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Case KK, Gregson S, Mahy M, et al., 2017, Editorial: methodological developments in the Joint United Nations Programme on HIV/AIDS estimates, AIDS, Vol: 31, Pages: S1-S4, ISSN: 0269-9370
The Joint United Nations Programme on HIV/AIDS (UNAIDS) publishes estimates of the HIV epidemic every year [1]. For 2016, estimates are available for 160 countries representing 98% of the global population. These estimates are produced by countries with guidance from UNAIDS. The methods used in this process continue to evolve over time under the stewardship of the UNAIDS Reference Group on Estimates, Modelling and Projections [2].In 2014, the WHO convened the Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER) Working Group with the aim to define and promote good practice in reporting global health estimates [3]. The GATHER Statement is the outcome produced by this group. It defines a list of reporting requirements to allow for the accurate interpretation, and facilitate the appropriate use, of global health estimates [4]. UNAIDS fully endorses and supports the GATHER Statement.The current special supplement, which details the methods used to produce the 2016 UNAIDS estimates, further supports the routine publication of data sources and methods used as part of an open and transparent process. It provides updates of the evolving understanding of the data on which the estimates are based, the methods used to derive the estimates, justification of changes in these methods, and the sources of new data available to inform these modifications. It follows a series of such collections [5–10] which have documented and described the evolving methods used to produce the UNAIDS Global AIDS estimates since 2004.
Buttolph J, Inwani I, Agot K, et al., 2017, Gender-Specific Combination HIV Prevention for Youth in High-Burden Settings: The MP3 Youth Observational Pilot Study Protocol., JMIR Research Protocols, Vol: 6, ISSN: 1929-0748
BACKGROUND: Nearly three decades into the epidemic, sub-Saharan Africa (SSA) remains the region most heavily affected by human immunodeficiency virus (HIV), with nearly 70% of the 34 million people living with HIV globally residing in the region. In SSA, female and male youth (15 to 24 years) are at a disproportionately high risk of HIV infection compared to adults. As such, there is a need to target HIV prevention strategies to youth and to tailor them to a gender-specific context. This protocol describes the process for the multi-staged approach in the design of the MP3 Youth pilot study, a gender-specific, combination, HIV prevention intervention for youth in Kenya. OBJECTIVE: The objective of this multi-method protocol is to outline a rigorous and replicable methodology for a gender-specific combination HIV prevention pilot study for youth in high-burden settings, illustrating the triangulated methods undertaken to ensure that age, sex, and context are integral in the design of the intervention. METHODS: The mixed-methods, cross-sectional, longitudinal cohort pilot study protocol was developed by first conducting a systematic review of the literature, which shaped focus group discussions around prevention package and delivery options, and that also informed age- and sex- stratified mathematical modeling. The review, qualitative data, and mathematical modeling created a triangulated evidence base of interventions to be included in the pilot study protocol. To design the pilot study protocol, we convened an expert panel to select HIV prevention interventions effective for youth in SSA, which will be offered in a mobile health setting. The goal of the pilot study implementation and evaluation is to apply lessons learned to more effective HIV prevention evidence and programming. RESULTS: The combination HIV prevention package in this protocol includes (1) offering HIV testing and counseling for all youth; (2) voluntary medical circumcision and condoms for males; (3)
Elmes JAR, Skovdal M, Nhongo K, et al., 2017, A reconfiguration of the sex trade: How social and structural changes in eastern Zimbabwe left women involved in sex work and transactional sex more vulnerable, PLOS One, Vol: 12, ISSN: 1932-6203
