Investigating Voluntary Medical Male Circumcision Program Efficiency Gains through Subpopulation Prioritization: Insights from Application to Zambia

Understanding dynamics and overlapping epidemiologies of HIV, HSV-2, chlamydia, gonorrhea, and syphilis in sexual networks of men who have sex with men

Introduction

We aimed to investigate the overlapping epidemiologies of human immunodeficiency virus (HIV), herpes simplex virus type 2 (HSV-2), chlamydia, gonorrhea, and syphilis in sexual networks of men who have sex with men (MSM), and to explore to what extent the epidemiology of one sexually transmitted infection (STI) relates to or differs from that of another STI.

Methods

An individual-based Monte Carlo simulation model was employed to simulate the concurrent transmission of STIs within diverse sexual networks of MSM. The model simulated sexual partnering, birth, death, and STI transmission within each specific sexual network. The model parameters were chosen based on the current knowledge and understanding of the natural history, transmission, and epidemiology of each considered STI. Associations were measured using the Spearman's rank correlation coefficient (SRCC) and maximal information coefficient (MIC).

Results

A total of 500 sexual networks were simulated by varying the mean and variance of the number of partners for both short-term and all partnerships, degree correlation, and clustering coefficient. HSV-2 had the highest current infection prevalence across the simulations, followed by HIV, chlamydia, syphilis, and gonorrhea. Threshold and saturation effects emerged in the relationship between STIs across the simulated networks, and all STIs demonstrated moderate to strong associations. The strongest current infection prevalence association was between HIV and gonorrhea, with an SRCC of 0.84 (95% CI: 0.80-0.87) and an MIC of 0.81 (95% CI: 0.74-0.88). The weakest association was between HSV-2 and syphilis, with an SRCC of 0.54 (95% CI: 0.48-0.59) and an MIC of 0.57 (95% CI, 0.49-0.65). Gonorrhea exhibited the strongest associations with the other STIs while syphilis had the weakest associations. Across the simulated networks, proportions of the population with zero, one, two, three, four, and five concurrent STI infections were 48.6, 37.7, 11.1, 2.4, 0.3, and < 0.1%, respectively. For lifetime exposure to these infections, these proportions were 13.6, 21.0, 22.9, 24.3, 13.4, and 4.8%, respectively.

Conclusion

STI epidemiologies demonstrate substantial overlap and associations, alongside nuanced differences that shape a unique pattern for each STI. Gonorrhea exhibits an "intermediate STI epidemiology," reflected by the highest average correlation coefficient with other STIs.

Infectious Disease Modelling of HIV Prevention Interventions: A Systematic Review and Narrative Synthesis of Compartmental Models

BACKGROUND

The HIV epidemic remains a major public health problem. Critical to transmission control are HIV prevention strategies with new interventions continuing to be developed. Mathematical models are important for understanding the potential impact of these interventions and supporting policy decisions. This systematic review aims to answer the following question: when a new HIV prevention intervention is being considered or designed, what information regarding it is necessary to include in a compartmental model to provide useful insights to policy makers? The primary objective of this review is therefore to assess suitability of current compartmental HIV prevention models for informing policy development.

METHODS

Articles published in EMBASE, Medline, Econlit, and Global Health were screened. Included studies were identified using permutations of (i) HIV, (ii) pre-exposure prophylaxis (PrEP), circumcision (both voluntary male circumcision [VMMC] and early-infant male circumcision [EIMC]), and vaccination, and (iii) modelling. Data extraction focused on study design, model structure, and intervention incorporation into models. Article quality was assessed using the TRACE (TRAnsparent and Comprehensive Ecological modelling documentation) criteria for mathematical models.

RESULTS

Of 837 articles screened, 48 articles were included in the review, with 32 unique mathematical models identified. The substantial majority of studies included PrEP (83%), whilst fewer modelled circumcision (54%), and only a few focussed on vaccination (10%). Data evaluation, implementation verification, and model output corroboration were identified as areas of poorer model quality. Parameters commonly included in the mathematical models were intervention uptake and effectiveness, with additional intervention-specific common parameters identified. We identified key modelling gaps; critically, models insufficiently incorporate multiple interventions acting simultaneously. Additionally, population subgroups were generally poorly represented-with future models requiring improved incorporation of ethnicity and sexual risk group stratification-and many models contained inappropriate data in parameterisation which will affect output accuracy.

CONCLUSIONS

This review identified gaps in compartmental models to date and suggests areas of improvement for models focusing on new prevention interventions. Resolution of such gaps within future models will ensure greater robustness and transparency, and enable more accurate assessment of the impact that new interventions may have, thereby providing more meaningful guidance to policy makers.

Costs and Cost-Effectiveness of Biomedical, Non-Surgical HIV Prevention Interventions: A Systematic Literature Review

BACKGROUND

Considerable evidence on the costs and cost-effectiveness of biomedical, non-surgical interventions to prevent human immunodeficiency virus (HIV) transmission has been generated over the last decade. This study aims to synthesize findings and identify remaining knowledge gaps to suggest future research priorities.

METHODS

A systematic literature review was carried out in August 2020 using the MEDLINE, Embase, Global Health and EconLit databases to retrieve economic evaluations and costing studies of oral pre-exposure prophylaxis (PrEP), injectable long-acting PrEP, vaginal microbicide rings and gels, HIV vaccines and broadly neutralizing antibodies. Studies reporting costs from the provider or societal perspective were included in the analysis. Those reporting on behavioural methods of prevention, condoms and surgical approaches (voluntary medical male circumcision) were excluded. The quality of reporting of the included studies was assessed using published checklists.

RESULTS

We identified 3007 citations, of which 87 studies were retained. Most were set in low- and middle-income countries (LMICs; n = 53) and focused on the costs and/or cost-effectiveness of oral PrEP regimens (n = 70). Model-based economic evaluations were the most frequent study design; only two trial-based cost-effectiveness analyses and nine costing studies were found. Less than half of the studies provided practical details on how the intervention would be delivered by the health system, and only three of these, all in LMICs, explicitly focused on service integration and its implication for delivery costs. 'Real-world' programme delivery mechanisms and costs of intervention delivery were rarely considered. PrEP technologies were generally found to be cost-effective only when targeting high-risk subpopulations. Single-dose HIV vaccines are expected to be cost-effective for all groups despite substantial uncertainty around pricing.

CONCLUSIONS

A lack of primary, detailed and updated cost data, including above-service level costs, from a variety of settings makes it difficult to evaluate the cost-effectiveness of specific delivery modes at scale, or to evaluate strategies for services integration. Closing this evidence gap around real-world implementation is vital, not least because the strategies targeting high-risk groups that are recommended by PrEP models may incur substantially higher costs and be of limited practical feasibility in some settings.

Maximizing the Impact of Voluntary Medical Male Circumcision for HIV Prevention in Zambia by Targeting High-Risk Men: A Pre/Post Program Evaluation

A well-documented barrier to voluntary medical male circumcision (VMMC) is financial loss due to the missed opportunity to work while undergoing and recovering from VMMC. We implemented a 2-phased outcome evaluation to explore how enhanced demand creation and financial compensation equivalent to 3 days of missed work influence uptake of VMMC among men at high risk of HIV exposure in Zambia. In Phase 1, we implemented human-centered design-informed interpersonal communication. In Phase 2, financial compensation of ZMW 200 (~ US$17) was added. The proportion of men undergoing circumcision was significantly higher in Phase 2 compared to Phase 1 (38% vs 3%). The cost of demand creation and compensation per client circumcised was $151.54 in Phase 1 and $34.93 in Phase 2. Financial compensation is a cost-effective strategy for increasing VMMC uptake among high-risk men in Zambia, and VMMC programs may consider similar interventions suited to their context.

Uptake of voluntary medical male circumcision among men with sexually transmitted infections in Lilongwe, Malawi: a protocol for a pre-interventional and post-interventional study

INTRODUCTION

Voluntary medical male circumcision (VMMC) is one of the key interventions for HIV prevention. However, its uptake among men in Malawi is low. Implementation science strategies for demand creation of VMMC increase uptake. We designed an implementation science demand-creation intervention to increase the uptake of VMMC among men with sexually transmitted infections (STIs).

