Comparing Sexual Network Mean Active Degree Measurement Metrics Among Men Who Have Sex With Men.

BACKGROUND: Mean active degree is an important proxy measure of cross-sectional network connectivity commonly used in HIV/sexually transmitted infection epidemiology research. No current studies have compared measurement methods of mean degree using a cross-sectional study design for men who have sex with men (MSM) in the United States. We compared mean degree estimates based on reported ongoing main and casual sexual partnerships (current method) against dates of first and last sex (retrospective method). METHODS: We used data from ARTnet, a cross-sectional survey of MSM in the United States (2017-2019). ARTnet collected data on the number and types of sexual partners in the past year, limited to the 5 most recent partners (data truncation). We quantified partnerships for months 0 to 12 before the survey date (retrospective method) and compared that with ongoing partnerships on the day of survey (current method). We used linear regression to understand the impact of truncated partnership data on mean degree estimation. RESULTS: The retrospective method yielded similar degree estimates to the current for months proximate to the day of survey. The retrospective method mean degree systematically decreased as the month increased from 0 to 12 months before survey date. This was driven by data truncation: among participants with >5 partners in the past year compared with those with ≤5, the average change in main partnership degree between 12 and 0 months before survey date was -0.05 (95% confidence interval, -0.08 to -0.03) after adjusting for race/ethnicity, age, and education. The adjusted average change in casual partnership degree was -0.40 (95% confidence interval, -0.45 to -0.35). CONCLUSIONS: The retrospective method underestimates mean degree for MSM in surveys with truncated partnership data, especially for casual partnerships. The current method is less prone to bias from partner truncation when the target population has high rate of partners per year.

Associations between HIV Testing and Consent Policies among Sexually Active Adolescents: Differences by Sexual Behavior.

HIV incidence remains high among US youth, especially among sexual minority youth. However, only half of youth with HIV are aware of their status. One potential explanation for low HIV testing rates is that restrictive policies may prevent minors from access HIV testing due to parental consent requirements. Using pooled data from the local Youth Risk Behavior Survey, we assessed whether state HIV testing laws, including age restrictions and explicit inclusion of HIV in STI testing consent laws, were associated with differences in HIV testing rates; differences by sexual behavior were also examined. Among female youth, policies were not associated with HIV testing. However, among male youth, both the presence of age restrictions and explicit inclusion in STI services were significantly associated with increased odds of HIV testing. Results indicate that policy changes may be effective at increasing testing among male youth who have sex with other males.

Network Analysis of Organizations Providing HIV Services in Chicago: Toward an Integrated Response to the HIV Epidemic.

CONTEXT: The public health response to the HIV epidemic has increasingly centered on the uptake of and adherence to biomedical interventions (eg, pre-exposure prophylaxis [PrEP], treatment as prevention [TasP]). Traditionally, various community and health care organizations have worked to address different stages of PrEP or TasP care. OBJECTIVE: To understand the importance of how HIV prevention organizations providing these services interact to provide the comprehensive care needed for successful HIV and PrEP continuum outcomes. DESIGN: Utilizing an Organizational Network Survey, network ties were examined between formal and informal partnerships among community agencies. SETTING: This study examined community agencies in the current HIV prevention system in Chicago. PARTICIPANTS: Seventy-two community agencies across the Chicago metropolitan area. MAIN OUTCOME MEASURES: Using network analysis, this study examined ties between community agencies and assessed perceptions of collaboration and competitiveness in the current HIV prevention system in Chicago. RESULTS: Overall, respondents reported that the current environment of HIV prevention in Chicago was extremely (18.8%), moderately (37.5%), or somewhat collaborative (37.5%) and extremely (68.8%) or moderately competitive (25.0%). The majority of partnerships reported were informal, with less than a quarter being formalized. That said, those who reported formal partnerships reported being satisfied with those relationships. There was a significantly negative association between density and perceived collaboration-grantees experiencing a more collaborative also reported less dense networks. CONCLUSION: These findings indicate that, despite perceived competitiveness, agencies are willing to work together and create a cohesive HIV prevention and treatment system. However, more work should be done to foster an environment that can support the formation of partnerships, to improve a coordinated response to providing HIV care, and sustain mutually beneficial relationships.