Understanding the dynamic nature of sex work is important for explaining the course of HIV epidemics. While health and development interventions targeting sex workers may alter the dynamics of the sex trade in particular localities, little has been done to explore how large-scale social and structural changes, such as economic recessions–outside of the bounds of organizational intervention–may reconfigure social norms and attitudes with regards to sex work. Zimbabwe’s economic collapse in 2009, following a period (2000–2009) of economic decline, within a declining HIV epidemic, provides a unique opportunity to study community perceptions of the impact of socio-economic upheaval on the sex trade. We conducted focus group discussions with 122 community members in rural eastern Zimbabwe in January-February 2009. Groups were homogeneous by gender and occupation and included female sex workers, married women, and men who frequented bars. The focus groups elicited discussion around changes (comparing contemporaneous circumstances in 2009 to their memories of circumstances in 2000) in the demand for, and supply of, paid sex, and how sex workers and clients adapted to these changes, and with what implications for their health and well-being. Transcripts were thematically analyzed. The analysis revealed how changing economic conditions, combined with an increased awareness and fear of HIV–changing norms and local attitudes toward sex work–had altered the demand for commercial sex. In response, sex work dispersed from the bars into the wider community, requiring female sex workers to employ different tactics to attract clients. Hyperinflation meant that sex workers had to accept new forms of payment, including sex-on-credit and commodities. Further impacting the demand for commercial sex work was a poverty-driven increase in transactional sex. The economic upheaval in Zimbabwe effectively reorganized the market for sex by reducing previousl
Cremin I, McKinnon L, Kimani J, et al., 2017, PrEP for key populations in combination HIV prevention in Nairobi: a mathematical modelling study, LANCET HIV, Vol: 4, Pages: E214-E222, ISSN: 2352-3018
Smith JA, Heffron R, Butler AR, et al., 2016, Could misreporting of condom use explain the observed association between injectable hormonal contraceptives and HIV acquisition risk?, Contraception, Vol: 95, Pages: 424-430, ISSN: 0010-7824
OBJECTIVE: Some observational studies have suggested an association between the use of hormonal contraceptives (HC) and HIV acquisition. One major concern is that differential misreporting of sexual behavior between HC users and nonusers may generate artificially inflated risk estimates. STUDY DESIGN: We developed an individual-based model that simulates the South African HIV serodiscordant couples analyzed for HC-HIV risk by Heffron et al. (2012). We varied the pattern of misreporting condom use between HC users and nonusers and reproduced the trial data under the assumption that HC use is not associated with HIV risk. The simulated data were analyzed using Cox proportional hazards models, adjusting for the reported level of condom use. RESULTS: If HC users overreport condom use more than nonusers, an apparent excess risk could be observed even without any biological effect of HC on HIV acquisition. With 45% overreporting by HC users (i.e., 9 out of every 20 sex acts reported with condoms are actually unprotected) and accurate condom reporting by nonusers, a true null effect can be inflated to give an observed hazard ratio (HR̂) of 2.0. In a different population with lower overall reported condom use, artificially high HR̂s can only be generated if non-HC users underreport condom use. CONCLUSION: Differential condom misreporting can theoretically produce inflated HR̂ values for an association between HC and HIV even without a true association. However, to produce a doubling of HIV risk that is entirely spurious requires substantially different levels of misreporting among HC users and nonusers, which may be unrealistic. IMPLICATIONS: Considerably differential amounts of condom use misreporting by HC users and nonusers would be needed to produce entirely spurious observed levels of excess HIV acquisition risk among HC users when there is actually no true association.
