Current Efforts

This project is a continuation of the HIV partner services model completed during CAMP 2.0 FY2. These extensions are investigating the role of targeting previously diagnosed persons living with HIV for partner services, whereas the Y2 version had targeted only newly HIV-diagnosed persons. Additionally, this project will build in the functionality of treating partners identified through partner services as index patients that can subsequently be targeted. 

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.

HIV, viral hepatitis, STIs, and tuberculosis remain critical threats to the public’s health in the United States. With millions of people estimated to be living with these infections – many of whom may be unaware of their infection - successful implementation of routine screening and linkage to care for HIV, viral hepatitis, STIs, and TB are critical. This project aims to use mathematical modeling to explore the implementation of integrated screening to identify the most impactful and cost-effective routine screening interventions in clinical settings for HIV, viral hepatitis, STIs, and TB under a prescribed set of scenarios. 

Mitigation strategies to reduce the spread of COVID-19 have likely impacted HIV-1 epidemiology. This project seeks to estimate changes in opportunities for sexual transmission and use of HIV testing, PrEP, and treatment over the course of the first year of the pandemic for MSM in New York City and Metro Atlanta. This project then aims to use these findings to parametrize a model designed to estimate the impacts of the COVID-19 pandemic on Ending the HIV Epidemic (EHE) timelines.  

Significant disparities have led to disproportionate HIV prevalence among some racial and ethnic groups. Additional improvements in viral suppression and PrEP coverage are needed to address these disparities and achieve the EHE goals for each racial and ethnic group and the overall population. This project aims to inform public health priorities by estimating the race-and-sex-specific changes in viral suppression and PrEP uptake required to reduce HIV incidence by 90% among different demographic groups in the Southeastern US over ten years. This project directly addresses the “Treatment” and “Prevention” pillars of the EHE and quantifies their relative impact in terms of sex-and-race-specific reductions in incidence. As an expansion of this project, an additional set of simulations will be run to estimate the possible changes in viral suppression and HIV incidence we might expect with the expansion of proven interventions to improve each step along the HIV continuum of care

In 2018, youth aged 13 to 24 made up 21% (7,807) of the 37,832 new HIV diagnoses in the United States. The goal of EHE to reduce new HIV infections by 90% in 10 years includes reducing incidence among youth. This project aims to estimate the impact of HIV incidence among adolescents and to address the “Treatment” and “Prevention” pillars of ending the HIV epidemic (EHE) by quantifying their relative impact in terms of reductions in incidence. This project will also estimate the level of additional PrEP coverage needed to reduce incidence among adolescents over a ten-year period and will include simulations to determine expected increases in viral suppression and reductions in incidence if the continuum of care were to be improved to the degree demonstrated in empirical intervention studies. 

Despite advances in prevention and treatment, significant disparities still exist in rates of HIV and sexually transmitted infections (STIs) in the United States. The root causes of these disparities are social determinants of health (e.g., pervasive stigma, lack of access to quality health care, housing insecurity). The purpose of this project is to take the first step towards quantifying the potential benefits of addressing social determinates of health (SDoH) and reducing disparities. The project aims to estimate the potential benefits, in terms of infections averted, that can be achieved by closing some of the gaps in HIV and STI disparities among priority racial/ethnic minority populations. 

Disease intervention specialists (DIS) play a critical role in partner notification, counseling, and referral services for HIV and other sexually transmitted diseases (STDs); and such programs are integral components of HIV/STD prevention activities by state and local health departments. With rising rates of STDs, emerging infections such as COVID-19, and an evolving role of DIS, numerous questions can be addressed through economic analysis such as quantifying the return on investment of DIS activities, determining the budget requirements to deliver partner services to all eligible populations, or developing a prioritization model for allocating DIS resources. This two-phase project will include both a systematic literature review of the existing evidence on the costs and outcomes of DIS and partner services across diseases and an economic analysis.

Potential changes in injection behaviors and limited availability of harm reduction services due to the COVID-19 pandemic are likely to have impacted HIV and HCV infection among persons who inject drugs (PWID). This project aims to understand COVID-19-relatedchanges 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. 