METHODS AND ANALYSIS

We designed a pragmatic pre-interventional and post-interventional quasi-experimental study combined with a prospective observational design to determine the uptake, acceptability, appropriateness and feasibility of a multifaceted intervention for scale up of uptake of VMMC among men with STIs at Bwaila STI clinic in Lilongwe, Malawi. The intervention includes transport reimbursement (R), intensified health education (I) and short messaging service (SMS)/telephonic tracing (Te) (RITe). The intervention will be implemented in phases: pre-implementation and implementation. Pre-implementation phase will be used for collecting baseline data, while the RITe intervention will be rolled-out in the implementation phase. The RITe intervention will be implemented in a sequential and incremental manner called implementation blocks: block 1: intensified health education; block 2: intensified health education and SMS/telephonic tracing; and block 3: intensified health education, SMS/telephonic tracing and transport reimbursement. The target sample size is 80 uncircumcised men for each intervention block, including the pre-implementation sample, making a total of 320 men (280 total, 70 per block will be surveyed). The primary outcome is uptake of VMMC during the implementation period. Mixed methods assessments will be conducted to evaluate the acceptability, appropriateness and feasibility of the RITe intervention.

ETHICS AND DISSEMINATION

The study protocol was approved by the Malawi's National Health Sciences Research Ethics Committee (approval number: 19/10/2412), University of North Carolina at Chapel Hill's Institutional Review Board (approval number: 19-2559) and University of the Witwatersrand's Health Research Ethics Committee (approval number: M200328). Results will be disseminated via publication in a peer-reviewed journal and presentations at relevant scientific conferences and meetings.

TRIAL REGISTRATION NUMBER

NCT04677374.

Analytic Characterization of the Herpes Simplex Virus Type 2 Epidemic in the United States, 1950-2050

Background

We analytically characterized the past, present, and future levels and trends of the national herpes simplex virus type 2 (HSV-2) epidemic in the United States.

Methods

A population-level mathematical model was constructed to describe HSV-2 transmission dynamics and was fitted to the data series of the National Health and Nutrition Examination Survey.

Results

Over 1950–2050, antibody prevalence (seroprevalence) increased rapidly from 1960, peaking at 19.9% in 1983 in those aged 15–49 years, before reversing course to decline to 13.2% by 2020 and 8.5% by 2050. Incidence rate peaked in 1971 at 11.9 per 1000 person-years, before declining by 59% by 2020 and 70% by 2050. Annual number of new infections peaked at 1 033 000 in 1978, before declining to 667 000 by 2020 and 600 000 by 2050. Women were disproportionately affected, averaging 75% higher seroprevalence, 95% higher incidence rate, and 71% higher annual number of infections. In 2020, 78% of infections were acquired by those 15–34 years of age.

Conclusions

The epidemic has undergone a major transition over a century, with the greatest impact in those 15–34 years of age. In addition to 47 million prevalent infections in 2020, high incidence will persist over the next 3 decades, adding >600 000 new infections every year.

Sexually transmitted infections (STI) and antenatal care (ANC) clinics in Malawi: effective platforms for improving engagement of men at high HIV risk with voluntary medical male circumcision services

Introduction

Voluntary medical male circumcision (VMMC), an effective HIV prevention programme for men, is implemented in East and Southern Africa. Approximately 50% of VMMC clients are aged below 15 years. More targeted interventions to reach older men and others at higher short-term HIV risk are needed.

Methods

We implemented a quality improvement project testing the effectiveness of an active referral-based VMMC recruitment approach, targeting men attending STI clinics and those escorting partners to antenatal care (ANC) clinics, at Bwaila Hospital in Lilongwe, Malawi. We compared the proportions aged older than 15 years among men who received VMMC following referral from STI and ANC clinics with those among men referred from standard community mobilisation. We also analysed referral cascades to VMMC.

Results

In total, 330 clients were circumcised after referral from STI (242) and ANC (88) clinics, as compared with 3839 other clients attributed to standard community mobilisation. All clients from ANC and STI clinics were aged over 15 years, as compared with 69% from standard community mobilisation. STI clinics had a higher conversion rate from counselling to VMMC than ANC (12% vs 9%) and a higher contribution to total circumcisions performed at the VMMC clinic (6% vs 2%).

Conclusions

Integrating VMMC recruitment and follow-up in STI and ANC clinics co-located with VMMC services can augment demand creation and targeting of men at risk of HIV, based on age and STI history. This approach can be replicated at least in similar health facilities with ANC and STI services in close proximity to VMMC service delivery.

Age could be driving variable SARS-CoV-2 epidemic trajectories worldwide

Current geographic spread of documented severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections shows heterogeneity. This study explores the role of age in potentially driving differentials in infection spread, epidemic potential, and rates of disease severity and mortality across countries. An age-stratified deterministic mathematical model that describes SARS-CoV-2 transmission dynamics was applied to 159 countries and territories with a population ≥1 million. Assuming worst-case scenario for the pandemic, the results indicate that there could be stark regional differences in epidemic trajectories driven by differences in the distribution of the population by age. In the African Region (median age: 18.9 years), the median R0 was 1.05 versus 2.05 in the European Region (median age: 41.7 years), and the median (per 100 persons) for the final cumulative infection incidence was 22.5 (versus 69.0), for severe and/or critical disease cases rate was 3.3 (versus 13.0), and for death rate was 0.5 (versus 3.9). Age could be a driver of variable SARS-CoV-2 epidemic trajectories worldwide. Countries with sizable adult and/or elderly populations and smaller children populations may experience large and rapid epidemics in absence of interventions. Meanwhile, countries with predominantly younger age cohorts may experience smaller and slower epidemics. These predictions, however, should not lead to complacency, as the pandemic could still have a heavy toll nearly everywhere.

Epidemiological Impact of Novel Preventive and Therapeutic HSV-2 Vaccination in the United States: Mathematical Modeling Analyses

This study aims to inform herpes simplex virus type 2 (HSV-2) vaccine development, licensure, and implementation by delineating the population-level impact of vaccination. Mathematical models were constructed to describe the transmission dynamics in presence of prophylactic or therapeutic vaccines assuming 50% efficacy, with application to the United States. Catch-up prophylactic vaccination will reduce, by 2050, annual number of new infections by 58%, incidence rate by 60%, seroprevalence by 21%, and avert yearly as much as 350,000 infections. Number of vaccinations needed to avert one infection was only 50 by 2050, 34 by prioritizing those aged 15-19 years, 4 by prioritizing the highest sexual risk group, 43 by prioritizing women, and 47 by prioritizing men. Therapeutic vaccination of infected adults with symptomatic disease will reduce, by 2050, annual number of new infections by 12%, incidence rate by 13%, seroprevalence by 4%, and avert yearly as much as 76,000 infections. Number of vaccinations needed to avert one infection was eight by 2050, two by prioritizing those aged 15-19 years, three by prioritizing the highest sexual risk group, seven by prioritizing men, and ten by prioritizing women. HSV-2 vaccination offers an impactful and cost-effective intervention to prevent genital herpes medical and psychosexual disease burden.

Targeting for male medical circumcision: profiles from two South African cities

Male circumcision is considered by some to be an acceptable global approach to reduce HIV infections. Consequently, many governments in sub-Saharan Africa run voluntary male circumcision programmes. South Africa also provides male circumcision for free at state clinics and hospitals. Very little is known about the men who use this service. This study uses data from Cape Town, a sample of 1194 in 2016, and from Mangaung, a sample of 277 in 2017 and 2018, to fill this gap. The study finds that age targeting is inadequate, risk targeting is absent, and religious and cultural factors have a negative effect on the cost-efficiency of the service in the long run.

