Updates to the Spectrum/Estimations and Projections Package model for estimating trends and current values for key HIV indicators

Dynamic models augmented by hierarchical data: an application of estimating HIV epidemics at sub-national level

Dynamic models have been successfully used in producing estimates of HIV epidemics at the national level due to their epidemiological nature and their ability to estimate prevalence, incidence, and mortality rates simultaneously. Recently, HIV interventions and policies have required more information at sub-national levels to support local planning, decision-making and resource allocation. Unfortunately, many areas lack sufficient data for deriving stable and reliable results, and this is a critical technical barrier to more stratified estimates. One solution is to borrow information from other areas within the same country. However, directly assuming hierarchical structures within the HIV dynamic models is complicated and computationally time-consuming. In this article, we propose a simple and innovative way to incorporate hierarchical information into the dynamical systems by using auxiliary data. The proposed method efficiently uses information from multiple areas within each country without increasing the computational burden. As a result, the new model improves predictive ability and uncertainty assessment.

Global, regional, and national burdens of HIV/AIDS acquired through sexual transmission 1990-2019: an observational study

Background Sexual transmission accounts for a substantial proportion of HIV infections. Although some countries are experiencing an upward trend in HIV infections, there has been a lack of studies assessing the global burden of HIV/AIDS acquired through sexual transmission. We assessed the global, regional, and national burdens of HIV/AIDS acquired through sexual transmission from 1990 to 2019. Methods Data on deaths, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life years (DALY) of HIV/AIDS acquired through sexual transmission in 204 countries and territories from 1990 to 2019 were retrieved from the Global Burden of Disease Study (GBD) 2019. The burdens and trends were evaluated using the age-standardised rates (ASR) and estimated annual percentage change (EAPC). Results Globally, HIV/AIDS acquired through sexual transmission accounted for ~695.8 thousand (95% uncertainty interval 628.0-811.3) deaths, 33.0million (28.7-39.9) YLLs, 3.4million (2.4-4.6) YLDs, and 36.4million (32.2-43.1) DALYs in 2019. In 2019, Southern sub-Saharan Africa (11350.94), Eastern sub-Saharan Africa (3530.91), and Western sub-Saharan Africa (2037.74) had the highest ASR of DALYs of HIV/AIDS acquired through sexual transmission per 100,000. In most regions of the world, the burden of HIV/AIDS acquired through sexual transmission has been increasing from 1990 to 2019, mainly in Oceania (EAPC 17.20, 95% confidence interval 12.82-21.75), South Asia (9.00, 3.94-14.30), and Eastern Europe (7.09, 6.35-7.84). Conclusions HIV/AIDS acquired through sexual transmission results in a major burden globally, regionally, and nationally.

A sub-national HIV epidemic appraisal in Kenya: a new approach for identifying priority geographies, populations and programmes for optimizing coverage for HIV prevention

INTRODUCTION

The HIV Prevention 2025 Roadmap, developed by UNAIDS, recommends the adoption of a precision prevention approach focused on priority populations and geographies. With reduction in new HIV acquisitions in many countries, designing a differentiated HIV prevention response, using a Programme Science approach, based on the understanding of the epidemic and transmission dynamics at a sub-national level, is critical.

METHODS

To support strategic planning, an epidemic appraisal at the sub-national level across 47 counties, with the 2019 population ranging from 0.14 million in Lamu to 4.40 million in Nairobi City, was conducted in Kenya using several existing data sources. Using 2021 Spectrum/EPP/Naomi model estimates of national and sub-national HIV incidence and prevalence, counties with high HIV incidence and prevalence were identified for geographic prioritization. The size of local key population (KP) networks and HIV prevalence in key and general populations were used to define epidemic typology and prioritize populations for HIV prevention programmes. Analysis of routine programme monitoring data for 2021 was used to assess coverage gaps in HIV prevention programmes, including prevention of vertical transmission, anti-retroviral therapy, KP programmes, adolescent girls and young women programme, and voluntary male medical circumcision programme.

RESULTS

Ten counties with more than 1000 incident acquisitions in 2021 accounted for 57% of new acquisitions. Twenty-four counties were grouped into the concentrated epidemic type-due to their low prevalence in the general population, high prevalence in KPs and relatively higher density of female sex workers and men who have sex with men populations. Four counties reflected a generalized epidemic, where HIV prevalence was more than 10% and 30%, respectively, among the general and key populations. The remaining 19 counties were classified as having mixed epidemics. Gaps in programmes were identified and counties where these gaps need to be addressed were also prioritized.

CONCLUSIONS

The HIV burden in Kenya is unevenly distributed and hence the mix of prevention strategies may vary according to the epidemic typology of the county. Prioritization of programmes based not only on disease burden and epidemic typology, but also on the prevailing gaps in coverage for reducing inequities is a key aspect of this appraisal.

Methods and Assumptions for Estimating Key HIV Indicators in the UNAIDS Annual Estimates Process

BACKGROUND

Each year UNAIDS supports national teams to estimate key HIV indicators using their latest data. These estimates are produced using a collection of models and software tools. This paper describes the demographic and HIV projection models used in this process.

METHODS

The demographic model (DemProj) projects the population by sex and single age for each year of the estimate. This information is fed into the HIV model (AIDS Impact Model) to estimate key HIV indicators. The model uses program, survey and surveillance data along with incidence trends produced through 1 of several separate models, to estimate new HIV infections, HIV-related deaths, and the population living with HIV by sex, age, CD4 category, and treatment status.

RESULTS

These models allow the annual production of estimates of key HIV indicators including uncertainty intervals. This information is used to track progress toward national and global goals and to develop national strategic plans, Global Fund applications and PEPFAR country operational plans.

