Assessing the individual benefits of reducing HIV diagnosis delay and increasing adherence to HIV care and treatment.

We used an agent-based simulation model (Progression and Transmission of HIV) to follow for 20 years a cohort of persons in the United States infected with HIV in 2015. We assessed the benefits of reducing the delay between HIV infection and diagnosis and increasing adherence to HIV care and treatment on the percent of persons surviving 20 years after infection, average annual HIV transmission rates, and time spent virally suppressed. We examined average diagnosis delays of 1.0-7.0 years, monthly care drop-out rates of 5% to 0.1%, and combinations of these strategies. The percent of the cohort surviving the first 20 years of infection varied from 70.8% to 77.5%, and the annual transmission risk, from 1.5 to 5.2 HIV transmissions per 100 person-years. Thus, individuals can enhance their survival and reduce their risk of transmission to partners by frequent testing for HIV and adhering to care and treatment.

Estimating the HIV Effective Reproduction Number in the United States and Evaluating HIV Elimination Strategies.

CONTEXT: The reproduction number is a fundamental epidemiologic concept used to assess the potential spread of infectious diseases and whether they can be eliminated. OBJECTIVE: We estimated the 2017 United States HIV effective reproduction number, Re, the average number of secondary infections from an infected person in a partially infected population. We analyzed the potential effects on Re of interventions aimed at improving patient flow rates along different stages of the HIV care continuum. We also examined these effects by individual transmission groups. DESIGN: We used the HIV Optimization and Prevention Economics (HOPE) model, a compartmental model of disease progression and transmission, and the next-generation matrix method to estimate Re. We then projected the impact of changes in HIV continuum-of-care interventions on the continuum-of-care flow rates and the estimated Re in 2020. SETTING: United States. PARTICIPANTS: The HOPE model simulated the sexually active US population and persons who inject drugs, aged 13 to 64 years, which was stratified into 195 subpopulations by transmission group, sex, race/ethnicity, age, male circumcision status, and HIV risk level. MAIN OUTCOME MEASURES: The estimated value of Re in 2017 and changes in Re in 2020 from interventions affecting the continuum-of-care flow rates. RESULTS: Our estimated HIV Re in 2017 was 0.92 [0.82, 0.94] (base case [min, max across calibration sets]). Among the interventions considered, the most effective way to reduce Re substantially below 1.0 in 2020 was to maintain viral suppression among those receiving HIV treatment. The greatest impact on Re resulted from changing the flow rates for men who have sex with men (MSM). CONCLUSIONS: Our results suggest that current prevention and treatment efforts may not be sufficient to move the country toward HIV elimination. Reducing Re to substantially below 1.0 may be achieved by an ongoing focus on early diagnosis, linkage to care, and sustained viral suppression especially for MSM.

Optimal Allocation of Societal HIV Prevention Resources to Reduce HIV Incidence in the United States.

Objectives. To optimize combined public and private spending on HIV prevention to achieve maximum reductions in incidence.Methods. We used a national HIV model to estimate new infections from 2018 to 2027 in the United States. We estimated current spending on HIV screening, interventions that move persons with diagnosed HIV along the HIV care continuum, pre-exposure prophylaxis, and syringe services programs. We compared the current funding allocation with 2 optimal scenarios: (1) a limited-reach scenario with expanded efforts to serve eligible persons and (2) an ideal, unlimited-reach scenario in which all eligible persons could be served.Results. A continuation of the current allocation projects 331 000 new HIV cases over the next 10 years. The limited-reach scenario reduces that number by 69%, and the unlimited reach scenario by 94%. The most efficient funding allocations resulted in prompt diagnosis and sustained viral suppression through improved screening of high-risk persons and treatment adherence support for those infected.Conclusions. Optimal allocations of public and private funds for HIV prevention can achieve substantial reductions in new infections. Achieving reductions of more than 90% under current funding will require that virtually all infected receive sustained treatment.

Health Utility Estimates and Their Application to HIV Prevention in the United States: Implications for Cost-Effectiveness Modeling and Future Research Needs.

