Preexposure Prophylaxis for HIV Infection Integrated With Municipal- and Community-Based Sexual Health Services

Abstract

Importance: Several randomized clinical trials have demonstrated the efficacy of preexposure prophylaxis (PrEP) in preventing human immunodeficiency virus (HIV) acquisition. Little is known about adherence to the regimen, sexual practices, and overall effectiveness when PrEP is implemented in clinics that treat sexually transmitted infections (STIs) and community-based clinics serving men who have sex with men (MSM).

Objective: To assess PrEP adherence, sexual behaviors, and the incidence of STIs and HIV infection in a cohort of MSM and transgender women initiating PrEP in the United States.

Design, setting, and participants: Demonstration project conducted from October 1, 2012, through February 10, 2015 (last date of follow-up), among 557 MSM and transgender women in 2 STI clinics in San Francisco, California, and Miami, Florida, and a community health center in Washington, DC. Data were analyzed from December 18, 2014, through August 8, 2015.

Interventions: A combination of daily, oral tenofovir disoproxil fumarate and emtricitabine was provided free of charge for 48 weeks. All participants received HIV testing, brief client-centered counseling, and clinical monitoring.

Main outcomes and measures: Concentrations of tenofovir diphosphate in dried blood spot samples, self-reported numbers of anal sex partners and episodes of condomless receptive anal sex, and incidence of STI and HIV acquisition.

Results: Overall, 557 participants initiated PrEP, and 437 of these (78.5%) were retained through 48 weeks. Based on the findings from the 294 participants who underwent measurement of tenofovir diphosphate levels, 80.0% to 85.6% had protective levels (consistent with ≥4 doses/wk) at follow-up visits. African American participants (56.8% of visits; P = .003) and those from the Miami site (65.1% of visits; P < .001) were less likely to have protective levels, whereas those with stable housing (86.8%; P = .02) and those reporting at least 2 condomless anal sex partners in the past 3 months (88.6%; P = .01) were more likely to have protective levels. The mean number of anal sex partners declined during follow-up from 10.9 to 9.3, whereas the proportion engaging in condomless receptive anal sex remained stable at 65.5% to 65.6%. Overall STI incidence was high (90 per 100 person-years) but did not increase over time. Two individuals became HIV infected during follow-up (HIV incidence, 0.43 [95% CI, 0.05-1.54] infections per 100 person-years); both had tenofovir diphosphate levels consistent with fewer than 2 doses/wk at seroconversion.

Conclusions and relevance: The incidence of HIV acquisition was extremely low despite a high incidence of STIs in a large US PrEP demonstration project. Adherence was higher among those participants who reported more risk behaviors. Interventions that address racial and geographic disparities and housing instability may increase the impact of PrEP.

Figure 1. PrEP engagement, by visit week and site (Figure 1A) and race/ethnicity (Figure 1B)

A: Distribution of PrEP engagement (visit attendance and adherence by DBS concentrations) by visit week and study site. BLQ=below limit of quantitation. Numbers at top of each bar indicate number of participants contributing data at each time point. B: Distribution of PrEP engagement (visit attendance and adherence by DBS concentrations) by visit week and race/ethnicity. BLQ=below limit of quantitation. Numbers at top of each bar indicate number of participants contributing data at each time point.

Figure 2. PrEP engagement at week 48, based on engagement at week 4

Proportion of participants with no visit attendance or DBS concentrations in different adherence categories at week 48, stratified by visit attendance and DBS concentrations at week 4. BLQ=below limit of quantitation. This analysis includes 325 participants, 287 of whom had DBS tested at week 4, and 38 who missed the week 4 visit.

Figure 3. Sexual Behaviors and STIs in the Demo Project

A: Proportion of participants reporting condomless receptive anal sex (ncRAI) and mean number of receptive anal sex episodes with and without a condom. B: Percent of STI tests that were positive during each visit interval, by anatomic site. The week 48 visit interval includes testing performed at the optional follow-up visit 4 weeks after week 48.