CONCLUSIONS

Under the guidance of the UNAIDS Reference Group on Estimates, Modeling and Projections, these models are updated on a regular basis in response to evolving programmatic needs, new data, and analyses. This process of continuous review and improvement has led to mature models that make the best use of available data to provide estimates of indicators important to monitoring progress and developing future plans.

The AIDS Epidemic Model 2023 for Estimating HIV Trends and Transmission Dynamics in Asian Epidemic Settings

BACKGROUND

Thirteen Asian countries use the AIDS Epidemic Model (AEM) as their HIV model of choice. This article describes AEM, its inputs, and its application to national modeling.

SETTING

AEM is an incidence tool used by Spectrum for the Joint United Nations Programme on HIV/AIDS global estimates process.

METHODS

AEM simulates transmission of HIV among key populations (KPs) using measured trends in risk behaviors. The inputs, structure and calculations, interface, and outputs of AEM are described. The AEM process includes (1) collating and synthesizing data on KP risk behaviors, epidemiology, and size to produce model input trends; (2) calibrating the model to observed HIV prevalence; (3) extracting outputs by KP to describe epidemic dynamics and assist in improving responses; and (4) importing AEM incidence into Spectrum for global estimates. Recent changes to better align AEM mortality with Spectrum and add preexposure prophylaxis are described.

RESULTS

The application of AEM in Thailand is presented, describing the outputs and uses in-country. AEM replicated observed epidemiological trends when given observed behavioral inputs. The strengths and limitations of AEM are presented and used to inform thoughts on future directions for global models.

CONCLUSIONS

AEM captures regional HIV epidemiology well and continues to evolve to meet country and global process needs. The addition of time-varying mortality and progression parameters has improved the alignment of the key population compartmental model of AEM with the age-sex-structured national model of Spectrum. Many of the features of AEM, including tracking the sources of infections over time, should be incorporated in future global efforts to build more generalizable models to guide policy and programs.

Spatial distribution, magnitude, and predictors of high fertility status among reproductive age women in Ethiopia: Further analysis of 2016 Ethiopia Demographic and Health Survey

BACKGROUND

Women's health and welfare, as well as the survival of their children, are adversely affected by high fertility rates in developing countries. The fertility rate in Ethiopia has been high for a long time, with some pockets still showing poor improvement. Thus, the current study is aimed to assess the spatial distribution and its predictors of high fertility status in Ethiopia.

METHODS

Secondary data analysis was used using the 2016 Ethiopian Demographic and Health Survey (EDHS). The Bernoulli model was used by applying Kulldorff methods using the SaTScan software to analyze the purely spatial clusters of high fertility status. ArcGIS version 10.8 was used to visualize the distribution of high fertility status across the country. Mixed-effect logistic regression analysis was also used to identify the predictors of high fertility.

RESULT

High fertility among reproductive-age women had spatial variation across the country. In this study, a higher proportion of fertility occurred in Somali region, Southeastern part of Oromia region, and Northeastern part of SNNPR. About 45.33% (confidence interval: (44.32, 46.33) of reproductive-age women had high fertility. Education; no formal (aOR: 13.12, 95% CI: 9.27, 18.58) and primary (aOR: 5.51, 95% CI: 3.88, 7.79), religion; Muslim (aOR: 1.52, 95% CI: 1.28, 1.81) and Protestant (aOR: 1.48, 95% CI: 1.23, 1.78), age at first birth (aOR: 2.94, 95% CI: 2.61, 3.31), age at first sex (aOR: 1.70, 95% CI: 1.49, 1.93), rural resident (aOR: 3.76, 95% CI: 2.85, 4.94) were predictors of high fertility in Ethiopia.

CONCLUSION

The spatial pattern of high fertility status in Ethiopia is clustered. Hotspot areas of a problem were located in Somali, Central Afar, Northeastern part of SNNPR, and Southeastern part of Oromia region. Therefore, designing a hotspot area-based interventional plan could help to reduce high fertility. Moreover, much is needed to be done among rural residents, reducing early sexual initiations and early age at first birth, and enhancing women's education. All the concerned bodies including the kebele administration, religious leaders, and community leaders should be in a position to ensure the practicability of the legal age of marriage.

Comparison of programmatic data from antenatal clinics with population-based HIV prevalence estimates in the era of universal test and treat in western Kenya

OBJECTIVE

To compare HIV prevalence estimates from routine programme data in antenatal care (ANC) clinics in western Kenya with HIV prevalence estimates in a general population sample in the era of universal test and treat (UTT).

METHODS

The study was conducted in the area covered by the Siaya Health Demographic Surveillance System (Siaya HDSS) in western Kenya and used data from ANC clinics and the general population. ANC data (n = 1,724) were collected in 2018 from 13 clinics located within the HDSS. The general population was a random sample of women of reproductive age (15-49) who reside in the Siaya HDSS and participated in an HIV sero-prevalence survey in 2018 (n = 2,019). Total and age-specific HIV prevalence estimates were produced from both datasets and demographic decomposition methods were used to quantify the contribution of the differences in age distributions and age-specific HIV prevalence to the total HIV prevalence estimates.

RESULTS

Total HIV prevalence was 18.0% (95% CI 16.3-19.9%) in the ANC population compared with 18.4% (95% CI 16.8-20.2%) in the general population sample. At most ages, HIV prevalence was higher in the ANC population than in the general population. The age distribution of the ANC population was younger than that of the general population, and because HIV prevalence increases with age, this reduced the total HIV prevalence among ANC attendees relative to prevalence standardised to the general population age distribution.

CONCLUSION

In the era of UTT, total HIV prevalence among ANC attendees and the general population were comparable, but age-specific HIV prevalence was higher in the ANC population in most age groups. The expansion of treatment may have led to changes in both the fertility of women living with HIV and their use of ANC services, and our results lend support to the assertion that the relationship between ANC and general population HIV prevalence estimates are highly dynamic.