McGillen JB, Anderson S-J, Hallett TB, 2016, Introducing optimism to models of resource allocation to reduce HIV incidence Reply, LANCET HIV, Vol: 4, Pages: E12-E12, ISSN: 2352-3018
Nayagam S, Conteh L, Sicuri E, et al., 2016, Community-based screening and treatment for chronic hepatitis B in sub-Saharan Africa - Authors' reply., Lancet Global Health, Vol: 5, Pages: e35-e35, ISSN: 2214-109X
Garnett G, Hallett T, Gregson S, 2016, HIV Prevention Cascades: Identifying Gaps in the Delivery of HIV Prevention Interventions, Conference on HIV Research for Prevention (HIV R4P), Publisher: Mary Ann Liebert, Pages: 245-245, ISSN: 0889-2229
Olney JJ, Braitstein P, Eaton JW, et al., 2016, Evaluating strategies to improve HIV care outcomes in Kenya: a modelling study, Lancet HIV, Vol: 3, Pages: e592-e600, ISSN: 2405-4704
BackgroundWith expanded access to antiretroviral therapy (ART) in sub-Saharan Africa, HIV mortality has decreased, yet life-years are still lost to AIDS. Strengthening of treatment programmes is a priority. We examined the state of an HIV care programme in Kenya and assessed interventions to improve the impact of ART programmes on population health.MethodsWe created an individual-based mathematical model to describe the HIV epidemic and the experiences of care among adults infected with HIV in Kenya. We calibrated the model to a longitudinal dataset from the Academic Model Providing Access To Healthcare (known as AMPATH) programme describing the routes into care, losses from care, and clinical outcomes. We simulated the cost and effect of interventions at different stages of HIV care, including improvements to diagnosis, linkage to care, retention and adherence of ART, immediate ART eligibility, and a universal test-and-treat strategy.FindingsWe estimate that, of people dying from AIDS between 2010 and 2030, most will have initiated treatment (61%), but many will never have been diagnosed (25%) or will have been diagnosed but never started ART (14%). Many interventions targeting a single stage of the health-care cascade were likely to be cost-effective, but any individual intervention averted only a small percentage of deaths because the effect is attenuated by other weaknesses in care. However, a combination of five interventions (including improved linkage, point-of-care CD4 testing, voluntary counselling and testing with point-of-care CD4, and outreach to improve retention in pre-ART care and on-ART) would have a much larger impact, averting 1·10 million disability-adjusted life-years (DALYs) and 25% of expected new infections and would probably be cost-effective (US$571 per DALY averted). This strategy would improve health more efficiently than a universal test-and-treat intervention if there were no accompanying improvements to care ($1760 per DALY avert
McGillen JB, Anderson SJ, Hallett TB, 2016, PrEP as a feature in the optimal landscape of combination HIV prevention in sub-Saharan Africa, Journal of the International AIDS Society, Vol: 19, ISSN: 1758-2652
INTRODUCTION: The new WHO guidelines recommend offering pre-exposure prophylaxis (PrEP) to people who are at substantial risk of HIV infection. However, where PrEP should be prioritised, and for which population groups, remains an open question. The HIV landscape in sub-Saharan Africa features limited prevention resources, multiple options for achieving cost saving, and epidemic heterogeneity. This paper examines what role PrEP should play in optimal prevention in this complex and dynamic landscape. METHODS: We use a model that was previously developed to capture subnational HIV transmission in sub-Saharan Africa. With this model, we can consider how prevention funds could be distributed across and within countries throughout sub-Saharan Africa to enable optimal HIV prevention (that is, avert the greatest number of infections for the lowest cost). Here, we focus on PrEP to elucidate where, and to whom, it would optimally be offered in portfolios of interventions (alongside voluntary medical male circumcision, treatment as prevention, and behaviour change communication). Over a range of continental expenditure levels, we use our model to explore prevention patterns that incorporate PrEP, exclude PrEP, or implement PrEP