Service delivery interventions to increase uptake of voluntary medical male circumcision for HIV prevention: A systematic review

BACKGROUND

Voluntary medical male circumcision (VMMC) remains an essential component of combination HIV prevention services, particularly in priority countries in sub-Saharan Africa. As VMMC programs seek to maximize impact and efficiency, and to support World Health Organization guidance, specific uptake-enhancing strategies are critical to identify.

METHODS

We systematically reviewed the literature to evaluate the impact of service delivery interventions (e.g., facility layout, service co-location, mobile outreach) on VMMC uptake among adolescent and adult men. For the main effectiveness review, we searched for publications or conference abstracts that measured VMMC uptake or uptake of HIV testing or risk reduction counselling within VMMC services. We synthesized data by coding categories and outcomes. We also reviewed studies assessing acceptability, values/preferences, costs, and feasibility.

RESULTS

Four randomized controlled trials and five observational studies were included in the effectiveness review. Studies took place in South Africa, Tanzania, Uganda, Zambia, and Zimbabwe. They assessed a range of service delivery innovations, including community-, school-, and facility-based interventions. Overall, interventions increased VMMC uptake; some successfully improved uptake among age-specific subpopulations, but urban-rural stratification showed no clear trends. Interventions that increased adult men's uptake included mobile services (compared to static facilities), home-based testing with active referral follow-up, and facility-based HIV testing with enhanced comprehensive sexual education. Six acceptability studies suggested interventions were generally perceived to help men choose to get circumcised. Eleven cost studies suggested interventions create economies-of-scale and efficiencies. Three studies suggested such interventions were feasible, improving facility preparedness, service quality and quantity, and efficiencies.

CONCLUSIONS

Innovative changes in male-centered VMMC services can improve adult men's and adolescent boys' VMMC uptake. Limited evidence on interventions that enhance access and acceptability show promising results, but evidence gaps persist due to inconsistent intervention definition and delivery, due in part to contextual relevance and limited age disaggregation.

Male circumcision and global HIV/AIDS epidemic challenges

Background

Given the devastating mortality and morbidity associated with HIV/AIDS, many potential prevention measures against HIV infection continue to be explored. Most prevention methods are in the realm of sexual behavior change. However, of all aspects of human behavior, it is sexual behavior that is least amenable to change. Newer and simpler interventions are therefore required. Male circumcision, the surgical removal of some or all of the foreskin (or prepuce) from the penis, is one of the ways being promoted as a preventive measure. This paper reviews the scientific basis and evidence for the efficacy of male circumcision within the context of the global challenges involved.

Main body

We reviewed articles with emphasis on male circumcision and HIV/AIDS transmission. Published abstracts of presentations at international scientific meetings were also reviewed.

Conclusions

Current epidemiological evidence supports the promotion of male circumcision for HIV prevention, especially in populations with high HIV prevalence and low circumcision rates. Three notable randomized control trials strengthen the case for applied research studies to demonstrate that safe male circumcision is protective at the population level, particularly as ideal and well-resourced conditions of a randomized trial are often not replicated in other service delivery settings. Ethically and culturally responsive strategies in promoting circumcision in a culturally heterogenous world need to be developed, too. Male circumcision should also be viewed as a complementary measure along with other proven approaches to turn the HIV/AIDS epidemic around.

Identifying population segments for effective intervention design and targeting using unsupervised machine learning: an end-to-end guide

One-size-fits-all interventions that aim to change behavior are a missed opportunity to improve human health and well-being, as they do not target the different reasons that drive people's choices and behaviors. Psycho-behavioral segmentation is an approach to uncover such differences and enable the design of targeted interventions, but is rarely implemented at scale in global development. In part, this may be due to the many choices program designers and data scientists face, and the lack of available guidance through the process. Effective segmentation encompasses conceptualization and selection of the dimensions to segment on, which often requires the design of suitable qualitative and quantitative primary research. The choice of algorithm and its parameters also profoundly shape the resulting output and how useful the results are in the field. Analytical outputs are not self-explanatory and need to be subjectively evaluated and described. Finally, segments can be prioritized and targeted with matching interventions via appropriate channels. Here, we provide an end-to-end overview of all the stages from planning, designing field-based research, analyzing, and implementing a psycho-behavioral segmentation solution. We illustrate the choices and critical steps along the way, and discuss a case study of segmentation for voluntary medical male circumcision that implemented the method described here. Though our examples mostly draw on health interventions in the developing world, the principles in this approach can be used in any context where understanding human heterogeneity in driving behavior change is valuable.

Scaling Up Voluntary Medical Male Circumcision for Human Immunodeficiency Virus Prevention for Adolescents and Young Adult Men: A Modeling Analysis of Implementation and Impact in Selected Countries

Background

The new World Health Organization and Joint United Nations Programme on HIV/AIDS strategic framework for voluntary medical male circumcision (VMMC) aims to increase VMMC coverage among males aged 10-29 years in priority settings to 90% by 2021. We use mathematical modeling to assess the likelihood that selected countries will achieve this objective, given their historical VMMC progress and current implementation options.

Methods

We use the Decision Makers' Program Planning Toolkit, version 2, to examine 4 ambitious but feasible scenarios for scaling up VMMC coverage from 2017 through 2021, inclusive in Lesotho, Malawi, Mozambique, Namibia, South Africa, Swaziland, Tanzania, Uganda, and Zimbabwe.

Results

Tanzania is the only country that would reach the goal of 90% VMMC coverage in 10- to 29-year-olds by the end of 2021 in the scenarios assessed, and this was true in 3 of the scenarios studied. Mozambique, South Africa, and Lesotho would come close to reaching the objective only in the most ambitious scenario examined.

Conclusions

Major changes in VMMC implementation in most countries will be required to increase the proportion of circumcised 10- to 29-year-olds to 90% by the end of 2021. Scaling up VMMC coverage in males aged 10-29 years will require significantly increasing the number of circumcisions provided to 10- to 14-year-olds and 15- to 29-year-olds.

Identifying population segments for effective intervention design and targeting using unsupervised machine learning: an end-to-end guide

One-size-fits-all interventions that aim to change behavior are a missed opportunity to improve human health and well-being, as they do not target the different reasons that drive people’s choices and behaviors. Psycho-behavioral segmentation is an approach to uncover such differences and enable the design of targeted interventions, but is rarely implemented at scale in global development. In part, this may be due to the many choices program designers and data scientists face, and the lack of available guidance through the process. Effective segmentation encompasses conceptualization and selection of the dimensions to segment on, which often requires the design of suitable qualitative and quantitative primary research. The choice of algorithm and its parameters also profoundly shape the resulting output and how useful the results are in the field. Analytical outputs are not self-explanatory and need to be subjectively evaluated and described. Finally, segments can be prioritized and targeted with matching interventions via appropriate channels. Here, we provide an end-to-end overview of all the stages from planning, designing field-based research, analyzing, and implementing a psycho-behavioral segmentation solution. We illustrate the choices and critical steps along the way, and discuss a case study of segmentation for voluntary medical male circumcision that implemented the method described here. Though our examples mostly draw on health interventions in the developing world, the principles in this approach can be used in any context where understanding human heterogeneity in driving behavior change is valuable.

Treatment as prevention for hepatitis C virus in Pakistan: mathematical modelling projections

OBJECTIVE

Direct-acting antivirals have opened an opportunity for controlling hepatitis C virus (HCV) infection in Pakistan, where 10% of the global infection burden is found. We aimed to evaluate the implications of five treatment programme scenarios for HCV treatment as prevention (HCV-TasP) in Pakistan.

DESIGN

An age-structured mathematical model was used to evaluate programme impact using epidemiological and programme indicators.

SETTING

Total Pakistan population.

PARTICIPANTS

Total Pakistan HCV-infected population.

INTERVENTIONS

HCV treatment programme scenarios from 2018 up to 2030.