Subnational HIV incidence trends in Malawi: large, heterogeneous declines across space

The rate of new HIV infections globally has decreased substantially from its peak in the late 1990s, but the epidemic persists and remains highest in many countries in eastern and southern Africa. Previous research hypothesised that, as the epidemic recedes, it will become increasingly concentrated among sub-populations and geographic areas where transmission is the highest and that are least effectively reached by treatment and prevention services. However, empirical data on subnational HIV incidence trends is sparse, and the local transmission rates in the context of effective treatment scale-up are unknown. In this work, we developed a novel Bayesian spatio-temporal epidemic model to estimate adult HIV prevalence, incidence and treatment coverage at the district level in Malawi from 2010 through the end of 2021. We found that HIV incidence decreased in every district of Malawi between 2010 and 2021 but the rate of decline varied by area. National-level treatment coverage more than tripled between 2010 and 2021 and more than doubled in every district. Large increases in treatment coverage were associated with declines in HIV transmission, with 12 districts having incidence-prevalence ratios of 0.03 or less (a previously suggested threshold for epidemic control). Across districts, incidence varied more than HIV prevalence and ART coverage, suggesting that the epidemic is becoming increasingly spatially concentrated. Our results highlight the success of the Malawi HIV treatment programme over the past decade, with large improvements in treatment coverage leading to commensurate declines in incidence. More broadly, we demonstrate the utility of spatially resolved HIV modelling in generalized epidemic settings. By estimating temporal changes in key epidemic indicators at a relatively fine spatial resolution, we were able to directly assess, for the first time, whether the ART scaleup in Malawi resulted in spatial gaps or hotspots. Regular use of this type of analysis will allow HIV program managers to monitor the equity of their treatment and prevention programmes and their subnational progress towards epidemic control.

Recent HIV Infection: Diagnosis and Public Health Implications

The early period of infection with human immunodeficiency virus (HIV) has been associated with higher infectiousness and, consequently, with more transmission events. Over the last 30 years, assays have been developed that can detect viral and immune biomarkers during the first months of HIV infection. Some of them depend on the functional properties of antibodies including their changing titers or the increasing strength of binding with antigens over time. There have been efforts to estimate HIV incidence using antibody-based assays that detect recent HIV infection along with other laboratory and clinical information. Moreover, some interventions are based on the identification of people who were recently infected by HIV. This review summarizes the evolution of efforts to develop assays for the detection of recent HIV infection and to use these assays for the cross-sectional estimation of HIV incidence or for prevention purposes.

Cost-effectiveness of implementing HIV and HIV/syphilis dual testing among key populations in Viet Nam: a modelling analysis

OBJECTIVES

Key populations, including sex workers, men who have sex with men, and people who inject drugs, have a high risk of HIV and sexually transmitted infections. We assessed the health and economic impacts of different HIV and syphilis testing strategies among three key populations in Viet Nam using a dual HIV/syphilis rapid diagnostic test (RDT).

SETTING

We used the spectrum AIDS impact model to simulate the HIV epidemic in Viet Nam and evaluated five testing scenarios among key populations. We used a 15-year time horizon and a provider perspective for costs.

PARTICIPANTS

We simulate the entire population of Viet Nam in the model.

INTERVENTIONS

We modelled five testing scenarios among key populations: (1) annual testing with an HIV RDT, (2) annual testing with a dual RDT, (3) biannual testing using dual RDT and HIV RDT, (4) biannual testing using HIV RDT and (5) biannual testing using dual RDT.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome is incremental cost-effectiveness ratios. Secondary outcomes include HIV and syphilis cases.

RESULTS

Annual testing using a dual HIV/syphilis RDT was cost-effective (US$10 per disability-adjusted life year (DALY)) and averted 3206 HIV cases and treated 27 727 syphilis cases compared with baseline over 15 years. Biannual testing using one dual test and one HIV RDT (US$1166 per DALY), or two dual tests (US$5672 per DALY) both averted an additional 875 HIV cases, although only the former scenario was cost-effective. Annual or biannual HIV testing using HIV RDTs and separate syphilis tests were more costly and less effective than using one or two dual RDTs.

CONCLUSIONS

Annual HIV and syphilis testing using dual RDT among key populations is cost-effective in Vietnam and similar settings to reach global reduction goals for HIV and syphilis.

HIV incidence estimates by sex and age group in the population aged 15 years or over, Brazil, 1986-2018

INTRODUCTION

HIV incidence estimates are essential to monitor the progress of prevention and control interventions.

METHODS

Data collected by Brazilian surveillance systems were used to derive HIV incidence estimates by age group (15-24; 25+) and sex from 1986 to 2018. This study used a back-calculation method based on the first CD4 count among treatment-naïve cases. Incidence estimates for the population aged 15 years or over were compared to Global Burden of Disease Study (GBD) estimates from 2000 to 2018.

RESULTS

Among young men (15-24 years), HIV incidence increased from 6,400 (95% CI: 4,900-8,400), in 2000, to 12,800 (95% CI: 10,800-15,900), in 2015, reaching incidence rates higher than 70/100,000 inhabitants and an annual growth rate of 3.7%. Among young women, HIV incidence decreased from 5,000 (95% CI: 4,200-6,100) to 3,200 (95% CI: 3,000-3,700). Men aged ≥25 years and both female groups showed significant annual decreases in incidence rates from 2000 to 2018. In 2018, the estimated number of new infections was 48,500 (95% CI: 45300-57500), 34,800 (95% CI: 32800-41500) men, 13,600 (95% CI: 12,500-16,000) women. Improvements in the time from infection to diagnosis and in the proportion of cases receiving antiretroviral therapy immediately after diagnosis were found for all groups. Comparison with GBD estimates shows similar rates for men with overlapping confidence intervals. Among women, differences are higher mainly in more recent years.

