Estimated Number of Men Who Have Sex With Men With Indications for HIV Pre-exposure Prophylaxis in a National Sexual Network Study.

BACKGROUND: A 2015 CDC analysis estimated that 24.7% of sexually active men who have sex with men (MSM) had indications for HIV pre-exposure prophylaxis (PrEP) based on 2014 US Public Health Service (USPHS) clinical practice guidelines. Given that the USPHS revised these guidelines in 2017, updated estimates of the fraction of MSM indicated for PrEP overall and stratified by demographic factors and geography are needed to scale-up PrEP for MSM in the US. METHODS: We conducted a national web-based study of 4904 MSM aged 15-65 who had ever had sex with another man between July 2017 and January 2019. We estimated the percentage of HIV-negative, sexually active MSM meeting USPHS indications for PrEP by demographic category. RESULTS: Of 3511 sexually active, HIV-negative MSM, 34.0% (95% confidence interval: 32.4 to 35.6) met USPHS indications for PrEP, with percentages consistent across US census region and varying slightly by race/ethnicity (Black: 32.2%, White: 33.7%, Hispanic: 36.4%, Other: 33.6%). Among individuals meeting USPHS PrEP indications, 93.5% reported condomless anal intercourse in the prior 6 months. Among all survey respondents, PrEP eligibility was lowest among non-Hispanic black (18.4%) and younger respondents (15-17: 4.1%; 18-24: 18.1%). CONCLUSIONS: Estimated percentages of MSM meeting indications for PrEP exceeded the previous CDC estimate across race/ethnicity, age, and census regions, with one-third of adult, sexually active, HIV-negative MSM exhibiting indications for PrEP. This study suggests, given current guidelines for PrEP indications, that a different fraction of eligible MSM could be receiving PrEP than previously estimated.

Egocentric sexual networks of men who have sex with men in the United States: Results from the ARTnet study.

In this paper, we present an overview and descriptive results from one of the first egocentric network studies of men who have sex with men (MSM) from across the United States: the ARTnet study. ARTnet was designed to support prevention research for human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs) that are transmitted across partnership networks. ARTnet implemented a population-based egocentric network study design that sampled egos from the target population and asked them to report on the number, attributes, and timing of their sexual partnerships. Such data provide the foundation needed for parameterizing stochastic network models that are used for disease projection and intervention planning. ARTnet collected data online from 2017 to 2019, with a final sample of 4904 participants who reported on 16198 sexual partnerships. The aims of this paper were to characterize the joint distribution of three network parameters needed for modeling: degree distributions, assortative mixing, and partnership age, with heterogeneity by partnership type (main, casual and one-time), demography, and geography. Participants had an average of 1.19 currently active partnerships ("mean degree"), which was higher for casual partnerships (0.74) than main partnerships (0.45). The mean rate of one-time partnership acquisition was 0.16 per week (8.5 partners per year). Main partnerships lasted 272.5 weeks on average, while casual partnerships lasted 133.0 weeks. There was strong but heterogenous assortative mixing by race/ethnicity for all groups. The mean absolute age difference for all partnership types was 9.5 years, with main partners differing by 6.3 years compared to 10.8 years for casual partners. Our analysis suggests that MSM may be at sustained risk for HIV/STI acquisition and transmission through high network degree of sexual partnerships. The ARTnet network study provides a robust and reproducible foundation for understanding the dynamics of HIV/STI epidemiology among U.S. MSM and supporting the implementation science that seeks to address persistent challenges in HIV/STI prevention.