A mathematical model of comprehensive test-and-treat services and HIV incidence among men who have sex with men in the United States

HIV and adolescent girls and young women in sub-Saharan Africa: A call for expedited action to reduce new infections

Adolescent girls and young women (AGYW) from sub-Saharan Africa (SSA), aged 15-24, remain at substantial risk of acquiring HIV. AGYW accounted for 63% of all new HIV infections in 2021. Reducing incident infections in AGYW and among the other key populations is key to eliminating HIV infections. Expedited prioritization and actions to reduce incident infections among AGYW from sub-Saharan Africa are therefore required to attain the UNAIDS 95-95-95 targets by 2030. In this article, we discuss the factors contributing to higher HIV infections among AGYW and strategies that can be used to reduce HIV infection among them. Several biological, socio-economic, religious, and cultural factors continue to put the AGYW at a disproportionately high risk of acquiring HIV. Many AGYW in SSA are economically marginalized and therefore are unable to negotiate condom use and monogamy. Patriarchal culture predominant in SSA also exacerbates AGYW's inferiority in sexual matters. To address these factors, a multi-pronged approach is required. Some of the strategies we recommend are passing stricter sentences for sexual offenders and abusers, economically empowering AGYW, increasing the provision of sexual and reproductive health and rights (SRHR) education and services to AGYW, increasing access to pre-exposure and post-exposure prophylaxis, treatment of HIV as prevention, and engaging and educating communities on SRHR matters.

Past dynamics of HIV transmission among men who have sex with men in Montréal, Canada: a mathematical modeling study

BACKGROUND

Gay, bisexual, and other men who have sex with men (gbMSM) experience disproportionate risks of HIV acquisition and transmission. In 2017, Montréal became the first Canadian Fast-Track City, setting the 2030 goal of zero new HIV infections. To inform local elimination efforts, we estimate the evolving role of prevention and sexual behaviours on HIV transmission dynamics among gbMSM in Montréal between 1975 and 2019.

METHODS

Data from local bio-behavioural surveys were analyzed to develop, parameterize, and calibrate an agent-based model of sexual HIV transmission. Partnership dynamics, HIV's natural history, and treatment and prevention strategies were considered. The model simulations were analyzed to estimate the fraction of HIV acquisitions and transmissions attributable to specific groups, with a focus on age, sexual partnering level, and gaps in the HIV care-continuum.

RESULTS

The model-estimated HIV incidence peaked in 1985 (2.3 per 100 person years (PY); 90% CrI: 1.4-2.9 per 100 PY) and decreased to 0.1 per 100 PY (90% CrI: 0.04-0.3 per 100 PY) in 2019. Between 2000-2017, the majority of HIV acquisitions and transmissions occurred among men aged 25-44 years, and men aged 35-44 thereafter. The unmet prevention needs of men with > 10 annual anal sex partners contributed 90-93% of transmissions and 67-73% of acquisitions annually. The primary stage of HIV played an increasing role over time, contributing to 11-22% of annual transmissions over 2000-2019. In 2019, approximately 70% of transmission events occurred from men who had discontinued, or never initiated antiretroviral therapy.

CONCLUSIONS

The evolving HIV landscape has contributed to the declining HIV incidence among gbMSM in Montréal. The shifting dynamics identified in this study highlight the need for continued population-level surveillance to identify gaps in the HIV care continuum and core groups on which to prioritize elimination efforts.

Comprehensive HIV/AIDS knowledge and HIV testing among men in sub-Saharan Africa: a multilevel modelling

This study investigated the association between comprehensive HIV/AIDS knowledge and HIV testing among men in sub-Saharan Africa (SSA). Data were taken from the most recent (2010-2019) Demographic and Health Survey men's recode files of 29 countries in SSA. A total of 104,398 men who had complete information on all the variables of interest were included in the study. The outcome variable was HIV testing. A multilevel logistic regression analysis was conducted to determine the association between comprehensive HIV/AIDS knowledge and HIV testing. The results of the fixed effects model were presented as adjusted odds ratios (AORs) with 95% confidence intervals (CIs). The average prevalences of HIV testing and comprehensive HIV/AIDS knowledge among men in SSA were 53.5% and 50.8% respectively. Rwanda and Niger recorded the highest (93.6%) and lowest prevalences (9.8%) respectively. The prevalence of comprehensive HIV/AIDS knowledge among men in the 29 countries was 50.8%, with the highest in Rwanda (76.4%) and the lowest in Benin (31.1%). Men who had no comprehensive HIV/AIDS knowledge were less likely to test for HIV compared with those who had comprehensive HIV/AIDS knowledge (AOR=0.59, CI: 0.57-0.60). Men who were older than 20 years, married or cohabiting, with at least secondary education, in the richest wealth quintile, exposed to mass media, used condoms and with multiple sexual partners were more likely to test for HIV. To improve HIV testing among men in SSA, this study recommends that policymakers and stakeholders step up comprehensive HIV/AIDS knowledge sensitization and education using effective tools such as mass media.

Impact of immediate initiation of antiretroviral therapy among men who have sex with men infected with HIV in Chengdu, southwest China: trends analysis, 2008-2018

Background

Given the rampant HIV epidemic among men who have sex with men (MSM) in Chengdu, southwest China, Treat All policy, defined as immediate antiretroviral therapy (ART) initiation after HIV diagnosis, was implemented since 2014. Real-world research evaluating impacts of immediate ART on HIV epidemics is needed to optimize policy-making as national and international guidelines have been lowering ART eligibility threshold. The purpose of this study is to: assess temporal trends of the HIV epidemic and impacts of Treat All policy among MSM; and lay foundation for HIV-related policy evaluation using longitudinal routine data from health information systems.

Methods

Data used in this study were HIV sentinel seroprevalence, annual reported HIV cases and ART coverage rate among MSM in Chengdu from 2008 to 2018, derived from national HIV/AIDS information system. Temporal trends of the HIV epidemic were described using Joinpoint Regression Program. Interrupted time-series method was deployed to evaluate Treat All policy.

Results

HIV sentinel seroprevalence rose from 11.20% in 2008 to 17.67% in 2013 and Annual Percent Change (APC) was 8.25% (95% CI − 2.40%, 20.07%), then decreased to 5.17% in 2018 (APC = − 19.63%, 95% CI − 27.54%, − 10.86%). Newly reported HIV cases increased from 168 cases in 2008 to 1232 cases in 2015 (APC = 26.99%, 95% CI 21.32%, 32.93%), and reduced to 1014 cases in 2018 (APC = − 8.80%, 95% CI − 18.45%, 2.01%). ART coverage rate has been climbing from 11.11% in 2008 to 92.29% in 2018 and Average Annual Percent Change was 16.09% (95% CI 11.76%, 20.59%). Results of interrupted time-series models showed that compared to an annual increase of 0.87% during pre-policy period, there was a decline of 3.08% (95% CI − 0.0366%, − 0.0250%) per year of HIV sentinel seroprevalence since 2014; and compared to an annual increase of 116 cases before 2014, there was an annual drop of 158 newly reported HIV cases (95% CI − 194.87%, − 121.69%) during the post-policy period.

Conclusions

Immediate ART after HIV diagnosis could potentially curb HIV transmission at population level among MSM, along with other strategies. Future assessment of HIV prevention and control policy can be carried out using routinely collected longitudinal data from health information systems.