CONCLUSIONS

The results indicate that efforts to control the HIV epidemic are having an impact. However, there is an urgent need to address the vulnerability of young men.

A Framework for Assessing the Impact of Disease Treatment

OBJECTIVES

To address ongoing pandemics and epidemics, policy makers need good data on not only the need for treatments but also on new interventions' impacts. We present a mathematical model of medicines' health consequences using disease surveillance data to inform health policy and scientific research that can be extended to address the current public health crisis.

METHODS

The Global Health Impact (GHI) index calculates the amount of mortality and morbidity averted by key medicines for malaria, TB, HIV/AIDS, and several NTDs using data on outcomes in the absence of treatment, treatment effectiveness, and access to needed treatment. Country-level data were extracted from data repositories maintained by the Global Burden of Disease study, Global Health Observatory, WHO, UNICEF, and a review of the scientific literature.

RESULTS

The index aggregates drug impact by country, disease, company, and treatment regimen to identify the spatial and temporal patterns of treatment impact and can be extended across multiple diseases. Approximately 62 million life-years were saved by key drugs that target malaria, TB, HIV/AIDS, and NTDs in our latest model year. Malaria and TB medicines together were responsible for alleviating 95% of this burden, while HIV/AIDS and NTD medicines contribute 4% and 1% respectively. However, the burden of disease in the absence of treatment was nearly evenly distributed among malaria, TB, and HIV/AIDS.

CONCLUSIONS

A common framework that standardizes health impact across diseases and their interventions can aid in identifying current shortcomings on a global scale.

Declining HIV incidence in sub-Saharan Africa: a systematic review and meta-analysis of empiric data

Introduction

UNAIDS models suggest HIV incidence is declining in sub‐Saharan Africa. The objective of this study was to assess whether modelled trends are supported by empirical evidence.

Methods

We conducted a systematic review and meta‐analysis of adult HIV incidence data from sub‐Saharan Africa by searching Embase, Scopus, PubMed and OVID databases and technical reports published between 1 January 2010 and 23 July 2019. We included prospective and cross‐sectional studies that directly measured incidence from blood samples. Incidence data were abstracted according to population risk group, geographic location, sex, intervention arm and calendar period. Weighted regression models were used to assess incidence trends across general population studies by sex. We also identified studies reporting greater than or equal to three incidence measurements since 2010 and assessed trends within them.

Results

Total 291 studies, including 22 sub‐Saharan African countries, met inclusion criteria. Most studies were conducted in South Africa (n = 102), Uganda (n = 46) and Kenya (n = 41); there were 26 countries with no published incidence data, most in western and central Africa. Data were most commonly derived from prospective observational studies (n = 163; 56%) and from geographically defined populations with limited demographic or risk‐based enrolment criteria other than age (i.e., general population studies; n = 151; 52%). Across general population studies, average annual incidence declines since 2010 were 0.12/100 person‐years (95% CI: 0.06–0.18; p = 0.001) among men and 0.10/100 person‐years (95% CI: −0.02–0.22; p = 0.093) among women in eastern Africa, and 0.25/100 person‐years (95% CI: 0.17–034; p < 0.0001) among men and 0.42/100 person‐years (95% CI: 0.23–0.62; p = 0.0002) among women in southern Africa. In nine of 10 studies with multiple measurements, incidence declined over time, including in two studies of key populations. Across all population risk groups, the highest HIV incidence estimates were observed among men who have sex with men, with rates ranging from 1.0 to 15.4/100 person‐years. Within general population studies, incidence was typically higher in women than men with a median female‐to‐male incidence rate ratio of 1.47 (IQR: 1.11 to 1.83) with evidence of a growing sex disparity over time.

Conclusions

Empirical incidence data show the rate of new HIV infections is declining in eastern and southern Africa. However, recent incidence data are non‐existent or very limited for many countries and key populations.

Updates to Spectrum's case surveillance and vital registration tool for HIV estimates and projections

INTRODUCTION

The Case Surveillance and Vital Registration (CSAVR) model within Spectrum estimates HIV incidence trends from surveillance data on numbers of new HIV diagnoses and HIV-related deaths. This article describes developments of the CSAVR tool to more flexibly model diagnosis rates over time, estimate incidence patterns by sex and age group and by key population group.

METHODS

We modelled HIV diagnosis rate trends as a mixture of three factors, including temporal and opportunistic infection components. The tool was expanded to estimate incidence rate ratios by sex and age for countries with disaggregated reporting of new HIV diagnoses and AIDS deaths, and to account for information on key populations such as men who have sex with men (MSM), males who inject drugs (MWID), female sex workers (FSW) and females who inject drugs (FWID). We used a Bayesian framework to calibrate the tool in 71 high-income or low-HIV burden countries.

RESULTS

Across countries, an estimated median 89% (interquartile range [IQR]: 78%-96%) of HIV-positive adults knew their status in 2019. Mean CD4 counts at diagnosis were stable over time, with a median of 456 cells/μl (IQR: 391-508) across countries in 2019. In European countries reporting new HIV diagnoses among key populations, median estimated proportions of males that are MSM and MWID was 1.3% (IQR: 0.9%-2.0%) and 0.56% (IQR: 0.51%-0.64%), respectively. The median estimated proportions of females that are FSW and FWID were 0.36% (IQR: 0.27%-0.45%) and 0.14 (IQR: 0.13%-0.15%), respectively. HIV incidence per 100 person-years increased among MSM, with median estimates reaching 0.43 (IQR: 0.29-1.73) in 2019, but remained stable in MWID, FSW and FWID, at around 0.12 (IQR: 0.04-1.9), 0.09 (IQR: 0.06-0.69) and 0.13% (IQR: 0.08%-0.91%) in 2019, respectively. Knowledge of HIV status among HIV-positive adults gradually increased since the early 1990s to exceed 75% in more than 75% of countries in 2019 among each key population.