A Behavioral Cascade of HIV Seroadaptation Among US Men Who Have Sex with Men in the Era of PrEP and U = U.

Seroadaptive behaviors help reduce HIV risk for some men who have sex with men (MSM), and have been well documented across MSM populations. Advancements in biomedical prevention have changed the contexts in which seroadaptive behaviors occur. We thus sought to estimate and compare the prevalence of four stages of the "seroadaptive cascade" by PrEP use in the recent era: knowledge of own serostatus, knowledge of partner serostatus; serosorting (matching by status), and condomless anal intercourse. Serosorting overall appeared to remain common, especially with casual and one-time partners. Although PrEP use did not impact status discussion, it did impact serosorting and the likelihood of having condomless anal intercourse. For respondents not diagnosed with HIV and not on PrEP, condomless anal intercourse occurred in just over half of relationships with HIV-positive partners who were not on treatment. Biomedical prevention has intertwined with rather than supplanted seroadaptive behaviors, while contexts involving neither persist.

RESUMEN: Los comportamientos seroadaptivos ayudan a reducir el riesgo de VIH en algunos hombres que tienen sexo con otros hombres (HSH) y han sido bien documentados en varias comunidades de HSH. Los avances en prevención biomédica han cambiado los contextos de los comportamientos seroadaptivos. Por ello buscamos estimar y comparar la prevalencia de cuatro fases de la 'cascada seroadaptiva' mediante el uso de PrEP en la era reciente: conocimiento del seroestatus personal, conocimiento del seroestatus del compañero, serosorting (emparejamiento por estatus) y coito anal sin condón. En general, el serosorting parece seguir siendo común especialmente con parejas casuales o de una noche. A pesar de que el uso de PrEP no impactó la discusión sobre el estatus, sí impactó el serosorting y la probabilidad de coito anal sin condón. Los encuestados no diagnosticados con VIH y sin PrEP tuvieron coito anal sin condón en la mitad de las relaciones con parejas VIH-positivo que no estaban bajo tratamiento. La prevención biomédica se ha entremezclado en lugar de suplantar los comportamientos seropositivos, mientras persisten los contextos en los que no aparece ninguno.

Substance Use Predicts Sustained Viral Suppression in a Community Cohort of Sexual and Gender Minority Youth Living with HIV.

Retention in care and sustained viral suppression are integral outcomes in the care continuum for people living with HIV (PLWH) and HIV prevention; however, less is known about how substance use predicts sustained viral suppression over time. This study seeks to examine the predictive effects of substance use on sustained viral suppression in a sample of cisgender sexual minority men and gender minority PLWH (n = 163) drawn from a longitudinal sample in the Chicago area collected 2015-2019. Using data from 3 visits separated by 6 months, participants were coded persistently detectable, inconsistently virally suppressed, and consistently virally suppressed (< 40 copies/mL at all visits). Multinomial logistic regressions were utilized. About 40% of participants had sustained viral suppression. In multinomial logistic regressions, CUDIT-R predicted persistent detectable status and stimulant use was associated with inconsistent viral suppression. Substance use may create challenges in achieving sustained viral suppression, which has important implications for care and prevention.

RESUMEN: Retención en el cuidado de la salud y supresión viral sostenida son resultados integrales en la cascada del tratamiento de VIH para personas viviendo con el virus del SIDA (PVVS) y prevención del VIH. Sin embargo, no se sabe mucho acerca de cómo el uso de substancias predice la supresión viral sostenida a través del tiempo. Este estudio busca examinar los efectos predictivos del uso de substancias en la supresión viral sostenida en una muestra de minoría de hombres cisgéneros y minorías de género PVVS (n = 163) basada en una muestra longitudinal en la región de Chicago obtenida en 2015­2019. Utilizando datos de 3 visitas con un intervalo de 6 meses, participantes fueron identificados como detectables persistentemente, inconsistentemente viralmente suprimido, y consistentemente viralmente suprimido (< 40 copias/mL en todas las visitas). Regresión logística multinomial fue utilizada. Cerca de 40% de los participantes tenían supresión viral sostenida. En regresión logística multinomial, CUDIT-R predicho status detectable persistente y uso de estimulantes fueron asociados a la supresión viral inconsistente. Uso de substancias crean desafíos para lograr la supresión viral sostenida, lo que tiene importante trascendencia para el cuidado y prevención.

