSMSM) may engage in behaviors that increase their risk of infection with human immunodeficiency virus (HIV) and sexually transmitted infections (STI). Respondent-driven sampling (RDS) has become a popular method for discretely recruiting marginalized populations into HIV/STI research. We conducted formative research to assess appropriateness and acceptability of RDS in recruiting TSMSM into a prospective HIV/STI bio-behavioral survey in Nairobi, Kenya. Methods: Between September and October 2020, semi-structured qualitative interviews were held with service providers from organizations that serve MSM (n=3), and TSMSM (n=13). Interviews explored social networks of TSMSM, acceptability of using RDS as a sampling method, potential RDS implementation challenges, and proposed solutions to these challenges. Interviews were done in English, audio-recorded and transcribed then analyzed thematically using NVivo version 11. Results: Service providers reflected that TSMSM had large though concealed networks, thus making RDS an appropriate sampling method. Risk of ineligible persons attempting to participate due to the associated double incentive was noted, and using student identification documents as part of eligibility screening recommended. TSMSM also perceived RDS to be an acceptable strategy based on their large social network sizes (10-40), and the trust amongst themselves. TSMSM were concerned about participating due to the risk of being outed as MSM, seeing as same sex behavior is criminalized in Kenya, and hence emphasized that researchers needed to assure them of their confidentiality, and include MSM as part of the study team to encourage participation. TSMSM suggested coupons should indicate value of reimbursement, be pocket-sized and placed in an envelope to avoid loss, and provide directions to and contacts of the survey site for easy access. Conclusion: RDS was perceived as both an appropriate and acceptable sampling method. Anticipated challenges of RDS implementation were highlighted, and possible solutions to these challenges suggested.