CONCLUSIONS

CSAVR offers an approach to using routine surveillance and vital registration data to estimate and project trends in both HIV incidence and knowledge of HIV status.

Updates to the Spectrum/AIM model for the UNAIDS 2020 HIV estimates

INTRODUCTION

The Spectrum/AIM model is used by national HIV programs and UNAIDS to prepare annual estimates of key HIV indicators. This article describes key updates to paediatric and adult models for the 2021 round of HIV estimates.

METHODS

Potential updates to Spectrum arise due to newly available data, new analyses of existing data, and the need for new issues to be addressed. Updates are guided by experts through the UNAIDS Reference Group on Estimates, Modelling and Projections. Changes are tested and assessed for impact before being accepted into the final model.

RESULTS

Spectrum tracks children living with HIV by CD4% for ages 0-4 and CD4 count for ages 5-14. Data from IeDEA treatment sites have been used to map the transition from CD4% to CD4 count at age 5. Breastfeeding patterns in sub-Saharan Africa have been updated with the latest survey data and estimates of continuation on antiretroviral therapy (ART) with breastfeeding have been revised based on recent studies. Model assumptions about the CD4 counts of people who drop out of ART have been revised to account for CD4 count increases while on treatment. If available, monthly data on numbers on ART can now be used to estimate the effects of COVID-19-related disruptions during 2020.

CONCLUSIONS

These changes are intended to provide more accurate estimates of HIV burden. The effects of these changes on paediatric indicators are small except in countries with new surveys that might have updated patterns of breastfeeding. Changes to the adult model have little effect on total new infections. AIDS-related deaths will be somewhat lower in countries that have data on ART drop out but might be increased by HIV care disruptions due to COVID-19. The updated model uses newly available data to improve the estimation of paediatric and adult HIV indicators.

HIV-1 Recent Infection Testing Algorithm With Antiretroviral Drug Detection to Improve Accuracy of Incidence Estimates

BACKGROUND

HIV-1 incidence calculation currently includes recency classification by HIV-1 incidence assay and unsuppressed viral load (VL ≥ 1000 copies/mL) in a recent infection testing algorithm (RITA). However, persons with recent classification not virally suppressed and taking antiretroviral (ARV) medication may be misclassified.

SETTING

We used data from 13 African household surveys to describe the impact of an ARV-adjusted RITA on HIV-1 incidence estimates.

METHODS

HIV-seropositive samples were tested for recency using the HIV-1 Limiting Antigen (LAg)-Avidity enzyme immunoassay, HIV-1 viral load, ARVs used in each country, and ARV drug resistance. LAg-recent result was defined as normalized optical density values ≤1.5. We compared HIV-1 incidence estimates using 2 RITA: RITA1: LAg-recent + VL ≥ 1000 copies/mL and RITA2: RITA1 + undetectable ARV. We explored RITA2 with self-reported ARV use and with clinical history.

RESULTS

Overall, 357 adult HIV-positive participants were classified as having recent infection with RITA1. RITA2 reclassified 55 (15.4%) persons with detectable ARV as having long-term infection. Those with detectable ARV were significantly more likely to be aware of their HIV-positive status (84% vs. 10%) and had higher levels of drug resistance (74% vs. 26%) than those without detectable ARV. RITA2 incidence was lower than RITA1 incidence (range, 0%-30% decrease), resulting in decreased estimated new infections from 390,000 to 341,000 across the 13 countries. Incidence estimates were similar using detectable or self-reported ARV (R2 > 0.995).

CONCLUSIONS

Including ARV in RITA2 improved the accuracy of HIV-1 incidence estimates by removing participants with likely long-term HIV infection.

Prevalence and incidence of HIV among female sex workers and their clients: modelling the potential effects of intervention in Rwanda

BACKGROUND

Rwanda has identified several targeted HIV prevention strategies, such as promotion of condom use and provision of antiretroviral therapy (ART) and pre-exposure prophylaxis (PrEP) for female sex workers (FSWs). Given this country's limited resources, understanding how the HIV epidemic will be affected by these strategies is crucial.

METHODS

We developed a Markov model to estimate the effects of targeted strategies to FSWs on the HIV prevalence/incidence in Rwanda from 2017 to 2027. Our model consists of the six states: HIV-; HIV+ undiagnosed/diagnosed pre-ART; HIV+ diagnosed with/without ART; and death. We considered three populations: FSWs, sex clients and the general population. For the period 2017-2027, the HIV epidemic among each of these population was estimated using Rwanda's demographic, sexual risk behaviour and HIV-associated morbidity and mortality data.

RESULTS

Between 2017 and 2027, with no changes in the current condom and ART use, the overall number of people living with HIV is expected to increase from 344,971 to 402,451. HIV incidence will also decrease from 1.36 to 1.20 100 person-years. By 2027, a 30% improvement in consistent condom use among FSWs will result in absolute reduction of HIV prevalence among FSWs, sex clients and the general population by 7.86%, 5.97% and 0.17%, respectively. While recurring HIV testing and improving the ART coverage mildly reduced the prevalence/incidence among FSWs and sex clients, worsening the two (shown by our worst-case scenario) will result in an increase in the HIV prevalence/incidence among FSWs and sex clients. Introduction of PrEP to FSWs in 2019 will reduce the HIV incidence among FSWs by 1.28%.

CONCLUSIONS

Continued efforts toward improving condom and ART use will be critical for Rwanda to continue their HIV epidemic control. Implementing a targeted intervention strategy in PrEP for FSWs will reduce the HIV epidemic in this high-risk population.