RESULTS

By 2030 across the five HCV-TasP scenarios, 0.6-7.3 million treatments were administered, treatment coverage reached between 3.7% and 98.7%, prevalence of chronic infection reached 2.4%-0.03%, incidence reduction ranged between 41% and 99%, program-attributed reduction in incidence rate ranged between 7.2% and 98.5% and number of averted infections ranged between 126 221 and 750 547. Annual incidence rate reduction in the first decade of the programme was around 6%-18%. Number of treatments needed to prevent one new infection ranged between 4.7-9.8, at a drug cost of about US$900. Cost of the programme by 2030, in the most ambitious elimination scenario, reached US$708 million. Stipulated WHO target for 2030 cannot be accomplished without scaling up treatment to 490 000 per year, and maintaining it for a decade.

CONCLUSION

HCV-TasP is a highly impactful and potent approach to control Pakistan's HCV epidemic and achieve elimination by 2030.

Cost-effectiveness of HIV Prevention Interventions in Sub-Saharan Africa: A Systematic Review

BACKGROUND

Sub-Saharan Africa carries the highest HIV burden globally. It is important to understand how interventions cost-effectively fit within guidelines and implementation plans, especially in low- and middle-income settings. We reviewed the evidence from economic evaluations of HIV prevention interventions in sub-Saharan Africa to help inform the allocation of limited resources.

METHODS

We searched PubMed, Web of Science, Econ-Lit, Embase, and African Index Medicus. We included studies published between January 2009 and December 2018 reporting cost-effectiveness estimates of HIV prevention interventions. We extracted health outcomes and cost-effectiveness ratios (CERs) and evaluated study quality using the CHEERS checklist.

FINDINGS

60 studies met the full inclusion criteria. Prevention of mother-to-child transmission interventions had the lowest median CERs ($1144/HIV infection averted and $191/DALY averted), while pre-exposure prophylaxis interventions had the highest ($13,267/HIA and $799/DALY averted). Structural interventions (partner notification, cash transfer programs) have similar CERs ($3576/HIA and $392/DALY averted) to male circumcision ($2965/HIA) and were more favourable to treatment-as-prevention interventions ($7903/HIA and $890/DALY averted). Most interventions showed increased cost-effectiveness when prioritizing specific target groups based on age and risk.

INTERPRETATION

The presented cost-effectiveness information can aid policy makers and other stakeholders as they develop guidelines and programming for HIV prevention plans in resource-constrained settings.

Characterizing the transitioning epidemiology of herpes simplex virus type 1 in the USA: model-based predictions

BACKGROUND

Herpes simplex virus type 1 (HSV-1) is a prevalent lifelong infection that appears to be undergoing an epidemiologic transition in the United States (US). Using an analytical approach, this study aimed to characterize HSV-1 transitioning epidemiology and estimate its epidemiologic indicators, past, present, and future.

METHODS

An age-structured mathematical model was developed to describe HSV-1 transmission through oral and sexual modes of transmission. The model was fitted to the National Health and Nutrition Examination Surveys, 1976-2016 data series.

RESULTS

HSV-1 seroprevalence was projected to decline from 61.5% in 1970 to 54.8% in 2018, 48.5% in 2050, and 42.0% in 2100. In < 3 decades, seroprevalence declined by > 30% for those aged 0-19 years, but < 5% for those aged > 60. Meanwhile, the number of new infections per year (oral and genital) was persistent at 2,762,000 in 1970, 2,941,000 in 2018, 2,933,000 in 2050, and 2,960,000 in 2100. Of this total, genital acquisitions contributed 252,000 infections in 1970, 410,000 in 2018, 478,000 in 2050, and 440,000 in 2100-a quarter of which are symptomatic with clinical manifestations. For those aged 15-49 years, nearly 25% of incident infections are genital. Most genital acquisitions (> 85%) were due to oral-to-genital transmission through oral sex, as opposed to genital-to-genital transmission through sexual intercourse.

CONCLUSION

HSV-1 epidemiology is undergoing a remarkable transition in the US, with less exposure in childhood and more in adulthood, and less oral but more genital acquisition. HSV-1 will persist as a widely prevalent infection, with ever-increasing genital disease burden.

Who to Test for Hepatitis C Virus in the Middle East and North Africa?: Pooled Analyses of 2,500 Prevalence Measures, Including 49 Million Tests

Expanding hepatitis C virus (HCV) treatment coverage is challenged by limited testing and diagnosis. This study assessed the risk of exposure, for the Middle East and North Africa, by population, yields of testing, and program efficiency of testing strategies. A standardized and systematically assembled database of 2,542 HCV antibody prevalence studies on 49 million individuals was analyzed. Random effects meta-analyses were conducted to estimate pooled measures for risk of exposure, risk ratio (RR) of exposure, and yields of testing. Program expansion path curves were calculated to assess program efficiency. Countries clustered into two patterns: generalized versus concentrated epidemics. In generalized epidemics (Egypt and Pakistan) relative to general populations, RR of exposure was 6.8 for people who inject drugs (PWID), 6.7 for populations with liver conditions, and 5.0 for populations with high-risk health care exposures. In concentrated epidemics (remaining countries), corresponding RRs were 97.2, 45.1, and 22.2, respectively. In generalized epidemics, the number of tests needed to identify a chronic infection was 2.5 for PWID, 2.4 for populations with liver conditions, 2.7 for populations with high-risk health care exposures, and 14.2 for general populations. In concentrated epidemics, corresponding numbers were 2.8, 8.6, 5.1, and 222.2, respectively. Program expansion path curves demonstrated major gains in program efficiency by targeting specific populations. Risk of exposure varies immensely by population and shows a distinctive hierarchy, particularly in concentrated epidemics. Testing strategies can be much more efficient through population prioritization by risk of exposure. General population testing is not programmatically efficient in concentrated epidemics.

Data triangulation to estimate age-specific coverage of voluntary medical male circumcision for HIV prevention in four Kenyan counties

BACKGROUND

Kenya is 1 of 14 priority countries in Africa scaling up voluntary medical male circumcision (VMMC) for HIV prevention following the recommendations of the World Health Organization and the Joint United Nations Programme on HIV/AIDS. To inform VMMC target setting, we modeled the impact of circumcising specific client age groups across several Kenyan geographic areas.

METHODS

The Decision Makers' Program Planning Tool, Version 2 (DMPPT 2) was applied in Kisumu, Siaya, Homa Bay, and Migori counties. Initial modeling done in mid-2016 showed coverage estimates above 100% in age groups and geographic areas where demand for VMMC continued to be high. On the basis of information obtained from country policy makers and VMMC program implementers, we adjusted circumcision coverage for duplicate reporting, county-level population estimates, migration across county boundaries for VMMC services, and replacement of traditional circumcision with circumcisions in the VMMC program. To address residual inflated coverage following these adjustments we applied county-specific correction factors computed by triangulating model results with coverage estimates from population surveys.

RESULTS

A program record review identified duplicate reporting in Homa Bay, Kisumu, and Siaya. Using county population estimates from the Kenya National Bureau of Statistics, we found that adjusting for migration and correcting for replacement of traditional circumcision with VMMC led to lower estimates of 2016 male circumcision coverage especially for Kisumu, Migori, and Siaya. Even after addressing these issues, overestimation of 2016 male circumcision coverage persisted, especially in Homa Bay. We estimated male circumcision coverage in 2016 by applying correction factors. Modeled estimates for 2016 circumcision coverage for the 10- to 14-year age group ranged from 50% in Homa Bay to approximately 90% in Kisumu. Results for the 15- to 19-year age group suggest almost complete coverage in Kisumu, Migori, and Siaya. Coverage for the 20- to 24-year age group ranged from about 80% in Siaya to about 90% in Homa Bay, coverage for those aged 25-29 years ranged from about 60% in Siaya to 80% in Migori, and coverage in those aged 30-34 years ranged from about 50% in Siaya to about 70% in Migori.

CONCLUSIONS

Our analysis points to solutions for some of the data issues encountered in Kenya. Kenya is the first country in which these data issues have been encountered because baseline circumcision rates were high. We anticipate that some of the modeling methods we developed for Kenya will be applicable in other countries.