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 at-risk individuals 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 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.

Sexual and gender minorities (SGM) bear very different burdens of HIV and 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 population 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, etc.) 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.

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 (MSAs) with different profiles of HIV burden and healthcare coverage: Atlanta, Washington, D.C., and New York City.

Men who have sex with men (MSM) are disproportionately impacted by syphilis. In 2019, 56.7% of all primary and secondary (P&S) syphilis infections among men were among MSM. Rates of P&S syphilis have increased more rapidly among MSM than any other subpopulation, from 20.6 per 100,000 in 2000 to 272.8 per 100,000 in 2015. Untreated syphilis can lead to severe medical complications, including infertility, pregnancy loss, and severe neurological and ocular complications. However, little is known about how temporal changes in sexual network structures among MSM may influence syphilis epidemiology, promote racial/ethnic disparities, and hinder efforts to control syphilis with traditional network-informed interventions, including contact tracing. This project aims to bridge gaps in current knowledge and understanding of syphilis epidemiology among MSM using a prospective longitudinal cohort study called the Network Epidemiology of Syphilis Transmission Study (NEST) to model the individual-level and network-level factors contributing to epidemic syphilis among MSM in the US.

During NEEMA 1.0, we developed teen-SPARC, an Excel tool designed to help public health jurisdictions and other entities explore the potential impact of behavior change on reducing sexually transmitted infections (STIs) among the sexually active high-school-attending adolescent population. This tool has been parameterized by default using national data, but is designed to be tailored to other jurisdictions, particularly those that participate in YRBSS. Recent dissemination activities include a well-attended webinar and a case study paper under review demonstrating the use of this tool and its possible applications.

We propose additional activities to enhance the uptake and use of teen-SPARC. In Year 1, we will work to build the teen-SPARC user community in multiple ways.  We will begin by adding user registration and visitation/download metrics to the teen-SPARC website that allow for us to monitor usage. We will reach out to all webinar attendees to determine ongoing usage and identify means to support that usage.  We will develop a user listserv that provides a discussion forum for users. We will present at multiple conferences, through workshops and/or scientific presentation sessions. Throughout, we will query current and potential users about features to improve or add to teen-SPARC.  We will summarize progress on all steps in an end-of-year report to CDC. All of these steps will feed into our efforts to expand and enhance teen-SPARC in Y2.

HIV, viral hepatitis, STIs, and tuberculosis remain critical threats to the public’s health in the United States. With millions of people estimated to be living with these infections – many of whom may be unaware of their infection - successful implementation of routine screening and linkage to care for HIV, viral hepatitis, STIs, and TB are critical. This project aims to use mathematical modeling to explore the implementation of integrated screening to identify the most impactful and cost-effective routine screening interventions in clinical settings for HIV, viral hepatitis, STIs, and TB under a prescribed set of scenarios. 

With rates of gonorrhea and chlamydia on the rise in the US, this project seeks to understand the role of behavior change in these increased rates. Using data from the National Survey of Family Growth, this project is using epidemiologic and modeling approaches to describe patterns of changes in sexual behaviors, networks, and STI screening and to understand how these changes have contributed to increasing STI rates. The project focuses on cisgender heterosexual people ages 15-44 and describes differences in behaviors by sex, age, and race/ethnicity. It will develop a model of STI transmission that explores major components of behavior change among heterosexual populations over time.

CDC’s Division of STD Prevention has two existing cost modeling tools that state and local STI programs can use for planning, resource allocation decisions, and advocacy for additional state resources. This project aims to update and enhance these tools to incorporate the most recent scientific information and meet the usability requirements and information needs of end-users. Activities include collecting updated model estimates, soliciting end users’ input on model enhancements, creating enhanced models that incorporate updated scientific research and end users’ feedback into the interface, and testing model prototypes to ensure they meet design requirements.