Integrated screening and treatment services for HIV, hypertension and diabetes in Kenya: assessing the epidemiological impact and cost-effectiveness from a national and regional perspective

INTRODUCTION

As people with HIV age, prevention and management of other communicable and non-communicable diseases (NCDs) will become increasingly important. Integration of screening and treatment for HIV and NCDs is a promising approach for addressing the dual burden of these diseases. The aim of this study was to assess the epidemiological impact and cost-effectiveness of a community-wide integrated programme for screening and treatment of HIV, hypertension and diabetes in Kenya.

METHODS

Coupling a microsimulation of cardiovascular diseases (CVDs) with a population-based model of HIV dynamics (the Spectrum), we created a hybrid HIV/CVD model. Interventions were modelled from year 2019 (baseline) to 2023, and population was followed to 2033. Analyses were carried at a national level and for three selected regions (Nairobi, Coast and Central).

RESULTS

At a national level, the model projected 7.62 million individuals living with untreated hypertension, 692,000 with untreated diabetes and 592,000 individuals in need of ART in year 2018. Improving ART coverage from 68% at baseline to 88% in 2033 reduced HIV incidence by an estimated 64%. Providing NCD treatment to 50% of diagnosed cases from 2019 to 2023 and maintaining them on treatment afterwards could avert 116,000 CVD events and 43,600 CVD deaths in Kenya over the next 15 years. At a regional level, the estimated impact of expanded HIV services was highest in Nairobi region (averting 42,100 HIV infections compared to baseline) while Central region experienced the highest impact of expanded NCD treatment (with a reduction of 22,200 CVD events). The integrated HIV/NCD intervention could avert 7.76 million disability-adjusted-life-years (DALYs) over 15 years at an estimated cost of $6.68 billion ($445.27 million per year), or $860.30 per DALY averted. At a cost-effectiveness threshold of $2,010 per DALY averted, the probability of cost-effectiveness was 0.92, ranging from 0.71 in Central to 0.92 in Nairobi region.

CONCLUSIONS

Integrated screening and treatment of HIV and NCDs can be a cost-effective and impactful approach to save lives of people with HIV in Kenya, although important variation exists at the regional level. Containing the substantial costs required for scale-up will be critical for management of HIV and NCDs on a national scale.

Effect of HIV Infection and Antiretroviral Treatment on Pregnancy Rates in the Western Cape Province of South Africa

BACKGROUND

Previous studies suggest that untreated human immunodeficiency virus (HIV) infection is associated with a reduced incidence of pregnancy, but studies of the effect of antiretroviral treatment (ART) on pregnancy incidence have been inconsistent.

METHODS

Routine data from health services in the Western Cape province of South Africa were linked to identify pregnancies during 2007-2017 and maternal HIV records. The time from the first (index) pregnancy outcome date to the next pregnancy was modeled using Cox proportional hazards models.

RESULTS

During 2007-2017, 1 042 647 pregnancies were recorded. In all age groups, pregnancy incidence rates were highest in women who had started ART, lower in HIV-negative women, and lowest in ART-naive HIV-positive women. In multivariable analysis, after controlling for the most recent CD4+ T-cell count, pregnancy incidence rates in HIV-positive women receiving ART were higher than those in untreated HIV-positive women (adjusted hazard ratio, 1.63; 95% confidence interval, 1.59-1.67) and those in HIV-negative women.

CONCLUSION

Among women who have recently been pregnant, receipt of ART is associated with high rates of second pregnancy. Better integration of family planning into HIV care services is needed.

New HIV infections from blood transfusions averted in 28 countries supported by PEPFAR blood safety programs, 2004-2015

BACKGROUND

To quantify the impact of the US President's Emergency Plan for AIDS Relief (PEPFAR) on the risk of HIV transmission through infected blood donations in countries supported by PEPFAR blood safety programs.

METHODS

Data reported to the World Health Organization Global Database on Blood Safety were analyzed from 28 countries in sub-Saharan Africa (SSA), Asia, and the Caribbean during 2004-2015. We used the Goals model of Spectrum Spectrum System Software, version 5.53, to perform the modeling, assuming laboratory quality for HIV testing had 91.9% sensitivity and 97.7% specificity irrespective of testing method based on results of two external quality assurance and proficiency testing studies of transfusion screening for HIV in SSA blood centers. We calculated the number of new HIV infections from the number of transfusions and the prevalence of HIV infection acquired from blood transfusions with infected blood donations. We determined the impact of laboratory testing programs by estimating the number of new HIV infections averted since PEPFAR implementation.

RESULTS

Assuming that HIV testing would not be performed in any of these countries without PEPFAR funding, the number of new HIV infections acquired from blood transfusions averted by laboratory testing increased over time in all 28 countries. The total number of HIV infections averted was estimated at 229 278 out of 20 428 373 blood transfusions during 2004-2015.

CONCLUSION

Our mathematical modeling suggests a positive impact achieved over 12 years of PEPFAR support for blood safety. Standardized HIV testing of donated blood has reduced the risk of HIV transmission through blood transfusions in SSA, Asia, and the Caribbean.

Assessing the use of surveillance data to estimate the impact of prevention interventions on HIV incidence in cluster-randomized controlled trials

BACKGROUND

In cluster-randomized controlled trials (C-RCTs) of HIV prevention strategies, HIV incidence is expensive to measure directly. Surveillance data on HIV diagnoses or viral suppression could provide cheaper incidence estimates. We used mathematical modelling to evaluate whether these measures can replace HIV incidence measurement in C-RCTs.