Psychometric Data Linking Across HIV and Substance Use Cohorts.

Psychometric data linking of psychological and behavioral questionnaires can facilitate the harmonization of data across HIV and substance use cohorts. Using data from the Collaborating Consortium of Cohorts Producing NIDA Opportunities (C3PNO), we demonstrate how to capitalize on previous linking work with a common linked depression metric across multiple questionnaires. Cohorts were young men who have sex with men (MSM), substance-using MSM, HIV/HCV cocaine users, and HIV-positive patients. We tested for differential item functioning (DIF) by comparing C3PNO cohort data with general population data. We also fit a mixed-effects model for depression, entering HIV-status and recent opioid/heroin use as fixed effects and cohort as a random intercept. Our results suggest a minimal level of DIF between the C3PNO cohorts and general population samples. After linking, descriptive statistics show a wide range of depression score means across cohorts. Our model confirmed an expected positive relationship between substance use and depression, though contrary to expectations, no significant association with HIV status. The study reveals the likely role of cohort differences, associated patient characteristics, study designs, and administration settings.

No Evidence of Bias in Sexual Partnership Corroboration by Race and Ethnicity Among a Diverse Cohort of Young Men Who Have Sex with Men and Transgender Women.

Black men who have sex with men (MSM) continue to experience disproportionately high HIV incidence rates relative to their white peers. Yet, Black MSM do not report higher levels of sexual risk behavior, and contextual factors such as access to care and sexual networks only partially explain these disparities. However, risk misclassification could help explain this paradox, if measurement biases systematically underestimate sexual risk behavior among Black MSM relative to their peers. The current study examined variation in sexual partnership corroboration in the RADAR study, a large and diverse cohort of young MSM and transgender women. Network data were elicited regarding all sexual partners in the prior 6 months, including instances where participants reported other participants as sexual partners. Using these data, anal and condomless anal sex partners were separately examined using a series of exponential random graph models to estimate the rate of corroboration of sexual connections between participants and examine whether this parameter varied by race/ethnicity. For both types of behavior, providing separate estimates for corroboration across race/ethnicity groups reduced model fit and did not significantly vary across groups. Accordingly, we found no evidence of measurement bias by race/ethnicity in the current data. However, overall rates of corroboration (41.2-50.3%) were low, suggesting substantial levels of measurement error. Accordingly, it is vital that researchers continue to improve upon methods to measure risk behavior in order to maximize their validity. We discuss the implications of these findings, including potential alternative causes of risk misclassification (e.g., sampling bias) and future directions to reduce measurement error.

Comparable viral decay with initial dolutegravir plus lamivudine versus dolutegravir-based triple therapy.

OBJECTIVES: To expand understanding of the virological potency of initial dolutegravir plus lamivudine dual therapy (dolutegravir/lamivudine), we compared the viral decay seen in the pilot ACTG A5353 study with the decay observed with dolutegravir plus two NRTIs in the SPRING-1 and SINGLE studies, while also exploring the impact of baseline viral load (VL). METHODS: Change in VL from baseline was calculated for timepoints shared by A5353 (n = 120, including 37 participants with pretreatment VL >100000 copies/mL), SPRING-1 (n = 51) and SINGLE (n = 417). The 95% CIs of change from baseline were determined for each observed week, using the mean log10-transformed VL, and compared between the dolutegravir/lamivudine and triple therapy groups using the Wilcoxon Rank Sum test for non-inferiority (δ = 0.5). To assess the impact of baseline VL on viral decay, we examined a bi-exponential non-linear mixed-effect model. RESULTS: The mean VL change from baseline to week 24 was -2.9 log10 copies/mL for dolutegravir/lamivudine versus -3.0 log10 copies/mL for dolutegravir-based three-drug therapy (P < 0.001). In the decay model, baseline VL >100000 copies/mL was associated with a slower initial decay rate (d1). A faster initial decay rate was seen with dolutegravir/lamivudine, which was partially offset when baseline VL was >100000 copies/mL as indicated by a significant interaction between baseline VL and drug therapy group. The secondary decay rate (d2) was not significantly different from zero, with no significant associations. CONCLUSIONS: Viral decay with dolutegravir/lamivudine was comparable to viral decay with dolutegravir-based triple therapy, even in individuals with higher pretreatment VL (>100000 copies/mL).