Objectives. Health utility estimates from the current era of HIV treatment, critical for cost-effectiveness analyses (CEA) informing HIV health policy, are limited. We examined peer-reviewed literature to assess the appropriateness of commonly referenced utilities, present previously unreported quality-of-life data from two studies, and discuss future implications for HIV-related CEA. Methods. We searched a database of cost-effectiveness analyses specific to HIV prevention efforts from 1999 to 2016 to identify the most commonly referenced sources for health utilities and to examine practices around using and reporting health utility data. Additionally, we present new utility estimates from the Centers of Disease Control and Prevention's Medical Monitoring Project (MMP) and the INSIGHT Strategies for Management of Anti-Retroviral Therapy (SMART) trial. We compare data collection time frames, sample characteristics, assessment methods, and key estimates. Results. Data collection for the most frequently cited utility estimates ranged from 1985 to 1997, predating modern HIV treatment. Reporting practices around utility weights are poor and lack details on participant characteristics, which may be important stratifying factors for CEA. More recent utility estimates derived from MMP and SMART were similar across CD4+ count strata and had a narrower range than pre-antiretroviral therapy (ART) utilities. Conclusions. Despite the widespread use of ART, cost-effectiveness analysis of HIV prevention interventions frequently apply pre-ART health utility weights. Use of utility weights reflecting the current state of the US epidemic are needed to best inform HIV research and public policy decisions. Improved practices around the selection, application, and reporting of health utility data used in HIV prevention CEA are needed to improve transparency.

Estimating the costs and cost-effectiveness of HIV self-testing among men who have sex with men, United States.

INTRODUCTION: HIV testing is an essential prerequisite for accessing treatment with antiretroviral therapy or prevention using pre-exposure prophylaxis. Internet distribution of HIV self-tests is a novel approach, and data on the programmatic cost of this approach are limited. We analyse the costs and cost-effectiveness of a self-testing programme. METHODS: Men who have sex with men (MSM) reporting unknown or negative HIV status were enrolled from March to August 2015 into a 12-month trial of HIV self-testing in the United States. Participants were randomly assigned either to the self-testing arm or the control arm. All participants received information on HIV testing services and locations in their community. Self-testing participants received up to four self-tests each quarter, which they could use themselves or distribute to their social network associates. Quarterly follow-up surveys collected testing outcomes, including number of tests used and new HIV diagnoses. Using trial expenditure data, we estimated the cost of implementing a self-testing programme. Primary outcomes of this analysis included total programme implementation costs, cost per self-test completed, cost per person tested, cost per new HIV diagnosis among those self-tested and cost per quality adjusted life year (QALY) saved. RESULTS: A total of 2665 men were assigned either to the self-testing arm (n = 1325) or the control arm (n = 1340). HIV testing was reported by 971 self-testing participants who completed a total of 5368 tests. In the control arm, 619 participants completed 1463 HIV tests. The self-testing participants additionally distributed 2864 self-tests to 2152 social network associates. Testing during the trial identified 59 participants and social network associates with newly diagnosed HIV infection in the self-testing arm; 11 control participants were newly diagnosed with HIV. The implementation cost of the HIV self-testing programme was $449,510. The cost per self-test completed, cost per person tested at least once, and incremental cost per new HIV diagnosis was $61, $145 and $9365 respectively. We estimated that self-testing programme potentially averted 3.34 transmissions, saved 14.86 QALYs and nearly $1.6 million lifetime HIV treatment costs. CONCLUSIONS: The HIV self-testing programme identified persons with newly diagnosed HIV infection at low cost, and the programme is cost saving.

Vital Signs: HIV Transmission Along the Continuum of Care - United States, 2016.