The impact of market segmentation and social marketing on uptake of preventive programmes: the example of voluntary medical male circumcision. A literature review

Background: The business world has long recognized the power of defining discrete audiences within a target population. However, market segmentation's full potential has not been applied to the public health context. While some broad elements of market segmentation (e.g., age, geography) are considered, a nuanced look at behavioural and psychographic segmentation, which could greatly enhance the possibility of lasting behaviour change, is often missing.   Segmentation, and the associated mindset which acknowledges the multi-dimensional differences between people, allows service providers, implementers, policymakers, and government officials to target initiatives and lead to a greater likelihood of lasting behavioural change. This paper investigates what segmentation is, how it has been applied to voluntary medical male circumcision (VMMC), how it can be applied in development, and the challenges in both measuring and adopting segmentation as part of program design. Methods: We performed a detailed search of peer-reviewed literature using PubMed, ProQuest, ScienceDirect, Google Scholar, and the abstract directories of the International AIDS Society (IAS) published between January 2015 and September 2018. We also accessed articles from business databases such as the Harvard Business Review.   Results: Results from a VMMC-focused intervention that successfully designed and delivered segmentation-based programs in two countries demonstrated that it is possible to adapt private sector approaches. However, within the sector of global development that is most familiar with segmentation, these efforts rarely go beyond basic demographic segments. Conclusions: Existing published material tends not to measure the impact of segmentation itself, but the impact of the intervention to which segmentation was applied, which makes it challenging for the development sector to invest in the approach without evidence that it works. Nonetheless, the experiences of segmentation and demand creation for VMMC do highlight the opportunity for better integrating this approach in HIV prevention and in global development and measurement initiatives.

Use of routine HIV testing data for early detection of emerging HIV epidemics in high-risk subpopulations: A concept demonstration study

Introduction

HIV epidemics in hard-to-reach high-risk subpopulations are often discovered years after epidemic emergence in settings with poor surveillance infrastructure. Using hypothesis-generation modeling, we aimed to investigate and demonstrate the concept of using routine HIV testing data to identify and characterize hidden epidemics in high-risk subpopulations. We also compared this approach to surveillance based on AIDS case notifications.

Methods

A deterministic mathematical model was developed to simulate an emerging HIV epidemic in a high-risk subpopulation. A stochastic Monte Carlo simulation was implemented on the total population to simulate the sampling process of generating routine HIV testing data. Epidemiological measures were estimated on the simulated epidemic and on the generated testing sample. Sensitivity analyses were conducted on the results.

Results

In the simulated epidemic, HIV prevalence saturated at 32% in the high-risk subpopulation and at 0.33% in the total population. The epidemic started its emerging-epidemic phase 28 years after infection introduction, and saturated 67 years after infection introduction. In the simulated HIV testing sample, a significant time trend in prevalence was identified, and the generated metrics of epidemic emergence and saturation were similar to those of the simulated epidemic. The epidemic was identified 4.0 (95% CI 3.4–4.6) years after epidemic emergence using routine HIV testing, but 29.7 (95% CI 15.8–52.1) years after emergence using AIDS case notifications. In the sensitivity analyses, none of the sampling biases affected the conclusion of an emerging epidemic, but some affected the estimated epidemic growth rate.

Conclusions

Routine HIV testing data provides a tool to identify and characterize hidden and emerging epidemics in high-risk subpopulations. This approach can be specially useful in resource-limited settings, and can be applied alone, or along with other complementary data, to provide a meaningful characterization of emerging but hidden epidemics.

Does infection with Chlamydia trachomatis induce long-lasting partial immunity? Insights from mathematical modelling

OBJECTIVES

To explore whether existence of long-lasting partial immunity against reinfection with Chlamydia trachomatis is necessary to explain C. trachomatis prevalence patterns by age and sexual risk, and to provide a plausible estimate for the effect size, defined here as a reduction in susceptibility to reinfection.

METHODS

A population-based mathematical model was constructed to describe C. trachomatis natural history and transmission dynamics by age and sexual risk. The model was parameterised using natural history, and epidemiological and sexual behaviour data, and applied for UK and US data. Sensitivity analyses were conducted to assess the robustness of predictions to variations in model structure and to examine the impact of alternative assumptions for the mechanism underlying partial immunity.

RESULTS

Partial immunity against reinfection was found necessary to explain observed C. trachomatis prevalence patterns by age and sexual risk. The reduction in susceptibility to reinfection was estimated at 93% using UK data (95% uncertainty interval (UI)=88%-97%) and at 67% using US data (95% UI=24%-88%). The model-structure sensitivity analyses affirmed model predictions. The immunity-mechanism sensitivity analyses suggested a mechanism of susceptibility reduction against reinfection or a mechanism of infectious-period duration reduction upon reinfection.

CONCLUSIONS

A strong long-lasting partial immunity against C. trachomatis reinfection should be present to explain observed prevalence patterns. The mechanism of immunity could be either a reduction in susceptibility to reinfection or a reduction in duration of infection on reinfection. C. trachomatis infection appears to naturally elicit a strong long-lasting immune response, supporting the concept of vaccine development.

Temporal evolution of HIV sero-discordancy patterns among stable couples in sub-Saharan Africa

INTRODUCTION

Objective was to examine the temporal variation of HIV sero-discordancy in select representative countries (Kenya, Lesotho, Mali, Niger, Tanzania, and Zimbabwe) in sub-Saharan Africa at different HIV epidemic scales. A sero-discordant couple is defined as a stable couple (SC) in which one partner is HIV-positive while the other is HIV-negative.

METHODS

A deterministic compartmental mathematical model was constructed to describe HIV transmission dynamics. The model was pair-based, that is explicitly modeling formation of SCs and infection dynamics in both SCs and in single individuals. The model accommodated for different forms of infection statuses in SCs. Using population-based nationally-representative epidemiologic and demographic input data, historical (1980-2014) and future (2015-2030) trends of sero-discordancy and other demographic and epidemiologic indicators were projected throughout HIV epidemic phases.

RESULTS

As the epidemics emerged, about 90% of SCs affected by HIV were sero-discordant. This proportion declined to 45%-88% at epidemic peak and stabilized as the epidemics started their natural decline. The largest reductions in sero-discordancy were in high HIV-prevalence countries. As the epidemics further declined with antiretroviral therapy (ART) scale-up, the proportion of sero-discordant couples among HIV-affected couples was projected to increase to 70%-92% by 2030. The proportion of sero-discordant couples among all SCs increased as the epidemics emerged and evolved, then peaked at 2%-20% as the epidemics peaked, and then declined as the epidemics declined to reach 0.3%-16% by 2030.

CONCLUSIONS

Sero-discordancy patterns varied with the evolution of the epidemics, and were affected by both epidemic phase and scale. The largest variations were found in high HIV-prevalence countries. The fraction of stable couples that are sero-discordant, as opposed to being sero-concordant positive, was projected to increase with ART scale-up and further HIV incidence decline over the coming two decades. These findings inform strategic planning and resource allocation for interventions among sero-discordant couples.

The City of Johannesburg can end AIDS by 2030: modelling the impact of achieving the Fast-Track targets and what it will take to get there

INTRODUCTION

In 2014, city leaders from around the world endorsed the Paris Declaration on Fast-Track Cities, pledging to achieve the 2020 and 2030 HIV targets championed by UNAIDS. The City of Johannesburg - one of South Africa's metropolitan municipalities and also a health district - has over 600,000 people living with HIV (PLHIV), more than any other city worldwide. We estimate what it would take in terms of programmatic targets and costs for the City of Johannesburg to meet the Fast-Track targets, and demonstrate the impact that this would have.

METHODS

We applied the Optima HIV epidemic and resource allocation model to demographic, epidemiological and behavioural data on 26 sub-populations in Johannesburg. We used data on programme costs and coverage to produce baseline projections. We calculated how many people must be diagnosed, put onto treatment and maintained with viral suppression to achieve the 2020 and 2030 targets. We also estimated how treatment needs - and therefore fiscal commitments - could be reduced if the treatment targets are combined with primary HIV prevention interventions (voluntary medical male circumcision (VMMC), an expanded condom programme, and comprehensive packages for female sex workers (FSW) and young females).

