The Epidemiologic and Economic Impact of Improving HIV Testing, Linkage, and Retention in Care in the United States

National HIV and HCV Screening Rates for Hospitalized People who Use Drugs Are Suboptimal and Heterogeneous Across 11 US Hospitals

Background

To end the HIV and hepatitis C virus (HCV) epidemics, people who use drugs (PWUD) need more opportunities for testing. While inpatient hospitalizations are an essential opportunity to test people who use drugs (PWUD) for HIV and HCV, there is limited research on rates of inpatient testing for HIV and HCV among PWUD.

Methods

Eleven hospital sites were included in the study. Each site created a cohort of inpatient encounters associated with injection drug use. From these cohorts, we collected data on HCV and HIV testing rates and HIV testing consent policies from 65 276 PWUD hospitalizations.

Results

Hospitals had average screening rates of 40% for HIV and 32% for HCV, with widespread heterogeneity in screening rates across facilities. State consent laws and opt-out testing policies were not associated with statistically significant differences in HIV screening rates. On average, hospitals that reflexed HCV viral load testing on HCV antibody testing did not have statistically significant differences in HCV viral load testing rates. We found suboptimal testing rates during inpatient encounters for PWUD. As treatment (HIV) and cure (HCV) are necessary to end these epidemics, we need to prioritize understanding and overcoming barriers to testing.

Evaluation of an HIV homecare program for lost-to-follow-up populations: a mixed methods study in Detroit, Michigan

BACKGROUND

Maintaining people living with HIV (PLWHIV) in clinical care is a global priority. In the Metro Detroit area of Michigan, approximately 30% of PLWHIV are out of care. To re-engage lost-to-follow-up patients, Wayne Health Infectious Disease clinic launched an innovative Homecare program in 2017. In addition to home healthcare delivery, the program included links to community resources and quarterly community meetings. We aimed to evaluate Homecare's impact on participants' ability to stay engaged in HIV care and reach viral suppression. We included data from PLWHIV and their healthcare workers.

METHODS

We used a convergent mixed-methods design, including first year program record review, semi-structured interviews, and a validated Likert scale questionnaire rating illness perception before and after Homecare. Interview data were collected from 15 PLWHIV in Metro Detroit and two healthcare workers responsible for program delivery. Semi-structured interviews focused on obstacles to clinic-based care, support networks, and illness perceptions. Interview data were transcribed and analyzed using a thematic approach. A fully coded analysis was used to create a conceptual framework of factors contributing to Homecare's success. Means in eight categories of the Brief Illness Perception (IPQ) were compared using paired T-tests.

RESULTS

In the first year of Homecare, 28 of 34 participants (82%) became virally suppressed at least once. The program offered (1) social support and stigma reduction through strong relationships with healthcare workers, (2) removal of physical and resource barriers such as transportation, and (3) positive changes in illness perceptions. PLWHIV worked towards functional coping strategies, including improvements in emotional regulation, acceptance of their diagnosis, and more positive perspectives of control. Brief-IPQ showed significant changes in six domains before and after Homecare.

CONCLUSION

Homecare offers an innovative system for successfully re-engaging and maintaining lost-to-follow-up PLWHIV in care. These findings have implications for HIV control efforts and could inform the development of future programs for difficult to reach populations.

Providing telemedicine services to persons living with HIV in an urban community: a demonstration project

Although HIV incidence and mortality rates have declined over the past 20 years, HIV health disparities continue to persist among patients living in urban communities. Barriers to proficient health outcomes for persons with HIV (PWH) in urban communities include lack of access to care, resulting from limited transportation or clinic availability. While healthcare systems in rural communities provide telemedicine (TM) services to PWH to eliminate transportation and accessibility barriers, few examples exist regarding TM use for PWH in urban communities. This project's goal was to increase the provision of healthcare services in an urban setting to PWH, using TM. As guided by "Integration of Healthcare Delivery Service" theories and key principles, we created an integration framework comprised of several simultaneous, overlapping activities to include: (1) capacity building (2) clinical standardization (3) community and patient engagement and (4) evaluation performance and measurements. This paper describes major activities involved with developing, implementing and evaluating a TM program for PWH. We discuss results, challenges, and lessons learned from integrating this program into our existing healthcare system.

Understanding effective post-test linkage strategies for HIV prevention and care: a scoping review

INTRODUCTION

Following HIV testing services (HTS), the World Health Organization recommends prompt linkage to prevention and treatment. Scale-up of effective linkage strategies is essential to achieving the global 95-95-95 goals for maintaining low HIV incidence by 2030 and reducing HIV-related morbidity and mortality. Whereas linkage to care including same-day antiretroviral therapy (ART) initiation for all people with HIV is now routinely implemented in testing programmes, linkage to HIV prevention interventions including behavioural or biomedical strategies, for HIV-negative individuals remains sub-optimal. This review aims to evaluate effective post-HTS linkage strategies for HIV overall, and highlight gaps specifically in linkage to prevention.

METHODS

Using the five-step Arksey and O'Malley framework, we conducted a scoping review searching existing published and grey literature. We searched PubMed, Cochrane Library, CINAHL, Web of Science and EMBASE databases for English-language studies published between 1 January 2010 and 30 November 2023. Linkage interventions included as streamlined interventions-involving same-day HIV testing, ART initiation and point-of-care CD4 cell count/viral load, case management-involving linkage coordinators developing personalized HIV care and risk reduction plans, incentives-financial and non-financial, partner services-including contact tracing, virtual-like social media, quality improvement-like use of score cards, and peer-based interventions. Outcomes of interest were linkage to any form of HIV prevention and/or care including ART initiation.

RESULTS

Of 2358 articles screened, 66 research studies met the inclusion criteria. Only nine linkage to prevention studies were identified (n = 9/66, 14%)-involving pre-exposure prophylaxis, voluntary medical male circumcision, sexually transmitted infection and cervical cancer screening. Linkage to care studies (n = 57/66, 86%) focused on streamlined interventions in the general population and on case management among key populations.

DISCUSSION

Despite a wide range of HIV prevention interventions available, there was a dearth of literature on HIV prevention programmes and on the use of messaging on treatment as prevention strategy. Linkage to care studies were comparatively numerous except those evaluating virtual interventions, incentives and quality improvement.

CONCLUSIONS

The findings give insights into linkage strategies but more understanding of how to provide these effectively for maximum prevention impact is needed.

Barriers and facilitators to improving the cascade of HIV care in Ontario: a mixed method study

BACKGROUND

Engagement in care is important for people living with HIV (PLH) to achieve optimal outcomes. Several strategies have been developed to improve client flow through the HIV care cascade, specifically targeting initiation of treatment, adherence to antiretroviral therapy (ART), retention in care, and engagement in care. We have previously identified effective care cascade strategies in a systematic review. Initiation of ART could be improved by mobile health interventions, and changes in healthcare delivery. Adherence to ART could be improved by mobile health interventions, incentives, counselling, and psychotherapy. Retention in care could be improved by mobile health interventions, incentives, education, and electronic interventions. The aim of this study was to investigate barriers and facilitators to implementing these effective interventions in HIV clinics in Ontario, Canada.

METHODS

We conducted a sequential explanatory mixed methods study. In the quantitative strand, we administered a survey to health workers who provide care to PLH to identify barriers and facilitators. In the qualitative strand, we conducted in-depth interviews informed by the theoretical domains framework (TDF) with health workers and with PLH to explain our quantitative findings. Qualitative and quantitative data were merged to create meta-inferences.

RESULTS

Twenty health workers from 8 clinics in 9 cities in Ontario took the survey. Nine PLH and 10 health workers participated in the qualitative interviews. Clinics in Ontario implemented all the effective interventions identified from the literature for initiation of treatment, adherence to ART, and retention in care despite concerns about resources. Barriers to physical and financial access to care, the workload for tailored care, and expertise were identified by both health workers and PLH. Key facilitators were virtual care and client preparedness through education and peer support.

CONCLUSION

Clinics in Ontario appear to implement several evidence-based strategies to improve PLH engagement. There is a need for more health workers with skills to address unique PLH needs. Virtual care is beneficial to both health workers and PLH.

Systematic Review and Meta-analysis of Linkage to HIV Care Interventions in the United States, Canada, and Ukraine (2010-2021)

We conducted a systematic review and meta-analysis of interventions targeting linkage to HIV care in the US, Canada, and Europe. We searched six databases (PubMed, Embase, Cochrane Library, Web of Science and CINAHL). Inclusion criteria were English language studies in adults in the US, Canada, or Europe, published January 1, 2010 to January 1, 2021. We synthesized interventions by type and linkage to care outcome. The outcome was cumulative incidence of 3-month linkage. We estimated cumulative incidence ratios of linkage with 95% confidence intervals (CIs). We screened 945 studies; 13 met selection criteria (n = 1 from Canada, n = 1 from Ukraine, n = 11 from the US) and were included after full text review (total 37,549 individuals). The cumulative incidence of 3-month linkage in the intervention group was 0.82 (95% CI 0.68-0.94) and control group 0.71 (95% CI 0.50-0.90); cIR of linkage for intervention versus control was 1.30 (95% CI 1.13, 1.49). Interventions to improve linkage to care after HIV diagnosis warrant further attention.

HIV medical care interruption among people living with HIV in Spain, 2004-2020

OBJECTIVE

We estimated the incidence rate of HIV medical care interruption (MCI) and its evolution over a 16-year-period, and identified associated risk factors among HIV-positive individuals from the Cohort of the Spanish AIDS Research Network in 2004-2020.