BACKGROUND: In 2016, an estimated 1.1 million persons had human immunodeficiency virus (HIV) infection in the United States; 38,700 were new infections. Knowledge of HIV infection status, behavior change, and antiretroviral therapy (ART) all prevent HIV transmission. Persons who achieve and maintain viral suppression (achieved by most persons within 6 months of starting ART) can live long, healthy lives and pose effectively no risk of HIV transmission to their sexual partners. METHODS: A model was used to estimate transmission rates in 2016 along the HIV continuum of care. Data for sexual and needle-sharing behaviors were obtained from National HIV Behavioral Surveillance. Estimated HIV prevalence, incidence, receipt of care, and viral suppression were obtained from National HIV Surveillance System data. RESULTS: Overall, the HIV transmission rate was 3.5 per 100 person-years in 2016. Along the HIV continuum of care, the transmission rates from persons who were 1) acutely infected and unaware of their infection, 2) non-acutely infected and unaware, 3) aware of HIV infection but not in care, 4) receiving HIV care but not virally suppressed, and 5) taking ART and virally suppressed were 16.1, 8.4, 6.6, 6.1, and 0 per 100 person-years, respectively. The percentages of all transmissions generated by each group were 4.0%, 33.6%, 42.6%, 19.8%, and 0%, respectively. CONCLUSION: Approximately 80% of new HIV transmissions are from persons who do not know they have HIV infection or are not receiving regular care. Going forward, increasing the percentage of persons with HIV infection who have achieved viral suppression and do not transmit HIV will be critical for ending the HIV epidemic in the United States.

Optimal allocation of HIV prevention funds for state health departments.

OBJECTIVE: To estimate the optimal allocation of Centers for Disease Control and Prevention (CDC) HIV prevention funds for health departments in 52 jurisdictions, incorporating Health Resources and Services Administration (HRSA) Ryan White HIV/AIDS Program funds, to improve outcomes along the HIV care continuum and prevent infections. METHODS: Using surveillance data from 2010 to 2012 and budgetary data from 2012, we divided the 52 health departments into 5 groups varying by number of persons living with diagnosed HIV (PLWDH), median annual CDC HIV prevention budget, and median annual HRSA expenditures supporting linkage to care, retention in care, and adherence to antiretroviral therapy. Using an optimization and a Bernoulli process model, we solved for the optimal CDC prevention budget allocation for each health department group. The optimal allocation distributed the funds across prevention interventions and populations at risk for HIV to prevent the greatest number of new HIV cases annually. RESULTS: Both the HIV prevention interventions funded by the optimal allocation of CDC HIV prevention funds and the proportions of the budget allocated were similar across health department groups, particularly those representing the large majority of PLWDH. Consistently funded interventions included testing, partner services and linkage to care and interventions for men who have sex with men (MSM). Sensitivity analyses showed that the optimal allocation shifted when there were differences in transmission category proportions and progress along the HIV care continuum. CONCLUSION: The robustness of the results suggests that most health departments can use these analyses to guide the investment of CDC HIV prevention funds into strategies to prevent the most new cases of HIV.

Impact of Improved HIV Care and Treatment on PrEP Effectiveness in the United States, 2016-2020.

BACKGROUND: The effect of improving diagnosis, care, and treatment of persons living with HIV (PLWH) on pre-exposure prophylaxis (PrEP) effectiveness in the United States has not been well established. METHODS: We used a dynamic, compartmental model that simulates the sexually active US population. We investigated the change in cumulative HIV incidence from 2016 to 2020 for 3 HIV care-continuum levels and the marginal benefit of PrEP compared with each. We also explored the marginal benefit of PrEP for individual risk groups, and as PrEP adherence, coverage and dropout rates varied. RESULTS: Delivering PrEP in 2016 to persons at high risk of acquiring HIV resulted in an 18.1% reduction in new HIV infections from 2016 to 2020 under current care-continuum levels. Achieving HIV national goals of 90% of PLWH with diagnosed infection, 85% of newly diagnosed PLWH linked to care at diagnosis, and 80% of diagnosed PLWH virally suppressed reduced cumulative incidence by 34.4%. Delivery of PrEP in addition to this scenario resulted in a marginal benefit of 11.1% additional infections prevented. When national goals were reached, PrEP prevented an additional 15.2% cases among men who have sex with men, 3.9% among heterosexuals, and 3.8% among persons who inject drugs. CONCLUSIONS: The marginal benefit of PrEP was larger when current HIV-care-continuum percentages were maintained but continued to be substantial even when national care goals were met. The high-risk men who have sex with men population was the chief beneficiary of PrEP.

Effects of Reaching National Goals on HIV Incidence, by Race and Ethnicity, in the United States.