RESULTS

If current programmatic coverage were maintained, Johannesburg could expect 303,000 new infections and 96,000 AIDS-related deaths between 2017 and 2030 and 769,000 PLHIV by 2030. Achieving the Fast-Track targets would require an additional 135,000 diagnoses and 232,000 people on treatment by 2020 (an increase in around 80% over 2016 treatment numbers), but would avert 176,000 infections and 56,500 deaths by 2030. Assuming stable ART unit costs, this would require ZAR 29 billion (USD 2.15 billion) in cumulative treatment investments over the 14 years to 2030. Plausible scale-ups of other proven interventions (VMMC, condom distribution and FSW strategies) could yield additional reductions in new infections (between 4 and 15%), and in overall treatment investment needs. Scaling up VMMC in line with national targets is found to be cost-effective in the medium term.

CONCLUSIONS

The scale-up in testing and treatment programmes over this decade has been rapid, but these efforts must be doubled to reach 2020 targets. Strategic investments in proven interventions will help Johannesburg achieve the treatment targets and be on track to end AIDS by 2030.

A case study for a psychographic-behavioral segmentation approach for targeted demand generation in voluntary medical male circumcision

Public health programs are starting to recognize the need to move beyond a one-size-fits-all approach in demand generation, and instead tailor interventions to the heterogeneity underlying human decision making. Currently, however, there is a lack of methods to enable such targeting. We describe a novel hybrid behavioral-psychographic segmentation approach to segment stakeholders on potential barriers to a target behavior. We then apply the method in a case study of demand generation for voluntary medical male circumcision (VMMC) among 15-29 year-old males in Zambia and Zimbabwe. Canonical correlations and hierarchical clustering techniques were applied on representative samples of men in each country who were differentiated by their underlying reasons for their propensity to get circumcised. We characterized six distinct segments of men in Zimbabwe, and seven segments in Zambia, according to their needs, perceptions, attitudes and behaviors towards VMMC, thus highlighting distinct reasons for a failure to engage in the desired behavior.

Sexual network drivers of HIV and herpes simplex virus type 2 transmission

OBJECTIVES

HIV and herpes simplex virus type 2 (HSV-2) infections are sexually transmitted and propagate in sexual networks. Using mathematical modeling, we aimed to quantify effects of key network statistics on infection transmission, and extent to which HSV-2 prevalence can be a proxy of HIV prevalence.

DESIGN/METHODS

An individual-based simulation model was constructed to describe sex partnering and infection transmission, and was parameterized with representative natural history, transmission, and sexual behavior data. Correlations were assessed on model outcomes (HIV/HSV-2 prevalences) and multiple linear regressions were conducted to estimate adjusted associations and effect sizes.

RESULTS

HIV prevalence was one-third or less of HSV-2 prevalence. HIV and HSV-2 prevalences were associated with a Spearman's rank correlation coefficient of 0.64 (95% confidence interval: 0.58-0.69). Collinearities among network statistics were detected, most notably between concurrency versus mean and variance of number of partners. Controlling for confounding, unmarried mean/variance of number of partners (or alternatively concurrency) were the strongest predictors of HIV prevalence. Meanwhile, unmarried/married mean/variance of number of partners (or alternatively concurrency), and clustering coefficient were the strongest predictors of HSV-2 prevalence. HSV-2 prevalence was a strong predictor of HIV prevalence by proxying effects of network statistics.

CONCLUSION

Network statistics produced similar and differential effects on HIV/HSV-2 transmission, and explained most of the variation in HIV and HSV-2 prevalences. HIV prevalence reflected primarily mean and variance of number of partners, but HSV-2 prevalence was affected by a range of network statistics. HSV-2 prevalence (as a proxy) can forecast a population's HIV epidemic potential, thereby informing interventions.

Impact of treatment on hepatitis C virus transmission and incidence in Egypt: A case for treatment as prevention

Egypt has launched a hepatitis C virus (HCV) treatment programme using direct-acting antivirals (DAAs). Our aim was to assess the impact of five plausible programme scale-up and sustainability scenarios for HCV treatment as prevention in Egypt. We developed and analysed a mathematical model to assess programme impact using epidemiologic, programming and health economics measures. The model was parametrized with current and representative natural history, HCV prevalence and programme data. HCV incidence in Egypt is declining, but will persist at a considerable level for decades unless controlled by interventions. Across the five programme scenarios, 1.75-5.60 million treatments were administered by 2030. Reduction in incidence (annual number of new infections) by 2030 ranged between 29% and 99%, programme-attributed reduction in incidence rate (new infections per susceptible person per year) ranged between 18% and 99%, number of infections averted ranged between 42 393 and 469 599, and chronic infection prevalence reached as low as 2.8%-0.1%. Reduction in incidence rate year by year hovered around 7%-15% in the first decade of the programme in most scenarios. Treatment coverage in 2030 ranged between 24.9% and 98.8%, and number of treatments required to avert one new infection ranged between 9.5 and 12.1. Stipulated targets for HCV by 2030 could not be achieved without scaling-up treatment to 365 000 per year and sustaining it for a decade. In conclusion, DAA scale-up will have an immense and immediate impact on HCV incidence in Egypt. Elimination by 2030 is feasible if sufficient resources are committed to programme scale-up and sustainability. HCV treatment as prevention is a potent and effective prevention approach.

Circumcision and its effects in Africa

Male circumcision is one of the most commonly performed procedures in Africa, with a wide variation between the different regions on the practice. This is because circumcision is often done for religious and cultural or traditional reasons, which includes being part of rituals or rite of passage to adulthood. There had been few medical indications for the procedure until the human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) pandemic, which is prevalent in many of the countries in the region. Evidence from randomized controlled trials conducted in the continent had shown that male circumcision could be instrumental to reducing the transmission of HIV/AIDS in heterosexual couples in high disease prevalent and low circumcision prevalent areas. This had led to the roll-out of large population-based adult male circumcisions as well as the development of tools to facilitate the procedure. Circumcision, however, is not without complications and the incidence appears related to the age of the patient, where the procedure was done, technique used and level of proficiency of the practitioners. This article reviews the practice of circumcision in Africa and highlights the impact of the procedure on the continent.

Could Circumcision of HIV-Positive Males Benefit Voluntary Medical Male Circumcision Programs in Africa? Mathematical Modeling Analysis

Background

The epidemiological and programmatic implications of inclusivity of HIV-positive males in voluntary medical male circumcision (VMMC) programs are uncertain. We modeled these implications using Zambia as an illustrative example.

Methods and Findings

We used the Age-Structured Mathematical (ASM) model to evaluate, over an intermediate horizon (2010–2025), the effectiveness (number of VMMCs needed to avert one HIV infection) of VMMC scale-up scenarios with varying proportions of HIV-positive males. The model was calibrated by fitting to HIV prevalence time trend data from 1990 to 2014. We assumed that inclusivity of HIV positive males may benefit VMMC programs by increasing VMMC uptake among higher risk males, or by circumcision reducing HIV male-to-female transmission risk. All analyses were generated assuming no further antiretroviral therapy (ART) scale-up.

The number of VMMCs needed to avert one HIV infection was projected to increase from 12.2 VMMCs per HIV infection averted, in a program that circumcises only HIV-negative males, to 14.0, in a program that includes HIV-positive males. The proportion of HIV-positive males was based on their representation in the population (e.g. 12.6% of those circumcised in 2010 would be HIV-positive based on HIV prevalence among males of 12.6% in 2010). However, if a program that only reaches out to HIV-negative males is associated with 20% lower uptake among higher-risk males, the effectiveness would be 13.2 VMMCs per infection averted. If improved inclusivity of HIV-positive males is associated with 20% higher uptake among higher-risk males, the effectiveness would be 12.4. As the assumed VMMC efficacy against male-to-female HIV transmission was increased from 0% to 20% and 46%, the effectiveness of circumcising regardless of HIV status improved from 14.0 to 11.5 and 9.1, respectively. The reduction in the HIV incidence rate among females increased accordingly, from 24.7% to 34.8% and 50.4%, respectively.

