NEEMA Funded Projects by Topic Area – HIV

NEEMA 2.0 (2019-2024)

Estimating the Annual Number of HIV Tests Conducted and HIV Testing Targets in the US

HIV testing is an integral component of the Ending the HIV Epidemic in the U.S. (EHE) Initiative, specifically the diagnose pillar. Estimating and evaluating the reach of HIV testing efforts allows national, state, and local partners to make informed decisions to improve access and reach of HIV testing. The overall aim of the project is to summarize key HIV measures with a focus on testing needs and uptake, including coverage of HIV testing over time, HIV tests performed annually in the U.S., and people who should be tested for HIV following CDC recommendations.

Evaluation of expanded HIV home-test distribution

The only way to know your HIV status is to get tested so you can get linked to HIV treatment and prevention; yet 1 in 7 (13%) of the estimated more than 1 million people with HIV in America still don’t know they have HIV. HIV self-tests can help us to reach individuals at increased risk who would not otherwise test for HIV, or if they are used to supplement testing, they can reduce overall incidence. CDC’s recent direct-to-consumer free HIV self-test distribution program demonstrated that HIV self-testing has the potential to increase testing, but there are concerns that HIV self-tests may increase incidence if they replace clinic-based testing or if they are used in response to a specific risk event before the test window of the home-test has passed. This project seeks to assess the long-term (10-year) impact on HIV incidence and racial/ethnic disparities in HIV incidence if HIV self-tests were distributed to populations reached through CDC’s HIV self-test distribution program.

Growth in sexual and gender minority status in the US: assessing association with behaviors and implications for HIV/STI prevention and care

Sexual and gender minorities (SGM) bear very different burdens of HIV and sexually transmitted infection (STI) than the general population. Recent reports from the Census Bureau suggest that the proportion of Americans identifying as some form of SGM is growing. However, what is not clear is how these identities impact our understanding of short- and long-term sexual behavior trends and changes. An improved understanding of the populations is crucial for anticipating changes in prevention needs and, likely, HIV/STI epidemiology. This project aims to compare measures of SGM status for different groups (e.g., gay male, bisexual male, lesbian, bisexual female, trans male, trans female) across data sources and years, including those with parallel measures of sexual partner genders, to identify the consistency, scale, stability of changing identities, and their relationships to sexual partnering patterns. Future project efforts will utilize these initial findings to model demographic and behavioral shifts and associated changes with one or more STI.

Modeling Implementation Strategies to Improve the Scale-Up of Pre-Exposure Prophylaxis (PrEP) with a National PrEP Program

A national PrEP program could provide direct assistance to purchase health insurance for individuals with low incomes who are not eligible for other insurance due to gaps in Medicaid coverage and ineligibility for Affordable Care Act marketplace subsidies. However, the potential population benefit of a comprehensive national PrEP program remains unclear. This project will use an existing sexual-network model of HIV/STI transmission dynamics among men who have sex men (MSM) to investigate the optimal strategy for a national PrEP program targeted to MSM with indications for PrEP and varying needs for financial assistance. This project aims to develop models for three metropolitan statistical areas with different profiles of HIV burden and healthcare coverage: Atlanta, Washington, D.C., and New York City.

Impact of social distancing and stay-at-home orders on risk behaviors, provision and receipt of prevention and care services, and HIV transmission among men who have sex with men (MSM)

Mitigation strategies to reduce the spread of COVID-19, such as social distancing and stay-at-home orders, may impact HIV epidemiology in at least two different ways. On the one hand, stay-at-home orders may reduce opportunities for sexual transmission among people who do not live together. On the other hand, reduced access to HIV testing and possibly to care and biomedical prevention could lead to additional opportunities for transmission. This project aims to disentangle these potentially differing effects, leading to a clearer understanding of the independent effects and to a proactive strategy for prevention during possible future social distancing or stay-at-home mitigation strategies.