CONTEXT: Human immunodeficiency virus (HIV) incidence and prevalence in the United States are characterized by significant disparities by race/ethnicity. National HIV care goals, such as boosting to 90% the proportion of persons whose HIV is diagnosed and increasing to 80% the proportion of persons living with diagnosed HIV who are virally suppressed, will likely reduce HIV incidence, but their effects on HIV-related disparities are uncertain. OBJECTIVE: We sought to understand by race/ethnicity how current HIV care varies, the level of effort required to achieve national HIV care goals, and the effects of reaching those goals on HIV incidence and disparities. DESIGN: Using a dynamic model of HIV transmission, we identified 2016 progress along the HIV care continuum among blacks, Hispanics, and whites/others compared with national 2020 goals. We examined disparities over time. SETTING: United States. PARTICIPANTS: Beginning in 2006, our dynamic compartmental model simulated the sexually active US population 13 to 64 years of age, which was stratified into 195 subpopulations by transmission group, sex, race/ethnicity, age, male circumcision status, and HIV risk level. MAIN OUTCOME MEASURE: We compared HIV cumulative incidence from 2016 to 2020 when goals were reached compared with base case assumptions about progression along the HIV care continuum. RESULTS: The 2016 proportion of persons with diagnosed HIV who were on treatment and virally suppressed was 50% among blacks, 56% among Hispanics, and 61% among whites/others, compared with a national goal of 80%. When diagnosis, linkage, and viral suppression goals were reached in 2020, cumulative HIV incidence fell by 32% (uncertainty range: 18%-37%) for blacks, 25% (22%-31%) for Hispanics, and 25% (21%-28%) for whites/others. Disparity measures changed little. CONCLUSIONS: Achieving national HIV care goals will require different levels of effort by race/ethnicity but likely will result in substantial declines in cumulative HIV incidence. HIV-related disparities in incidence and prevalence may be difficult to resolve.

Sex Practices by HIV Awareness and Engagement in the Continuum of Care Among MSM: A National HIV Behavioral Surveillance Analysis in 21 U.S. Cities.

Using National HIV Behavioral Surveillance (NHBS) cross-sectional survey and HIV testing data in 21 U.S. metropolitan areas, we identify sex practices among sexually active men who have sex with men (MSM) associated with: (1) awareness of HIV status, and (2) engagement in the HIV care continuum. Data from 2008, 2011, and 2014 were aggregated, yielding a sample of 5079 sexually active MSM living with HIV (MLWH). Participants were classified into HIV status categories: (1) unaware; (2) aware and out of care; (3) aware and in care without antiretroviral therapy (ART); and (4) aware and on ART. Analyses were conducted examining sex practices (e.g. condomless sex, discordant condomless sex, and number of sex partners) by HIV status. Approximately 30, 5, 10 and 55% of the sample was classified as unaware, aware and out of care, aware and in care without ART, and aware and on ART, respectively. Unaware MLWH were more likely to report condomless anal sex with a last male partner of discordant or unknown HIV status (25.9%) than aware MLWH (18.0%, p value < 0.0001). Unaware MLWH were 3 times as likely to report a female sex partner in the prior 12 months as aware MLWH (17.3 and 5.6%, p-value < 0.0001). When examining trends across the continuum of care, reports of any condomless anal sex with a male partner in the past year (ranging from 65.0 to 70.0%), condomless anal sex with a male partner of discordant or unknown HIV status (ranging from 17.7 to 21.3%), and median number of both male and female sex partners were similar. In conclusion, awareness of HIV and engagement in care was not consistently associated with protective sex practices, highlighting the need for continued prevention efforts.

Combinations of interventions to achieve a national HIV incidence reduction goal: insights from an agent-based model.