The National Notifiable Diseases Surveillance System (NNDSS) is used by local and state jurisdictions to send STD case notification data to CDC. Trends in NNDSS data are influenced by changes in incidence, as well as changes in reporting practices. DSTDP monitors trends in NNDSS case data, reaching out to jurisdictions when an aberration is detected to see if data quality improvement activities are indicated or if the jurisdiction needs outbreak assistance. Although DSTDP engages in multiple activities to identify data quality and morbidity aberrations, there is an opportunity to develop a modeling tool that can identify a wider range of data aberrations more efficiently and effectively. In turn, this can improve data quality and outbreak response. This project will develop a SAS-based aberration detection tool that DSTDP can apply to weekly NNDSS syphilis case report data to quickly identify and summarize significant changes in data transmitted by jurisdictions that indicate shifts in syphilis morbidity or actionable data quality issues. 

Despite advances in prevention and treatment, significant disparities still exist in rates of HIV and sexually transmitted infections (STIs) in the United States. The root causes of these disparities are social determinants of health (e.g., pervasive stigma, lack of access to quality health care, housing insecurity). The purpose of this project is to take the first step towards quantifying the potential benefits of addressing social determinates of health (SDoH) and reducing disparities. The project aims to estimate the potential benefits, in terms of infections averted, that can be achieved by closing some of the gaps in HIV and STI disparities among priority racial/ethnic minority populations. 

Over the course of the COVID-19 pandemic, the US has seen a dramatic shift in the routines of daily life as we have worked to reduce transmission. One of the most dramatic shifts has been the reduction or elimination of in-person learning in many high schools, a change that may have influenced the spread of STIs among adolescents. School closures may have resulted in a decline in sexual contacts and thereby a reduction in the spread of STI, or conversely, may have provided an opportunity for social interactions to move to less regulated spaces where earlier or more frequent sexual contact may occur, thereby increasing STI transmission. This project will use two waves of the Youth Risk Behavior Survey (YRBS) and STI surveillance data to quantify the relationship between school closures and changes in sexual behavior among high school students or STI incidence, and possible unintended consequences of school closures. 

Disease intervention specialists (DIS) play a critical role in partner notification, counseling, and referral services for HIV and other sexually transmitted diseases (STDs); and such programs are integral components of HIV/STD prevention activities by state and local health departments. With rising rates of STDs, emerging infections such as COVID-19, and an evolving role of DIS, numerous questions can be addressed through economic analysis such as quantifying the return on investment of DIS activities, determining the budget requirements to deliver partner services to all eligible populations, or developing a prioritization model for allocating DIS resources. This two-phase project will include both a systematic literature review of the existing evidence on the costs and outcomes of DIS and partner services across diseases and an economic analysis.

Sexual and gender minorities (SGM) bear very different burdens of HIV and 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 population 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, etc.) 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.

During NEEMA 1.0, we developed teen-SPARC, an Excel tool designed to help public health jurisdictions and other entities explore the potential impact of behavior change on reducing sexually transmitted infections (STIs) among the sexually active high-school-attending adolescent population. This tool has been parameterized by default using national data, but is designed to be tailored to other jurisdictions, particularly those that participate in YRBSS. Recent dissemination activities include a well-attended webinar and a case study paper under review demonstrating the use of this tool and its possible applications.

We propose additional activities to enhance the uptake and use of teen-SPARC. In Year 1, we will work to build the teen-SPARC user community in multiple ways.  We will begin by adding user registration and visitation/download metrics to the teen-SPARC website that allow for us to monitor usage. We will reach out to all webinar attendees to determine ongoing usage and identify means to support that usage.  We will develop a user listserv that provides a discussion forum for users. We will present at multiple conferences, through workshops and/or scientific presentation sessions. Throughout, we will query current and potential users about features to improve or add to teen-SPARC.  We will summarize progress on all steps in an end-of-year report to CDC. All of these steps will feed into our efforts to expand and enhance teen-SPARC in Y2.

This effort builds off a NEEMA/CAMP 1.0 project that assessed the impact of changes in risk behaviors on STI levels among adolescents. This follow-on project focuses on pregnancies expected over ten years looking at how behavioral changes contribute to trends, including delays in age at first sex and use of a wide range of types of contraception. The analysis estimates both the pregnancies and societal costs averted by each type of behavioral change.