DESIGN

We included antiretroviral-naive individuals aged at least 18 years at enrolment, recruited between January 1, 2004, and August 30, 2019, and followed-up until November 30, 2020.

METHODS

Individuals with any time interval of at least 15 months between two visits were defined as having a MCI. We calculated the incidence rate (IR) of having at least one MCI and used multivariable Poisson regression models to identify associated risk factors.

RESULTS

Of 15 274 individuals, 5481 (35.9%) had at least one MCI. Of those, 2536 (46.3%) returned to HIV care after MCI and 3753 (68.5%) were lost to follow-up at the end of the study period. The incidence rate (IR) of MCI was 7.2/100 person-years (py) [95% confidence interval (CI): 7.0-7.4]. The annual IR gradually decreased from 20.5/100 py (95% CI: 16.4-25.6) in 2004 to 4.9/100 py (95% CI: 4.4-5.5) in 2014, a slight increase was observed between 2015 and 2018, reaching 9.3/100 py (95% CI: 8.6-10.2) in 2019. Risk factors for MCI included younger age, lower educational level, having contracted HIV infection through injecting drug use or heterosexual intercourse, having been born outside of Spain, and CD4 + cell count >200 cell/μl, viral load <100 000 and co-infection with hepatitis C virus at enrolment.

CONCLUSIONS

Around a third of individuals had at least one MCI during the follow-up. Identified predictors of MCI can help health workers to target and support most vulnerable individuals.

Relationships Between Patient Race and Residential Race Context With Missed Human Immunodeficiency Virus Care Visits in the United States, 2010-2015

BACKGROUND

Racial inequities exist in retention in human immunodeficiency virus (HIV) care and multilevel analyses are needed to contextualize and address these differences. Leveraging data from a multisite clinical cohort of people with HIV (PWH), we assessed the relationships between patient race and residential characteristics with missed HIV care visits.

METHODS

Medical record and patient-reported outcome (PRO; including mental health and substance-use measures) data were drawn from 7 participating Center for AIDS Research Network of Integrated Clinical Systems (CNICS) sites including N = 20 807 PWH from January 2010 through December 2015. Generalized estimating equations were used to account for nesting within individuals and within census tracts in multivariable models assessing the relationship between race and missed HIV care visits, controlling for individual demographic and health characteristics and census tract characteristics.

RESULTS

Black PWH resided in more disadvantaged census tracts, on average. Black PWH residing in census tracts with higher proportion of Black residents were more likely to miss an HIV care visit. Non-Black PWH were less likely to miss a visit regardless of where they lived. These relationships were attenuated when PRO data were included.

CONCLUSIONS

Residential racial segregation and disadvantage may create inequities between Black PWH and non-Black PWH in retention in HIV care. Multilevel approaches are needed to retain PWH in HIV care, accounting for community, healthcare setting, and individual needs and resources.

Financing Benefits and Barriers to Routine HIV Screening in Clinical Settings in the United States: A Scoping Review

The Centers for Disease Control and Prevention recommends everyone between 13-64 years be tested for HIV at least once as a routine procedure. Routine HIV screening is reimbursable by Medicare, Medicaid, expanded Medicaid, and most commercial insurance plans. Yet, scaling-up HIV routine screening remains a challenge. We conducted a scoping review for studies on financial benefits and barriers associated with HIV screening in clinical settings in the U.S. to inform an evidence-based strategy to scale-up routine HIV screening. We searched Ovid MEDLINE^®, Cochrane, and Scopus for studies published between 2006-2020 in English. The search identified 383 Citations; we screened 220 and excluded 163 (outside the time limit, irrelevant, or outside the U.S.). Of the 220 screened articles, we included 35 and disqualified 155 (did not meet the eligibility criteria). We organized eligible articles under two themes: financial benefits/barriers of routine HIV screening in healthcare settings (9 articles); and Cost-effectiveness of routine screening in healthcare settings (26 articles). The review concluded drawing recommendations in three areas: (1) Finance: Incentivize healthcare providers/systems for implementing HIV routine screening and/or separate its reimbursement from bundle payments; (2) Personnel: Encourage nurse-initiated HIV screening programs in primary care settings and educate providers on CDC recommendations; and (3) Approach: Use opt-out approach.

A qualitative inquiry into the patient-related barriers to linkage and retention in HIV care within the community setting

Background

People with the Human Immunodeficiency Virus (PWH) experience barriers to care within the community that impedes their progress from when they discover that they are HIV positive to becoming virally suppressed. For individuals with HIV to achieve sustained viral suppression, they must be linked to care to start receiving anti-retroviral therapy and remain retained in care for continuous treatment. However, HIV surveillance data shows that many PWH are not linked to care and become lost to continuous follow-up care. Although pharmacists, PWH, and social workers interact with one another and are aware of their roles in HIV care, their perspectives on barriers to linkage and retention in care have not been investigated collectively.

Objectives

Explore the perspectives of PWH, pharmacists, and social workers on barriers to linkage and retention of HIV care within the community setting.

Methods

Convenience sampling was used to recruit 15 stakeholders (five PWH, five community pharmacists, and five social workers) who participated in 1-h, semi-structured interviews based on three domains of the Patient-centered Medical Home Model including (1) experiences (individual and system-level barriers to care experienced by PWH), (2) activities (social workers and pharmacists initiatives that impact adherence to care)and (3) interventions (critical issues pharmacists can address in the community to engage PWH in their HIV care). We conducted a directed content analysis based on deductive coding. To establish rigor, we focused on Lincoln and Guba's criteria of rigorous qualitative methodology: credibility, dependability, confirmability, and transferability. Similarities and divergences of themes were discussed during data analysis and agreement was reached before interpretation.

Results

Emergent themes uncovered barriers to linkage and retention in HIV care as HIV-related stigma, having mental health illnesses including a history of substance abuse and social determinants of health such as homelessness, food insecurity, and insurance issues.

Conclusion

The perspectives of pharmacists, social workers, and PWH can provide insight into barriers that should be identified and addressed in people living with HIV to enhance their linkage and retention in care.

A Cost-effectiveness Analysis of a Mobile Phone-Based Integrated HIV-Prevention Intervention Among Men Who Have Sex With Men in China: Economic Evaluation

BACKGROUND

Mobile phone-based digital interventions have been shown to be a promising strategy for HIV prevention among men who have sex with men (MSM).

OBJECTIVE

This study aimed to evaluate the cost-effectiveness of a mobile phone-based digital intervention for HIV prevention among MSM in China from the perspective of a public health provider.

METHODS

The cost-effectiveness of the mobile phone-based digital intervention was estimated for a hypothetical cohort of 10,000 HIV-negative MSM who were followed for 1 year. A model was developed with China-specific data to project the clinical impact and cost-effectiveness of two mobile phone-based digital strategies for HIV prevention among MSM. The intervention group received an integrated behavioral intervention that included 1) individualized HIV infection risk assessment, 2) recommendation of centers testing for HIV and other STIs, 3) free online order of condoms and HIV and syphilis self-test kits and 4) educational materials about HIV/AIDS. The control group was only given educational materials about HIV/AIDS. Outcomes of interest were the number of HIV infections among MSM averted by the intervention, intervention costs, cost per HIV infection averted by the mobile phone-based digital intervention, and quality-adjusted life-years (QALYs). Univariate and multivariate sensitivity analyses were also conducted to examine the robustness of the results.

RESULTS

It is estimated that the intervention can prevent 48 MSM from becoming infected with HIV and can save 480 QALYs. The cost of preventing 1 case of HIV infection was US $2599.87, and the cost-utility ratio was less than 0. Sensitivity analysis showed that the cost-effectiveness of the mobile phone-based digital intervention was mainly impacted by the average number of sexual behaviors with each sexual partner. Additionally, the higher the HIV prevalence among MSM, the greater the benefit of the intervention.

CONCLUSIONS

Mobile phone-based digital interventions are a cost-effective HIV-prevention strategy for MSM and could be considered for promotion and application among high-risk MSM subgroups.

Clinical decision support systems to guide healthcare providers on HIV testing

OBJECTIVE

To understand the impact of clinical decision support systems (CDSSs) on improving HIV testing and diagnosis.

DESIGN

An original global systematic review (PROSPERO Number: CRD42020175576) of peer-reviewed articles reporting on electronic CDSSs that generate triggers encouraging healthcare providers to perform an HIV test.

METHODS

Medline, Embase, Cochrane CENTRAL and CINAHL EBSCOhost were searched up to 17 November 2020 and reference lists of included articles were checked. Qualitative and quantitative syntheses (using meta-analyses) of identified studies were performed.

RESULTS

The search identified 1424 records. Twenty-two articles met inclusion criteria (19 of 22 non-HIV endemic settings); 18 clinical and four laboratory-driven reminders. Reminders promoted 'universal' HIV testing for all patients without a known HIV infection and no recent documented HIV test, or 'targeted' HIV testing in patients with clinical risk-factors or specific diagnostic tests. CDSSs increased HIV testing in hospital and nonhospital setting, with the pooled risk-ratio amongst studies reporting comparable outcome measures in hospital settings (n = 3) of 2.57 [95% confidence interval (CI) 1.53-4.33, random-effect model] and in nonhospital settings (n = 4) of 2.13 (95% CI 1.78-4.14, random effect model). Results of the clinical impact of CDSSs on HIV diagnosis were mixed.

CONCLUSION

CDSSs improve HIV testing and may, potentially, improve diagnosis. The data support the broader study of CDSSs in low- and high prevalent HIV settings to determine their precise impact on UNAIDS goals to reach universal HIV testing and treatment coverage.