according to a fixed incidence threshold. RESULTS: At low-to-moderate levels of total prevention expenditure, we find that the optimal intervention portfolios would include PrEP in only a few regions and primarily for female sex workers (FSW). Prioritisation of PrEP would expand with increasing total expenditure, such that the optimal prevention portfolios would offer PrEP in more subnational regions and increasingly for men who have sex with men (MSM) and the lower incidence general population. The marginal benefit of including PrEP among the available interventions increases with overall expenditure by up to 14% (relative to excluding PrEP). The minimum baseline incidence for the optimal offer of PrEP declines for all population groups as expenditure
Garnett GP, Krishnaratne S, Rush SH, et al., 2016, The Cost-effectiveness, Affordability and Impact of HIV Prevention: Concepts and Reviews, Conference on HIV Research for Prevention (HIV R4P), Publisher: MARY ANN LIEBERT, INC, Pages: 299-299, ISSN: 0889-2229
Smit M, Cassidy R, Cozzi-Lepri A, et al., 2016, Quantifying the future clinical burden of an ageing HIV-positive population in Italy: a mathematical modelling study, International Congress of Drug Therapy in HIV Infection, Publisher: JOHN WILEY & SONS LTD
Odhiambo J, Onyango M, Stover J, et al., 2016, Evaluating the Impact of the Voluntary Medical Male Circumcision (VMMC) Program in Kenya, Conference on HIV Research for Prevention (HIV R4P), Publisher: MARY ANN LIEBERT, INC, Pages: 105-105, ISSN: 0889-2229
Smit M, Cassidy R, Hallett T, 2016, Quantifying the future clinical burden of an ageing HIV-positive population in the USA: a mathematical modelling, Publisher: JOHN WILEY & SONS LTD
Nayagam S, Thursz M, Sicuri E, et al., 2016, Requirements for global elimination of hepatitis B: a modelling study, Lancet Infectious Diseases, Vol: 16, Pages: 1399-1408, ISSN: 1473-3099
BackgroundDespite the existence of effective prevention and treatment interventions, hepatitis B virus (HBV) infection continues to cause nearly 1 million deaths each year. WHO aspires to global control and elimination of HBV infection. We aimed to evaluate the potential impact of public health interventions against HBV, propose targets for reducing incidence and mortality, and identify the key developments required to achieve them.MethodsWe developed a simulation model of the global HBV epidemic, incorporating data on the natural history of HBV, prevalence, mortality, vaccine coverage, treatment dynamics, and demographics. We estimate the impact of current interventions and scaling up of existing interventions for prevention of infection and introducing wide-scale population screening and treatment interventions on the worldwide epidemic.FindingsVaccination of infants and neonates is already driving a large decrease in new infections; vaccination has already prevented 210 million new chronic infections by 2015 and will have averted 1·1 million deaths by 2030. However, without scale-up of existing interventions, our model showed that there will be a cumulative 63 million new cases of chronic infection and 17 million HBV-related deaths between 2015 and 2030 because of ongoing transmission in some regions and poor access to treatment for people already infected. A target of a 90% reduction in new chronic infections and 65% reduction in mortality could be achieved by scaling up the coverage of infant vaccination (to 90% of infants), birth-dose vaccination (to 80% of neonates), use of peripartum antivirals (to 80% of hepatitis B e antigen-positive mothers), and population-wide testing and treatment (to 80% of eligible people). These interventions would avert 7·3 million deaths between 2015 and 2030, including 1·5 million cases of cancer deaths. An elimination threshold for incidence of new chronic infections would be reached by 2090 worldwide. The a
Bórquez A, Cori A, Pufall EL, et al., 2016, The Incidence Patterns Model to Estimate the Distribution of New HIV Infections in Sub-Saharan Africa: Development and Validation of a Mathematical Model., PLOS Medicine, Vol: 13, ISSN: 1549-1277