Conclusion

Improving inclusivity of males in VMMC programs regardless of HIV status increases VMMC effectiveness, if there is moderate increase in VMMC uptake among higher-risk males and/or if there is moderate efficacy for VMMC against male-to-female transmission. In these circumstances, VMMC programs can reduce the HIV incidence rate in males by nearly as much as expected by some ART programs, and additionally, females can benefit from the intervention nearly as much as males.

HCV prevalence can predict HIV epidemic potential among people who inject drugs: mathematical modeling analysis

BACKGROUND

Hepatitis C virus (HCV) and HIV are both transmitted through percutaneous exposures among people who inject drugs (PWID). Ecological analyses on global epidemiological data have identified a positive association between HCV and HIV prevalence among PWID. Our objective was to demonstrate how HCV prevalence can be used to predict HIV epidemic potential among PWID.

METHODS

Two population-level models were constructed to simulate the evolution of HCV and HIV epidemics among PWID. The models described HCV and HIV parenteral transmission, and were solved both deterministically and stochastically.

RESULTS

The modeling results provided a good fit to the epidemiological data describing the ecological HCV and HIV association among PWID. HCV was estimated to be eight times more transmissible per shared injection than HIV. A threshold HCV prevalence of 29.0% (95% uncertainty interval (UI): 20.7-39.8) and 46.5% (95% UI: 37.6-56.6) were identified for a sustainable HIV epidemic (HIV prevalence >1%) and concentrated HIV epidemic (HIV prevalence >5%), respectively. The association between HCV and HIV was further described with six dynamical regimes depicting the overlapping epidemiology of the two infections, and was quantified using defined and estimated measures of association. Modeling predictions across a wide range of HCV prevalence indicated overall acceptable precision in predicting HIV prevalence at endemic equilibrium. Modeling predictions were found to be robust with respect to stochasticity and behavioral and biological parameter uncertainty. In an illustrative application of the methodology, the modeling predictions of endemic HIV prevalence in Iran agreed with the scale and time course of the HIV epidemic in this country.

CONCLUSIONS

Our results show that HCV prevalence can be used as a proxy biomarker of HIV epidemic potential among PWID, and that the scale and evolution of HIV epidemic expansion can be predicted with sufficient precision to inform HIV policy, programming, and resource allocation.

Modeling Impact and Cost-Effectiveness of Increased Efforts to Attract Voluntary Medical Male Circumcision Clients Ages 20-29 in Zimbabwe

Background

Zimbabwe aims to increase circumcision coverage to 80% among 13- to 29-year-olds. However, implementation data suggest that high coverage among men ages 20 and older may not be achievable without efforts specifically targeted to these men, incurring additional costs per circumcision. Scale-up scenarios were created based on trends in implementation data in Zimbabwe, and the cost-effectiveness of increasing efforts to recruit clients ages 20–29 was examined.

Methods

Zimbabwe voluntary medical male circumcision (VMMC) program data were used to project trends in male circumcision coverage by age into the future. The projection informed a base scenario in which, by 2018, the country achieves 80% circumcision coverage among males ages 10–19 and lower levels of coverage among men above age 20. The Zimbabwe DMPPT 2.0 model was used to project costs and impacts, assuming a US$109 VMMC unit cost in the base scenario and a 3% discount rate. Two other scenarios assumed that the program could increase coverage among clients ages 20–29 with a corresponding increase in unit cost for these age groups.

Results

When circumcision coverage among men ages 20–29 is increased compared with a base scenario reflecting current implementation trends, fewer VMMCs are required to avert one infection. If more than 50% additional effort (reflected as multiplying the unit cost by >1.5) is required to double the increase in coverage among this age group compared with the base scenario, the cost per HIV infection averted is higher than in the base scenario.

Conclusions

Although increased investment in recruiting VMMC clients ages 20–29 may lead to greater overall impact if recruitment efforts are successful, it may also lead to lower cost-effectiveness, depending on the cost of increasing recruitment. Programs should measure the relationship between increased effort and increased ability to attract this age group.

Voluntary Medical Male Circumcision for HIV Prevention: New Mathematical Models for Strategic Demand Creation Prioritizing Subpopulations by Age and Geography

Over 11 million voluntary medical male circumcisions (VMMC) have been performed of the projected 20.3 million needed to reach 80% adult male circumcision prevalence in priority sub-Saharan African countries. Striking numbers of adolescent males, outside the 15-49-year-old age target, have been accessing VMMC services. What are the implications of overall progress in scale-up to date? Can mathematical modeling provide further insights on how to efficiently reach the male circumcision coverage levels needed to create and sustain further reductions in HIV incidence to make AIDS no longer a public health threat by 2030? Considering ease of implementation and cultural acceptability, decision makers may also value the estimates that mathematical models can generate of immediacy of impact, cost-effectiveness, and magnitude of impact resulting from different policy choices. This supplement presents the results of mathematical modeling using the Decision Makers' Program Planning Tool Version 2.0 (DMPPT 2.0), the Actuarial Society of South Africa (ASSA2008) model, and the age structured mathematical (ASM) model. These models are helping countries examine the potential effects on program impact and cost-effectiveness of prioritizing specific subpopulations for VMMC services, for example, by client age, HIV-positive status, risk group, and geographical location. The modeling also examines long-term sustainability strategies, such as adolescent and/or early infant male circumcision, to preserve VMMC coverage gains achieved during rapid scale-up. The 2016-2021 UNAIDS strategy target for VMMC is an additional 27 million VMMC in high HIV-prevalence settings by 2020, as part of access to integrated sexual and reproductive health services for men. To achieve further scale-up, a combination of evidence, analysis, and impact estimates can usefully guide strategic planning and funding of VMMC services and related demand-creation strategies in priority countries. Mid-course corrections now can improve cost-effectiveness and scale to achieve the impact needed to help turn the HIV pandemic on its head within 15 years.

Optimum resource allocation to reduce HIV incidence across sub-Saharan Africa: a mathematical modelling study

BACKGROUND

Advances in HIV prevention methods offer promise to accelerate declines in incidence, but how these methods can be deployed to have the best effect on the heterogeneous landscape and drivers of the pandemic remains unclear. We postulated that use of epidemic heterogeneity to inform the allocation of resources for combination HIV prevention could enhance the impact of HIV funding across sub-Saharan Africa.

METHODS

We developed a compartmental mathematical model of HIV transmission and disease progression by risk group to subnational resolution in 18 countries, capturing 80% of the adult HIV burden in sub-Saharan Africa. Adults aged 15-49 years were grouped by risk of HIV acquisition and transmission, and those older than 50 years were assumed to have negligible risk. For each top-level administrative division, we calibrated the model to historical data for HIV prevalence, sexual behaviours, treatment scale-up, and demographics. We then evaluated four strategies for allocation of prevention funding over a 15 year period from 2016 to 2030, which exploited epidemic differences between subnational regions to varying degrees.

FINDINGS

For a $US20 billion representative expenditure over the 15 year period, scale-up of prevention along present funding channels could avert 5·3 million infections relative to no scale-up. Prioritisation of key populations could avert 3·7 million more infections than present funding channels, and additional prioritisation by within-country geography could avert 400 000 more infections. Removal of national constraints could avert a further 600 000 infections. Risk prioritisation has greater marginal impact than geographical prioritisation across multiple expenditure levels. However, targeting by both risk and geography is best for total impact and could achieve gains of up to three times more than present channels. A shift from the present pattern to the optimum pattern would rebalance resources towards more cost-effective interventions and emerging epidemics.

INTERPRETATION

If domestic and international funders were to align strategically to build an aggregate funding pattern that is guided by the epidemiology of HIV, and particularly by the emerging understanding of local dynamics and epidemic drivers, more cost-effective and impactful HIV prevention investments could be achieved across sub-Saharan Africa.

FUNDING

The Bill & Melinda Gates Foundation.