Intersectional Identities and HIV: Race and Ethnicity Drive Patterns of Sexual Mixing.

Large disparities exist in HIV across racial and ethnic populations-with Black and Latino populations disproportionately affected. This study utilizes a large cohort of young men who have sex with men (YMSM) to examine how race and ethnicity drive sexual partner selection, and how those with intersecting identities (Latinos who identify as White or Black) differ from Latinos without a specific racial identification (Latinos who identify as "Other"). Data come from YMSM (N = 895) who reported on sexual partners (N = 3244). Sexual mixing patterns differed substantially by race and ethnicity. Latinos who self-identified as "Black" reported mainly Black partners, those who self-identified as "White" predominantly partnered with Whites, while those who self-identified as "Other" mainly partnered with Latinos. Results suggested that Black-Latino YMSM are an important population for prevention, as their HIV prevalence neared that of Black YMSM, and their patterns of sexual partnership suggested that they may bridge Black YMSM and Other-Latino YMSM populations.

An Investigation of Racial and Ethnic Homophily on Grindr Among an Ongoing Cohort Study of YMSM.

Men who have sex with men (MSM), and especially MSM of color, are disproportionately affected by HIV. Previous research shows that MSM have high levels of racial/ethnic homophily (the tendency for people to have sex with others who share the same racial/ethnic identification) in sexual dyads, which may help explain HIV disparities. This study fills a gap in previous research by grounding network data from a cohort study of young MSM in Chicago (RADAR) in the contexts of virtual spaces (VSs) and examining differences in levels of racial/ethnic homophily using multilevel-logistic-regression models. Results show that Grindr differs from other VSs in proportions of racially/ethnically homophilous dyads and by partner racial/ethnic identification. After controlling for general homophily trends, sex partnerships formed on Grindr by Black MSM were significantly less likely to be homophilous than those of White MSM. While racial/ethnic groups differ in likelihood to form homophilous partnerships, this trend varies by VS.

Utilization and avoidance of sexual health services and providers by YMSM and transgender youth assigned male at birth in Chicago.

Young men who have sex with men (YMSM) and transgender youth assigned male at birth (AMAB) bear a disproportionate burden of the HIV epidemic, yet are sub optimally engaged by sexual health service providers and HIV prevention services. To increase sexual health and HIV prevention behaviors and address disparities in HIV incidence and outcomes among YMSM and AMAB transgender youth, it is critical to understand patterns of service utilization and avoidance. This study examined how and why YMSM and AMAB transgender youth use or avoid sexual health services and service providers in a large Midwestern city within a survey administered to 890 participants from a longitudinal cohort study (RADAR). Results demonstrate low overall use of sexual health services and minimal interest in seeking pre-exposure prophylaxis (PrEP), consistent with prior research. Low awareness of available services was associated with how and where YMSM and trans youth AMAB seek care, with 76% of our sample reporting this as their primary reason for not seeking specific sexual health services. Additional associations are discussed, and recommendations are made for how to improve available services and access.

Role of Social and Sexual Network Factors in PrEP Utilization Among YMSM and Transgender Women in Chicago.