Progression and transmission of HIV (PATH 4.0)-A new agent-based evolving network simulation for modeling HIV transmission clusters

We present the Progression and Transmission of HIV (PATH 4.0), a simulation tool for analyses of cluster detection and intervention strategies. Molecular clusters are groups of HIV infections that are genetically similar, indicating rapid HIV transmission where HIV prevention resources are needed to improve health outcomes and prevent new infections. PATH 4.0 was constructed using a newly developed agent-based evolving network modeling (ABENM) technique and evolving contact network algorithm (ECNA) for generating scale-free networks. ABENM and ECNA were developed to facilitate simulation of transmission networks for low-prevalence diseases, such as HIV, which creates computational challenges for current network simulation techniques. Simulating transmission networks is essential for studying network dynamics, including clusters. We validated PATH 4.0 by comparing simulated projections of HIV diagnoses with estimates from the National HIV Surveillance System (NHSS) for 2010-2017. We also applied a cluster generation algorithm to PATH 4.0 to estimate cluster features, including the distribution of persons with diagnosed HIV infection by cluster status and size and the size distribution of clusters. Simulated features matched well with NHSS estimates, which used molecular methods to detect clusters among HIV nucleotide sequences of persons with HIV diagnosed during 2015-2017. Cluster detection and response is a component of the U.S. Ending the HIV Epidemic strategy. While surveillance is critical for detecting clusters, a model in conjunction with surveillance can allow us to refine cluster detection methods, understand factors associated with cluster growth, and assess interventions to inform effective response strategies. As surveillance data are only available for cases that are diagnosed and reported, a model is a critical tool to understand the true size of clusters and assess key questions, such as the relative contributions of clusters to onward transmissions. We believe PATH 4.0 is the first modeling tool available to assess cluster detection and response at the national-level and could help inform the national strategic plan.

A Surveillance Data-Based Model System for Assessing the Effects of HIV Intervention and Prevention Strategies

OBJECTIVE

Build a dynamic model system to assess the effects of HIV intervention and prevention strategies on future annual numbers of new HIV infections, newly diagnosed cases of HIV infection, and deaths among persons infected with HIV.

DESIGN AND SETTING

Model parameters are defined to quantify the putative effects of HIV prevention strategies that would increase HIV testing, thereby diagnosing infection earlier; increase linkage to care and viral suppression, thereby reducing infectiousness; and increase the use of preexposure prophylaxis, thereby protecting persons at risk of infection. Surveillance data are used to determine the initial values of the model system's variables and parameters, and the impact on the future course of various outcome measures of achieving either specified target values or specified rates of change for the model parameters is examined.

PARTICIPANTS

A hypothetical population of persons with HIV infection and persons at risk of acquiring HIV infection.

MAIN OUTCOME MEASURES

HIV incidence, HIV prevalence, proportion of persons infected with HIV whose infection is diagnosed, and proportion of persons with diagnosed HIV infection who are virally suppressed.

RESULTS

A model system based on the basic year-to-year algebraic relationships among the model variables and relying almost exclusively on HIV surveillance data was developed to project the course of HIV disease over a specified time period. Based on the most recent HIV surveillance data in the United States-which show a relatively high proportion of infections having been diagnosed but a relatively low proportion of diagnosed persons being virally suppressed-increasing the proportion of diagnosed persons who are virally suppressed and increasing preexposure prophylaxis use appear to be the most effective ways of reducing new HIV infections and accomplishing national HIV prevention and care goals.

CONCLUSIONS

Both having current and accurate information regarding the epidemiologic dynamics of HIV infection and knowing the potential impact of prevention strategies are critical in order for limited HIV prevention resources to be optimally allocated.

Impact of frequent testing on the transmission of HIV and N. gonorrhoeae among men who have sex with men: a mathematical modelling study

OBJECTIVES

To investigate the impact and efficiency of combined testing for HIV and other STIs on HIV and STI transmission among men who have sex with men (MSM) and to assess what subgroups of MSM should be targeted for frequent testing.

METHODS

We developed an agent-based transmission model that simulates infection with HIV or Neisseria gonorrhoeae (NG) among MSM. We examined scenarios with increased percentages of MSM getting tested six monthly, among all MSM or only specific subgroups of MSM (defined according to recent gonorrhoea, number of partners and engagement in condomless anal intercourse (CAI)) and scenarios with reduced intervals between HIV/STI tests.

RESULTS

The most efficient strategies were those with increased percentage of MSM getting tested every 6 months among MSM with a recent gonorrhoea diagnosis; or among MSM who had CAI and ≥10 partners; or MSM who had ≥10 partners. Over 10 years, these strategies resulted in 387-718 averted HIV infections and required 29-164 additional HIV tests per averted HIV infection or one to seven additional gonorrhoea tests per averted NG infection. The most effective strategy in reducing HIV transmission was the one where the intervals between tests were reduced by half, followed by the strategy with increased percentage of MSM getting tested every 6 months among all MSM. Over 10 years, these strategies resulted in 1362 and 1319 averted HIV infections, but required 663 and 584 additional HIV tests per averted HIV infection, respectively.

CONCLUSIONS

Targeting MSM with recent gonorrhoea diagnosis or MSM with many partners is efficient in terms of HIV/STI tests needed to prevent new HIV or NG infections. Major reductions in HIV incidence can be achieved with consistent HIV/STI testing every 6 months among larger groups, including low-risk MSM. To impede HIV transmission, frequent testing should be combined with other prevention measures.

Prevalence and protective factors of HIV and syphilis infection among men who have sex with men in Northwest China

BACKGROUND

Men who have sex with men (MSM) continue to be disproportionately impacted by human immunodeficiency virus (HIV) and syphilis in China. Little is known about HIV and syphilis infections among MSM in Xi'an, a developing city in Northwest China. A cross-sectional study with recruitment via snowball sampling was conducted to collect HIV and syphilis infection status and risk factors among MSM in Xi'an between April 2013 to December 2016. Among the 5000 participants, the mean age was 29.0 years (SD 7.7) and the prevalence of HIV, syphilis, and coinfection was 6.5%, 2.2%, and 0.4%, respectively. There was no significant change in HIV prevalence from 2013 to 2016, while the prevalence of syphilis and coinfection showed a downward trend. Multiple logistic regression analyses found that being over 25 years old (OR = 1.647), junior high school/middle school education and below (OR = 3.085), with a sexual role of passive or versatile (OR = 3.300; OR = 2.337), rush poppers use during the last 6 months (OR = 1.660) and syphilis infection (OR = 2.235) were more likely to acquire HIV infection, whereas used condoms in the last episode of anal sex (OR = 0.572) and tested HIV antibody previously (OR = 0.252) were protective factors for HIV infection. HIV prevalence among MSM in Xi'an was stable, whereas the prevalence of syphilis and coinfection showed a downward trend. Interventions to promote HIV and sexually transmitted disease testing and condom use should be strengthened, especially for MSM with low education.

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.

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.

Cost-effectiveness of increased HIV testing among MSM in The Netherlands

OBJECTIVES

To assess the cost-effectiveness of increased consistent HIV testing among MSM in the Netherlands.

METHODS

Among MSM testing at sexually transmitted infection clinics in the Netherlands in 2014-2015, approximately 20% tested consistently every 6 months. We examined four scenarios with increased percentage of MSM testing every 6 months: a small and a moderate increase among all MSM; a small and a moderate increase only among MSM with at least 10 partners in the preceding 6 months. We used an agent-based model to calculate numbers of HIV infections and AIDS cases prevented with increased HIV testing. These numbers were used in an economic model to calculate costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) due to increased testing, over 2018-2027, taking a healthcare payer perspective.

RESULTS

A small increase in the percentage testing every 6 months among all MSM resulted in 490 averted HIV infections and an average ICER of &OV0556;27 900/QALY gained. A moderate increase among all MSM, resulted in 1380 averted HIV infections and an average ICER of &OV0556;36 700/QALY gained. Both were not cost-effective, with a &OV0556;20 000 willingness-to-pay threshold. Increasing the percentage testing every 6 months only among MSM with at least 10 partners in the preceding 6 months resulted in less averted HIV infections than increased testing among all MSM, but was on average cost-saving.

