Impact of the Centers for Disease Control's HIV Preexposure Prophylaxis Guidelines for Men Who Have Sex With Men in the United States

Abstract

Background. Preexposure prophylaxis (PrEP) is effective for preventing human immunodeficiency virus (HIV) infection among men who have sex with men (MSM) within trial settings. Population impact will depend on clinical indications for PrEP initiation, coverage levels, and drug adherence. No modeling studies have estimated the impact of clinical practice guidelines for PrEP issued by the Centers for Disease Control and Prevention (CDC).Methods. Mathematical models of HIV transmission among MSM were used to estimate the percentage of infections averted (PIA) and the number needed to treat (NNT) under behavioral indications of the CDC's PrEP guidelines. We modeled the contribution of these indications while varying treatment coverage and adherence.Results. At 40% coverage of indicated MSM over the next decade, application of CDC guidelines would avert 1162 infections per 100 000 person-years, 33.0% of expected infections. The predicted NNT for the guidelines would be 25. Increasing coverage and adherence jointly raise the PIA, but reductions to the NNT were associated with better adherence only.Conclusions. Implementation of CDC PrEP guidelines would result in strong and sustained reductions in HIV incidence among MSM in the United States. The guidelines strike a good balance between epidemiological impact (PIA) and efficiency (NNT) at plausible scale-up levels. Adherence counseling could maximize public health investment in PrEP by decreasing the NNT.

Covariation between the physiological and behavioral components of pathogen transmission: host heterogeneity determines epidemic outcomes

“…The EpiModel package provides a suite of prewritten and modifiable functions for simulating infectious disease dynamics, including stochastic network models that rely on temporal ERGMs from the 'statnat' package. The EpiModel package has been used to investigate complex disease dynamics and interventions for diseases like HIV (Jenness et al 2016b). Fully annotated sample code is provided in the Supplementary material Appendix 2, and all code and simulation data for the manuscript are available from the Dryad Digital Repository (White et al 2017b).…”

Addressing Gaps in HIV Preexposure Prophylaxis Care to Reduce Racial Disparities in HIV Incidence in the United States

“…Our prior applications investigated the sources of HIV racial disparities among MSM in Atlanta and the potential impact of PrEP for MSM in the US [30,31]. For this study, we integrated these two research streams to develop the model structure, parameterization, and analyses for simulating PrEP in a race-stratified approach to understand the implications of the PrEP continuum.…”

“…Our model simulates the dynamics of main, casual, and one-time MSM sexual partnerships for non-Hispanic BMSM and WMSM [30,31]. Predictors of partnership formation included partnership type, number of ongoing partnerships (degree), race and age mixing, and sorting by receptive versus insertive sexual position.…”

Development of an Agent-Based Model to Investigate the Impact of HIV Self-Testing Programs on Men Who Have Sex With Men in Atlanta and Seattle (Preprint)

“…diagnosis status, treatment status, stage of infection, plasma HIV RNA level). Similar to prior studies [16][17], sexual contact networks employed separable-temporal exponential random graph models (STERGMs) [14]-a flexible statistical framework for simulating partnership formation and dissolution across networks [15] in ways that allow one to match data on complex cross-sectional network structure as well as reported relational durations. STERGMs were implemented in the R package suite statnet (www.statnet.org/trac/wiki) and EpiModel (www.epimodel.org).…”

“…MSM who started PrEP were assigned a fixed adherence profile that reflected an average weekly dosage using data from the U.S. PrEP Demo Project [27] weighted by race/ethnicity using methods from Jenness et al 2016 [17], which investigated the impact of the implementation of the U.S. Centers for Disease Control and Prevention's PrEP guidelines on the national HIV epidemic among MSM. For Atlanta, we assigned 21.1% of men as nonadherent (0 doses), 7.0% as taking fewer than 2 doses per week, 10.0% taking 2-3 doses per week, and 61.9% taking ≥4 doses per week; for Seattle, we assigned 14.4% as non-adherent, 4.1% taking <2 doses per week, 5.3% 2-3 doses per week, and 76.2% ≥4 doses per week [17]. The probability of HIV acquisition per sex act was reduced according to the level of adherence.…”