Cost-Effectiveness of HIV Retention and Re-engagement Interventions in High-Income Countries: A Systematic Literature Review

Engagement in lifelong HIV care is critical for both patient and public health, yet there are limited resources to invest in improving HIV outcomes. We systematically reviewed evidence on the cost-effectiveness of retention and re-engagement interventions. We searched five databases for peer-reviewed studies published between 2010 and 2020. We assessed reporting and methods quality, extracted data on target populations, interventions, and cost-effectiveness, and evaluated overall strength of evidence. Eleven studies met inclusion criteria, and eight had moderate-high quality. Cost-effectiveness estimates ranged from cost-saving to over $1,000,000/quality-adjusted life year (QALY) gained. Of the 73 cost-effectiveness ratios reported, 64% were < $100,000/QALY gained. Interventions were more likely to be cost-effective when targeted to high-risk groups, implemented in locations where baseline retention levels were low, and when used in combination with other high-impact HIV interventions (such as prevention). Overall, existing evidence is moderately strong that retention and/or re-engagement interventions can be cost-effective in high-income countries.

Treatment Outcomes of HIV Infected Children After Initiation of Antiretroviral Therapy in Southwest China: An Observational Cohort Study

BACKGROUND

The number of HIV infected children receiving antiviral treatment in Guangxi is increasing. Understanding factors and trends of mortality and attrition in HIV-infected children under antiretroviral therapy (ART) was an urgent need to improve treatment outcomes. This study aimed to estimate mortality and attrition rates and identify factors that were associated with mortality and attrition after ART initiation among children with HIV in Guangxi, China between 2004 and 2018.

METHODS

Cohort study data were extracted from the National Free Antiretroviral Treatment Program (NFATP) database, which has standard guidelines for core treatment indicators and other data at all HIV/AIDS treatment facilities in Guangxi. A total of 901 HIV-infected children who have started ART were included in the study. The study collected the following data: age, gender, WHO clinic stages before ART, CD4 cell count before ART, Cotrimoxazole prophylaxis (CTX) use before ART, initial ART regimen, malnutrition before ART, abnormal liver function before ART, abnormal kidney function before ART, severe anemia before ART, and the time lag between an HIV diagnosis and ART initiation.

RESULTS

HIV-infected children under ART had a mortality rate of 0.87 per 100 person-years [95% Confidence Interval (CI) 0.63-1.11], and an attrition rate of 3.02 per 100 person-years (95% CI 2.57-3.47). Mortality was lower among children with a CD4 count between 200 and 500 copies/ml [Adjusted Hazard Ratio (AHR) 0.22, 95% CI 0.09-0.55], and CD4 count ≥500 copies/ml (AHR 0.10, 95% CI 0.03-0.29); but higher among children with late ART initiation at 1-3 months (AHR 2.30, 95% CI 1.07-4.94), and at ≥3 months (AHR 2.22, 95% CI 1.04-4.74). Attrition was lower among children with a CD4 count ≥500 copies/ml (AHR 0.62, 95% CI 0.41-0.95), but higher among children with late ART initiation at 1-3 months (AHR 1.55, 95% CI 1.05-2.30).

CONCLUSION

Supportive programs are needed to educate children's families and parents on early ART, link HIV-infected children to care and retain them in care among other programs that treat and manage the medical conditions of HIV-infected children before ART initiation.

Patients, Social Workers, and Pharmacists' Perceptions of Barriers to Providing HIV Care in Community Pharmacies in the United States

Retaining people living with HIV (PLWH) in clinical care is a global priority to end the HIV epidemic. Community pharmacies in the United States have structural influences on the success or failure of retention in HIV care by supporting patients’ complex needs. However, to date, barriers to retention in care in the community pharmacy setting have not been examined beyond pharmacy services of medication therapy management. We utilized the patient-centered medical home model to examine the barriers to HIV care in the community pharmacy setting. We utilized semi-structured interviews to collect data from 15 participants: five PLWH, five community pharmacists, and five social workers from a midwestern state. Interview data were transcribed and analyzed using directed content analysis. Four key themes emerged regarding the barriers that impact utilization of community pharmacy services by PLWH: the perception of the role of community pharmacists in HIV care, perceptions of pharmacists’ HIV knowledge, perceptions of pharmacy operation and services, and negative experiences within the community pharmacy space. Participants’ perceptions of solutions for improving HIV care in the community pharmacy focused on improving the relationship between pharmacists and patients, ensuring that the community pharmacy is a private and safe space for patients, and having a diverse pharmacy staff that is equipped to take care of the diverse and marginalized HIV population, such as transgender people.

What Will It Take to End HIV in the United States? : A Comprehensive, Local-Level Modeling Study

BACKGROUND

The Ending the HIV Epidemic (EHE) initiative aims to reduce incident HIV infections by 90% over a span of 10 years. The intensity of interventions needed to achieve this for local epidemics is unclear.

OBJECTIVE

To estimate the effect of HIV interventions at the city level.

DESIGN

A compartmental model of city-level HIV transmission stratified by age, race, sex, and HIV risk factor was developed and calibrated.

SETTING

32 priority metropolitan statistical areas (MSAs).

PATIENTS

Simulated populations in each MSA.

INTERVENTION

Combinations of HIV testing and preexposure prophylaxis (PrEP) coverage among those at risk for HIV, plus viral suppression in persons with diagnosed HIV infection.

MEASUREMENTS

The primary outcome was the projected reduction in incident cases from 2020 to 2030.

RESULTS

Absent intervention, HIV incidence was projected to decrease by 19% across all 32 MSAs. Modest increases in testing (1.25-fold per year), PrEP coverage (5 percentage points), and viral suppression (10 percentage points) across the population could achieve reductions of 34% to 67% by 2030. Twenty-five percent PrEP coverage, testing twice a year on average, and 90% viral suppression among young Black and Hispanic men who have sex with men (MSM) achieved similar reductions (13% to 68%). Including all MSM and persons who inject drugs could reduce incidence by 48% to 90%. Thirteen of 32 MSAs could achieve greater than 90% reductions in HIV incidence with large-scale interventions that include heterosexuals. A web application with location-specific results is publicly available (www.jheem.org).

LIMITATION

The COVID-19 pandemic was not represented.

CONCLUSION

Large reductions in HIV incidence are achievable with substantial investment, but the EHE goals will be difficult to achieve in most locations. An interactive model that can help policymakers maximize the effect in their local environments is presented.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Retention in Medical Care Among Insured Adolescents and Young Adults With Diagnosed HIV Infection, United States, 2010-2014

OBJECTIVES

Retention in care is a critical component of effective HIV treatment, and adolescents and young adults are at higher risk of inadequate retention than older adults. The objective of our study was to examine the patterns of retention in care among adolescents and young adults with HIV infection by analyzing Medicaid and commercial health insurance claims data.

METHODS

We evaluated retention in care for HIV-diagnosed adolescents and young adults aged 13-24 using the 2010-2014 MarketScan Medicaid and MarketScan Commercial Claims health insurance databases. The study period extended 36 months from the date of the first claim with a code for HIV or AIDS. We determined the unweighted proportion retained in care for the Medicaid and Commercial Claims cohorts for months 0-24 and 25-36. We assessed associations between demographic characteristics and retention in care using logistic regression.

RESULTS

A total of 378 adolescents and young adults were in the Medicaid cohort and 1028 in the Commercial Claims cohort. In the Medicaid and Commercial Claims cohorts, respectively, 186 (49%) and 591 (57%) adolescents and young adults were retained in care during months 0-24. In the Medicaid cohort, 113 (73%) people retained in care and 69 (45%) people not retained in care during months 0-24 were retained in care during months 25-36. In the Commercial Claims cohort, 313 (77%) and 94 (31%) retained and not retained people, respectively, were found to be in care during months 25-36.

CONCLUSIONS

Notable proportions of HIV-diagnosed adolescents and young adults are not adequately retained in care; public health interventions tailored to this population are needed.

Continuous quality improvement in HIV and TB services at selected healthcare facilities in South Africa

Background

Continuous quality improvement (CQI) is essential for HIV and tuberculosis (TB) services. Similarly, a thorough understanding of the requirements and impact of CQI is critical to its successful institutionalisation. However, this is currently lacking.

Objectives

The objective of this study is to describe the CQI implementation process and examine its effect on HIV and TB service delivery at selected primary healthcare facilities in two South African districts.

Method

We used a separate sample, pre- and post-test, quasi-experimental study design based on data collected from the clinical audit of patient cohorts seen in 2014 and 2015 respectively. Quality was measured based on the extent to which prescribed services were provided. Tailored CQI interventions were implemented based on service delivery gaps identified by the 2014 CQI audit. Data were summarised and analysed using a combination of univariate and multivariate analysis.

Results

The services identified as low quality were related to opportunistic infections management and laboratory practices. Compliance to prescribed service items in antiretroviral treatment initiation and monitoring, pharmacy and laboratory management, exceeded 70% across study sites. Over 80% of low quality service delivery items were optimised in less than six months with targeted quality improvement support.

Conclusion

The observed improvements signal the effectiveness of the CQI approach, its capacity to rapidly improve under-performance, its high replicability and the need to provide quality maintenance support to sustain or improve healthcare facilities performing well. The study strongly underscores the need to improve the management of opportunistic infections and complications, particularly TB.

