Past NEEMA Funded Projects by Topic Area – HIV

The questions explored in this project all relate to understanding the interlocking relationships between HIV prevention methods (primarily pre-exposure prophylaxis, or PrEP), and STD transmission and treatment, to understand the future course of the HIV and STD epidemics for men who have sex with men (MSM) overall and by race. Because of the complex feedback and high-dimensionality of the behaviors and subgroups of interest, and the infeasibility of conducting randomized trials to probe the questions of interest, agent-based modeling is well-suited. Agent-based models of MSM have been developed to represent the epidemics in Atlanta, GA and Baltimore, MD.

Preventing new HIV infections is essential to improving health in the United States. The HIV care continuum (diagnosis, retention in medical care, prescription of antiretroviral therapy, and viral suppression) has been an important framework for understanding HIV care, morbidity, and mortality, and has been recently extended by CDC and CAMP team members into models of HIV transmission and prevention. This project builds on these models to answer priority questions about the future trajectory of the HIV epidemic and impact of interventions, develop web-based tools of those models, and conduct analyses to strengthen national estimates of the HIV care continuum, and the cost-effectiveness of prevention interventions.

Men who have sex with men (MSM) experience a very high burden of new and existing HIV infections and sexually transmitted infections. This project specifically focuses on the Adolescent Sexual Minority Male (ASMM) population to create estimates and models of the impact of HIV prevention interventions, particularly HIV pre-exposure prophylaxis (PrEP), among this population. In the first phase, literature searches and data analyses were conducted in order to publish estimates of behavioral and testing parameters for ASMM. In the second phase, agent-based models are being adapted to understand the impact of PrEP-targeting strategies in the ASMM population.

Men who have sex with men (MSM), are a group highly-impacted by HIV and STI. Accurate estimates of this population are needed in order to compute measures of disease burden, yet MSM are not systematically enumerated in the US Census. The primary goal of this project is to develop methods that synthesize existing data sources to estimate the population sizes of men who have sex with men within US states. The first phase of this effort involved producing manuscripts and online tools the provided the number MSM at the US state, metropolitan statistical area (MSA), and county levels. Subsequent work has merged these estimates with HIV and syphilis diagnoses data to yield disease rates for MSM. Given stark HIV/STI disparities between demographic subpopulations of MSM, work is ongoing to extend these results to race- and age-specific population estimates.

Current CDC guidelines calling for routine HIV screening among youth are rarely followed: only 13% had ever been tested for HIV by 2012. This project projected the potential clinical impact, cost, and cost-effectiveness of alternative strategies of HIV screening in youth aged 13-24 years in the US. The Cost-Effectiveness of Preventing AIDS Complications (CEPAC)-US model was used to simulate HIV-uninfected 12-year olds at average-risk, and high-risk for HIV. Annual HIV incidence per 100,000 persons was stratified by age and risk. In addition to current (“background”) US screening practices for average-risk youth (13% ever tested before age 18) and high-risk youth (21% ever tested before age 18), Five HIV screening strategies were modeled: current practice plus an additional test at age 13, 15, 18, 21, or 24. Published data on HIV disease progression, treatment response, and healthcare costs were used. Model outcomes included mean CD4 count at diagnosis; proportion of HIV-infected youth diagnosed, linked to care, and retained by age 24 (“HIV cascade” outcomes); life expectancy (LE) and per-person lifetime healthcare costs for the total population and those HIV-infected, and incremental cost-effectiveness ratios in dollars/life-year saved (LYS).

This project is providing rigorous input values on intervention efficacy for HIV-RAMP and other purposes. Systematic review and meta-analysis using Cochrane and GRADE methods are being conducting on the following topics: community-based condom distribution, school-based condom distribution, and the effect of testing positive for HIV on sexual behaviors.

The US has an estimated 168,000 individuals living with undiagnosed HIV infection, based on back-calculations from newly diagnosed individuals. CDC is exploring what would be involved to cut that number in half by 2020. This project is gathering all relevant studies on people living with undiagnosed HIV infection in order to better describe their characteristics (race/ethnicity, contact with the health care system, prior testing, recency of infection, risk behaviors). Probability trees will be constructed to represent the relationship of these characteristics, in order to guide the design of expanded testing strategies.

Young persons who inject drugs (PWID) are at increased risk of HIV and HCV infection, and drug use is increasing in part due to rising rates of prescription opioid abuse. A coordinated effort is needed to reduce prescription opioid misuse, understand transitions to heroin use and injection, and reduce high risk injection and sex practices in PWID. This project is estimating opioid use over the next 10 years in representative rural and urban settings, estimating HIV and HCV infections, and assessing prevention scenarios to reduce transmission of HIV and HCV by 25%.

This project will address three questions: (1) What strategies are most effective for recruitment of PWID and homeless persons into HIV, HCV, and TB prevention and treatment programs? (2) What portion of PWID and homeless persons not-in-care for HIV, HCV, and TB can be identified with novel (e.g., chain-referral) methods? (3) What is the cost per subject contacted, recruited, tested, and treated by population (PWID, Homeless) and recruitment method?