OBJECTIVE: Analyzing HIV care service targets for achieving a national goal of a 25% reduction in annual HIV incidence and evaluating the use of annual HIV diagnoses to measure progress in incidence reduction. DESIGN: Because there are considerable interactions among HIV care services, we model the dynamics of 'combinations' of increases in HIV care continuum targets to identify those that would achieve 25% reductions in annual incidence and diagnoses. METHODS: We used Progression and Transmission of HIV/AIDS 2.0, an agent-based dynamic stochastic simulation of HIV in the United States. RESULTS: A 25% reduction in annual incidence could be achieved by multiple alternative combinations of percentages of persons with diagnosed infection and persons with viral suppression including 85 and 68%, respectively, and 90 and 59%, respectively. The first combination corresponded to an 18% reduction in annual diagnoses, and infections being diagnosed at a median CD4 cell count of 372 cells/µl or approximately 3.8 years from time of infection. The corresponding values on the second combination are 4%, 462 cells/µl, and 2.0 years, respectively. CONCLUSION: Our analysis provides policy makers with specific targets and alternative choices to achieve the goal of a 25% reduction in HIV incidence. Reducing annual diagnoses does not equate to reducing annual incidence. Instead, progress toward reducing incidence can be measured by monitoring HIV surveillance data trends in CD4 cell count at diagnosis along with the proportion who have achieved viral suppression to determine where to focus local programmatic efforts.

Progression and Transmission of HIV/AIDS (PATH 2.0).

BACKGROUND: HIV transmission is the result of complex dynamics in the risk behaviors, partnership choices, disease stage and position along the HIV care continuum-individual characteristics that themselves can change over time. Capturing these dynamics and simulating transmissions to understand the chief sources of transmission remain important for prevention. METHODS: The Progression and Transmission of HIV/AIDS (PATH 2.0) is an agent-based model of a sample of 10,000 people living with HIV (PLWH), who represent all men who have sex with men (MSM) and heterosexuals living with HIV in the U.S.A. Persons uninfected were modeled as populations, stratified by risk and gender. The model included detailed individual-level data from several large national surveillance databases. The outcomes focused on average annual transmission rates from 2008 through 2011 by disease stage, HIV care continuum, and sexual risk group. RESULTS: The relative risk of transmission of those in the acute phase was nine-times [5th and 95th percentile simulation interval (SI): 7, 12] that of those in the non-acute phase, although, on average, those with acute infections comprised 1% of all PLWH. The relative risk of transmission was 24- to 50-times as high for those in the non-acute phase who had not achieved viral load suppression as compared with those who had. The relative risk of transmission among MSM was 3.2-times [SI: 2.7, 4.0] that of heterosexuals. Men who have sex with men and women generated 46% of sexually acquired transmissions among heterosexuals. CONCLUSIONS: The model results support a continued focus on early diagnosis, treatment and adherence to ART, with an emphasis on prevention efforts for MSM, a subgroup of whom appear to play a role in transmission to heterosexuals.

Assessing HIV acquisition risks among men who have sex with men in the United States of America / Evaluación del riesgo de transmisión del VIH entre hombres que tienen relaciones sexuales con otros hombres en los Estados Unidos de América

ABSTRACT Men who have sex with men (MSM) can reduce their risk of acquiring human immunodeficiency virus (HIV) by using various prevention strategies and by understanding the effectiveness of each option over the short- and long-term. Strategies examined were: circumcision; insertive anal sex only; consistent, 100% self-reported condom use; and pre-exposure prophylaxis (PrEP). PrEP efficacy was based on three levels of adherence. The cumulative HIV acquisition risk among MSM over periods of 1 year and 10 years were estimated with and without single and combinations of prevention strategies. A Bernoulli process model was used to estimate risk. In the base case with no prevention strategies, the 1-year risk of HIV acquisition among MSM was 8.8%. In contrast, the 1-year risk associated with circumcision alone was 6.9%; with insertive sex only, 5.5%; with 100% self-reported condom use, 2.7%; and with average, high, and very high PrEP adherence, 5.1%, 2.5%, and 0.7%, respectively. The 10-year risk of HIV acquisition among MSM with no prevention strategy was 60.3%. In contrast, that associated with circumcision alone was 51.1%; with insertive sex only, 43.1%; with 100% self-reported condom use, 24.0%; and with average, high, and very high PrEP adherence, 40.5%, 22.2%, and 7.2%, respectively. While MSM face substantial risk of HIV, there are now a number of prevention strategies that reduce risk. Very high adherence to PrEP alone or with other strategies appears to be the most powerful tool for HIV prevention.(AU)