Outcomes and costs of publicly funded patient navigation interventions to enhance HIV care continuum outcomes in the United States: A before-and-after study

BACKGROUND

In the United States, patients with HIV face significant barriers to linkage to and retention in care which impede the necessary steps toward achieving the desired clinical outcome of viral suppression. Individual-level interventions, such as patient navigation, are evidence based, effective strategies for improving care engagement. In addition, use of surveillance and clinical data to identify patients who are not fully engaged in care may improve the effectiveness and cost-effectiveness of these programs.

METHODS AND FINDINGS

We employed a pre-post design to estimate the outcomes and costs, from the program perspective, of 5 state-level demonstration programs funded under the Health Resources and Services Administration's Special Projects of National Significance Program (HRSA/SPNS) Systems Linkages Initiative that employed existing surveillance and/or clinical data to identify individuals who had never entered HIV care, had fallen out of care, or were at risk of falling out of care and navigation strategies to engage patients in HIV care. Outcomes and costs were measured relative to standard of care during the first year of implementation of the interventions (2013 to 2014). We followed patients to estimate the number and proportion of additional patients linked, reengaged, retained, and virally suppressed by 12 months after enrollment in the interventions. We employed inverse probability weighting to adjust for differences in patient characteristics across programs, missing data, and loss to follow-up. We estimated the additional costs expended during the first year of each intervention and the cost per outcome of each intervention as the additional cost per HIV additional care continuum target achieved (cost per patient linked, reengaged, retained, and virally suppressed) 12 months after enrollment in each intervention. In this study, 3,443 patients were enrolled in Louisiana (LA), Massachusetts (MA), North Carolina (NC), Virginia (VA), and Wisconsin (WI) (147, 151, 2,491, 321, and 333, respectively). Patients were a mean of 40 years old, 75% male, and African American (69%) or Caucasian (22%). At baseline, 24% were newly diagnosed, 2% had never been in HIV care, 45% had fallen out of care, and 29% were at risk of falling out of care. All 5 interventions were associated with increases in the number and proportion of patients with viral suppression [percent increase: LA = 90.9%, 95% confidence interval (CI) = 88.4 to 93.4; MA = 78.1%, 95% CI = 72.4 to 83.8; NC = 47.5%, 95% CI = 45.2 to 49.8; VA = 54.6, 95% CI = 49.4 to 59.9; WI = 58.4, 95% CI = 53.4 to 63.4]. Overall, interventions cost an additional $4,415 (range = $3,746 to $5,619), $2,009 (range = $1,516 to $2,274), $920 (range = $627 to $941), $2,212 (range = $1,789 to $2,683), and $3,700 ($2,734 to $4,101), respectively per additional patient virally suppressed. The results of this study are limited in that we did not have contemporaneous controls for each intervention; thus, we are only able to assess patients against themselves at baseline and not against standard of care during the same time period.

CONCLUSIONS

Patient navigation programs were associated with improvements in engagement of patients in HIV care and viral suppression. Cost per outcome was minimized in states that utilized surveillance data to identify individuals who were out of care and/or those that were able to identify a larger number of patients in need of improvement at baseline. These results have the potential to inform the targeting and design of future navigation-type interventions.

The Potential Impact of One-Time Routine HIV Screening on Prevention and Clinical Outcomes in the United States: A Model-Based Analysis

BACKGROUND

US guidelines recommend routine human immunodeficiency virus (HIV) screening of all adults and adolescents at least once. The population-level impact of this strategy is unclear and will vary across the country.

METHODS

We constructed a static linear model to estimate the optimal ages and incremental impact of adding 1-time routine HIV screening to risk-based, prenatal, symptom-based, and partner notification testing. Using surveillance data and published studies, we parameterized the model at the national level and for 2 settings representing subnational variability in the rates and distribution of infection: King County, WA and Philadelphia County, PA. Screening strategies were evaluated in terms of the percent of tests that result in new diagnoses (test positivity), cumulative person-years of undiagnosed infection, and the number of symptomatic HIV/acquired immune deficiency syndrome cases.

RESULTS

Depending on the frequency of risk-based screening, routine screening test positivity was maximized at ages 30 to 34 years in the national model. The optimal age for routine screening was higher in a setting with a lower proportion of cases among men who have sex with men. Across settings, routine screening resulted in incremental reductions of 3% to 8% in years of undiagnosed infection and 3% to 11% in symptomatic cases, compared with reductions of 36% to 69% and 41% to 76% attributable to risk-based screening.

CONCLUSIONS

Although routine HIV screening may contribute meaningfully to increased case detection in persons not captured by targeted testing programs in some settings, this strategy will have a limited impact on population-level outcomes. Our findings highlight the importance of a multipronged testing strategy with continued investment in risk-based screening programs.

Adherence predictor variables in AIDS patients: an empirical study using the data mining-based RFM model

Background

Highly active antiretroviral therapy (ART) is still the only effective method to stop the disease progression in acquired immunodeficiency syndrome (AIDS) patients. However, poor adherence to the therapy makes it ineffective. In this work, we construct an adherence prediction model of AIDS patients using the classical recency, frequency and monetary value (RFM) model in the data mining-based customer relationship management model to obtain adherence predictor variables.

Methods

We cleaned 257,305 diagnostic data elements of AIDS outpatients in Shanghai from August 2009 to December 2019 to obtain 16,440 elements. We tested the RFM and RFm (R: recent consultation month, F: consultation frequency, M/m: total/average medical costs per visit) models, three clustering methods (K-means, Kohonen and two-step clustering) and four decision algorithms (C5.0, the classification and regression tree, Chi-square Automatic Interaction Detector and Quick, Unbiased, Efficient, Statistical Tree) to select the optimal combination. The optimal model and clustering analysis were used to divide the patients into two groups (good and poor adherence), then the optimal decision algorithm was used to construct the prediction model of adherence and obtain its predictor variables.

Results

The results revealed that the RFm model, K-means clustering analysis and C5.0 algorithm were optimal. After three rounds of k-means clustering analysis, the optimal RFm clustering model quality was 0.8, 10,614 elements were obtained, including 9803 and 811 from patients with good or poor adherence, respectively, and five types of patients were identified. The prediction model had an accuracy of 100% with the recent consultation month as an important adherence predictor variable.

Conclusions

This work presented a prediction model for medication adherence in AIDS patients at the designated AIDS center in Shanghai, using the RFm model and the k-means and C5.0 algorithms. The model can be expanded to include patients from other centers in China and worldwide.

Recruitment of Youth Living With HIV to Optimize Adherence and Virologic Suppression: Testing the Design of Technology-Based Community Health Nursing to Improve Antiretroviral Therapy (ART) Clinical Trials

Background

Despite advances in HIV diagnosis and treatment, adolescents and young adults 12-25 years old have high HIV incidence, poor engagement and retention in treatment, and low rates of adherence and virologic suppression when compared to their older counterparts. HIV has emerged as a chronic disease for which antiretroviral therapy (ART) adherence is critical for virologic suppression and long-term survival. Virologic suppression has been elusive for many youth with HIV (YHIV). Novel strategies designed to facilitate health care systems’ support for YHIV between medical visits are essential for improving ART adherence, virologic suppression, and long-term survival.

Objective

The aim of this study is to compare the effectiveness of a technology-enhanced community health nursing intervention (TECH2CHECK) to a standard of care (SOC) control group for improving ART adherence and subsequent viral suppression using a randomized trial design. The objectives are to assess the feasibility, acceptability, and cost-effectiveness of TECH2CHECK as compared to SOC for management of HIV in the outpatient setting and to examine the sustainability of self-care behavior, adherence, and virologic suppression among youth following the intervention period.

Methods

We will recruit 120 adherence-challenged YHIV being followed at clinics specializing in HIV care in the Baltimore-Washington metropolitan area and in Jacksonville. Eligible participants complete an audio, computer-assisted self-interview and are randomized to either TECH2CHECK intervention or the SOC (60 participants in each arm). The primary outcome of interest is virologic suppression (viral load <20 copies/mL) and improved treatment adherence. Participants in the intervention arm receive community health nursing visits at 2 weeks, 6 weeks, 10 weeks, 14 weeks, and 26 weeks. The intervention arm also receives SMS messaging comprising daily adherence and appointment reminders and positive reinforcement for medication adherence daily for 2 weeks, on alternate days for 2 weeks, thrice weekly for 1 month, weekly for 3 months, and every 2 weeks for the rest of the study duration. The control group receives appointment reminders and SOC per clinic protocol. Exploratory analysis will be conducted to determine differences in medication adherence and virologic suppression in the 2 arms and to assess cost-effectiveness and study feasibility and acceptability.

Results

In the first 23 months of the study (July 2018-April 2020), 56 (55%) of 102 eligible patients were enrolled and randomized. At present, participating youths are primarily African American (53/56, 95%), male (37/56, 66%), and ≥18 years old (53/56, 95%). Follow-up study visits, as required per the protocol, have been completed by 77% (43/56), 94% (45/48), 95% (37/39), 96% (24/25), and 100% (10/10) of participants at the 1-month, 3-month, 6-month, 12-month, and 18-month follow-ups, respectively.

Conclusions

Preliminary accrual and retention data suggest that TECH2CHECK is feasible and acceptable.

Trial Registration

ClinicalTrials.gov NCT03600103 https://clinicaltrials.gov/ct2/show/NCT03600103

International Registered Report Identifier (IRRID)

DERR1-10.2196/23480

Modeling an integrated HIV prevention and care continuum to achieve the Ending the HIV Epidemic goals

OBJECTIVE

We sought to evaluate, which combinations of HIV prevention and care activities would have the greatest impact towards reaching the US Ending the HIV Epidemic (EHE) plan goals of HIV incidence reduction.