Voluntary Medical Male Circumcision for HIV Prevention in Malawi: Modeling the Impact and Cost of Focusing the Program by Client Age and Geography

Background

In 2007, the World Health Organization (WHO) recommended scaling up voluntary medical male circumcision (VMMC) in priority countries with high HIV prevalence and low male circumcision (MC) prevalence. According to the Joint United Nations Programme on HIV/AIDS (UNAIDS), an estimated 5.8 million males had undergone VMMC by the end of 2013. Implementation experience has raised questions about the need to refocus VMMC programs on specific subpopulations for the greatest epidemiological impact and programmatic effectiveness. As Malawi prepared its national operational plan for VMMC, it sought to examine the impacts of focusing on specific subpopulations by age and region.

Methods

We used the Decision Makers’ Program Planning Toolkit, Version 2.0, to study the impact of scaling up VMMC to different target populations of Malawi. National MC prevalence by age group from the 2010 Demographic and Health Survey was scaled according to the MC prevalence for each district and then halved, to adjust for over-reporting of circumcision. In-country stakeholders advised a VMMC unit cost of $100, based on implementation experience. We derived a cost of $451 per patient-year for antiretroviral therapy from costs collected as part of a strategic planning exercise previously conducted in- country by UNAIDS.

Results

Over a fifteen-year period, circumcising males ages 10–29 would avert 75% of HIV infections, and circumcising males ages 10–34 would avert 88% of infections, compared to the current strategy of circumcising males ages 15–49. The Ministry of Health’s South West and South East health zones had the lowest cost per HIV infection averted. Moreover, VMMC met WHO’s definition of cost-effectiveness (that is, the cost per disability-adjusted life-year [DALY] saved was less than three times the per capita gross domestic product) in all health zones except Central East. Comparing urban versus rural areas in the country, we found that circumcising men in urban areas would be both cost-effective and cost-saving, with a VMMC cost per DALY saved of $120 USD and with 15 years of VMMC implementation resulting in lifetime HIV treatment costs savings of $331 million USD.

Conclusions

Based on the age analyses and programmatic experience, Malawi’s VMMC operational plan focuses on males ages 10–34 in all districts in the South East and South West zones, as well as Lilongwe (an urban district in the Central zone). This plan covers 14 of the 28 districts in the country.

Age Targeting of Voluntary Medical Male Circumcision Programs Using the Decision Makers' Program Planning Toolkit (DMPPT) 2.0

BACKGROUND

Despite considerable efforts to scale up voluntary medical male circumcision (VMMC) for HIV prevention in priority countries over the last five years, implementation has faced important challenges. Seeking to enhance the effect of VMMC programs for greatest and most immediate impact, the U. S. President's Plan for AIDS Relief (PEPFAR) supported the development and application of a model to inform national planning in five countries from 2013-2014.

METHODS AND FINDINGS

The Decision Makers' Program Planning Toolkit (DMPPT) 2.0 is a simple compartmental model designed to analyze the effects of client age and geography on program impact and cost. The DMPPT 2.0 model was applied in Malawi, South Africa, Swaziland, Tanzania, and Uganda to assess the impact and cost of scaling up age-targeted VMMC coverage. The lowest number of VMMCs per HIV infection averted would be produced by circumcising males ages 20-34 in Malawi, South Africa, Tanzania, and Uganda and males ages 15-34 in Swaziland. The most immediate impact on HIV incidence would be generated by circumcising males ages 20-34 in Malawi, South Africa, Tanzania, and Uganda and males ages 20-29 in Swaziland. The greatest reductions in HIV incidence over a 15-year period would be achieved by strategies focused on males ages 10-19 in Uganda, 15-24 in Malawi and South Africa, 10-24 in Tanzania, and 15-29 in Swaziland. In all countries, the lowest cost per HIV infection averted would be achieved by circumcising males ages 15-34, although in Uganda this cost is the same as that attained by circumcising 15- to 49-year-olds.

CONCLUSIONS

The efficiency, immediacy of impact, magnitude of impact, and cost-effectiveness of VMMC scale-up are not uniform; there is important variation by age group of the males circumcised and countries should plan accordingly.

Effectiveness of and Financial Returns to Voluntary Medical Male Circumcision for HIV Prevention in South Africa: An Incremental Cost-Effectiveness Analysis

BACKGROUND

Empirical studies and population-level policy simulations show the importance of voluntary medical male circumcision (VMMC) in generalized epidemics. This paper complements available scenario-based studies (projecting costs and outcomes over some policy period, typically spanning decades) by adopting an incremental approach-analyzing the expected consequences of circumcising one male individual with specific characteristics in a specific year. This approach yields more precise estimates of VMMC's cost-effectiveness and identifies the outcomes of current investments in VMMC (e.g., within a fiscal budget period) rather than of investments spread over the entire policy period.

METHODS/FINDINGS

The model has three components. We adapted the ASSA2008 model, a demographic and epidemiological model of the HIV epidemic in South Africa, to analyze the impact of one VMMC on HIV incidence over time and across the population. A costing module tracked the costs of VMMC and the resulting financial savings owing to reduced HIV incidence over time. Then, we used several financial indicators to assess the cost-effectiveness of and financial return on investments in VMMC. One circumcision of a young man up to age 20 prevents on average over 0.2 HIV infections, but this effect declines steeply with age, e.g., to 0.08 by age 30. Net financial savings from one VMMC at age 20 are estimated at US$617 at a discount rate of 5% and are lower for circumcisions both at younger ages (because the savings occur later and are discounted more) and at older ages (because male circumcision becomes less effective). Investments in male circumcision carry a financial rate of return of up to 14.5% (for circumcisions at age 20). The cost of a male circumcision is refinanced fastest, after 13 y, for circumcisions at ages 20 to 25. Principal limitations of the analysis arise from the long time (decades) over which the effects of VMMC unfold-the results are therefore sensitive to the discount rate applied, and more generally to the future course of the epidemic and of HIV/AIDS-related policies pursued by the government.

CONCLUSIONS

VMMC in South Africa is highly effective in reducing both HIV incidence and the financial costs of the HIV response. The return on investment is highest if males are circumcised between ages 20 and 25, but this return on investment declines steeply with age.

A Reevaluation of the Voluntary Medical Male Circumcision Scale-Up Plan in Zimbabwe

BACKGROUND

The voluntary medical male circumcision (VMMC) program in Zimbabwe aims to circumcise 80% of males aged 13-29 by 2017. We assessed the impact of actual VMMC scale-up to date and evaluated the impact of potential alterations to the program to enhance program efficiency, through prioritization of subpopulations.

METHODS AND FINDINGS

We implemented a recently developed analytical approach: the age-structured mathematical (ASM) model and accompanying three-level conceptual framework to assess the impact of VMMC as an intervention. By September 2014, 364,185 males were circumcised, an initiative that is estimated to avert 40,301 HIV infections by 2025. Through age-group prioritization, the number of VMMCs needed to avert one infection (effectiveness) ranged between ten (20-24 age-group) and 53 (45-49 age-group). The cost per infection averted ranged between $811 (20-24 age-group) and $5,518 (45-49 age-group). By 2025, the largest reductions in HIV incidence rate (up to 27%) were achieved by prioritizing 10-14, 15-19, or 20-24 year old. The greatest program efficiency was achieved by prioritizing 15-24, 15-29, or 15-34 year old. Prioritizing males 13-29 year old was programmatically efficient, but slightly inferior to the 15-24, 15-29, or 15-34 age groups. Through geographic prioritization, effectiveness varied from 9-12 VMMCs per infection averted across provinces. Through risk-group prioritization, effectiveness ranged from one (highest sexual risk-group) to 60 (lowest sexual risk-group) VMMCs per infection averted.

CONCLUSION

The current VMMC program plan in Zimbabwe is targeting an efficient and impactful age bracket (13-29 year old), but program efficiency can be improved by prioritizing a subset of males for demand creation and service availability. The greatest program efficiency can be attained by prioritizing young sexually active males and males whose sexual behavior puts them at higher risk for acquiring HIV.