Evaluation of testing and linkage to care interventions for partners of men who have sex with men (MSM)

The Ending the HIV Epidemic: A Plan for America (EHE) initiative aims to reduce new HIV infections by 75% in five years and by 90% in 10 years. The initiative leverages critical scientific advances in HIV prevention, diagnosis, treatment, and outbreak response. This project follows up on our previous efforts to estimate the population attributable fraction of chlamydia and gonorrhea (CT/GC) on HIV incidence among MSM and the possible impact of screening and treatment for CT/GC on HIV incidence. For this analysis, we will estimate the cost-effectiveness of different CT/GC screening scenarios with an outcome of HIV-related quality-adjusted life years (QALYs).

Impact of racial and ethnic disparities on achievement of Ending the HIV Epidemic in the U.S. (EHE) initiative goals

Significant disparities have led to disproportionate HIV prevalence among some racial and ethnic groups. Additional improvement in viral suppression and PrEP coverage will be needed to address these disparities and achieve the EHE goals for each racial and ethnic group and the overall population. Prior agent-based models that include racial groups have focused on MSM alone and did not address the 19% of new diagnoses that occur in women. This project will integrate two agent-based network models (for heterosexual people and MSM, respectively) into a single unified population model of HIV transmission, expand those models to include additional ethnic groups (Hispanic/Latino), and determine the increase in viral suppression and PrEP coverage necessary for each racial and ethnic group to reach EHE goals over the next 10 years.

Estimating cost-effectiveness and HIV prevention impact of screening men who have sex with men (MSM) for chlamydia and gonorrhea

Sexually transmitted infections (STIs) can increase the risk of getting or transmitting HIV. A previous study found that overall, an estimated 10% of HIV infections were attributable to gonorrhea and chlamydia infection. This project builds on the previous study to estimate the probability of gonorrhea or chlamydia infection leading to an HIV infection. This project also aims to estimate the cost-effectiveness of gonorrhea and chlamydia screening programs on reducing HIV incidence among MSM in the United States.

Estimating the population size of sexually active adults and adolescents

Estimating the size of sexually active adult and adolescent populations at a sub-national level (e.g., county) would improve the local understanding of disease burden of STIs, including HIV. These estimates would also facilitate comparisons of disease rates, including syphilis and HIV, between MSM and other populations. Building on the methods used to estimate the size of the MSM population, this project will develop state and county-level estimates for the population of men who have sex with women (exclusively), women who have sex with men, and sexually active adolescent sexual minority males, overall and by race and ethnicity. These estimates can then be used to generate estimates of disease rates for each of these population groups.

Improving the national estimates of the population size of persons who inject drugs (PWID)

In the United States, injection is an increasingly common and high-risk route of administration for prescription and illicit opioids, as well as other drugs such as methamphetamine. Unsafe injection drug use (IDU) behaviors increase risk for bloodborne infectious diseases such as hepatitis C virus and HIV, making these infectious diseases secondary but deleterious consequences of the opioid crisis for PWID. Due to the stigmatized and illicit nature of non-medical IDU, population-level prevalence is difficult to measure using survey methods typically used to monitor health-related behaviors. Estimation of the national population size of PWID is critical for informing infectious disease prevention efforts among PWID. The current national PWID population size estimate is based on household survey data from 2011 and does not reflect current opioid and methamphetamine injection. This project will update the PWID prevalence estimates nationally and for specific subpopulations of interest.

Evaluating syringe services program (SSP) and medication for opioid use disorder (MOUD) program coverage needed to reduce HIV and HCV infections in the United States