CONCLUSION

Increased HIV testing can prevent considerable numbers of new HIV infections among MSM, but may be cost-effective only if targeted at high-risk individuals, such as those with many partners.

Population uptake and effectiveness of test-and-treat antiretroviral therapy guidelines for preventing the global spread of HIV: an ecological cross-national analysis

OBJECTIVES

Although the benefits of adopting test-and-treat antiretroviral therapy (ART) guidelines that recommend initiation of ART regardless of CD4 cell counts have been demonstrated at the individual level, there is uncertainty about how this translates to the population level. Here, we explored whether adopting ART guidelines recommending earlier treatment initiation improves population ART access and viral suppression and reduces overall disease transmission.

METHODS

Data on ART initiation guidelines and treatment coverage, viral suppression, and HIV incidence from 37 European and Central Asian countries were collected from the European Centre for Disease Prevention and Control and the Global HIV Policy Watch and HIV 90-90-90 Watch databases. We used multivariate linear regression models to quantify the association of ART initiation guidelines with population ART access, viral suppression, and HIV incidence, adjusting for potential confounding factors.

RESULTS

Test-and-treat policies were associated with 15.2 percentage points (pp) [95% confidence interval (CI) 0.8-29.6 pp; P = 0.039] greater treatment coverage (proportion of HIV-positive people on ART) compared with countries with ART initiation at CD4 cell counts ≤ 350 cells/μL. The presence of test-and-treat policies was associated with 15.8 pp (95% CI 2.4-29.1 pp; P = 0.023) higher viral suppression rates (people on ART virally suppressed) compared with countries with treatment initiation at CD4 counts ≤ 350 cells/μL. ART initiation at CD4 counts ≤ 500 cells/μL did not significantly improve ART coverage compared to initiation at CD4 counts ≤ 350 cells/μL but achieved similar degrees of viral suppression as test-and-treat.

CONCLUSIONS

Test-and-treat was found to be associated with substantial improvements in population-level access to ART and viral suppression, further strengthening evidence that rapid initiation of treatment will help curb the spread of HIV.

A novel Bayesian approach to predicting reductions in HIV incidence following increased testing interventions among gay, bisexual and other men who have sex with men in Vancouver, Canada

Increasing HIV testing rates among high-risk groups should lead to increased numbers of cases being detected. Coupled with effective treatment and behavioural change among individuals with detected infection, increased testing should also reduce onward incidence of HIV in the population. However, it can be difficult to predict the strengths of these effects and thus the overall impact of testing. We construct a mathematical model of an ongoing HIV epidemic in a population of gay, bisexual and other men who have sex with men. The model incorporates different levels of infection risk, testing habits and awareness of HIV status among members of the population. We introduce a novel Bayesian analysis that is able to incorporate potentially unreliable sexual health survey data along with firm clinical diagnosis data. We parameterize the model using survey and diagnostic data drawn from a population of men in Vancouver, Canada. We predict that increasing testing frequency will yield a small-scale but long-term impact on the epidemic in terms of new infections averted, as well as a large short-term impact on numbers of detected cases. These effects are predicted to occur even when a testing intervention is short-lived. We show that a short-lived but intensive testing campaign can potentially produce many of the same benefits as a campaign that is less intensive but of longer duration.

Scaling Up Human Immunodeficiency Virus Screening and Antiretroviral Therapy Among Men Who Have Sex With Men to Achieve the 90-90-90 Targets in China

INTRODUCTION

The Joint United Nations Programme on human immunodeficiency virus (HIV)/acquired immune deficiency syndrome has proposed the 90-90-90 targets by 2020. Human immunodeficiency virus epidemic is spreading rapidly among men who have sex with men (MSM) in China. This study investigates how the scale-up of HIV testing and treatment in achieving the targets and its cost-effectiveness.

METHODS

We constructed a compartmental model to forecast the HIV epidemic in Chinese MSM based on various "test-and-treat" scale-up scenarios. We assessed their cost effectiveness based on the cost for each HIV infection, death, and disability-adjusted life years (DALYs) prevented by the scale-up.

RESULTS

If the current epidemic continued, HIV prevalence among Chinese MSM would increase from 9.2% in 2016 to 12.6% (9.2-15.6%) in 2020 and 16.2% (11.3-20.0%) in 2025. By 2020, 49.2% of infected MSM would be diagnosed and 40.1% of whom on treatment, falling short of the 90-90-90 targets, so would be even by 2025. To achieve these targets by 2020, additional 850,000 HIV screening tests and 112,500 person-years of antiretroviral treatment (ART) annually are necessary. This spending is US $478 million during 2016 to 2020, which almost tripled the status quo. However, by delaying to 2025, an investment of US $1210 million over 2016 to 2025 corresponding to 52% increase to the status quo, will enable extra 340,000 HIV screening tests and 60,000 person-year on ART annually. In both scenarios, the incremental cost-effectiveness ratio was US $733 to 960 for each DALY prevented, indicating highly cost-effective scenarios.

CONCLUSIONS

Achieving the 90-90-90 targets by 2020 requires steep increase in investment, but delaying the targets to 2025 is practical and cost-effective.

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.

Projected Cancer Incidence Rates and Burden of Incident Cancer Cases in HIV-Infected Adults in the United States Through 2030

Background

Persons living with HIV (PLWH) have an elevated risk for certain types of cancer. With modern antiretroviral therapy, PLWH are aging and cancer rates are changing.

Objective

To project cancer incidence rates and burden (number of new cancer diagnoses) among adult PLWH in the United States through 2030.

Design

Descriptive.

Setting

HIV/AIDS Cancer Match Study to project cancer rates and HIV Optimization and Prevention Economics model to project HIV prevalence.

Participants

HIV-infected adults.

Measurements

Projected cancer rates and burden among HIV-infected adults in the United States by age during 2006 to 2030 for AIDS-defining cancer (ADC)-that is, Kaposi sarcoma, non-Hodgkin lymphoma, and cervical cancer-and certain types of non-AIDS-defining cancer (NADC). All other cancer types were combined.

Results

The proportion of adult PLWH in the United States aged 65 years or older is projected to increase from 8.5% in 2010 to 21.4% in 2030. Age-specific rates are projected to decrease through 2030 across age groups for Kaposi sarcoma, non-Hodgkin lymphoma, cervical cancer, lung cancer, Hodgkin lymphoma, and other cancer types combined, and among those aged 65 years or older for colon cancer. Prostate cancer rates are projected to increase. The estimated total cancer burden in PLWH will decrease from 8150 cases in 2010 (2730 of ADC and 5420 of NADC) to 6690 cases in 2030 (720 of ADC and 5980 of NADC). In 2030, prostate cancer (n = 1590) and lung cancer (n = 1030) are projected to be the most common cancer types.

Limitation

Projections assume that current trends in cancer incidence rates, HIV transmission, and survival will continue.

Conclusion

The cancer burden among PLWH is projected to shift, with prostate and lung cancer expected to emerge as the most common types by 2030. Cancer will remain an important comorbid condition, and expanded access to HIV therapies and cancer prevention, screening, and treatment is needed.

Primary Funding Source

National Cancer Institute.

Incorporation of Social Determinants of Health in the Peer-Reviewed Literature: A Systematic Review of Articles Authored by the National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention

OBJECTIVES

Social determinants of health (SDHs) are the complex, structural, and societal factors that are responsible for most health inequities. Since 2003, the National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP) has researched how SDHs place communities at risk for communicable diseases and poor adolescent health. We described the frequency and types of SDHs discussed in articles authored by NCHHSTP.

METHODS

We used the MEDLINE/PubMed search engine to systematically review the frequency and type of SDHs that appeared in peer-reviewed publications available in PubMed from January 1, 2009, through December 31, 2014, with a NCHHSTP affiliation. We chose search terms to identify articles with a focus on the following SDH categories: income and employment, housing and homelessness, education and schooling, stigma or discrimination, social or community context, health and health care, and neighborhood or built environment. We classified articles based on the depth of topic coverage as "substantial" (ie, one of ≤3 foci of the article) or "minimal" (ie, one of ≥4 foci of the article).