RESUMEN Los hombres que tienen relaciones sexuales con otros hombres (HSH) pueden reducir su riesgo de contraer el virus de la inmunodeficiencia humana (VIH) si utilizan diversas estrategias de prevención y comprenden la eficacia de cada opción a corto y largo plazo. Las estrategias examinadas fueron: la circuncisión; las relaciones anales insertivas solamente; el 100% de uso sostenido y autonotificado de condones; y la profilaxis preexposición (PrEP). La eficacia de la PrEP se basó en tres niveles de adherencia. Se calculó el riesgo acumulativo de la transmisión del VIH entre los HSH en períodos de 1 y 10 años con a) una única estrategia de prevención, b) sin estrategia de prevención y c) con combinaciones de estrategias de prevención. Se usó un modelo del proceso de Bernoulli para calcular el riesgo. En el caso base sin estrategias de prevención, el riesgo de transmisión del VIH a 1 año entre HSH fue 8,8%. En contraste, el riesgo de 1 año asociado a la circuncisión solamente fue de 6,9%; a las relaciones insertivas solamente fue de 5,5%; al 100% de uso autonotificado de condón, 2,7%; y a la adherencia media, alta y muy alta a la PrEP, 5,1%, 2,5% y 0,7%, respectivamente. El riesgo de transmisión del VIH a los 10 años entre HSH sin estrategia de prevención fue de 60,3%. En contraste, la transmisión asociada a la circuncisión solamente fue de 51,1%; a las relaciones insertivas solamente, 43,1%; al 100% de uso autonotificado de condón, 24,0%; y a la adherencia media, alta y muy alta a la PrEP, 40,5%, 22,2% y 7,2%, respectivamente. Si bien los HSH enfrentan un riesgo sustancial de contraer el VIH, existen ahora varias estrategias de prevención que reducen dicho riesgo. Una adherencia muy alta a la PrEP sola o en combinación con otras estrategias parece ser la herramienta más potente para la prevención de la infección por el VIH.(AU)

Assessing HIV acquisition risks among men who have sex with men in the United States of America / Evaluación del riesgo de transmisión del VIH entre hombres que tienen rela¬ciones sexuales con otros hombres en los Estados Unidos de América

Men who have sex with men (MSM) can reduce their risk of acquiring human immunodeficiency virus (HIV) by using various prevention strategies and by understanding the effectiveness of each option over the short- and long-term. Strategies examined were: circumcision; insertive anal sex only; consistent, 100% self-reported condom use; and pre-exposure prophylaxis (PrEP). PrEP efficacy was based on three levels of adherence. The cumulative HIV acquisition risk among MSM over periods of 1 year and 10 years were estimated with and without single and combinations of prevention strategies. A Bernoulli process model was used to estimate risk. In the base case with no prevention strategies, the 1-year risk of HIV acquisition among MSM was 8.8%. In contrast, the 1-year risk associated with circumcision alone was 6.9%; with insertive sex only, 5.5%; with 100% self-reported condom use, 2.7%; and with average, high, and very high PrEP adherence, 5.1%, 2.5%, and 0.7%, respectively. The 10-year risk of HIV acquisition among MSM with no prevention strategy was 60.3%. In contrast, that associated with circumcision alone was 51.1%; with insertive sex only, 43.1%; with 100% self-reported condom use, 24.0%; and with average, high, and very high PrEP adherence, 40.5%, 22.2%, and 7.2%, respectively. While MSM face substantial risk of HIV, there are now a number of prevention strategies that reduce risk. Very high adherence to PrEP alone or with other strategies appears to be the most powerful tool for HIV prevention.

