ABSTRACT: Young black men who have sex with men (YBMSM) bear a significant burden of new HIV diagnoses in the U.S. It is widely recognized that HIV prevention interventions such as PrEP are efficacious, but successful PrEP implementation among YBMSM is limited by several structural factors that impede engagement. Identifying places where HIV-negative (YBMSM-) who are at increased risk for HIV but not on PrEP can inform place-based HIV prevention strategies among YBMSM. A new line of research indicates the place-based affiliation network wherein people are connected with others through visiting the same places shapes individuals' drug use and sex behaviors. However, little is known about how place-based affiliation networks are associated with uptake of biobehavioral interventions such as PrEP. This proposal will identify regular places where YBMSM- spend time who are at increased risk for HIV, but not yet on PrEP. To reduce redundancy in intervention targets, we will prioritize places with high connectivity to other places frequented by people who are candidates for PrEP. Furthermore, the interconnectivity between GPS and survey data enables researchers to understand the social norms in health care engagement behaviors among people who attend the same place(s) but who may or may not know each other, and this can direct a better design for a contextually relevant intervention. However, little work has been conducted on place-based affiliation networks and PrEP readiness among YBMSM, and most of the existing research relies on survey data with self-report data on places frequented. The use of Global Positioning System (GPS) technology can provide real-time and objective data on which places YBMSM attend and can reduce the biased and inaccurate measurement. This proposal aims to utilize GPS data to identify: 1) regular places that YBMSM- attend; 2) place-to-place affiliation networks formed through co-attendance at a place(s) by two or more individuals; and 3) individual-to-individual attendance networks (i.e., individuals who attend one or more shared places). We will conduct secondary data analysis from an ongoing Neighborhoods and Networks (N2) cohort study in Chicago among 393 YBMSM. Participants completed a two-week GPS protocol and a survey on their PrEP use, drug use, sexual behaviors, and social/sexual network. Electronical Health Record data are also collected to evaluate PrEP clinical engagement. The specific aims for the proposed study are to: Aim 1) Identify and determine the spatio- temporal distribution of regular places commonly frequented by YBMSM. Aim 2) Construct and characterize dynamic place-to-place attendance networks. Aim 3) Determine whether HIV-negative YBMSM who attend the same place(s) have similar sex and drug-using behaviors, % of HIV-positive network, and uptake of PrEP. This study will demonstrate how place-based affiliation approach can (1) inform and maximize place-based intervention by pinpointing optimal places for interventions and (2) direct a contextually relevant intervention by demonstrating health care engagement behaviors among people who attend the same place(s).

Project Narrative: PrEP is an effective HIV prevention intervention, but successful PrEP implementation among YBMSM is limited by several structural factors that impede engagement. This proposal will identify places where YBMSM spend time who are at increased risk for HIV, but not yet on PrEP through a construction of place-based affiliation networks using objective GPS data. This study will demonstrate how place-based affiliation approach can reach large numbers of PrEP candidates by targeting a small number of places that are connected to more people who would be good candidates for PrEP uptake.