RESULTS

Of 862 articles authored by NCHHSTP, 366 (42%) addressed the SDH factors of interest. Some articles addressed >1 SDH factor (366 articles appeared 568 times across the 7 categories examined), and we examined them for each category that they addressed. Most articles that addressed SDHs (449/568 articles; 79%) had a minimal SDH focus. SDH categories that were most represented in the literature were health and health care (190/568 articles; 33%) and education and schooling (118/568 articles; 21%).

CONCLUSIONS

This assessment serves as a baseline measurement of inclusion of SDH topics from NCHHSTP authors in the literature and creates a methodology that can be used in future assessments of this topic.

Statewide Evaluation of New HIV Diagnoses in Rhode Island: Implications for Prevention

OBJECTIVES

Patterns of HIV transmission vary widely across demographic groups. Identifying and engaging these groups are necessary to prevent new infections and diagnose disease among people who are unaware of their infection. The objective of this study was to determine characteristics of newly diagnosed individuals across an entire state to determine patterns of HIV transmission.

METHODS

We evaluated data on people with new HIV diagnoses in Rhode Island from 2013 through 2015. We performed a latent class analysis (LCA) to identify underlying demographic and behavioral characteristics of people with newly diagnosed HIV.

RESULTS

Of 167 people with new HIV diagnoses interviewed in Rhode Island from 2013 through 2015, 132 (79%) were male, 84 (50%) were nonwhite, 112 (67%) were men who have sex with men (MSM), 112 (67%) were born in the United States, and 61 (37%) were born in Rhode Island. LCA revealed 2 major classes. Of the 98 people in class 1, 96% were male, 85% were MSM, 80% were white, 94% were born in the United States, and 80% believed they acquired HIV in Rhode Island. Class 2 was 63% male and 69% Hispanic/Latino; 29% were born in the United States, and 61% believed they acquired HIV in Rhode Island.

CONCLUSIONS

Most new HIV diagnoses in Rhode Island were among MSM born in the United States, and a substantial number were likely infected in-state. People with newly diagnosed HIV who were foreign-born, including Hispanic/Latino and heterosexual groups, were less likely to have acquired HIV in Rhode Island than were MSM. HIV prevention approaches, including pre-exposure prophylaxis, should be adapted to the needs of specific groups. Rhode Island offers lessons for other states focused on eliminating HIV transmission.

Efficacy of a Small-Group Intervention for Post-Incarcerated Black Men Who Have Sex with Men and Women (MSMW)

We conducted a randomized controlled trial of a six-session behavioral intervention designed to reduce frequency of condomless sex and numbers of sex partners among recently incarcerated, bisexual Black men. One hundred participants were assigned to the small-group intervention, Men in Life Environments (MILE), and 112 were assigned to the control condition. Among those assigned to MILE, 69% attended at least one session, 88% of whom attended all sessions. At 3-months' follow-up, large reductions in risk behaviors were reported by both groups. Means for episodes of condomless sex in the previous 3 months declined from 27.7 to 8.0 for the intervention and 25.6 to 6.7 for the control group. Reductions were not greater for the intervention than those of the control group. Regression to the mean, respondent burden, and implementation issues, such as moving from office-based to field-based survey administration at follow-up, may have contributed to the large declines reported by both groups.

Can we afford to offer pre-exposure prophylaxis to MSM in Catalonia? Cost-effectiveness analysis and budget impact assessment

Pre-exposure prophylaxis (PrEP) effectiveness has been well established. This study aims to assess the cost-effectiveness of providing PrEP, estimate the number of eligible MSM, and its budget impact in Catalonia. Cost-effectiveness analysis compared costs of on daily basis and "on demand" PrEP to prevent one infection with lifetime costs of one HIV infection. We estimated the total cost of providing PrEP by estimating number of eligible MSM, and included in the budget impact assessment antiretroviral and laboratory costs. Costs were lower for the on-demand PrEP group by €64015.1 and the incremental benefit was nearly 15 life-years and 17 quality-adjusted life-years gained. The incremental cost-effectiveness ratio (ICER) was cost-effective at €6281.62 when undiscounted PrEP was given daily. On-demand PrEP can be considered cost-saving in 20 years if the price is reduced by 90%. The number of eligible MSM in Catalonia ranges from 5,989 to 10,972. At current antiretroviral costs, the annual cost would range between €25.3-46.7 million/year (on demand PrEP), and €42.9-78.7 million/year (daily basis PrEP). PrEP is most cost-effective if targeted towards groups with high incidence rates of over 3%/year. Beneficial ICER depends on reducing the current price of Truvada® and ensuring that effectiveness is maintained at high levels.

Facilitators and Barriers to Pre-Exposure Prophylaxis Willingness Among Young Men Who Have Sex with Men Who Use Geosocial Networking Applications in California

While correlates of pre-exposure prophylaxis (PrEP) uptake have been explored among older men who have sex with men (MSM), less is known about the facilitators and barriers that encourage uptake among younger MSM (YMSM). This study explores the association between willingness to take PrEP and demographic characteristics, sexual risk, and substance use, and attitudinal factors among YMSM in California who use geosocial networking applications (GSN apps). Based on survey data from YMSM recruited through GSN apps (n = 687), PrEP willingness was positively associated with Hispanic ethnicity [adjusted odds ratio (aOR): 1.73; confidence interval (CI): 1.01-2.98; p = 0.046], concerns about drug effects (aOR: 0.46; CI: 0.33-0.65; p < 0.001), medical mistrust (aOR: 0.71; CI: 0.53-0.96; p < 0.001), and concerns about adherence (aOR: 0.65; CI: 0.49-0.89; p = 0.005). PrEP willingness was positively associated with medium (aOR: 1.87; CI: 1.14-3.07; p = 0.014) and high concern (aOR: 1.84; CI: 1.13-3.01; p < 0.001) about contracting HIV and perceived benefits of taking PrEP (aOR: 2.59; CI: 1.78-3.78; p < 0.001). In addition to emphasizing the benefits of using PrEP, campaigns that address concerns regarding adherence and side effects may increase interest in and demand for PrEP among YMSM. More opportunities are needed to educate YMSM about PrEP, including addressing their concerns about this new prevention strategy. Providers should speak openly and honestly to YMSM considering PrEP about what to do if side effects occur and how to handle missed doses. Outreach using GSN apps for PrEP education and screening may be an effective way to reach YMSM.

HIV testing practices and the potential role of HIV self-testing among men who have sex with men in Mexico

The objective of this study was to characterize HIV testing practices among men who have sex with men in Mexico and intention to use HIV self-testing. In 2012, members of one of the largest social/sexual networking websites for men who have sex with men in Latin America completed an anonymous online survey. This analysis was restricted to HIV-uninfected men who have sex with men residing in Mexico. Multivariable logistic regression models were fit to assess factors associated with HIV testing and intention to use a HIV self-test. Of 4537 respondents, 70.9% reported ever having a HIV test, of whom 75.5% reported testing at least yearly. The majority (94.3%) indicated that they would use a HIV home self-test if it were available. Participants identifying as bisexual less often reported ever HIV testing compared to those identifying as gay/homosexual (adjusted odds ratio = 0.52, 95% confidence interval: 0.44-0.62). Having a physical exam in the past year was associated with increased ever HIV testing (adjusted odds ratio = 4.35, 95% confidence interval: 3.73-5.07), but associated with decreased interest in HIV self-testing (adjusted odds ratio = 0.66, 95% confidence interval: 0.48-0.89). The high intention to use HIV home self-testing supports the use of this method as an acceptable alternative to clinic- or hospital-based HIV testing.