Los hombres que tienen relaciones sexuales con otros hombres (HSH) pueden reducir su riesgo de contraer el virus de la inmunodeficiencia humana (VIH) si utilizan diversas estrategias de prevención y comprenden la eficacia de cada opción a corto y largo plazo. Las estrategias examinadas fueron: la circuncisión; las relaciones anales insertivas solamente; el 100% de uso sostenido y autonotificado de condones; y la profilaxis preexposición (PrEP). La eficacia de la PrEP se basó en tres niveles de adherencia. Se calculó el riesgo acumulativo de la transmisión del VIH entre los HSH en períodos de 1 y 10 años con a) una única estrategia de prevención, b) sin estrategia de prevención y c) con combinaciones de estrategias de prevención. Se usó un modelo del proceso de Bernoulli para calcular el riesgo. En el caso base sin estrategias de prevención, el riesgo de transmisión del VIH a 1 año entre HSH fue 8,8%. En contraste, el riesgo de 1 año asociado a la circuncisión solamente fue de 6,9%; a las relaciones insertivas solamente fue de 5,5%; al 100% de uso autonotificado de condón, 2,7%; y a la adherencia media, alta y muy alta a la PrEP, 5,1%, 2,5% y 0,7%, respectivamente. El riesgo de transmisión del VIH a los 10 años entre HSH sin estrategia de prevención fue de 60,3%. En contraste, la transmisión asociada a la circuncisión solamente fue de 51,1%; a las relaciones insertivas solamente, 43,1%; al 100% de uso autonotificado de condón, 24,0%; y a la adherencia media, alta y muy alta a la PrEP, 40,5%, 22,2% y 7,2%, respectivamente. Si bien los HSH enfrentan un riesgo sustancial de contraer el VIH, existen ahora varias estrategias de prevención que reducen dicho riesgo. Una adherencia muy alta a la PrEP sola o en combinación con otras estrategias parece ser la herramienta más potente para la prevención de la infección por el VIH.

Cost Effectiveness of HIV Prevention Interventions in the U.S.

INTRODUCTION: The purpose of this study was to assess and compare the cost effectiveness of current HIV prevention interventions in the U.S. using a consistent, standardized methodology. METHODS: The cost effectiveness of common and emerging HIV biomedical and behavioral prevention interventions as delivered to men who have sex with men, injection drug users, and sexually active heterosexuals was estimated. Data on program costs, intervention efficacy, risk behaviors, and per contact transmission probabilities were collected from peer-reviewed papers and health department reports. These data were combined with 2010 national HIV incidence and prevalence surveillance data in a Bernoulli process model to estimate the reduced annual risk of HIV transmission or acquisition associated with these interventions. The cost per prevented case of HIV and the cost per saved quality-adjusted life year were then calculated. Analyses were conducted between 2014 and 2015. RESULTS: Interventions to diagnose HIV and provide ongoing care and treatment had the lowest cost per prevented case. Among interventions targeted at specific risk groups, interventions for men who have sex with men were the most cost effective. The least cost-effective interventions typically addressed people at risk of acquiring HIV rather than those at risk of transmitting the disease. CONCLUSIONS: HIV prevention interventions targeted at high-risk populations, those associated with the care continuum, and those that reduce the transmission risk of HIV-infected people are typically the most cost effective. Decision makers can consider these results in planning an efficient allocation of HIV prevention resources.

Cost-Effectiveness of Frequent HIV Testing of High-Risk Populations in the United States.

PURPOSE: Data showing a high incidence of HIV infection among men who have sex with men (MSM) who had annual testing suggest that more frequent HIV testing may be warranted. Testing technology is also a consideration given the availability of sensitive testing modalities and the increased use of less-sensitive rapid, point-of-care antibody tests. We assessed the cost-effectiveness of HIV testing of MSM and injection drug users (IDUs) at 3- and 6-month intervals using fourth-generation and rapid tests. METHODS: We used a published mathematical model of HIV transmission to evaluate testing intervals for each population using cohorts of 10,000 MSM and IDU. We incorporated HIV transmissions averted due to serostatus awareness and viral suppression. We included costs for HIV testing and treatment initiation, and also treatment costs saved from averted transmissions. RESULTS: For MSM, HIV testing was cost saving or cost effective over a 1-year period for both 6-month compared with annual testing and quarterly compared with 6-month testing using either test. Testing IDU every 6 months compared with annually was moderately cost effective over a 1-year period with a fourth-generation test, while testing with rapid, point-of-care tests or quarterly was not cost effective. MSM results remained robust in sensitivity analysis, whereas IDU results were sensitive to changes in HIV incidence and continuum-of-care parameters. Threshold analyses on costs suggested that additional implementation costs could be incurred for more frequent testing for MSM while remaining cost effective. CONCLUSIONS: HIV testing of MSM as frequently as quarterly is cost effective compared with annual testing, but testing IDU more frequently than annually is generally not cost effective.