BACKGROUND: Programmatic planning in HIV requires estimates of the distribution of new HIV infections according to identifiable characteristics of individuals. In sub-Saharan Africa, robust routine data sources and historical epidemiological observations are available to inform and validate such estimates. METHODS AND FINDINGS: We developed a predictive model, the Incidence Patterns Model (IPM), representing populations according to factors that have been demonstrated to be strongly associated with HIV acquisition risk: gender, marital/sexual activity status, geographic location, "key populations" based on risk behaviours (sex work, injecting drug use, and male-to-male sex), HIV and ART status within married or cohabiting unions, and circumcision status. The IPM estimates the distribution of new infections acquired by group based on these factors within a Bayesian framework accounting for regional prior information on demographic and epidemiological characteristics from trials or observational studies. We validated and trained the model against direct observations of HIV incidence by group in seven rounds of cohort data from four studies ("sites") conducted in Manicaland, Zimbabwe; Rakai, Uganda; Karonga, Malawi; and Kisesa, Tanzania. The IPM performed well, with the projections' credible intervals for the proportion of new infections per group overlapping the data's confidence intervals for all groups in all rounds of data. In terms of geographical distribution, the projections' credible intervals overlapped the confidence intervals for four out of seven rounds, which were used as proxies for administrative divisions in a country. We assessed model performance after internal training (within one site) and external training (between sites) by comparing mean posterior log-likelihoods and used the best model to estimate the distribution of HIV incidence in six countries (Gabon, Kenya, Malawi, Rwanda, Swaziland, and Zambia) in the region. We subsequ
McGillen JB, Anderson SJ, Dybul MR, et al., 2016, Optimum resource allocation to reduce HIV incidence across sub-Saharan Africa: a mathematical modelling study, Lancet HIV, Vol: 3, Pages: e441-e448, ISSN: 2352-3018
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-effe
Nayagam S, Conteh L, Sicuri E, et al., 2016, Cost-effectiveness of community-based screening and treatment for chronic hepatitis B in The Gambia: an economic modelling analysis, Lancet Global Health, Vol: 4, Pages: e568-e578, ISSN: 2214-109X
Background: Despite the high burden of hepatitis B virus (HBV)infection in sub-Saharan Africa (SSA), a lack of access to widespreadscreening or treatment leads to most people remaining undiagnosed untillater stages of disease when prognosis is poor and treatment options arelimited. We evaluated the cost-effectiveness of community-based screeningand early treatment with antiviral therapy for HBV in The Gambia.Methods: An economic evaluation comparing adult community-based screeningusing a Hepatitis B surface antigen (HBsAg) rapid test and subsequent HBVantiviral therapy to a status quo scenario, where no treatment isavailable, was performed by combining a decision tree with a Markov statetransition model. This was parameterised with primary screening and costdata from the PROLIFICA study. A health provider perspective was takenand costs and health outcomes were discounted at 3% per annum.Findings: In The Gambia, where the HBsAg prevalence is 8.8% among thoseaged over 30 years old, adult screening and treatment for HBV, has anIncremental Cost-Effectiveness Ratio (ICER) of $540 per DisabilityAdjusted Life Year (DALY) averted, $645 per Life Year (LY) saved and $511per Quality Adjusted Life Year (QALY) gained, compared to status quo.These ICERs are in line with willingness-to-pay levels of one times thecountry's Gross Domestic Product (GDP) per capita ($487) per DALYaverted, whilst remaining robust, over a wide range of epidemiologicaland cost parameters.Interpretation: Adult community-based screening and treatment for HBV inthe Gambia is likely to be a cost-effective intervention with an ICERthat is comparable with those of HIV screening and treatmentinterventions in SSA. Even higher cost-effectiveness, may be achievablewith targeted facility-based screening, price reductions of drug and diagnostics and integration of HBV screening with other public healthinterventions.