Enhancing HIV Testing and Treatment among Men Who Have Sex with Men in China: A Pilot Model with Two-Rapid Tests, Single Blood Draw Session, and Intensified Case Management in Six Cities in 2013

Objectives

To explore models to improve HIV testing, linkage to care and treatment among men who have sex with men (MSM) in cooperation with community-based organizations (CBOs) in China.

Methods

We introduced a new model for HIV testing services targeting MSM in six cities in 2013.These models introduced provision of rapid HIV testing by CBO staff and streamlined processes for HIV screening, confirmation of initial reactive screening results, and linkage to care among diagnosed people. We monitored attrition along each step of the continuum of care from screening to treatment and compared program performance between 2012 and 2013. According to the providers of two rapid tests (HIV screening), four different services delivery models were examined in 2013: Model A = first screen at CDC, second at CDC (Model A = CDC+CDC), Model B = first and second screens at CBOs (Model B = CBO+CBO), Model C = first screen at CBO, second at Hospital (Model C = CBO+Hosp), and Model D = first screen at CBO, second at CDC (Model D = CBO+CDC). Logistic regressions were performed to assess advantages of different screening models of case finding and case management.

Results

Compared to 2012, the number of HIV screening tests performed for MSM increased 35.8% in 2013 (72,577 in 2013 vs. 53,455 in 2012). We observed a 5.6% increase in proportion of cases screened reactive receiving HIV confirmatory tests (93.9% in 2013 vs. 89.2% in 2012, χ² = 48.52, p<0.001) and 65% reduction in loss to CD4 cell count tests (15% in 2013 vs. 43% in 2012, χ² = 628.85, p<0.001). Regarding linkage to care and treatment, the 2013 pilot showed that the Model D had the highest rate of loss between screening reactive and confirmatory test among the four models, with 18.1% fewer receiving a second screening test and a further 5.9% loss among those receiving HIV confirmatory tests. The Model B and the Model C showed lower losses (0.8% and 1.3%) for newly diagnosed HIV positives receiving CD4 cell count tests, and higher rates of HIV positives referred to designated ART hospitals (88.0% and 93.3%) than the Model A and Model D (4.6% and 5.7% for CD4 cell count test, and 68.9% and 64.4% for referring to designated ART hospitals). The proportion of cases where the screening test was reactive that were commenced on ART was highest in Model C; 52.8% of cases commenced on ART compared to 38.9%, 34.2% and 21.1% in Models A, B and D respectively. Using Model A as a reference group, the multivariate logistic regression results also showed the advantages of Models B, C and D, which increased CD4 cell count test, referral to designated ART hospitals and initiation of ART, when controlling for program city and other factors.

Conclusions

This study has demonstrated that involvement of CBOs in HIV rapid testing provision, streamlining testing and care procedures and early hospital case management can improve testing, linkage to, and retention in care and treatment among MSM in China.

Trends in HIV testing and associated factors among men in South Africa: evidence from 2005, 2008 and 2012 national population-based household surveys

OBJECTIVES

In Sub-Saharan African countries, including South Africa, uptake of human immunodeficiency virus (HIV) testing among men remains a major challenge. Few studies have explored HIV testing uptake among men and factors that influence their testing behaviours. This article explores trends in HIV testing uptake and associated factors among men aged 15 years and older in South Africa using national HIV population-based household surveys conducted in 2005, 2008 and 2012.

STUDY DESIGN

A multistage cross-sectional design was used in the three nationally representative household-based surveys.

METHODS

P-trend Chi-squared statistic was used to analyze changes in HIV testing in relation to demographic factors, and HIV-related risk behaviours across the three surveys. Univariate and multivariate logistic regression models were used to assess the associations between ever testing for HIV, demographic factors and HIV-related risk behaviours.

RESULTS

HIV testing uptake among men was 28% in 2005, 43% in 2008 and 59% in 2012. A trend was also observed in HIV testing by sociodemographic factors, but differences existed within variables. HIV testing uptake was mainly influenced by the effects of selected population characteristics. Reduced likelihood of HIV testing was significantly associated with males aged 15-24 years, Black African race group, being single and unemployed, those residing in urban informal and rural informal areas, and those men who ever had sex.

CONCLUSION

The observed sociodemographic differentials suggest that an effective expansion strategy for HIV testing needs to prioritize those most unlikely to test as identified by the current findings.

Changing Clinician Practices and Attitudes Regarding the Use of Antiretroviral Therapy for HIV Treatment and Prevention

As part of the HPTN 065 study in the Bronx, New York and Washington, the authors, we surveyed clinicians to assess for shifts in their practices and attitudes around HIV treatment and prevention. Antiretroviral therapy (ART)-prescribing clinicians at 39 HIV care sites were offered an anonymous Web-based survey at baseline (2010-2011) and at follow-up (2013). The 165 respondents at baseline and 141 respondents at follow-up had similar characteristics-almost 60% were female, median age was 47 years, two-thirds were physicians, and nearly 80% were HIV specialists. The percentage who reported recommending ART irrespective of CD4 count was higher at follow-up (15% versus 68%), as was the percentage who would initiate ART earlier for patients having unprotected sex with partners of unknown HIV status (64% versus 82%), and for those in HIV-discordant partnerships (75% versus 87%). In line with changing HIV treatment guidelines during 2010 to 2013, clinicians increasingly supported early ART for treatment and prevention.

Impact of Population Recruitment on the HIV Epidemics and the Effectiveness of HIV Prevention Interventions

Mechanistic mathematical models are increasingly used to evaluate the effectiveness of different interventions for HIV prevention and to inform public health decisions. By focusing exclusively on the impact of the interventions, the importance of the demographic processes in these studies is often underestimated. In this paper, we use simple deterministic models to assess the effectiveness of pre-exposure prophylaxis in reducing the HIV transmission and to explore the influence of the recruitment mechanisms on the epidemic and effectiveness projections. We employ three commonly used formulas that correspond to constant, proportional and logistic recruitment and compare the dynamical properties of the resulting models. Our analysis exposes substantial differences in the transient and asymptotic behavior of the models which result in 47 % variation in population size and more than 6 percentage points variation in HIV prevalence over 40 years between models using different recruitment mechanisms. We outline the strong influence of recruitment assumptions on the impact of HIV prevention interventions and conclude that detailed demographic data should be used to inform the integration of recruitment processes in the models before HIV prevention is considered.

Impact of early treatment programs on HIV epidemics: An immunity-based mathematical model

While studies on pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) have demonstrated substantial advantages in controlling HIV transmission, the overall benefits of the programs with early initiation of antiretroviral therapy (ART) have not been fully understood and are still on debate. Here, we develop an immunity-based (CD4+ T cell count based) mathematical model to study the impacts of early treatment programs on HIV epidemics and the overall community-level immunity. The model is parametrized using the HIV prevalence data from South Africa and fully analyzed for stability of equilibria and infection persistence criteria. Using our model, we evaluate the effects of early treatment on the new infection transmission, disease death, basic reproduction number, HIV prevalence, and the community-level immunity. Our model predicts that the programs with early treatments significantly reduce the new infection transmission and increase the community-level immunity, but the treatments alone may not be enough to eliminate HIV epidemics. These findings, including the community-level immunity, might provide helpful information for proper implementation of HIV treatment programs.

Resilience, tipping, and hydra effects in public health: emergent collective behavior in two agent-based models

Background

Collective health behavior often demonstrates counter-intuitive dynamics, sometimes resisting interventions designed to produce change, or even producing effects that are in the opposite direction than intended by the intervention, e.g. lowering infectivity resulting in increased infections. At other times collective health behavior exhibits sudden large-scale change in response to small interventions or change in the environment, a phenomenon often called “tipping.” I hypothesize that these seemingly very different phenomena can all be explained by the same dynamic, a type of collective resilience.