METHODS

We used a US HIV transmission model to simulate C-RCTs of expanded antiretroviral therapy(ART), pre-exposure prophylaxis(PrEP) and HIV testing, together or alone. We tested whether modelled reductions in total new HIV diagnoses, diagnoses with acute infection, diagnoses with early infection(CD4 > 500 cells/μl), diagnoses adjusted for testing volume, or the proportion virally non-suppressed, reflected HIV incidence reductions.

RESULTS

Over a two-year trial expanding PrEP alone, modelled reductions in total diagnoses underestimated incidence reductions by a median six percentage points(pp), with acceptable variability(95 % credible interval -14,-2pp). For trials expanding HIV testing alone or alongside ART + PrEP, greater, highly variable bias was seen[-20pp(-128,-1) and -30pp(-134,-16), respectively]. Acceptable levels of bias were only seen over longer trial durations when levels of awareness of HIV-positive status were already high. Expanding ART alone, only acute and early diagnoses reductions reflected incidence reduction well, with some bias[-3pp(-6,-1) and -8pp(-16,-3), respectively]. Early and adjusted diagnoses also reliably reflected incidence when scaling up PrEP alone[bias -5pp(-11,1) and 10pp(3,18), respectively]. For trials expanding testing (alone or with ART + PrEP), bias for all measures explored was too variable for them to replace direct incidence measures, unless using diagnoses when HIV status awareness was already high.

CONCLUSIONS

Surveillance measures based on HIV diagnoses may sometimes be adequate surrogates for HIV incidence reduction in C-RCTs expanding ART or PrEP only, if adjusted for bias. However, all surveillance measures explored failed to approximate HIV incidence reductions for C-RCTs expanding HIV testing, unless levels of awareness of HIV-positive status were already high.

Challenges in estimating HIV prevalence trends and geographical variation in HIV prevalence using antenatal data: Insights from mathematical modelling

BACKGROUND

HIV prevalence data among pregnant women have been critical to estimating HIV trends and geographical patterns of HIV in many African countries. Although antenatal HIV prevalence data are known to be biased representations of HIV prevalence in the general population, mathematical models have made various adjustments to control for known sources of bias, including the effect of HIV on fertility, the age profile of pregnant women and sexual experience.

METHODS AND FINDINGS

We assessed whether assumptions about antenatal bias affect conclusions about trends and geographical variation in HIV prevalence, using simulated datasets generated by an agent-based model of HIV and fertility in South Africa. Results suggest that even when controlling for age and other previously-considered sources of bias, antenatal bias in South Africa has not been constant over time, and trends in bias differ substantially by age. Differences in the average duration of infection explain much of this variation. We propose an HIV duration-adjusted measure of antenatal bias that is more stable, which yields higher estimates of HIV incidence in recent years and at older ages. Simpler measures of antenatal bias, which are not age-adjusted, yield estimates of HIV prevalence and incidence that are too high in the early stages of the HIV epidemic, and that are less precise. Antenatal bias in South Africa is substantially greater in urban areas than in rural areas.

CONCLUSIONS

Age-standardized approaches to defining antenatal bias are likely to improve precision in model-based estimates, and further recency adjustments increase estimates of HIV incidence in recent years and at older ages. Incompletely adjusting for changing antenatal bias may explain why previous model estimates overstated the early HIV burden in South Africa. New assays to estimate the fraction of HIV-positive pregnant women who are recently infected could play an important role in better estimating antenatal bias.

Modelling impact and cost-effectiveness of oral pre-exposure prophylaxis in 13 low-resource countries

INTRODUCTION

Oral pre-exposure prophylaxis (PrEP) provision is a priority intervention for high HIV prevalence settings and populations at substantial risk of HIV acquisition. This mathematical modelling analysis estimated the impact, cost and cost-effectiveness of scaling up oral PrEP in 13 countries.

METHODS

We projected the impact and cost-effectiveness of oral PrEP between 2018 and 2030 using a combination of the Incidence Patterns Model and the Goals model. We created four PrEP rollout scenarios involving three priority populations-female sex workers (FSWs), serodiscordant couples (SDCs) and adolescent girls and young women (AGYW)-both with and without geographic prioritization. We applied the model to 13 countries (Eswatini, Ethiopia, Haiti, Kenya, Lesotho, Mozambique, Namibia, Nigeria, Tanzania, Uganda, Zambia and Zimbabwe). The base case assumed achievement of the Joint United Nations Programme on HIV/AIDS 90-90-90 antiretroviral therapy targets, 90% male circumcision coverage by 2020 and 90% efficacy and adherence levels for oral PrEP.

RESULTS

In the scenarios we examined, oral PrEP averted 3% to 8% of HIV infections across the 13 countries between 2018 and 2030. For all but three countries, more than 50% of the HIV infections averted by oral PrEP in the scenarios we examined could be obtained by rollout to FSWs and SDCs alone. For several countries, expanding oral PrEP to include medium-risk AGYW in all regions greatly increased the impact. The efficiency and impact benefits of geographic prioritization of rollout to AGYW varied across countries. Variations in cost-effectiveness across countries reflected differences in HIV incidence and expected variations in unit cost. For most countries, rolling out oral PrEP to FSWs, SDCs and geographically prioritized AGYW was not projected to have a substantial impact on the supply chain for antiretroviral drugs.

CONCLUSIONS

These modelling results can inform prioritization, target-setting and other decisions related to oral PrEP scale-up within combination prevention programmes. We caution against extensive use given limitations in cost data and implementation approaches. This analysis highlights some of the immediate challenges facing countries-for example, trade-offs between overall impact and cost-effectiveness-and emphasizes the need to improve data availability and risk assessment tools to help countries make informed decisions.