From Theory to Practice: Implementation of a Resource Allocation Model in Health Departments.

OBJECTIVE: To develop a resource allocation model to optimize health departments' Centers for Disease Control and Prevention (CDC)-funded HIV prevention budgets to prevent the most new cases of HIV infection and to evaluate the model's implementation in 4 health departments. DESIGN, SETTINGS, AND PARTICIPANTS: We developed a linear programming model combined with a Bernoulli process model that allocated a fixed budget among HIV prevention interventions and risk subpopulations to maximize the number of new infections prevented. The model, which required epidemiologic, behavioral, budgetary, and programmatic data, was implemented in health departments in Philadelphia, Chicago, Alabama, and Nebraska. MAIN OUTCOME MEASURES: The optimal allocation of funds, the site-specific cost per case of HIV infection prevented rankings by intervention, and the expected number of HIV cases prevented. RESULTS: The model suggested allocating funds to HIV testing and continuum-of-care interventions in all 4 health departments. The most cost-effective intervention for all sites was HIV testing in nonclinical settings for men who have sex with men, and the least cost-effective interventions were behavioral interventions for HIV-negative persons. The pilot sites required 3 to 4 months of technical assistance to develop data inputs and generate and interpret the results. Although the sites found the model easy to use in providing quantitative evidence for allocating HIV prevention resources, they criticized the exclusion of structural interventions and the use of the model to allocate only CDC funds. CONCLUSIONS: Resource allocation models have the potential to improve the allocation of limited HIV prevention resources and can be used as a decision-making guide for state and local health departments. Using such models may require substantial staff time and technical assistance. These model results emphasize the allocation of CDC funds toward testing and continuum-of-care interventions and populations at highest risk of HIV transmission.

Notification following new positive HIV test results.

Client notification of a new HIV diagnosis is critical for timely access to treatment and reduction in behaviours associated with HIV infection. It is also an important input in HIV transmission and disease progression models. We used national, Centers for Disease Control and Prevention-funded HIV testing events data collected through the National HIV Prevention Program Monitoring and Evaluation system to update estimates of the proportion of newly identified HIV-positives notified of their status. We compared estimates from 2008 to 2010 across test technologies, settings, and HIV risk groups. In 2010, notification following a positive rapid test was 99.6% compared with 99.3% in 2008. Notification following a positive conventional test was 81.5% in 2010 compared with 80.8% in 2008. To realise the full promise of early HIV diagnosis and treatment for the prevention of additional HIV cases, efforts to ensure prompt notification following a new HIV diagnosis will be crucial.

Assessing HIV acquisition risks among men who have sex with men in the United States of America.

Men who have sex with men (MSM) can reduce their risk of acquiring human immunodeficiency virus (HIV) by using various prevention strategies and by understanding the effectiveness of each option over the short- and long-term. Strategies examined were: circumcision; insertive anal sex only; consistent, 100% self-reported condom use; and pre-exposure prophylaxis (PrEP). PrEP efficacy was based on three levels of adherence. The cumulative HIV acquisition risk among MSM over periods of 1 year and 10 years were estimated with and without single and combinations of prevention strategies. A Bernoulli process model was used to estimate risk. In the base case with no prevention strategies, the 1-year risk of HIV acquisition among MSM was 8.8%. In contrast, the 1-year risk associated with circumcision alone was 6.9%; with insertive sex only, 5.5%; with 100% self-reported condom use, 2.7%; and with average, high, and very high PrEP adherence, 5.1%, 2.5%, and 0.7%, respectively. The 10-year risk of HIV acquisition among MSM with no prevention strategy was 60.3%. In contrast, that associated with circumcision alone was 51.1%; with insertive sex only, 43.1%; with 100% self-reported condom use, 24.0%; and with average, high, and very high PrEP adherence, 40.5%, 22.2%, and 7.2%, respectively. While MSM face substantial risk of HIV, there are now a number of prevention strategies that reduce risk. Very high adherence to PrEP alone or with other strategies appears to be the most powerful tool for HIV prevention.