Dimitrov DT, Boily MC, Hallett TB, et al., 2016, How Much Do We Know about Drug Resistance Due to PrEP Use? Analysis of Experts’ Opinion and Its Influence on the Projected Public Health Impact, PLOS One, Vol: 11, ISSN: 1932-6203
BACKGROUND: Randomized controlled trials reported that pre-exposure prophylaxis (PrEP) with tenofovir and emtricitabine rarely selects for drug resistance. However, drug resistance due to PrEP is not completely understood. In daily practice, PrEP will not be used under the well-controlled conditions available in the trials, suggesting that widespread use of PrEP can result in increased drug resistance. METHODS: We surveyed expert virologists with questions about biological assumptions regarding drug resistance due to PrEP use. The influence of these assumptions on the prevalence of drug resistance and the fraction of HIV transmitted resistance was studied with a mathematical model. For comparability, 50% PrEP-coverage of and 90% per-act efficacy of PrEP in preventing HIV acquisition are assumed in all simulations. RESULTS: Virologists disagreed on the following: the time until resistance emergence (range: 20-180 days) in infected PrEP users with breakthrough HIV infections; the efficacy of PrEP against drug-resistant HIV (25%-90%); and the likelihood of resistance acquisition upon transmission (10%-75%). These differences translate into projections of 0.6%- 1% and 3.5%-6% infected individuals with detectable resistance 10 years after introducing PrEP, assuming 100% and 50% adherence, respectively. The rate of resistance emergence following breakthrough HIV infection and the rate of resistance reversion after PrEP use is discontinued, were the factors identified as most influential on the expected resistance associated with PrEP. Importantly, 17-23% infected individuals could virologically fail treatment as a result of past PrEP use or transmitted resistance to PrEP with moderate adherence. CONCLUSIONS: There is no broad consensus on quantification of key biological processes that underpin the emergence of PrEP-associated drug resistance. Despite this, the contribution of PrEP use to the prevalence of the detectable drug resistance is expected to be small. However, i
Phillips AN, Cambiano V, Revill P, et al., 2016, Identifying Key Drivers of the Impact of an HIV Cure Intervention in Sub-Saharan Africa, Journal of Infectious Diseases, Vol: 214, Pages: 73-79, ISSN: 1537-6613
BACKGROUND: It is unknown what properties would be required to make an intervention in low income countries that can eradicate or control human immunodeficiency virus (HIV) without antiretroviral therapy (ART) cost-effective. METHODS: We used a model of HIV and ART to investigate the effect of introducing an ART-free viral suppression intervention in 2022 using Zimbabwe as an example country. We assumed that the intervention (cost: $500) would be accessible for 90% of the population, be given to those receiving effective ART, have sufficient efficacy to allow ART interruption in 95%, with a rate of viral rebound of 5% per year in the first 3 months, and a 50% decline in rate with each successive year. RESULTS: An ART-free viral suppression intervention with these properties would result in >0.53 million disability-adjusted-life-years averted over 2022-2042, with a reduction in HIV program costs of $300 million (8.7% saving). An intervention of this efficacy costing anything up to $1400 is likely to be cost-effective in this setting. CONCLUSIONS: Interventions aimed at curing HIV infection have the potential to improve overall disease burden and to reduce costs. Given the effectiveness and cost of ART, such interventions would have to be inexpensive and highly effective.
Hargreaves JR, Delany-Moretlwe S, Hallett TB, et al., 2016, The HIV prevention cascade: integrating theories of epidemiological, behavioural, and social science into programme design and monitoring, The Lancet HIV, Vol: 3, Pages: E318-E322, ISSN: 2352-3018
Theories of epidemiology, health behaviour, and social science have changed the understanding of HIV prevention in the past three decades. The HIV prevention cascade is emerging as a new approach to guide the design and monitoring of HIV prevention programmes in a way that integrates these multiple perspectives. This approach recognises that translating the efficacy of direct mechanisms that mediate HIV prevention (including prevention products, procedures, and risk-reduction behaviours) into population-level effects requires interventions that increase coverage. An HIV prevention cascade approach suggests that high coverage can be achieved by targeting three key components: demand-side interventions that improve risk perception and awareness and acceptability of prevention approaches; supply-side interventions that make prevention products and procedures more accessible and available; and adherence interventions that support ongoing adoption of prevention behaviours, including those that do and do not involve prevention products. Programmes need to develop delivery platforms that ensure these interventions reach target populations, to shape the policy environment so that it facilitates implementation at scale with high quality and intensity, and to monitor the programme with indicators along the cascade.