DESIGN

A stochastic network-based HIV transmission model for men who have sex with men (MSM), calibrated to surveillance estimates in the Atlanta area, a focal EHE jurisdiction.

METHODS

Model scenarios varied HIV screening rates under different assumptions of how HIV-negative MSM would be linked to PrEP initiation, and rates of HIV care linkage and retention for those screening positive.

RESULTS

A ten-fold relative increase in HIV screening rates (to approximately biannual screening for black and Hispanic MSM and quarterly for white MSM) would lead to 43% of infections averted if integrated with PrEP initiation. Improvements focused only on black MSM would achieve nearly the same outcome (37% of infections averted). Improvements to HIV care retention would avert 41% of infections if retention rates were improved ten-fold. If both screening and retention were jointly improved ten-fold, up to 74% of cumulative infections would be averted. Under this scenario, it would take 4 years to meet the 75% EHE goal and 12 years to meet the 90% goal for Atlanta MSM.

CONCLUSION

Reaching the EHE 75% incidence reduction goals by their target dates will require immediate and substantial improvements in HIV screening, PrEP, and ART care retention. Meeting these EHE goals in target jurisdictions like Atlanta will be possible only by addressing the HIV service needs of black MSM.

Development and Validation of a Risk Prediction Tool to Identify People with HIV Infection Likely Not to Achieve Viral Suppression

Identifying people with HIV infection (PHIV), who are at risk of not achieving viral suppression, is important for designing targeted intervention. The aim of this study was to develop and test a risk prediction tool for PHIV who are at risk of not achieving viral suppression after a year of being in care. We used retrospective data to develop an integer-based scoring method using backward stepwise logistic regression. We also developed risk score categories based on the quartiles of the total risk score. The risk prediction tool was internally validated by bootstrapping. We found that nonviral suppression after a year of being in care among PHIV can be predicted using seven variables, namely, age group, race, federal poverty level, current AIDS status, current homelessness status, problematic alcohol/drug use, and current viral suppression status. Those in the high-risk category had about a 23 increase in the odds of nonviral suppression compared with the low-risk group. The risk prediction tool has good discriminative performance and calibration. Our findings suggest that nonviral suppression after a year of being in care can be predicted using easily available variables. In settings with similar demographics, the risk prediction tool can assist health care providers in identifying high-risk individuals to target for intervention. Follow-up studies are required to externally validate this risk prediction tool.

Developing a triage tool for use in identifying people living with HIV who are at risk for non-retention in HIV care

Introduction:

Identifying PLHIV in HIV care who are at particular risk of non-retention in care is an important element in improving their HIV care outcomes. The purpose of this study was to develop a risk prediction tool to identify PLHIV at risk of non-retention in care over the course of the next year.

Method:

We used stepwise logistic regression to assess sociodemographic, clinical and behavioral predictors of non-retention in HIV care. Retention in care was defined as having evidence of at least two encounters with an HIV care provider (or CD4 or viral load lab tests as a proxy measure for the encounter), at least 3 months apart within a year. We validated the risk prediction tool internally using the bootstrap method.

Results:

The risk prediction tool included a total of six factors: age group, race, poverty level, homelessness, problematic alcohol/drug use and viral suppression status. The total risk score ranged from 0 to 17. Compared to those in the lowest quartile (0 risk score), those who were in the middle two quartiles (score 1–4) and those in the upper quartile (>4 risk score) were more likely not to be retained in care (odds ratio [OR] 1.63 [CI; 1.39–1.92] and OR 4.82 [CI; 4.04–5.78] respectively). The discrimination ability for the prediction model was 0.651.

Conclusion:

We found that increased risk for non-retention in care can be predicted with routinely available variables. Since the discrimination of the tool was low, future studies may need to include more prognostic factors in the risk prediction tool.

Predicting organizational readiness to implement HIV prevention with couples using practitioners' intentions: testing a heuristic

Couple-based interventions may play a key role in ending the AIDS epidemic. Progress has been made in demonstrating successful implementation of both manual-based and web-based modalities of couple-based HIV prevention in clinical trials. To ensure real world implementation, however, we need a better understanding of how best to prepare organizations to support such interventions. We sought to examine which domains of staff-reported organizational readiness predicted providers' intention to deliver a couple-based HIV-prevention intervention. Organizational readiness was assessed at baseline from 253 facilitators enrolled in a randomized clinical trial testing dissemination and implementation of a couple-based HIV prevention program (2007-2012). Consistent with current organizational-readiness theory, we measured general capacities; capacities specific to a couple-based intervention; and staff motivation to implement the intervention. We used multilevel regression models to examine the influence of these capacities on intention to implement at 6-, 12-, and 18-month follow-up, adjusting for staff age, education, role, years of service, and randomized condition. Higher perceived organizational resources (B = 0.126, p = .028) and better staff motivation (B = 0.510, p = .009) were significant predictors of increased intention to facilitate Connect. Higher organizational resource availability and stronger motivation to facilitate the intervention are key domains that could inform administrator and staff training to strengthen readiness for couple-based programs. However, further research is needed to clarify the role of these domains regarding actual implementation.

Van Lith L, Mallalieu EC, Kamara D, Dailly-Ajavon P, Cisse A, Seifert Ahanda K, Thaddeus S, Babalola S, Hoffmann CJ. "You Take Medications, You Live Normally": The Role of Antiretroviral Therapy in Mitigating Men's Perceived Threats of HIV in Côte d'Ivoire

Men diagnosed with HIV face gender-related barriers to initiating and adhering to antiretroviral therapy (ART). This qualitative study (73 in-depth interviews; 28 focus group discussions), conducted with men in three urban sites in Côte d'Ivoire in 2016, examined perceptions of ART, including benefits and challenges, to explore how ART mitigates HIV's threats to men's sexuality, economic success, family roles, social status, and health. Participants perceived that adhering to ART would reduce risk of transmitting HIV to others, minimize job loss and lost productivity, and help maintain men's roles as decision makers and providers. ART adherence was thought to help reduce the threat of HIV-related stigma, despite concerns about unintentional disclosure. While ART was perceived to improve health directly, it restricted men's schedules. Side effects were also a major challenge. Social and behavior change approaches building on these insights may improve male engagement across the HIV care continuum.

Sexual Orientation Identity, Race/Ethnicity, and Lifetime HIV Testing in a National Probability Sample of U.S. Women and Men: An Intersectional Approach

Purpose: We examined differences in lifetime human immunodeficiency virus (HIV) testing in relation to both sexual orientation identity and race/ethnicity among U.S. women and men. Methods: We used 2013-2017 National Health Interview Survey data and multivariable logistic regression to assess the distribution of lifetime HIV testing across and within sexual orientation identity and racial/ethnic groups of U.S. women (n = 60,867) and men (n = 52,201) aged 18-64 years. Results: Among women, Black lesbian (74.1%) and bisexual (74.0%) women had the highest prevalence whereas Asian lesbian women (32.5%) had the lowest prevalence of lifetime HIV testing. Among men, the prevalence of lifetime HIV testing was the highest among Latino gay men (92.6%) and the lowest among Asian heterosexual men (32.0%). In most cases, Black women and Black and Latino men had significantly higher adjusted odds whereas Asian women and men had lower adjusted odds of lifetime HIV testing compared with their White counterparts within sexual orientation identity groups. In many instances, bisexual women and gay men had significantly higher adjusted odds of lifetime HIV testing relative to their heterosexual counterparts within racial/ethnic groups. Compared with White heterosexual individuals, most sexual orientation identity and racial/ethnic subgroups had significantly higher adjusted odds whereas Asian heterosexual, bisexual, and lesbian women and Asian heterosexual and bisexual men may have lower adjusted odds of lifetime HIV testing. Conclusion: Culturally relevant, linguistically appropriate, and structurally competent programs and practices are needed to facilitate lifetime HIV testing among diverse sexual orientation identity and racial/ethnic subgroups of women and men, including multiply marginalized subgroups that are undertested or disproportionately affected by HIV/AIDS.

Undiagnosed HIV infections among gay and bisexual men increasingly contribute to new infections in Australia

Introduction

We determined the contribution of undiagnosed HIV to new infections among gay and bisexual men (GBM) over a 12‐year period in Australia where there has been increasing focus on improving testing and HIV treatment coverage.

Methods

We generated annual estimates for each step of the HIV cascade and the number of new HIV infections for GBM in Australia over 2004 to 2015 using relevant national data. Using Bayesian melding we then fitted a quantitative model to the cascade and incidence estimates to infer relative transmission coefficients associated with being undiagnosed, diagnosed and not on ART, on ART with unsuppressed virus, or on ART with suppressed virus.

Results

Between 2004 and 2015, we estimated the percentage of GBM with HIV in Australia who were unaware of their status to have decreased from 14.5% to 7.5%. During the same period, there was a substantial increase in the number and proportion of GBM living with HIV on treatment and with suppressed virus, with the number of virally suppressed GBM increasing from around 3900 (30.2% of all GBM living with HIV) in 2004 to around 14,000 (73.7% of all GBM living with HIV) in 2015. Despite the increase in viral suppression, the annual number of new infections rose from around 660 to around 760 over this period. Our results have a wide range due to the uncertainty in the cascade estimates and transmission coefficients. Nevertheless, undiagnosed GBM increasingly appear to contribute to new infections. The proportion of new infections attributable to undiagnosed GBM almost doubled from 33% in 2004 to 59% in 2015. Only a small proportion (<7%) originated from GBM with suppressed virus.