Methods

I compared two simple agent-based models of interactions in networks: a public health behavior game, in which individuals decide whether or not to adopt protective behavior, and a microbial-level game, in which three different strains of bacteria attack each other. I examined the type of networks and other conditions that support a dynamic balance, and determined what changes of conditions will tip the balance.

Results

Both models show lasting dynamic equilibrium and resilience, resulting from negative feedback that supports oscillating coexistence of diversity under a range of conditions. In the public health game, health protection is followed by free-riding defectors, followed by a rise in infection, in long-lasting cycles. In the microbial game, each of three strains takes turns dominating. In both games, the dynamic balance is tipped by lowering the level of local clustering, changing the level of benefit, or lowering infectivity or attack rate. Lowering infectivity has the surprising effect of increasing the numbers of infected individuals. We see parallel results in the microbial game of three bacterial strains, where lowering one strain’s attack rate (analogous to lowering infectivity) increases the numbers of the restrained attacker, a phenomenon captured by the phrase, “the enemy of my enemy is my friend.”

Conclusions

Collective behavior often shows a dynamic balance, resulting from negative feedback, supporting diversity and resisting change. Above certain threshold conditions, the dynamic balance is tipped towards uniformity of behavior. Under a certain range of conditions we see “hydra effects” in which interventions to lower attack rate or infectivity are self-defeating. Simple models of collective behavior can explain these seemingly disparate dynamics.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-2938-8) contains supplementary material, which is available to authorized users.

HIV Treatment in Resource-Limited Environments: Treatment Coverage and Insights

BACKGROUND

The effects of antiretroviral treatment on the HIV epidemic are complex. HIV-infected individuals survive longer with treatment, but are less likely to transmit the disease. The standard coverage measure improves with the deaths of untreated individuals and does not consider the fact that some individuals may acquire the disease and die before receiving treatment, making it susceptible to overestimating the long-run performance of antiretroviral treatment programs.

OBJECTIVE

The objective was to propose an alternative coverage definition to better measure the long-run performance of HIV treatment programs.

METHODS

We introduced cumulative incidence-based coverage as an alternative to measure an HIV treatment program's success. To numerically compare the definitions, we extended a simulation model of HIV disease and treatment to represent a dynamic population that includes uninfected and HIV-infected individuals. Also, we estimated the additional resources required to implement various treatment policies in a resource-limited setting.

RESULTS

In a synthetic population of 600,000 people of which 44,000 (7.6%) are infected, and eligible for treatment with a CD4 count of less than 500 cells/mm(3), assuming a World Health Organization (WHO)-defined coverage rate of 50% of eligible people, and treating these individuals with a single treatment regimen, the gap between the current WHO coverage definition and our proposed one is as much as 16% over a 10-year planning horizon.

CONCLUSIONS

Cumulative incidence-based definition of coverage yields a more accurate representation of the long-run treatment success and along with the WHO and other definitions of coverage provides a better understanding of the HIV treatment progress.

Partner Notification for Reduction of HIV-1 Transmission and Related Costs among Men Who Have Sex with Men: A Mathematical Modeling Study

Background

Earlier antiretroviral treatment initiation prevents new HIV infections. A key problem in HIV prevention and care is the high number of patients diagnosed late, as these undiagnosed patients can continue forward HIV transmission. We modeled the impact on the Dutch men-who-have-sex-with-men (MSM) HIV epidemic and cost-effectiveness of an existing partner notification process for earlier identification of HIV-infected individuals to reduce HIV transmission.

Methods

Reduction in new infections and cost-effectiveness ratios were obtained for the use of partner notification to identify 5% of all new diagnoses (Scenario 1) and 20% of all new diagnoses (Scenario 2), versus no partner notification. Costs and quality adjusted life years (QALYs) were assigned to each disease state and calculated over 5 year increments for a 20 year period.

Results

Partner notification is predicted to avert 18–69 infections (interquartile range [IQR] 13–24; 51–93) over the course of 5 years countrywide to 221–830 (IQR 140–299; 530–1,127) over 20 years for Scenario 1 and 2 respectively. Partner notification was considered cost-effective in the short term, with increasing cost-effectiveness over time: from €41,476 -€41, 736 (IQR €40,529-€42,147; €40,791-€42,397) to €5,773 -€5,887 (€5,134-€7,196; €5,411-€6,552) per QALY gained over a 5 and 20 year period, respectively. The full monetary benefits of partner notification by preventing new HIV infections become more apparent over time.

Conclusions

Partner notification will not lead to the end of the HIV epidemic, but will prevent new infections and be increasingly cost-effectiveness over time.

Measuring the Potential Impact of Combination HIV Prevention in Sub-Saharan Africa

A public health approach to combination HIV prevention is advocated to contain the epidemic in sub-Saharan Africa. We explore the implications of universal access to treatment along with HIV education scale-up in the region. We develop an HIV transmission model to investigate the impacts of universal access to treatment, as well as an analytical framework to estimate the effects of HIV education scale-up on the epidemic. We calibrate the model with data from South Africa and simulate the impacts of universal access to treatment along with HIV education scale-up on prevalence, incidence, and HIV-related deaths over a course of 15 years. Our results show that the impact of combined interventions is significantly larger than the summation of individual intervention impacts (super-additive property). The combined strategy of universal access to treatment and HIV education scale-up decreases the incidence rate by 74% over the course of 15 years, whereas universal access to treatment and HIV education scale up will separately decrease that by 43% and 8%, respectively. Combination HIV prevention could be notably effective in transforming HIV epidemic to a low-level endemicity. Our results suggest that in designing effective combination prevention in sub-Saharan Africa, priorities should be given to achieving universal access to treatment as quickly as possible and improving compliance to condom use.

Evaluating the Impact of Test-and-Treat on the HIV Epidemic among MSM in China Using a Mathematical Model

Background

Various studies have modeled the impact of test-and-treat policies on the HIV epidemics worldwide. However, few modeling studies have taken into account China’s context. To understand the potential effect of test-and-treat on the HIV epidemic among men who have sex with men (MSM) in China, we developed a mathematical model to evaluate the impact of the strategy.

Method

Based on the natural history of the CD4 count of people living with HIV and AIDS (PLWHA), we constructed a dynamic compartmental model of HIV transmission among Chinese MSM to project the number of HIV new infections and prevalence over 10 years. We predicted the annual number of HIV new infections and the total number of MSM living with HIV and AIDS (based on Beijing data) between 2010 and 2022 under the following conditions: (1) current practice (testing rate of 50% and ART coverage of 39%); (2) both testing rate and ART coverage increasing to 70% in 2013; (3) both testing rate and ART coverage increasing to 90% in 2013; and (4) both testing rate and ART coverage increasing gradually every year until 90% since 2013.

Results

Based on our model, if the HIV test-and-treat policy was implemented among Chinese MSM, the total number of HIV new infections over 10 years (2013-2022) would be reduced by 50.6-70.9% compared with the current policy. When ART coverage for PLWHA increased to 58% since 2013, the ‘turning point’ would occur on the curve of HIV new infections by 2015. A 25% reduction in annual number of HIV new infections by 2015 might be achieved if the testing rate increased from 50% to 70% and treatment coverage for PLWHA increased to 55% since 2013.

Conclusion

Implementation of the test-and-treat strategy may significantly reduce HIV new infections among MSM in China. Great efforts need to be made to scale up HIV testing rate and ART coverage among Chinese MSM.

Young, Online and in the Dark: Scaling Up HIV Testing among MSM in ASEAN

Background

Poor HIV testing uptake by MSM may be attributable to unique challenges that are localized in Southeast Asia.

Objective

To characterize MSM who never tested for HIV, to identify correlates of never testing, and to elucidate the perceived barriers to HIV testing.

