Peer Education Intervention Reduced Sexually Transmitted Infections Among Male Tajik Labor Migrants Who Inject Drugs: Results of a Cluster-randomized Controlled Trial.

Background: Male Tajik labour migrants who inject drugs in Russia are at high risk for HIV and other sexually transmitted infections. The "Migrants' Approached Self-Learning Intervention in HIV/AIDS for Tajiks" (MASLIHAT) trained Tajik labour migrants who inject drugs in Moscow as peer educators (PEs) in delivering HIV prevention information and promoting risk-reduction norms and practices within their diaspora social networks while reducing their own HIV risk. Our earlier analysis of a cluster-randomized controlled trial testing the intervention's effects found that MASLIHAT reduced condomless sex, condomless sex with female sex workers, and sex with multiple sexual partners. This analysis draws on data from this parent study to investigate if these observed changes in safer sex translated into fewer reported STIs over 12-months. Methods: Male Tajik migrant workers in Moscow who inject drugs (n=140) were recruited from construction worksites, local bazaars, and diaspora organizations serving labor migrants. Participants were assigned as PEs to either MASLIHAT or a comparison health education intervention. Each PE recruited two migrants who inject drugs from their social networks with whom to share what they learned during the 5 educational sessions of the arm to which they were assigned. All participants completed questionnaires at baseline and 3-month intervals for one year to assess their HIV/STI risk behaviour. Mixed effects robust Poisson regression analyses tested for possible differences between assignment conditions in self-reported STIs during 12 months of follow-up and the contribution of sexual risk behaviours to STI acquisition. We then tested the mediating effects of sexual behaviours during the first six months following the intervention on STIs reported at the 9 and 12-month follow-up. Results: Participants in the MASLIHAT intervention were significantly less likely to report an STI during follow-up (IRR=0.27). Condomless sex with a casual or commercial partner was significantly associated with STI acquisition (IRR=2.30). Causal mediation analysis indicated that the intervention's effect on reported STI was partially mediated by reductions among MASLIHAT participants in condomless sex with a casual or commercial partner. Conclusions: The MASLIHAT peer-education intervention reduced reported STIs among Tajik labour migrants partly through reduced condomless sex with casual and commercial partners. Clinical trial registration: ClinicalTrials.gov, 2021-04-16, NCT04853394.