Despite demonstrated efficacy, uptake of HIV pre-exposure prophylaxis (PrEP) remains low, particularly among high-risk demographics such as transgender women, Black men who have sex with men (BMSM), and young MSM (YMSM). Research thus far has largely focused on individual factors that may impede PrEP uptake in these demographics, leaving social network factors relatively unexplored. The present study used data collected from participants within RADAR, a longitudinal cohort study in Chicago focused on understanding the individual, dyadic, network, social, and biologic factors associated with HIV infection within YMSM. Of the 906 study participants who did not report an HIV diagnosis at baseline, 7.0% reported using PrEP in the prior 6 months. Recent PrEP use was associated with both individual-level (age and gender) and network-level factors (mean relationship strength, sexual network degree, etc.). These findings highlight the need to expand beyond focusing on individual-level drivers of PrEP uptake, as well as changing our understanding of who is most important within a network (centrality vs. strength of weak ties). Future work is needed to determine whether variables associated with PrEP uptake are similarly connected to PrEP adherence.

Evaluating HIV Knowledge Questionnaires Among Men Who Have Sex with Men: A Multi-Study Item Response Theory Analysis.

Knowledge about the transmission, prevention, and treatment of HIV remains a critical element in psychosocial models of HIV risk behavior and is commonly used as an outcome in HIV prevention interventions. However, most HIV knowledge questions have not undergone rigorous psychometric testing such as using item response theory. The current study used data from six studies of men who have sex with men (MSM; n = 3565) to (1) examine the item properties of HIV knowledge questions, (2) test for differential item functioning on commonly studied characteristics (i.e., age, race/ethnicity, and HIV risk behavior), (3) select items with the optimal item characteristics, and (4) leverage this combined dataset to examine the potential moderating effect of age on the relationship between condomless anal sex (CAS) and HIV knowledge. Findings indicated that existing questions tend to poorly differentiate those with higher levels of HIV knowledge, but items were relatively robust across diverse individuals. Furthermore, age moderated the relationship between CAS and HIV knowledge with older MSM having the strongest association. These findings suggest that additional items are required in order to capture a more nuanced understanding of HIV knowledge and that the association between CAS and HIV knowledge may vary by age.

Sexual Partner Typologies and the Association Between Drug Use and Sexual Risk Behavior Among Young Men Who Have Sex With Men.

Numerous partner and relationship characteristics are associated with sexual risk behavior among young men who have sex with men (YMSM), including being in a serious relationship and having older partners. However, most research in this area is limited by its reliance on variable-centered approaches. Using multilevel latent class analysis, this study identified subgroups of sexual partner types with a particular emphasis on examining whether partner type moderated the association between drug use and condomless anal sex (CAS). Data were utilized from an ongoing cohort study of YMSM (ages 16-29) recruited from previous studies as well as peers and serious partners of existing cohort members. A total of 469 participants reported on 1596 sexual partners in the past 6 months. We identified four distinct sexual partner typologies, which we refer to as: casual, older-online, much older, and serious. Results indicated that rates of CAS were highest for older-online and serious partners. Additionally, there was a positive association between drug use and CAS among a predominantly marijuana using sample, but only for serious partners. While previous research has found that CAS is highest in serious relationships, findings suggest that there may be another type of partnership in which CAS is likely to occur (older partners met online). If confirmed, these results suggest interventions focused on the intersection of marijuana use and CAS may be particularly important among YMSM with serious partners.

Validation of tie corroboration and reported alter characteristics among a sample of young men who have sex with men.

The differences between direct ties (i.e., ties between a respondent and their nominees) and ties between nominees (indirect) are key to understanding network structure, yet remain understudied. Within a sample of 175 young men who have sex with men, we explored the corroboration of sex and drug ties, and factors associated with corroboration. The majority of instances in which there was no corroboration for either sex or drug ties was due to one individual not appearing in another respondent's network. When an individual did appear in another respondent's network, direct sex and drug ties were corroborated in most cases. We also found that more indirect sex ties were corroborated than direct sex ties (95.7% vs. 88.9%), but the reverse was true for indirect versus direct drug ties (73.1% vs. 84.1%). Strength of relationship and frequency of communication were both associated with confirmed direct ties, but not with indirect ties. Based on these findings, we recommend that direct and indirect ties be treated differently in network analyses.

Creating Youth-Supportive Communities: Outcomes from the Connect-to-Protect® (C2P) Structural Change Approach to Youth HIV Prevention.