Discussion

Our study suggests that an increase in HIV treatment coverage in Australia has reduced the overall risk of HIV transmission from people living with HIV. However, the proportion of infections and the rate of transmission from undiagnosed GBM has increased substantially. These findings highlight the importance of HIV testing and intensified prevention for Australian GBM at high risk of HIV.

The Impact of "Churn" on Plasma HIV Burden Within a Population Under Care

Background

Cross-sectional reporting of viral suppression rates within a population underestimates the community viral load (VL) burden. Longitudinal approaches, while addressing cumulative effects, may still underestimate viral burden if “churn” (movement in and out of care) is not incorporated. We examined the impact of churn on the cumulative community HIV viral burden.

Methods

All HIV+ patients followed in 2016–2017 at the Southern Alberta Clinic (Calgary, Canada) were categorized as follows: (1) in continuous care, (2) newly diagnosed, (3) diagnosed elsewhere transferring care, (4) returning to care, (5) lost-to-follow-up, (6) moved care elsewhere, or (7) died. Patient days were classified by VL as suppressed (≤200copies/ml), unsuppressed (>200 copies/ml), and transmittable (>1500 copies/ml).

Results

Of 1934 patients, 78.4% had suppressed VL; 21.4% had ≥1 unsuppressed VL, and 18.7% ≥1 transmittable VL. Of 1 276 507 total patient days in care, 92.1% were spent suppressed, 7.9% unsuppressed (101 459 days), and 6.4% (81 847 days) transmittable. 88.7% of category 1 patients had suppressed VL, 11.3% ≥1 unsuppressed VL, and 8.9% ever a transmittable VL. Of category 2 patients, 90% became suppressed on treatment (mean – 62 days). 38.5% of category 3 patients presented with a transmittable VL. Category 4 and 5 patients combined had high rates of unsuppressed (54.5%) and transmittable (51.2%) VL and, while representing only 6.2% of all patients, they accounted for 37.1% of unsuppressed and 41.5% of all transmittable days.

Conclusion

Focus on VL of patients continuously in care misses those with unsuppressed and transmittable VL in a community. Patients moving in and out of care pose an underappreciated risk for HIV transmissions.

Characteristics of Out-of-Care Patients Who Required a Referral for Re-engagement Services by Public Health Bridge Counselors Following a Brief Clinic-Based Retention Intervention

The NC-LINK Project initiated both clinic-based retention services and state public health bridge counselor-based (SBCs) re-engagement services to retain and re-engage people living with HIV infection (PLWH) in care. The goal of this project is to compare efforts between clinic-based retention and SBC re-engagement services to determine whether patients are more or less likely to remain in HIV care services. Clinic appointment data were used to identify patients who were last seen more than 6-9 months prior. Patients either received clinic-based retention services only or were subsequently referred to the SBC re-engagement intervention if the retention services were unsuccessful. The frequency of re-engagement in care (180 days) and HIV suppression (VLS, within 1 year) was examined for patients in these two groups. The SBC group was less likely to have VLS at the visit prior to referral (adjusted OR 2.04, 95% CI 1.53, 2.72). Patients who were referred to the SBC were less likely to re-engage in care within 180 days as compared to those who received clinic-based retention services only (adjusted OR 0.29, 95% CI 0.21, 0.41).

Hospitalization and post-discharge care in South Africa: A critical event in the continuum of care

OBJECTIVES

The purpose of this prospective cohort study is to characterize the event of acute hospitalization for people living with and without HIV and describe its impact on the care continuum. This study describes care-seeking behavior prior to an index hospitalization, inpatient HIV testing and diagnosis, discharge instructions, and follow-up care for patients for patients being discharged from a single hospital in South Africa.

METHODS

A convenience sample of adult patients was recruited from the medical wards of a tertiary care facility. Baseline information at the time of hospital admission, subsequent diagnoses, and discharge instructions were recorded. Participants were prospectively followed with phone calls for six months after hospital discharge. Descriptive analyses were performed.

RESULTS

A total of 293 participants were enrolled in the study. Just under half (46%) of the participants were known to be living with HIV at the time of hospital admission. Most participants (97%) were given a referral for follow-up care; often that appointment was scheduled within two weeks of discharge (64%). Only 36% of participants returned to care within the first month, 50% returned after at least one month had elapsed, and 14% of participants did not return for any follow up.

CONCLUSIONS

Large discrepancies were found between the type of post-discharge follow-up care recommended by providers and what patients were able to achieve. The period of time following hospital discharge represents a key transition in care. Additional research is needed to characterize patients' risk following hospitalization and to develop patient-centered interventions.

Cost-Effectiveness Analysis of Early vs Late Diagnosis of HIV-Infected Patients in South Carolina

OBJECTIVES

It is anticipated that early diagnosis, linkage to care, initiation of antiretroviral therapy (ART), and retention in care would lead to reduced opportunistic infections, reduction in human immunodeficiency virus-related morbidity and mortality and reduced rates of HIV transmission. This would be expected to lead to a reduction in the lifetime cost of care (LCC). This study analyzed existing data to determine to what extent early-versus-late HIV diagnosis affects LCC.

METHODS

The South Carolina Department of Health and Environmental Control electronic HIV/acquired immunodeficiency syndrome reporting system data were used for this study. The first CD4 and viral load reported to the Enhanced HIV/AIDS Reporting System of the Centers for Disease Control and Prevention are considered the initial CD4 and viral load. Late HIV diagnosis was based on a CD4 count ≤200 at diagnosis. A previously validated simulation model developed by the John Snow Institute for the South Carolina Department of Health and Environmental Control was used to determine the discounted LCC. Comparisons were made between late and early HIV diagnosis.

RESULTS

From 2013 through 2015, 2138 individuals were diagnosed as having HIV in South Carolina; 180 individuals were excluded from further analysis because an initial CD4 count was missing. Final analysis was based on 1958 individuals. Late HIV diagnosis occurred in 509 individuals (26%). When stratified based on CD4 count at diagnosis, the discounted LCC per person in those with an initial CD4 count ≤200 was $262,374 and in those with an initial CD4 count >500 was $416,766. Those with lower CD4 counts at diagnosis had more lost quality-adjusted life-years (QALYs; 7.95 QALYs lost per person with an initial CD4 count ≤200 compared with 4.45 QALYs lost per person with an initial CD4 count >500), more lifetime HIV transmissions (1.4 per person with an initial CD4 count ≤200 compared with 0.72 per person with an initial CD4 count >500), and lower additional life expectancy (30.73 additional years with an initial CD4 count ≤200 compared with 38.08 additional years with an initial CD4 count >500).

CONCLUSIONS

Although individuals with lower CD4 counts at diagnosis had a lower discounted LCC, they had more lost QALYs, more lifetime HIV transmissions, and lower additional life expectancy.

Economic and epidemiologic impact of guidelines for early ART initiation irrespective of CD4 count in Spain

INTRODUCTION

Emerging data suggest that early antiretroviral therapy (ART) could reduce serious AIDS and non-AIDS events and deaths but could also increase costs. In January 2016, the Spanish guidelines were updated to recommend ART at any CD4 count. However, the epidemiologic and economic impacts of early ART initiation in Spain remain unclear.

METHODS

The Johns Hopkins HIV Economic-Epidemiologic Mathematical Model (JHEEM) was utilized to estimate costs, transmissions, and outcomes in Spain over 20 years. We compared implementation of guidelines for early ART initiation to a counterfactual scenario deferring ART until CD4-counts fall below 350 cells/mm3. We additionally studied the impact of early ART initiation in combination with improvements to HIV screening, care linkage and engagement.

RESULTS

Early ART initiation (irrespective of CD4-count) is expected to avert 20,100 [95% Uncertainty Range (UR) 11,100-83,000] new HIV cases over the next two decades compared to delayed ART (28% reduction), at an incremental health system cost of €1.05 billion [€0.66 - €1.63] billion, and an incremental cost-effectiveness ratio (ICER) of €29,700 [€13,700 - €41,200] per QALY gained. Projected ICERs declined further over longer time horizon; e.g., an ICER of €12,691 over 30 years. Furthermore, the impact of early ART initiation was potentiated by improved HIV screening among high-risk individuals, averting an estimated 41,600 [23,200-172,200] HIV infections (a 58% decline) compared to delayed ART.

CONCLUSIONS

Recommendations for ART initiation irrespective of CD4-counts are cost-effective and could avert > 30% of new cases in Spain. Improving HIV diagnosis can amplify this impact.

Cost-Utility of Access to Care, a National HIV Linkage, Re-engagement and Retention in Care Program

Linkage to HIV medical care and on-going engagement in HIV medical care are vital for ending the HIV epidemic. However, little is known about the cost-utility of HIV linkage, re-engagement and retention (LRC) in care programs. This paper presents the cost-utility analysis of Access to Care, a national HIV LRC program. Using standard methods from the US Panel on Cost-Effectiveness in Health and Medicine, we calculated the cost-utility ratio. Seven Access to Care programs were cost-effective and two were cost-saving. This study adds to a small but growing body of evidence to support the cost-effectiveness of LRC programs.

