AbstractBackgroundGame Changers for Cervical Cancer Prevention (GC-CCP), a peer-led, group advocacy training intervention, increased cervical cancer (CC) prevention advocacy not only among intervention recipients, but also their social network members (referred to as “alters”) who were targeted with advocacy in a pilot randomized controlled trial. We examined mediators and moderators of this effect on alter advocacy, to understand how and for whom the intervention had such an effect.MethodForty women (index participants) who had recently screened for CC enrolled and were randomly assigned to receive the GC-CCP intervention (n = 20) or the wait-list control (n = 20). Up to three alters from each participant (n = 103) were surveyed at baseline and month 6. Measures of CC-related cognitive constructs (knowledge, enacted stigma, and risk management self-efficacy), as well as extent of advocacy received from index participants, were assessed as mediators of the intervention effect on alter advocacy using multivariate regression analyses. Alter characteristics were examined as moderators.ResultsIncreased CC-related knowledge partially mediated the intervention effect on increased alter engagement in CC prevention advocacy; those with greater gains in knowledge reported greater engagement in advocacy. No moderators of the intervention effect were identified.ConclusionThe effect of GC-CCP on alter CC prevention advocacy is enhanced by increased alter knowledge pertaining to CC prevention, causes, and treatment and suggests this may be key for diffusion of intervention effects on increased CC prevention advocacy throughout a social network.Trial RegistrationNCT04960748 (registered on clinicaltrials.gov, 7/14/2021).