Methods

The present study used data from the Asian Internet MSM Sex Survey (AIMSS) and restricted the analysis to 4,310 MSM from the ten member countries of the Association of South East Asian Nations (ASEAN).

Results

Among MSM participants from ASEAN in our sample, 1290 (29.9%) reported having never been tested for HIV, 471 (10.9%) tested for HIV more than 2 years ago, and 2186 (50.7%) reported their last test date was between 6 months and two years ago, with only 363 (8.4%) of these men having been tested in the past 6 months. In multivariable logistic regression, younger MSM (age 15–22 years old [AOR: 4.60, 95% CI: 3.04–6.96]), MSM with lower education (secondary school or lower [AOR: 1.37, 95% CI: 1.03–1.83]), MSM who identify as bisexual or heterosexual (compared to gay-identified) (AOR: 1.94, 95% CI: 1.60–2.35), and MSM who had never used a condom with male partners (AOR: 1.61, 95% CI: 1.32–1.97) had higher odds of never been HIV tested. Main reason for not being tested was a low risk perception of HIV exposure (n = 390, 30.2%).

Conclusion

Current HIV prevention response must not leave MSM “in the dark,” but instead meet them where they are by utilizing the Internet creatively through social media and smart phones. As ASEAN Economic Community (AEC) is quickly becoming a reality, so must there be an equally fast and united response to slowing down the HIV epidemics among MSM in ASEAN.

The utility of population-based surveys to describe the continuum of HIV services for key and general populations

Monitoring the cascade or continuum of HIV services - ranging from outreach services to anti-retroviral treatment - has become increasingly important as the focus in prevention moves toward biomedical interventions, in particular, 'Treatment as Prevention.' The HIV continuum typically utilises clinic-based care and treatment monitoring data and helps identify gaps and inform programme improvements. This paper discusses the merits of a population-based survey-informed continuum of services. Surveys provide individual-level, population-based data by sampling persons both in and outside the continuum, which facilitate the estimation of population fractions, such as the proportion of people living with HIV in care, as well as the examination of determinants for being in or outside the continuum. Survey-informed cascades of services may especially benefit key populations at increased risk for HIV infection for who social marginalisation, criminalisation, and stigma result in barriers to access and retention in services, a low social visibility, mobility, and outreach-based services can compromise clinic-based monitoring. Adding CD4+ T-cell count and viral load measurements to such surveys may provide population-level information on viral load suppression, stage of disease, treatment needs, and population-level transmission potential. While routine clinic-based reporting will remain the mainstay of monitoring, a survey-informed service cascade can address some of its limitations and offer additional insights.

Using HIV surveillance registry data to re-link persons to care: the RSVP Project in San Francisco

BACKGROUND

Persons with unsuppressed HIV viral load (VL) who disengage from care may experience poor clinical outcomes and potentially transmit HIV. We assessed the feasibility and yield of using the San Francisco Department of Public Health (SFDPH) enhanced HIV surveillance system (eHARS) to identify and re-engage such persons in care.

METHODS

Using SFDPH eHARS data as of 4/20/2012 (index date), we selected HIV-infected adults who were alive, had no reported VL or CD4 cell count results in the past nine months (proxy for "out-of-care") and a VL >200 copies/mL drawn nine to 15 months earlier. We prioritized cases residing locally for investigation, and used information from eHARS and medical and public health databases to contact them for interview and referral to the SFDPH linkage services (LINCS). Twelve months later, we matched-back to eHARS data to assess how HIV laboratory reporting delays affected original eligibility, and if persons had any HIV laboratory results performed and reported within 12 months after index date ('new labs').

RESULTS

Among 434 eligible persons, 282 were prioritized for investigation, of whom 75 (27%) were interviewed, 79 (28%) could not be located, and 48 (17%) were located out of the area. Among the interviewed, 54 (72%) persons accepted referral to LINCS. Upon match-back to eHARS data, 324 (75%) in total were confirmed as eligible, including 221 (78%) of the investigated; most had new labs.

CONCLUSIONS

Among the investigated persons presumed out-of-care, we interviewed and offered LINCS referral to about one-quarter, demonstrating the feasibility but limited yield of our project. Matching to updated surveillance data revealed that a substantial minority did not disengage from care and that most re-engaged in HIV care. Verifying persons' HIV care status with medical providers and improving timeliness of transfer and cross-jurisdictional sharing of HIV laboratory data may aid future efforts.

HIV testing practices of South African township MSM in the era of expanded access to ART

While men who have sex with men (MSM) in Africa are at high risk for HIV infection, few of those already infected know their status. Effectively promoting frequent HIV testing-of increasing importance with the expanding accessibility of antiretroviral treatment-requires an understanding of the testing practices in this population. To understand men's HIV testing practices, including their behavior, experiences, and perceptions, we conducted in-depth interviews with 81 black South African MSM (ages 20-39), purposively recruited from four townships. Many men in the sample had tested for HIV. While ever having tested seemed to facilitate repeat testing, men still expressed a high level of discomfort with testing. It was common to test after having engaged in risky behavior, thus increasing anxiety about testing that was already present. Fear that they might test HIV positive caused some men to avoid testing until they were clearly sick, and others to avoid testing completely. HIV testing may increase in this population if it becomes a routine practice, instead of being driven by anxiety-inducing incidents. Mobilization through social support might facilitate frequent testing while education about current treatment options is needed.

Motivations to test for HIV among partners in concordant HIV-negative and HIV-discordant gay male couples

Previous studies of HIV testing among gay men describe the motivations, facilitators and barriers, behaviors, and demographic characteristics of individuals who test. What little research focuses on HIV testing among gay men in relationships shows that they do not test regularly or, in some cases, at all-their motivations to test have not been investigated. With so little data on HIV testing for this population, and the continued privileging of individually focused approaches, gay men in relationships fall into a blind spot of research and prevention efforts. This study examined motivations to test for HIV using qualitative data from both partners in 20 gay male couples. Analysis revealed that the partners' motivations were either event-related (e.g., participants testing at the beginning of their relationship or HIV-negative participants in an HIV-discordant relationship testing after risky episode with their discordant primary partner) or partner-related (e.g., participants testing in response to a request or suggestion to test from their primary partner or participants testing out of concern for their primary partner's health and well-being). These data provide insight into relationship-oriented motivations to test for HIV for gay men in relationships and, in doing so, evidence their commitment to their primary partner and relationship. These motivations can be leveraged to increase HIV testing among gay men in relationships, a population that tests less often than single gay men, yet, until recently, has been underserved by prevention efforts.

HIV treatment as prevention: contradictory perspectives from dynamic mathematical models

The preventative effects of antiretroviral therapy for people with HIV have been debated since they were first raised. Models commenced studying the preventive effects of treatment in the 1990s, prior to initial public reports. However, the outcomes of the preventive effects of antiretroviral use were not consistent. Some outcomes of dynamic models were based on unfeasible assumptions, such as no consideration of drug resistance, behavior disinhibition, or economic inputs in poor countries, and unrealistic input variables, for example, overstated initiation time, adherence, coverage, and efficacy of treatment. This paper reviewed dynamic mathematical models to ascertain the complex effects of ART on HIV transmission. This review discusses more conservative inputs and outcomes relative to antiretroviral use in HIV infections in dynamic mathematical models. ART alone cannot eliminate HIV transmission.

What can mathematical models tell us about the relationship between circular migrations and HIV transmission dynamics?