Persons who inject drugs (PWID) are at high risk for multiple bloodborne and sexually transmitted infections, including hepatitis C virus (HCV) and HIV. National and state-level planning for SSPs and MOUD relies on the accurate estimation of PWID population size and requires an understanding of how these interventions impact HCV and HIV transmission, in addition to other bloodborne infections, among this subpopulation. The particular structure of injection networks and sexual networks among PWID leads to heterogeneous risks of infection transmission and acquisition across the subpopulation. In addition to SSPs and MOUD, many other preventive strategies are available for both HCV and HIV, including biomedical interventions (e.g., HIV pre-exposure prophylaxis, HIV treatment, HCV treatment) and behavioral interventions (e.g., promoting safer injection practices, condom use). Interventions can interact with each other and generate synergistic (or antagonistic) effects on the prevention of HCV and HIV. What determines the optimal intervention package is unknown. This project will extend our existing agent-based network model of HCV transmission among PWID by adding the sexual partnership network and transmission dynamics of HIV and other sexually transmitted infections to the existing network of equipment-sharing, to: (1) determine the levels of SSP coverage needed to reduce new HIV and HCV infections among PWID by 25%, 50% and 90%; (2) compare the population health and economic impacts of different levels of program coverage for opioid use disorder; (3) identify intervention combinations among the different prevention strategies that may produce substantial reductions in HCV and HIV burden among PWID; and (4) compare the cost-effectiveness of different intervention packages.

Estimation of pre-exposure prophylaxis (PrEP) need among demographic strata in the US adults and adolescents

Awareness of PrEP for HIV and knowledge of its effectiveness have increased in recent years. USPSTF has recommended PrEP for people at high risk of HIV acquisition with evidence grade A, and PrEP is a crucial component in the Ending the HIV Epidemic in the U.S. (EHE) initiative. To estimate more accurate/representative PrEP coverage indicators, a denominator estimate is required to quantify the population who could benefit from PrEP; however, the currently applied denominator is relatively complex to estimate and may not reflect current need. Given advances in PrEP use for HIV prevention, the current definition of PrEP need may be too restrictive. This project will re-evaluate the population size of people who could benefit from PrEP and develop a revised metric for PrEP need in the US.

Impact of parent consent requirement on pre-exposure prophylaxis (PrEP) use among younger adolescents

Modeling studies have demonstrated that PrEP use among adolescent sexual minority males can reduce new infections and is potentially cost effective in high-incidence settings; however, initiation of PrEP use among adolescents remains low nationwide. One potential barrier that adolescents face in accessing PrEP services is parental consent requirements for HIV testing and/or treatment. Even in instances where minors are allowed to consent for HIV testing or treatment, parental consent may still be required for PrEP services because PrEP is typically considered a prevention tool. It is important that PrEP services are easily accessible among eligible adolescents, given that as part of the Ending the HIV Epidemic in the U.S. (EHE), state and local communities (in partnership with CDC and other federal agencies) employ innovative strategies to increase access to and use of PrEP. This policy analysis looks at the relationship between the interpretation of parental consent for PrEP services among adolescents (“minor consent law”) and the initiation of PrEP services among minors in the 50 states and District of Columbia.

Potential impacts of the COVID-19 pandemic on HIV and hepatitis C virus (HCV) risk among persons who inject drugs (PWID)

The COVID-19 pandemic is likely to increase HIV and HCV infection risk among PWID due to potential changes in injection behaviors and limited availability of harm reduction services. Frequency of injection, type(s) of drugs injected, sharing behaviors, and HIV/HCV testing behaviors may all change to some extent amid disruption of the drug supply, existing social networks, and harm reduction services. This project aims to understand COVID-19-related changes in the health risks of PWID. Multi-level impacts on PWID health will be considered, such as housing instability, access to syringe services programs (SSPs), sharing behaviors, and HIV/HCV testing behaviors.

Modeling the implementation effects of clinical practice guidelines for event-driven pre-exposure prophylaxis (PrEP) regimens among men who have sex with men

Despite increasing usage of HIV PrEP among populations at substantial risk of infection in the U.S. there remains a gap between recommended and actual levels of use. This project aims to explore transmission dynamics among MSM by investigating the integration of event-driven PrEP regimens in the context of current daily oral PrEP use among MSM, and the implications of clinical practice guideline elements (medication risk profile and ancillary services engagement) in the context of racial/ethnic disparities and geographic differences.

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