In 2018, youth aged 13 to 24 made up 21% (7,807) of the 37,832 new HIV diagnoses in the United States. The goal of EHE to reduce new HIV infections by 90% in 10 years includes reducing incidence among youth. This project aims to estimate the impact of HIV incidence among adolescents and to address the “Treatment” and “Prevention” pillars of ending the HIV epidemic (EHE) by quantifying their relative impact in terms of reductions in incidence. This project will also estimate the level of additional PrEP coverage needed to reduce incidence among adolescents over a ten-year period and will include simulations to determine expected increases in viral suppression and reductions in incidence if the continuum of care were to be improved to the degree demonstrated in empirical intervention studies. 

Over the course of the COVID-19 pandemic, the US has seen a dramatic shift in the routines of daily life as we have worked to reduce transmission. One of the most dramatic shifts has been the reduction or elimination of in-person learning in many high schools, a change that may have influenced the spread of STIs among adolescents. School closures may have resulted in a decline in sexual contacts and thereby a reduction in the spread of STI, or conversely, may have provided an opportunity for social interactions to move to less regulated spaces where earlier or more frequent sexual contact may occur, thereby increasing STI transmission. This project will use two waves of the Youth Risk Behavior Survey (YRBS) and STI surveillance data to quantify the relationship between school closures and changes in sexual behavior among high school students or STI incidence, and possible unintended consequences of school closures. 

HIV, viral hepatitis, STIs, and tuberculosis remain critical threats to the public’s health in the United States. With millions of people estimated to be living with these infections – many of whom may be unaware of their infection - successful implementation of routine screening and linkage to care for HIV, viral hepatitis, STIs, and TB are critical. This project aims to use mathematical modeling to explore the implementation of integrated screening to identify the most impactful and cost-effective routine screening interventions in clinical settings for HIV, viral hepatitis, STIs, and TB under a prescribed set of scenarios. 

Amid widespread hepatitis A virus (HAV) outbreaks in states across the U.S., this project aims to estimate the basic reproduction number (R0) and herd immunity threshold among people who use drugs, people experiencing homelessness, and men who have sex with men. This work will inform vaccination and other HAV prevention efforts.

Vaccination against hepatitis B virus (HBV) is a valuable tool in efforts to reduce transmission and meet U.S. viral hepatitis elimination goals. This project aims to examine the cost-effectiveness of a 2-dose vs 3-dose vaccine in various settings that serve persons considered to be at high risk for HBV infection.

Over the past decade, acute HCV incidence rates have been increasing and are highest among adults of reproductive age. As a result, the number of infants with perinatal exposure to HCV is also increasing. Neither CDC nor USPSTF have published testing recommendations for infants perinatally exposed to HCV and other recommendations from medical organizations are inconsistent and confusing for clinicians – leading to a lack of testing among HCV-exposed children and resulting in many undiagnosed pediatric HCV infections. This project's objective is to use an economic analysis framework to identify the optimal testing strategy for infants born to HCV-infected mothers.

Potential changes in injection behaviors and limited availability of harm reduction services due to the COVID-19 pandemic are likely to have impacted HIV and HCV infection among persons who inject drugs (PWID). This project aims to understand COVID-19-relatedchanges 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. 

Hepatitis C virus (HCV) infection is the most reported bloodborne infection in the United States despite being underreported. An accurate estimate of hepatitis C prevalence can inform public health interventions and resource allocation strategies aimed at reducing the health burden and economic costs caused by hepatitis C in the United States, and is necessary to monitor progress toward the global goal of eliminating viral hepatitis as a public health problem by 2030. The most recently available national HCV prevalence estimate in the United States is based on data from 2013–2016. This project will generate an updated estimate of HCV prevalence among the adult (?18 years) US noninstitutionalized civilian population using data from the National Health and Nutrition Examination Survey (NHANES) and compute additional prevalence estimates for populations that are not part of the NHANES sampling frame (e.g., incarcerated people, unsheltered homeless people, active-duty military personnel, and nursing home residents).