The HIV Care Cascade Among Individuals Under Community Supervision in Baltimore, Maryland

An estimated one in seven HIV-infected individuals pass through U.S. correctional facilities each year. Transitioning from correctional to community settings may increase HIV treatment interruptions and increase the risk of continued HIV transmission in the community. This study assessed access to HIV providers in the community, antiretroviral treatment, and viral suppression to inform the development of interventions to improve HIV treatment outcomes among individuals involved in community corrections. The sample included 100 individuals under community supervision (probation or parole) in Baltimore, Maryland. While a large proportion of the study sample had undetectable HIV viral loads, 39% did not, and this represents a significant HIV transmission risk. Given the large proportion of individuals involved in the criminal justice system who are under community supervision, community corrections may be an important point of intervention to engage or reengage HIV-positive individuals who are currently out of care.

p24 revisited: a landscape review of antigen detection for early HIV diagnosis

: Despite major advances in HIV testing, early detection of infection at the point of care (PoC) remains a key challenge. Although rapid antibody PoC and laboratory-based nucleic acid amplification tests dominate the diagnostics market, the viral capsid protein p24 is recognized as an alternative early virological biomarker of infection. However, the detection of ultra-low levels of p24 at the PoC has proven challenging. Here we review the landscape of p24 diagnostics to identify knowledge gaps and barriers and help shape future research agendas. Five hundred and seventy-four research articles to May 2018 that propose or evaluate diagnostic assays for p24 were identified and reviewed. We give a brief history of diagnostic development, and the utility of p24 as a biomarker in different populations such as infants, the newly infected, those on preexposure prophylaxis and self-testers. We review the performance of commercial p24 assays and consider elements such as immune complex disruption, resource-poor settings, prevalence, and assay antibodies. Emerging and ultrasensitive assays are reviewed and show a number of promising approaches but further translation has been limited. We summarize studies on the health economic benefits of using antigen testing. Finally, we speculate on the future uses of high-performance p24 assays, particularly, if available in self-test format.

Strategies to improve adherence to antiretroviral therapy and retention in care for people living with HIV in high-income countries: a protocol for an overview of systematic reviews

INTRODUCTION

While access to antiretroviral therapy (ART) for people living with HIV has expanded in recent years, additional efforts are required to support adherence to medication and retention in care. Interventions should be applicable in real-world settings and amenable to widespread use. The objectives of this overview are to identify effective pragmatic interventions that increase adherence to ART and retention in care for people living with HIV at high risk for suboptimal adherence and retention in high-income countries.

METHODS AND ANALYSIS

We will conduct an overview of systematic reviews of studies on interventions which target improved adherence to medication and retention in care among high-risk people living with HIV in high-income countries (men who have sex with men, African, Caribbean and black people, sex workers, people who inject drugs, indigenous people and other socially marginalised groups). We will search the following databases: PubMed, EMBASE (Exerpta Medica Database), CINAHL (Cumulative Index to Nursing and Allied Health Literature), PsycINFO, Web of Science and the Cochrane Library. We will conduct screening, data extraction and assessment of methodological quality of the systematic reviews. Analysis will be narrative. Our findings will be interpreted in light of the certainty of the evidence, level of pragmatism, setting and population of interest.

ETHICS AND DISSEMINATION

Only published secondary data will be used in this study, and therefore ethics approval is not required. Our findings will be disseminated as peer-reviewed manuscripts, conference abstracts and through community activities. The findings from this overview will inform a mixed-methods study among people living with HIV and health workers in Ontario, Canada.

Past Care Predicts Future Care in Out-of-Care People Living with HIV: Results of a Clinic-Based Retention-in-Care Intervention in North Carolina

Poor retention in care is associated with higher viral load (VL) results and decreased rates of viral load suppression (VS) in people living with HIV (PLWH). Therefore, improving retention in HIV care is a priority of national significance. The NC-LINK Retention Project utilized a systematic approach to identify, locate, and attempt to return to care patients who did not attend a clinic appointment for 6-9 months. Clinical and surveillance data were used to evaluate associations between patient characteristics and VL outcomes. Between January 1, 2013 and December 31, 2014, 1118 patients at participating clinics were identified as out-of-care and referred to retention staff. Of these, 712 (64%) were located in North Carolina. Patients with recent prior medical care (aPR 1.43, 95% CI 1.25, 1.66) and recent VS (aPR 1.28, 95% CI 1.16, 1.41) were more likely to be located. Of located patients, 58% re-engaged in care within 90 days of retention referral. Patients who achieved VS within 180 days were more likely to be 40-49 years (aPR 1.19 95% CI 1.01-1.40; compared with 18-29 age group), had insurance at their last visit (aPR 1.19 95% CI 1.01-1.77), had a care visit in the prior year (aPR 1.37 95% CI 1.05-1.77), and had VS at the prior care visit (aPR 2.54 95% CI 1.98-3.25). Clinic-based retention efforts may be effective at helping PLWH decrease out-of-care periods, but prior patterns of care usage persist.

Healthcare Empowerment and HIV Viral Control: Mediating Roles of Adherence and Retention in Care

INTRODUCTION

This study assessed longitudinal relationships between patient healthcare empowerment, engagement in care, and viral control in the Women's Interagency HIV Study, a prospective cohort study of U.S. women living with HIV.

METHODS

From April 2014 to March 2016, four consecutive 6-month visits were analyzed among 973 women to assess the impact of Time 1 healthcare empowerment variables (Tolerance for Uncertainty and the state of Informed Collaboration Committed Engagement) on Time 2 reports of ≥95% HIV medication adherence and not missing an HIV primary care appointment since last visit; and on HIV RNA viral control across Times 3 and 4, controlling for illicit drug use, heavy drinking, depression symptoms, age, and income. Data were analyzed in 2017.

RESULTS

Adherence of ≥95% was reported by 83% of women, 90% reported not missing an appointment since the last study visit, and 80% were categorized as having viral control. Logistic regression analyses revealed a significant association between the Informed Collaboration Committed Engagement subscale and viral control, controlling for model covariates (AOR=1.08, p=0.04), but not for the Tolerance for Uncertainty subscale and viral control (AOR=0.99, p=0.68). In separate mediation analyses, the indirect effect of Informed Collaboration Committed Engagement on viral control through adherence (β=0.04, SE=0.02, 95% CI=0.02, 0.08), and the indirect effect of Informed Collaboration Committed Engagement on viral control through retention (β=0.01, SE=0.008, 95% CI=0.001, 0.030) were significant. Mediation analyses with Tolerance for Uncertainty as the predictor did not yield significant indirect effects.

CONCLUSIONS

The Informed Collaboration Committed Engagement healthcare empowerment component is a promising pathway through which to promote engagement in care among women living with HIV.

Washington state satellite HIV clinic program: a model for delivering highly effective decentralized care in under-resourced communities

To improve access to high-quality HIV care in underserved regions of Western Washington (WA) State, we collaborated with the WA State Department of Health (DOH) and community partners to launch four satellite HIV clinics. Here, we describe this innovative clinical care model, present an estimate of costs, and evaluate patient care outcomes, including virologic suppression rates. To accomplish this, we assessed virologic suppression rates 12 months before and 12 months after the satellite clinics opened, comparing people living with HIV (PLWH) who enrolled in the satellite clinics versus all PLWH in the same regions who did not. We also determined virologic suppression rates in 2015 comparing satellite clinic versus non-satellite clinic patients and compared care quality indicators between the satellite clinics and the parent academic clinic. Results demonstrate that the change in virologic suppression rate 12 months before to 12 months after the satellite clinics opened was higher for patients who enrolled in the satellite clinics compared to all those in the same region who did not (18% versus 6%, p < 0.001). Virologic suppression in 2015 was significantly higher for satellite clinic than non-satellite clinic patients at three of four sites. Care quality indicators were met at a high level at the satellite clinics, comparable to the parent academic clinic. Overall, through community partnerships and WA DOH support, the satellite clinic program increased access to best practice HIV care and improved virologic suppression rates in difficult-to-reach areas. This model could be expanded to other regions with inadequate access to HIV practitioners, though financial support is necessary.

What Will It Take to Reduce HIV Incidence in the United States: A Mathematical Modeling Analysis

Background

The National HIV/AIDS Strategy has set ambitious goals to improve the epidemic in the United States. However, there is a paucity of usable program-level benchmarks tied to population-level epidemiologic goals. Our objective was to define tangible benchmarks for annual rates along the care continuum that are likely to translate to meaningful reductions in incidence.

Methods

We used a validated mathematical model of HIV transmission and care engagement to characterize care continuum parameters that would translate into 50% reductions in incidence by 2025, compared with a base case scenario of the current US care continuum. We generated a large pool of simulations in which rates of screening, linkage, and retention in care were varied across wide ranges to evaluate permutations that halved incidence by 2025.

Results

Among all simulations, 7% achieved a halving of incidence. It was impossible for our simulations to achieve this target if the annual rate of disengagement from care exceeded 20% per year, even at high rates of care reengagement. When retention in care was 95% per year and people living with HIV (PLWH) out of care reengaged within 1.5 years (on average), the probability of halving incidence by 2025 was approximately 90%.

Conclusions

HIV programs should aim to retain at least 95% of PLWH in care annually and reengage people living with HIV into care within an average of 1.5 years to achieve the goal of halving HIV incidence by 2025.

Informing Targeted Interventions to Optimize the Cascade of HIV Care Using Cluster Analyses of Health Resource Use Among People Living with HIV/AIDS

Increased awareness of the secondary preventive benefits of antiretroviral treatment (ART) has strengthened the desire to optimize health care systems' response to HIV/AIDS. We identified clusters of health resource utilization (HRU) among people living with HIV (PLHIV) to inform targeted interventions aimed to optimize the cascade of HIV care. Using linked population-level health databases in British Columbia, Canada, we selected two analytic samples of PLHIV with 3 years of follow-up between 2006-2011 that were classified as intermittently retained in care or intermittently engaged in ART, and executed a probabilistic model-based clustering analysis for each sample with 5 and 9 quarterly HRU variables, respectively. We found clear HRU profile differences among both samples with similar HIV-related care: one featured active involvement in non-HIV care, the other little or no health care interaction following linkage to care. Differential reengagement intervention strategies capitalizing on missed opportunities in non-HIV care and further engaging physicians delivering HIV care are needed to optimize the response to the HIV epidemic.

