Background International and global organisations advocate targeting interventions to areas of high HIV prevalence (ie, hotspots). To better understand the potential benefits of geo-targeted control, we assessed the extent to which HIV hotspots along Lake Victoria sustain transmission in neighbouring populations in south-central Uganda. Methods We did a population-based survey in Rakai, Uganda, using data from the Rakai Community Cohort Study. The study surveyed all individuals aged 15-49 years in four high-prevalence Lake Victoria fishing communities and 36 neighbouring inland communities. Viral RNA was deep sequenced from participants infected with HIV who were antiretroviral therapy-naive during the observation period. Phylogenetic analysis was used to infer partial HIV transmission networks, including direction of transmission. Reconstructed networks were interpreted through data for current residence and migration history. HIV transmission flows within and between high-prevalence and low-prevalence areas were quantified adjusting for incomplete sampling of the population. Findings Between Aug 10, 2011, and Jan 30, 2015, data were collected for the Rakai Community Cohort Study. 25 882 individuals participated, including an estimated 75•7% of the lakeside population and 16•2% of the inland population in the Rakai region of Uganda. 5142 participants were HIV-positive (2703 [13•7%] in inland and 2439 [40•1%] in fishing communities). 3878 (75•4%) people who were HIV-positive did not report antiretroviral therapy use, of whom 2652 (68•4%) had virus deep-sequenced at sufficient quality for phylogenetic analysis. 446 transmission networks were reconstructed, including 293 linked pairs with inferred direction of transmission. Adjusting for incomplete sampling, an estimated 5•7% (95% credibility interval 4•4-7•3) of transmissions occurred within lakeside areas, 89•2% (86•0-91•8) within inland areas, 1•3% (0•6-2•6) from lakeside to inland areas, and 3•7% (2•3-5•8) from inland to lakeside areas. Interpretation Cross-community HIV transmissions between Lake Victoria hotspots and surrounding inland populations are infrequent and when they occur, virus more commonly flows into rather than out of hotspots. This result suggests that targeted interventions to these hotspots will not alone control the epidemic in inland populations, where most transmissions occur. Thus, geographical targeting of high prevalence areas might not be effective for broader epidemic control depending on underlying epidemic dynamics.

National Institute of Mental Health, the National Institute of Allergy and Infectious Diseases, the National Institute of Child Health and Development, the National Institute for Allergy and Infectious Diseases Division of Intramural Research, National Institutes of Health; the Centers for Disease Control and Prevention; the Bill & Melinda Gates Foundation; and the Johns Hopkins University Center for AIDS Research.

HIV prevalence varies markedly throughout Africa, and it is often presumed areas of higher HIV prevalence (i.e., hotspots) serve as sources of infection to neighboring areas of lower prevalence. However, the small-scale geography of migration networks and movement of HIV-positive individuals between communities is poorly understood. Here, we use population-based data from~22,000 persons of known HIV status to characterize migratory patterns and their relationship to HIV among 38 communities in Rakai, Uganda with HIV prevalence ranging from 9 to 43%. We find that migrants moving into hotspots had significantly higher HIV prevalence than migrants moving elsewhere, but out-migration from hotspots was geographically dispersed, contributing minimally to HIV burden in destination locations. Our results challenge the assumption that high prevalence hotspots are drivers of transmission in regional epidemics, instead suggesting that migrants with high HIV prevalence, particularly women, selectively migrate to these areas.

BackgroundPeople living with human immunodeficiency virus (HIV) who have not yet initiated antiretroviral therapy (ART) can benefit from being engaged in care and utilizing preventive interventions. Community-based peer support may be an effective approach to promote these important HIV services.MethodsAfter conducting a randomized trial of the impact of peer support on pre-ART outcomes, we conducted a qualitative evaluation to better understand trial implementation, processes, and results. Overall, 75 participants, including trial participants (clients), peer supporters, and clinic staff, participated in 41 in-depth interviews and 6 focus group discussions. A situated Information Motivation, and Behavioral skills model of behavior change was used to develop semi-structured interview and focus group guides. Transcripts were coded and thematically synthesized.ResultsWe found that participant narratives were generally consistent with the theoretical model, indicating that peer support improved information, motivation, and behavioral skills, leading to increased engagement in pre-ART care. Clients described how peer supporters reinforced health messages and helped them better understand complicated health information. Peer supporters also helped clients navigate the health system, develop support networks, and identify strategies for remembering medication and clinic appointments. Some peer supporters adopted roles beyond visiting patients, serving as a bridge between the client and his or her family, community, and health system. Qualitative results demonstrated plausible processes by which peer support improved client engagement in care, cotrimoxazole use, and safe water vessel use. Challenges identified included insufficient messaging surrounding ART initiation, lack of care continuity after ART initiation, rare breaches in confidentiality, and structural challenges.ConclusionsThe evaluation found largely positive perceptions of the peer intervention across stakeholders and provided valuable information to inform uptake and scalability of the intervention. Study findings also suggest several areas for improvement for future implementation of pre-ART peer support programs.Trial registration NCT01366690. Registered June 2, 2011.

Distance traveled to HIV clinics was increased with higher socioeconomic status, suggesting that wealthier individuals exercise greater choice. However, distance traveled did not vary by those who were or were not virally suppressed.