Reducing HIV incidence among adolescents represents an urgent global priority. Structural change approaches to HIV prevention may reduce youth risk by addressing the economic, social, cultural, and political factors that elevate it. We assessed whether achievement of structural changes made by eight Connect-to-Protect (C2P) coalitions were associated with improvements in youth's views of their community over the first 4 years of coalitions' mobilization. We recruited annual cross-sectional samples of targeted youth from each C2P community. We sampled youth in neighborhood venues. We interviewed a total of 2461 youth over 4 years. Males (66 %) and youth of color comprised the majority (52 % Hispanic/Latinos; 41 % African Americans) of those interviewed. By year 4, youth reported greater satisfaction with their community as a youth-supportive setting. They reported their needs were better met by available community resources compared with year 1. However, these findings were moderated by risk population such that those from communities where C2P focused on young men who have sex with men (YMSM) reported no changes over time whereas those from communities focused on other at-risk youth reported significant improvements over time in satisfaction and resource needs being met. Internalized HIV stigma increased over time among those from communities serving other at-risk youth and was unchanged among those from YMSM communities. The very different results we observe over time between communities focused on YMSM versus other at-risk youth may suggest it is unreasonable to assume identical chains of structural causality across youth populations who have such different historical relationships to HIV and who encounter very different kinds of entrenched discrimination within their communities.

Improving measurement of injection drug risk behavior using item response theory.

BACKGROUND: Recent research highlights the multiple steps to preparing and injecting drugs and the resultant viral threats faced by drug users. This research suggests that more sensitive measurement of injection drug HIV risk behavior is required. In addition, growing evidence suggests there are gender differences in injection risk behavior. However, the potential for differential item functioning between genders has not been explored. OBJECTIVES: To explore item response theory as an improved measurement modeling technique that provides empirically justified scaling of injection risk behavior and to examine for potential gender-based differential item functioning. METHODS: Data is used from three studies in the National Institute on Drug Abuse's Criminal Justice Drug Abuse Treatment Studies. A two-parameter item response theory model was used to scale injection risk behavior and logistic regression was used to examine for differential item functioning. RESULTS: Item fit statistics suggest that item response theory can be used to scale injection risk behavior and these models can provide more sensitive estimates of risk behavior. Additionally, gender-based differential item functioning is present in the current data. CONCLUSION: Improved measurement of injection risk behavior using item response theory should be encouraged as these models provide increased congruence between construct measurement and the complexity of injection-related HIV risk. Suggestions are made to further improve injection risk behavior measurement. Furthermore, results suggest direct comparisons of composite scores between males and females may be misleading and future work should account for differential item functioning before comparing levels of injection risk behavior.

Evaluating the agreement between different substance use recall periods in multiple HIV cohorts.

BACKGROUND: This study aims to evaluate the agreement in substance use on both binary and ordinal scales between 3-month and 6-month recall periods with samples from different communities, demographic backgrounds, and HIV status. METHODS: We administered the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) to 799 participants from three different North American cohorts focused on substance use and HIV. We conducted a within-person agreement analysis by calculating the agreement levels and Kappa statistic between data collected using the 3-month recall ASSIST and 6-month custom substance use surveys as well as different terminology for each substance in multiple cohorts. RESULTS: For all drugs studied, the agreement on the binary use or ordinal frequency of use metrics showed a high agreement level between 80.4% and 97.9% and an adequate adjusted kappa value between 0.61 and 0.96, suggesting substantial agreement. According to the agreement criteria we proposed, substance use data collected using different recall periods and with variation in drug names can be harmonized across cohorts. CONCLUSIONS: This study is the first to evaluate the feasibility of data harmonization of substance use by demonstrating high level of agreement between different recall periods in different cohorts. The results can inform data harmonization efforts in consortia where data are collected from cohorts using different questions and recall periods.

Racial and Ethnic Differences in Mobile App Use for Meeting Sexual Partners Among Young Men Who Have Sex With Men and Young Transgender Women: Cross-Sectional Study.

