Understanding informal leadership in high HIV prevalence settings is important for the success of popular opinion leader (POL) and other HIV testing and treatment promotion strategies which aim to leverage the influence of these leaders. We conducted a study in Mpumalanga province, South Africa, in which we aimed to: (1) describe men's personal networks and key social relationships; and (2) describe the types of individuals men identify as leaders. We administered a structured questionnaire with 45 men (15 HIV-positive and 30 HIV-negative) in which men enumerated and described characteristics of individuals they share personal matters with, and people they considered as leaders. We further conducted in-depth interviews with 25 of these men to better understand men's conceptualisation of leadership in their community. Family members were prominent in men's personal networks and among the leaders they nominated. Men living with HIV were much more likely to know others living with HIV, and described friendships on the basis of the shared experience of HIV treatment. Future POL interventions aiming to promote HIV testing and care among men in rural South Africa should consider the importance of family in community leadership, and seek to leverage the influence of connections between men living with HIV.

Community mobilization has been recognized as a critical enabler for HIV prevention and is employed for challenging gender inequalities. We worked together with community partners to implement the 'One Man Can' intervention in rural Mpumalanga, South Africa to promote gender equality and HIV risk reduction. During the intervention, we conducted longitudinal qualitative interviews and focus group discussions with community mobilizers (n = 26), volunteer community action team members (n = 22) and community members (n = 52) to explore their experience of being part of the intervention and their experiences of change associated with the intervention. The objective of the study was to examine processes of change in community mobilization for gender equity and HIV prevention. Our analysis showed that over time, participants referred to three key elements of their engagement with the intervention: developing respect for others; inter-personal communication; and empathy. These elements were viewed as assisting them in adopting a 'better life' and associated with behaviour change in the intervention's main focus areas of promoting gender equality and HIV risk reduction behaviours. We discuss how these concepts relate to the essential domains contained within our theoretical framework of community mobilization-specifically critical consciousness, shared concerns and social cohesion -, as demonstrated in this community. We interpret the focus on these key elements as significant indicators of communities engaging with the community mobilization process and initiating movement towards structural changes for HIV prevention.