Circular migrations are the periodic movement of individuals between multiple locations, observed in parts of sub-Saharan Africa. Relationships between circular migrations and HIV are complex, entailing interactions between migration frequency, partnership structure, and exposure to acute HIV infection. Mathematical modeling is a useful tool for understanding these interactions. Two modeling classes have dominated the HIV epidemiology and policy literature for the last decade: one a form of compartmental models, the other network models. We construct models from each class, using ordinary differential equations and exponential random graph models, respectively. Our analysis suggests that projected HIV prevalence is highly sensitive to the choice of modeling framework. Assuming initial equal HIV prevalence across locations, compartmental models show no association between migration frequency and HIV prevalence or incidence, while network models show that migrations at frequencies shorter than the acute HIV period predict greater HIV incidence and prevalence compared to longer migration periods. These differences are statistically significant when network models are extended to incorporate a requirement for migrant men's multiple partnerships to occur in different locations. In settings with circular migrations, commonly-used forms of compartmental models appear to miss key components of HIV epidemiology stemming from interactions of relational and viral dynamics.

Modelling in concentrated epidemics: informing epidemic trajectories and assessing prevention approaches

PURPOSE OF THE REVIEW

This review summarizes recent mathematical modelling studies conducted among key populations including MSM, people who inject drugs (PWID), and female sex workers (FSWs) in low prevalence settings used as a marker of concentrated epidemics.

RECENT FINDINGS

Most recent studies focused on MSM, Asian settings or high-income countries, studied the transmission dynamics or modelled pre-exposure prophylaxis, treatment as prevention or behavioural interventions specific to each key population (e.g., needle exchange programme or use of low-dead space syringes for PWID). Biological interventions were deemed effective and cost-effective, though still expensive, and often deemed unlikely to result in HIV elimination if used alone. Targeting high-risk individuals even within key populations improved efficiency. Some studies made innovative use of models to formally evaluate HIV prevention programmes, to interpret genetic or co-infection data, and to address methodological questions and validate epidemiological tools.

CONCLUSION

More work is needed to optimize combination prevention focusing on key populations in different settings. The gaps identified include the limited number of studies modelling drug resistance, structural interventions, treatment as prevention among FSWs, and estimating the contribution of key populations to overall transmission in different settings.

Eradicating syphilis, hepatitis C and HIV in MSM through frequent testing strategies

PURPOSE OF REVIEW

The rates of sexual transmission of HIV, syphilis and hepatitis C in MSM are rising in most countries. Recent research has raised the question of whether increasing testing and treatment of these infections could substantially reduce their transmission.

RECENT FINDINGS

Although mathematical models suggest this strategy could be potentially effective in reducing transmission, there is currently very limited evidence that community-wide incidence has been curtailed by this strategy.

SUMMARY

If increasing in testing is to substantially reduce the incidence of these infections then significant increases in testing are required together with innovative approaches to testing and healthcare delivery. Notwithstanding this, relatively simple approaches to increasing testing are currently underutilized.

Monitored viral load: a measure of HIV treatment outcomes in an outpatient setting in Rhode Island

Community viral load measurements have been postulated to be a population-based biomarker of HIV disease. We propose the use of the monitored community viral load (mCVL) as an aggregate measure of viral load among persons receiving HIV care with available HIV-1 plasma viral loads and applied it to our clinic population from 2003-2010. We demonstrated a reduction in mCVL from 16,589 copies/ml to 11,992 copies/ml that correlated with a rising rate of antiretroviral use and HIV viral suppression; however, differences among risk populations were observed. The mCVL is a useful measure of HIV burden among patients in-care; it may reflect the HIV transmission risk in the community and help target preventive interventions.

Can treatment-based HIV prevention curb the epidemic among gay and other men who have sex with men? A narrative synthesis of increasing evidence for moderating and countervailing effects

As HIV epidemics among gay and other men who have sex with men (GMSM) persist worldwide, the importance of novel prevention approaches is recognised. Evidence that antiretroviral therapy (ART) can decrease the likelihood of infection is informing emerging HIV prevention approaches, encompassing early initiation of treatment as prevention by people living with HIV and use of antiretroviral drugs as pre-exposure prophylaxis for people presumed to be uninfected. Despite widespread excitement, robust evidence of the beneficial effects of ART-based HIV prevention for GMSM remains limited. Also, theoretical models project widely varying effects of ART-based prevention on the future course of HIV epidemics among GMSM, drawing attention to the possible moderating role of differences in the achievements of local HIV responses and the critical importance of sustained protective sexual practices into the future. Ecological analyses and simulations of ongoing epidemics in major gay communities illustrate that the preventive effects of ART in many settings are being offset by increased sexual risk-taking, as reflected in stable or increasing HIV infection rates. Also, the effects of scaling up HIV testing and treatment among GMSM in settings that are often considered prime examples of the success of ART-based prevention may be levelling as ‘scope for improvement’ diminishes. ART-based approaches further extend the HIV prevention toolkit and substantially increase people’s options to protect themselves and others. The future impact of ART-based prevention on HIV epidemics among GMSM ultimately depends on whether heralded responses offset, attenuate or compound the ongoing social and behavioural changes that drive increased sexual risk.

Incarceration is associated with used syringe lending among active injection drug users with detectable plasma HIV-1 RNA: a longitudinal analysis

Background

Informed by recent studies demonstrating the central role of plasma HIV-1 RNA viral load (VL) on HIV transmission, interventions to employ HIV antiretroviral treatment as prevention (TasP) are underway. To optimize these efforts, evidence is needed to identify factors associated with both non-suppressed VL and HIV risk behaviours. Thus, we sought to assess the possible role played by exposure to correctional facilities on VL non-suppression and used syringe lending among HIV-seropositive people who use injection drugs (PWID).

Methods

We used data from the ACCESS study, a community-recruited prospective cohort. We used longitudinal multivariate mixed-effects analyses to estimate the relationship between incarceration and plasma HIV-1 RNA > 500 copies/mL among antiretroviral therapy (ART)-exposed active PWID and, during periods of non-suppression, the relationship between incarceration and used syringe lending.

Results

Between May 1996 and March 2012, 657 ART-exposed PWID were recruited. Incarceration was independently associated with higher odds of VL non-suppression (Adjusted Odds Ratio [AOR] = 1.54, 95% Confidence Interval [95% CI]: 1.10, 2.16). In a separate multivariate model restricted to periods of VL non-suppression, incarceration was independently associated with lending used syringes (AOR = 1.81, 95% CI: 1.03, 3.18).

Conclusions

The current findings demonstrate that incarceration is associated with used syringe lending among active PWID with detectable plasma HIV-1 RNA. Our results provide a possible pathway for the commonly observed association between incarceration and increased risk of HIV transmission. Our results suggest that alternatives to incarceration of non-violent PWID and evidence-based combination HIV prevention interventions for PWID within correctional facilities are urgently needed.

HIV treatment as prevention: the key to an AIDS-free generation

The presence of elevated HIV viral load within blood and genital secretions is a critical driver of transmission events. Long-term suppression of viral load to undetectable levels through the use of antiretroviral therapy is now standard practice for clinical management of HIV. Antiretroviral therapy therefore can play a key role as a means to curb HIV transmission. Results of a randomized clinical trial, in conjunction with several observational studies, have now confirmed that antiretroviral therapy markedly decreases HIV transmission risk. Mathematical models and population-based ecologic studies suggest that further expansion of antiretroviral coverage within current guidelines can play a major role in controlling the spread of HIV. Expansion of so-called "Treatment as Prevention" initiatives relies upon maximal uptake of the HIV continuum-of-care cascade to allow for successful identification of those not yet known to be HIV-infected, engagement of patients in appropriate care, and subsequently achieving sustained virologic suppression in patients with the use of antiretroviral therapy. Since 2010, the Joint United Nations AIDS (UNAIDS) program has called for the inclusion of antiretroviral treatment as a key pillar in the global strategy to control the spread of HIV infection. This has now been invigorated by the release of the World Health Organization's 2013 Consolidated Antiretroviral Therapy Guidelines, recommending treatment to be offered to all HIV-infected individuals with CD4 cell counts below 500/mm³, and, regardless of CD4 cell count, to serodiscordant couples, TB and HBV co-infected individuals, pregnant women, and children below the age of 5 years.