In the United States, testing for HCV infection currently involves a two-step diagnosis process that is dependent on antibody testing — which can lead to underdiagnosis in populations with ongoing transmission. Current requirements for a prior test detecting HCV antibodies may be problematic in settings testing persons at higher risk for recent exposure/acute infection, such as syringe services programs and substance use treatment facilities, and for immunocompromised persons who may not have a reactive HCV antibody test. This project will assess the cost-effectiveness of one-step HCV testing versus the two-step HCV testing process to determine the best approach for early and reliable diagnosis of HCV infection. 

Enhancing surveillance for viral hepatitis is crucial to monitoring progress toward viral hepatitis elimination goals and understanding health disparities. This project will utilize existing data sources, including data collected through the CDC’s Integrated Viral Hepatitis Surveillance and Prevention Funding for Health Departments (IVHSP) – which aims to address data gaps identified in the HHS Viral Hepatitis Strategic Plan – to summarize the current landscape of state and local viral hepatitis surveillance systems. This work aims to describe the capacity of surveillance systems across jurisdictions and identify operational requirements needed to update surveillance systems as envisioned in the National Strategic Plan. Additionally, this project will include the development of a conceptual framework to be used in future budgeting impact analyses to enhance viral hepatitis surveillance. 

HIV, viral hepatitis, STIs, and tuberculosis remain critical threats to the public’s health in the United States. With millions of people estimated to be living with these infections – many of whom may be unaware of their infection - successful implementation of routine screening and linkage to care for HIV, viral hepatitis, STIs, and TB are critical. This project aims to use mathematical modeling to explore the implementation of integrated screening to identify the most impactful and cost-effective routine screening interventions in clinical settings for HIV, viral hepatitis, STIs, and TB under a prescribed set of scenarios. 

While TB transmission rates have declined nationally in the United States during the last two decades – owing largely to TB control efforts – responding to TB outbreaks (which often occur among people experiencing homelessness or incarceration) to prevent further transmission, remains an important priority for TB control. This project will collaborate closely with DTBE and state-level TB controllers to develop TB outbreak models in the US. These proposed models will focus on large TB outbreaks and aim to estimate the epidemiological impact and cost-effectiveness of TB outbreak response in the US.

The United States observed a sharp decline in TB incidence in 2020. Declines were pervasive, observed across almost all states, all age strata, both US- and non-US-born populations, and across all subpopulations disaggregated by race or ethnicity. The COVID-19 pandemic resulted in drastic changes that would be expected to result in short-term declines in TB notifications – but the implications for TB control differ tremendously, providing a unique opportunity to better understand how to control TB in the longer term, irrespective of the pandemic itself. This project will expand a model-based framework (developed in NEEMA/CAMP 1.0) to include mechanisms of change in TB transmission and epidemiology as a result of COVID-19 related disruptions. Using this updated model, the project aims to offer a better understanding of TB transmission and notification patterns following COVID-19 disruptions in CA, FL, NY, and TX, and to project changes in TB trends over the next 20 years in these four target states 

Tuberculosis (TB) transmission in the United States is both heterogeneous, with a few cases contributing to a large proportion of recent transmission, and disproportionately burdensome to disadvantaged populations – including racial and ethnic minorities, as well as people experiencing homelessness, who are incarcerated, and who use drugs (injection and non-injection). Public health efforts to reduce TB transmission have been instrumental in lowering incidence in the U.S. in the last few decades, but these interventions can be resource-intensive. This project aims to better understand tuberculosis genotype clusters in the United States and across four key states (CA, FL, NY, TX) in order to identify targeted interventions that are feasible to implement, might be prioritized by TB controllers and other health officials, and are likely to be impactful in reducing the risk of TB transmission and outbreaks, especially in vulnerable populations. 


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This work is supported by The Centers for Disease Control and Prevention [Grant # 1 1 NU38PS004650]

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