Garnett GP, Hallett TB, Takaruza A, et al., 2016, Providing a conceptual framework for HIV prevention cascades and assessing feasibility of empirical measurement with data from east Zimbabwe: a case study, Lancet HIV, Vol: 3, Pages: E297-E306, ISSN: 2352-3018
BackgroundThe HIV treatment cascade illustrates the steps required for successful treatment and is a powerful advocacy and monitoring tool. Similar cascades for people susceptible to infection could improve HIV prevention programming. We aim to show the feasibility of using cascade models to monitor prevention programmes.MethodsConceptual prevention cascades are described taking intervention-centric and client-centric perspectives to look at supply, demand, and efficacy of interventions. Data from two rounds of a population-based study in east Zimbabwe are used to derive the values of steps for cascades for voluntary medical male circumcision (VMMC) and for partner reduction or condom use driven by HIV testing and counselling (HTC).FindingsIn 2009 to 2011 the availability of circumcision services was negligible, but by 2012 to 2013 about a third of the population had access. However, where it was available only 12% of eligible men sought to be circumcised leading to an increase in circumcision prevalence from 3·1% to 6·9%. Of uninfected men, 85·3% did not perceive themselves to be at risk of acquiring HIV. The proportions of men and women tested for HIV increased from 27·5% to 56·6% and from 61·1% to 79·6%, respectively, with 30·4% of men tested self-reporting reduced sexual partner numbers and 12·8% reporting increased condom use.InterpretationPrevention cascades can be populated to inform HIV prevention programmes. In eastern Zimbabwe programmes need to provide greater access to circumcision services and the design and implementation of associated demand creation activities. Whereas, HTC services need to consider how to increase reductions in partner numbers or increased condom use or should not be considered as contributing to prevention services for the HIV-negative adults.
Smith JA, Anderson SJ, Harris KL, et al., 2016, Maximising HIV prevention - balancing the opportunities of today with the promises of tomorrow: a modelling study, The Lancet HIV, Vol: 3, Pages: e289-e296, ISSN: 2352-3018
Background: Many ways of preventing HIV infection have been proposed and more are being developed. We sought to construct a strategic approach to HIV prevention that would use limited resources to achieve the greatest possible prevention impact through the use of interventions available today and in the coming years.Methods: We developed a mathematical model of the HIV epidemic in South Africa and formed assumptions about the costs and effects of a range of interventions, encompassing the further scale-up of existing interventions (promoting condom use, male circumcision, outreach testing and early ART initiation for all, and oral PrEP), the introduction of new interventions in the medium-term (offering intravaginal rings (IVR), long-acting antiretrovirals (LA-ARVS)) and long-term (vaccine, broadly neutralising antibodies (bNAbs)). We examined how available resources could be allocated across these interventions to achieve maximal impact, and assessed how this would be affected by the failure of the interventions to be developed or scaled up.Findings: If all the above-listed interventions are available, the optimal mix of interventions would place great emphasis on: (i) scale-up of male circumcision and outreach testing and ART initiation, as these are available immediately and are assumed to be low cost and/or highly efficacious; (ii) IVR targeted to sex workers; and (iii) vaccines, as these can achieve a high impact if scaled-up even if imperfectly efficacious. It would rely less on longer-term developments, such as LA-ARVS and bNAbs, unless the costs of these reduced. However, if it were not possible to scale up existing interventions to the extent assumed, greater emphasis would be placed on oral PrEP, IVR and LA-ARVs. The long-term impact on the epidemic is most affected by scale-up of existing interventions and the successful development of a vaccine.Interpretation: With current information, a strategic approach in which limited resources are used to maximise
Hallett TB, Anderson S-J, Asante CA, et al., 2016, Evaluation of geospatial methods to generate subnational HIV prevalence estimates for local level planning, AIDS, Vol: 30, Pages: 1467-1474, ISSN: 0269-9370
Objective: There is evidence of substantial subnational variation in the HIV epidemic. However, robust spatial HIV data are often only available at high levels of geographic aggregation and not at the finer resolution needed for decision making. Therefore, spatial analysis methods that leverage available data to provide local estimates of HIV prevalence may be useful. Such methods exist but have not been formally compared when applied to HIV.Design/methods: Six candidate methods – including those used by the Joint United Nations Programme on HIV/AIDS to generate maps and a Bayesian geostatistical approach applied to other diseases – were used to generate maps and subnational estimates of HIV prevalence across three countries using cluster level data from household surveys. Two approaches were used to assess the accuracy of predictions: internal validation, whereby a proportion of input data is held back (test dataset) to challenge predictions; and comparison with location-specific data from household surveys in earlier years.Results: Each of the methods can generate usefully accurate predictions of prevalence at unsampled locations, with the magnitude of the error in predictions similar across approaches. However, the Bayesian geostatistical approach consistently gave marginally the strongest statistical performance across countries and validation procedures.Conclusions: Available methods may be able to furnish estimates of HIV prevalence at finer spatial scales than the data currently allow. The subnational variation revealed can be integrated into planning to ensure responsiveness to the spatial features of the epidemic. The Bayesian geostatistical approach is a promising strategy for integrating HIV data to generate robust local estimates.