Background: Young men who have sex with men and young transgender women (YMSM-YTW) use online spaces to meet sexual partners with increasing regularity, and research shows that experiences of racism online mimics the real world. Objective: We analyzed differences by race and ethnicity in web-based and mobile apps used to meet sexual partners as reported by Chicago-based YMSM-YTW in 2016-2017. Methods: A racially and ethnically diverse sample of 643 YMSM-YTW aged 16-29 years were asked to name websites or mobile apps used to seek a sexual partner in the prior 6 months, as well as provide information about sexual partnerships from the same period. We used logistic regression to assess the adjusted association of race and ethnicity with (1) use of any website or mobile apps to find a sexual partner, (2) use of a "social network" to find a sexual partner compared to websites or mobile apps predominantly used for dating or hookups, (3) use of specific websites or mobile apps, and (4) reporting successfully meeting a sexual partner online among website or mobile app users. Results: While most YMSM-YTW (454/643, 70.6%) used websites or mobile apps to find sexual partners, we found that Black non-Hispanic YMSM-YTW were significantly less likely to report doing so (comparing White non-Hispanic to Black non-Hispanic: adjusted odds ratio [aOR] 1.74, 95% CI 1.10-2.76). Black non-Hispanic YMSM-YTW were more likely to have used a social network site to find a sexual partner (comparing White non-Hispanic to Black non-Hispanic: aOR 0.20, 95% CI 0.11-0.37), though this was only reported by one-third (149/454, 32.8%) of all app-using participants. Individual apps used varied by race and ethnicity, with Grindr, Tinder, and Scruff being more common among White non-Hispanic YMSM-YTW (93/123, 75.6%; 72/123, 58.5%; and 30/123, 24.4%, respectively) than among Black non-Hispanic YMSM-YTW (65/178, 36.5%; 25/178, 14%; and 4/178, 2.2%, respectively) and Jack'd and Facebook being more common among Black non-Hispanic YMSM-YTW (105/178, 59% and 64/178, 36%, respectively) than among White non-Hispanic YMSM-YTW (6/123, 4.9% and 8/123, 6.5%, respectively). Finally, we found that while half (230/454, 50.7%) of YMSM-YTW app users reported successfully meeting a new sexual partner on an app, Black non-Hispanic YMSM-YTW app users were less likely to have done so than White non-Hispanic app users (comparing White non-Hispanic to Black non-Hispanic: aOR 2.46, 95% CI 1.50-4.05). Conclusions: We found that Black non-Hispanic YMSM-YTW engaged with websites or mobile apps and found sexual partners systematically differently than White non-Hispanic YMSM-YTW. Our findings give a deeper understanding of how racial and ethnic sexual mixing patterns arise and have implications for the spread of sexually transmitted infections among Chicago's YMSM-YTW.

Neighborhood-level characteristics as effect modifiers on the efficacy of the MyPEEPS mobile intervention in same-sex attracted adolescent men.

To estimate the effect of neighborhood-level modification on the efficacy of the MyPEEPS Mobile intervention on the reduction of condomless anal sex acts among same-sex attracted adolescent men. A series of generalized linear mixed model was used to examine if the effect of the MyPEEPS Mobile intervention on condomless anal sex acts was moderated by neighborhood-level factors using data from the 2019 American Community Survey US Census Bureau. "The magnitudes of intervention were significantly smaller at both 6- and 9-month follow-up among adolescents living in neighborhood with high proportions of Hispanic or Latino residents (IRR6M = 1.02, 95 % CI: 1.01, 1.02; IRR9M = 1.03, 95 % CI: 1.01, 1.05) and high proportions of families with income below the poverty level (IRR6M = 1.07, 95 % CI: 1.01, 1.12; IRR9M = 1.05, 95 % CI: 1.01, 1.10), which indicated that living in communities with a higher concentration of residents living under poverty or of Hispanic/and Latino ethnicity significantly modified the effective of program intervention on condomless sex among adolescent MSM. Understanding how neighborhood characteristics modify the effect of HIV prevention interventions may be useful in better targeting delivery and tailoring content of interventions based on neighborhood level characteristics such as the ones identified in this study.