The Optimal Age for Screening Adolescents and Young Adults Without Identified Risk Factors for HIV

PURPOSE

To assess the optimal age at which a one-time HIV screen should begin for adolescents and young adults (AYA) in the U.S. without identified HIV risk factors, incorporating clinical impact, costs, and cost-effectiveness.

METHODS

We simulated HIV-uninfected 12-year-olds in the U.S. without identified risk factors who faced age-specific risks of HIV infection (.6-71.3/100,000PY). We modeled a one-time screen ($36) at age 15, 18, 21, 25, or 30, each in addition to current U.S. screening practices (30% screened by age 24). Outcomes included retention in care, virologic suppression, life expectancy, lifetime costs, and incremental cost-effectiveness ratios in $/year-of-life saved (YLS) from the health-care system perspective. In sensitivity analyses, we varied HIV incidence, screening and linkage rates, and costs.

RESULTS

All one-time screens detected a small proportion of lifetime infections (.1%-10.3%). Compared with current U.S. screening practices, a screen at age 25 led to the most favorable care continuum outcomes at age 25: proportion diagnosed (77% vs. 51%), linked to care (71% vs. 51%), retained in care (68% vs. 44%), and virologically suppressed (49% vs. 32%). Compared with the next most effective screen, a screen at age 25 provided the greatest clinical benefit, and was cost-effective ($96,000/YLS) by U.S. standards (<$100,000/YLS).

CONCLUSIONS

For U.S. AYA without identified risk factors, a one-time routine HIV screen at age 25, after the peak of incidence, would optimize clinical outcomes and be cost-effective compared with current U.S. screening practices. Focusing screening on AYA ages 18 or younger is a less efficient use of a one-time screen among AYA than screening at a later age.

Depression and alcohol use disorder at antiretroviral therapy initiation led to disengagement from care in South Africa

We sought to assess mental health at the time of antiretroviral therapy (ART) initiation and subsequent retention in care over a six-month follow-up period. A total of 136 people living with HIV in South Africa were administered surveys measuring demographic information and mental health indicators at the time of ART initiation. Follow-up was completed via chart abstraction to assess for six-month outcomes of retention in care and viral suppression. At enrollment, 45/136 (33%), 67/136 (49%), and 45/136 (33%) participants screened positive for depression, anxiety, and alcohol use disorder, respectively. After six months of follow-up, 96/136 (71%) participants remained in care; 35/87 (40.2%) participants who remained in care had a level <50 copies/mL. Those with depression (49% vs. 77% retained; p < 0.01) and those with alcohol use disorder (52% vs. 76% retained; p < 0.01) were less likely to be retained in care. In multivariable logistic regression, depression OR 3.46 (95% CI: 1.33, 7.97; p < 0.01) and alcohol abuse OR 3.89 (95% CI: 1.70, 8.97; p < 0.01) were independently associated with loss from care. These results emphasize the importance of mental health on early ART outcomes and the HIV care continuum.

A Flow-Based Model of the HIV Care Continuum in the United States

BACKGROUND

Understanding the flow of patients through the continuum of HIV care is critical to determine how best to intervene so that the proportion of HIV-infected persons who are on antiretroviral treatment and virally suppressed is as large as possible.

METHODS

Using immunological and virological data from the Centers for Disease Control and Prevention and the North American AIDS Cohort Collaboration on Research and Design from 2009 to 2012, we estimated the distribution of time spent in and dropout probability from each stage in the continuum of HIV care. We used these estimates to develop a queueing model for the expected number of patients found in each stage of the cascade.

RESULTS

HIV-infected individuals spend an average of about 3.1 months after HIV diagnosis before being linked to care, or dropping out of that stage of the continuum with a probability of 8%. Those who link to care wait an additional 3.7 months on average before getting their second set of laboratory results (indicating engagement in care) or dropping out of care with probability of almost 6%. Those engaged in care spent an average of almost 1 year before achieving viral suppression on antiretroviral therapy or dropping out with average probability 13%. For patients who achieved viral suppression, the average time suppressed on antiretroviral therapy was an average of 4.5 years.

CONCLUSIONS

Interventions should be targeted to more rapidly identifying newly infected individuals, and increasing the fraction of those engaged in care that achieves viral suppression.

Barriers and facilitators of the HIV care continuum in Southern New England for people with drug or alcohol use and living with HIV/AIDS: perspectives of HIV surveillance experts and service providers

BACKGROUND

Contemporary studies about HIV care continuum (HCC) outcomes within substance using populations primarily focus on individual risk factors rather than provider- or systems-level influences. Over 25% of people living with HIV (PLWH) have substance use disorders that can alter their path through the HCC. As part of a study of HCC outcomes in nine small cities in Southern New England (population 100,000-200,000 and relatively high HIV prevalence particularly among substance users), this qualitative analysis sought to understand public health staff and HIV service providers' perspectives on how substance use may influence HCC outcomes.

METHODS

Interviews with 49 participants, collected between November 2015 and June 2016, were analyzed thematically using a modified social ecological model as the conceptual framework and codes for substance use, HCC barriers and facilitators, successes and failures of initiatives targeting the HCC, and criminal justice issues.

RESULTS

Eight themes were identified concerning the impact of substance use on HCC outcomes. At the individual level, these included coping and satisfying basic needs and could influence all HCC steps (i.e., testing, treatment linkage, adherence, and retention, and viral load suppression). The interpersonal level themes included stigma issues and providers' cultural competence and treatment attitudes and primarily influenced treatment linkage, retention, and viral load suppression. These same HCC steps were influenced at the health care systems level by organizations' physical environment and resources as well as intra-/inter-agency communication. Testing and retention were the most likely steps to affect at the policy/society level, and the themes included opposition within an organization or community, and activities with unintended consequences.

CONCLUSIONS

The most substantial HCC challenges for PLWH with substance use problems included linking and retaining in treatment those with multiple co-morbidities and meeting their basic living needs. Recommendations to improve HCC outcomes for PLWH with substance use problems include increasing easy access to effective drug and mental health treatment, expanding case management and peer navigation services, training staff about harm reduction, de-stigmatizing, and culturally competent approaches to interacting with patients, and increasing information-sharing and service coordination among service providers and the social service and criminal justice systems.

HIV Care Initiation Delay Among Rural Residents in the Southeastern United States, 1996 to 2012

BACKGROUND

Delaying HIV care initiation may lead to greater morbidity, mortality, and further HIV transmission. Rural residence may be associated with delayed diagnosis and linkage to care, with negative clinical outcomes.

OBJECTIVE

To examine the association between rural patient residence and CD4 cell count at HIV care initiation in a large HIV clinical cohort in the Southeastern United States.

METHODS

We included HIV-infected patients who initiated care between 1996 and 2012 with a geocodable address and no previous history of HIV clinical care. Patient residence was categorized as urban or rural using United States Department of Agriculture Rural Urban Commuting Area codes. Multivariable linear regression models were fit to estimate the association between patient residence and CD4 cell count at HIV care initiation.

RESULTS

Among 1396 patients who met study inclusion criteria, 988 had a geocodable address. Overall, 35% of patients resided in rural areas and presented to HIV care with a mean CD4 cell count of 351 cells/mm (SD, 290). Care initiation mean CD4 cell counts increased from 329 cells/mm (SD, 283) in 1996-2003 to 391 cells/mm (SD, 292) in 2008-2012 (P = 0.006). Rural in comparison with urban patients presented with lower CD4 cell counts with an unadjusted and adjusted mean difference of -48 cells/mm [95% confidence interval, -86 to -10) and -37 cells/mm (95% confidence interval: -73 to -2), respectively, consistently observed across calendar years.

CONCLUSIONS

HIV care initiation at low CD4 cell counts was common in this Southeastern US cohort and more common among rural area residents.

Test-and-treat approach to HIV/AIDS: a primer for mathematical modeling

The public benefit of test-and-treat has induced a need to justify goodness for the public, and mathematical modeling studies have played a key role in designing and evaluating the test-and-treat strategy for controlling HIV/AIDS. Here we briefly and comprehensively review the essence of contemporary understanding of the test-and-treat policy through mathematical modeling approaches and identify key pitfalls that have been identified to date. While the decrease in HIV incidence is achieved with certain coverages of diagnosis, care and continued treatment, HIV prevalence is not necessarily decreased and sometimes the test-and-treat is accompanied by increased long-term cost of antiretroviral therapy (ART). To confront with the complexity of assessment on this policy, the elimination threshold or the effective reproduction number has been proposed for its use in determining the overall success to anticipate the eventual elimination. Since the publication of original model in 2009, key issues of test-and-treat modeling studies have been identified, including theoretical problems surrounding the sexual partnership network, heterogeneities in the transmission dynamics, and realistic issues of achieving and maintaining high treatment coverage in the most hard-to-reach populations. To explicitly design country-specific control policy, quantitative modeling approaches to each single setting with differing epidemiological context would require multi-disciplinary collaborations among clinicians, public health practitioners, laboratory technologists, epidemiologists and mathematical modelers.