Cooke GS, Hallett T, 2016, HCV and HIV: shared challenges, shared solutions., Lancet Infectious Diseases, ISSN: 1473-3099
Cremin I, Morales F, Jewell BL, et al., 2016, Seasonal PrEP for partners of migrant miners in southern Mozambique: a highly focused PrEP intervention (vol 18, 19946, 2015), JOURNAL OF THE INTERNATIONAL AIDS SOCIETY, Vol: 19
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Smit M, Hallett T, 2016, Respiratory co-morbidities in people with HIV, Lancet Infectious Diseases, Vol: 16, Pages: 152-152, ISSN: 1473-3099
Nayagam S, Chan P, Zhao K, et al., 2016, INVESTMENT CASE FOR A COMPREHENSIVE PACKAGE OF INTERVENTIONS AGAINST HEPATITIS B IN CHINA, EASL International Liver Congress, Publisher: ELSEVIER SCIENCE BV, Pages: S469-S469, ISSN: 0168-8278
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Phillips A, Shroufi A, Vojnov L, et al., 2015, Sustainable HIV treatment in Africa through viral-load-informed differentiated care, Nature, Vol: 528, Pages: S68-S76, ISSN: 1476-4687
Eaton JW, Bacaer N, Bershteyn A, et al., 2015, Assessment of epidemic projections using recent HIV survey data in South Africa: a validation analysis of ten mathematical models of HIV epidemiology in the antiretroviral therapy era, Lancet Global Health, Vol: 3, Pages: e598-e608, ISSN: 2214-109X
BackgroundMathematical models are widely used to simulate the effects of interventions to control HIV and to project future epidemiological trends and resource needs. We aimed to validate past model projections against data from a large household survey done in South Africa in 2012.MethodsWe compared ten model projections of HIV prevalence, HIV incidence, and antiretroviral therapy (ART) coverage for South Africa with estimates from national household survey data from 2012. Model projections for 2012 were made before the publication of the 2012 household survey. We compared adult (age 15–49 years) HIV prevalence in 2012, the change in prevalence between 2008 and 2012, and prevalence, incidence, and ART coverage by sex and by age groups between model projections and the 2012 household survey.FindingsAll models projected lower prevalence estimates for 2012 than the survey estimate (18·8%), with eight models' central projections being below the survey 95% CI (17·5–20·3). Eight models projected that HIV prevalence would remain unchanged (n=5) or decline (n=3) between 2008 and 2012, whereas prevalence estimates from the household surveys increased from 16·9% in 2008 to 18·8% in 2012 (difference 1·9, 95% CI −0·1 to 3·9). Model projections accurately predicted the 1·6 percentage point prevalence decline (95% CI −0·3 to 3·5) in young adults aged 15–24 years, and the 2·2 percentage point (0·5 to 3·9) increase in those aged 50 years and older. Models accurately represented the number of adults on ART in 2012; six of ten models were within the survey 95% CI of 1·54–2·12 million. However, the differential ART coverage between women and men was not fully captured; all model projections of the sex ratio of women to men on ART were lower than the survey estimate of 2·22 (95% CI 1·73–2·71).InterpretationProjec
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