Potential impact of tuberculosis vaccines in China, South Africa, and India

More effective tuberculosis vaccines are needed to help reach World Health Organization tuberculosis elimination goals. Insufficient evidence exists on the potential impact of future tuberculosis vaccines with varying characteristics and in different epidemiological settings. To inform vaccine development decision making, we modeled the impact of hypothetical tuberculosis vaccines in three high-burden countries. We calibrated Mycobacterium tuberculosis (M.tb) transmission models to age-stratified demographic and epidemiological data from China, South Africa, and India. We varied vaccine efficacy to prevent infection or disease, effective in persons M.tb uninfected or infected, and duration of protection. We modeled routine early-adolescent vaccination and 10-yearly mass campaigns from 2025. We estimated median percentage population-level tuberculosis incidence rate reduction (IRR) in 2050 compared to a no new vaccine scenario. In all settings, results suggested vaccines preventing disease in M.tb-infected populations would have greatest impact by 2050 (10-year, 70% efficacy against disease, IRR 51%, 52%, and 54% in China, South Africa, and India, respectively). Vaccines preventing reinfection delivered lower potential impact (IRR 1, 12, and 17%). Intermediate impact was predicted for vaccines effective only in uninfected populations, if preventing infection (IRR 21, 37, and 50%) or disease (IRR 19, 36, and 51%), with greater impact in higher-transmission settings. Tuberculosis vaccines have the potential to deliver substantial population-level impact. For prioritizing impact by 2050, vaccine development should focus on preventing disease in M.tb-infected populations. Preventing infection or disease in uninfected populations may be useful in higher transmission settings. As vaccine impact depended on epidemiology, different development strategies may be required.

The declining trend of HIV-Infection among pregnant women in Cameroon infers an epidemic decline in the general population

Background

HIV remains a generalised epidemic in Cameroon, with regular sentinel surveillance surveys (SSS) conducted among pregnant women to monitor the epidemiological dynamics, and for strategic policy making. Our main objective was to actualise data on HIV epidemiology, and compare the trends overtime among pregnant women versus data from the general population in Cameroon.

Methods

Sentinel surveillance was conducted in 2016 among pregnant women in the 10 regions (60 sites) of Cameroon, targeting 7,000 first antenatal care (ANC-1) attendees (4,000 in urban; 3,000 in rural). HIV testing was done following the serial national algorithm at the National Public Health Laboratory. Results of 2016 were compared with 2009 and 2012 dataset, alongside reports from the general population; with p < 0.05 considered statistical significant.

Findings

A total of 6,859 ANC-1 (97.99% sampling) were enrolled in 2016, with 99.19% (6,513/6,566) acceptability for HIV testing; similar to performances in 2009 and 2012 (>99%). National prevalence of HIV was 5.70% (389/6,819), similar between urban (5.58%) and rural (5.87%) settings. HIV prevalence among pregnant women declined significantly from 2009 (7.6%), 2012 (7.8%) to 2016 (5.7%), p < 0.0001; with a similar declining trend in the general population: from 2004 (5.5%), 2011 (4.3%) to 2017 (3.4%), p < 0.0001. Difference between SSS and the population-based survey was non-significant (r = 0.6; p = 0.285). Following geographical settings, HIV prevalence was higher in urban vs. rural settings from 2009-2012 (p < 0.0001), followed by similar rates in 2016. Early-age infection (15–24 years) decreased from 6.7% in 2009 to 3.4% in 2016, with remarkable declines in new infections within the age ranges 15–19 years (5.1%–1.57%) and 20–24 years (7.8%–4.39%).

Interpretation

With high acceptability in HIV testing, the prevalence of HIV-infection through SSS indicates a declining but generalised epidemic among pregnant women in Cameroon. Of note, as the declining prevalence among pregnant women also reflects an epidemic reduction in the general population, SSS represents an efficient strategy to understand the dynamics of HIV epidemics in the general Cameroonian population, pending validation by periodic population surveys.

Smart cascades: using cost analysis to improve HIV care and treatment interventions to achieve global 95-95-95 goals

Background: HIV programmes are achieving significant scale, even as external financing plateaus. Maximising achievement from identification to viral suppression is key to epidemic control and reaching global 95-95-95 goals. Cost and technical efficiency analyses can help programs understand why losses occur along the cascade, which tactics prevent losses, and additional investments required for cost-efficient solutions.Methodology: The PEPFAR- and USAID-funded Health Policy Plus (HP+) project identified cascade failure points and interventions needed in six countries (Ghana, Indonesia, Kyrgyz Republic, Kenya, Tajikistan, Tanzania). Methods included secondary data analysis and expert interviews. HP+ estimated unit costs and effectiveness of tactics to model future costs and cascade outcomes across scenarios. Conclusions across countries are synthesised for overall best practices.Results: In Ghana, Indonesia, Tajikistan, and the Kyrgyz Republic, HIV identification strategies need to evolve to counter diminishing testing yields. Higher-yield testing modes may have higher costs per person tested, yet lower costs per person identified compared to previous strategies. In Kenya, investments in linkage and retention require additional funding, and will reduce the need for expensive loss-to-follow-up activities. In Tanzania, differentiated antiretroviral therapy can improve patient management while reducing facility-level costs.Conclusion: Results from diverse settings suggest that cost-efficiency analyses aimed at smart cascades will help countries identify and resolve reasons for poor outcomes. The analyses are predicated on contextual exploration of how interventions are linked, and should inform prioritisation and investment strategies. While improving the cascade often has incremental costs, it may be cost-efficient versus the long-term cost of poor outcomes.

Modeling methods for estimating HIV incidence: a mathematical review

Estimating HIV incidence is crucial for monitoring the epidemiology of this infection, planning screening and intervention campaigns, and evaluating the effectiveness of control measures. However, owing to the long and variable period from HIV infection to the development of AIDS and the introduction of highly active antiretroviral therapy, accurate incidence estimation remains a major challenge. Numerous estimation methods have been proposed in epidemiological modeling studies, and here we review commonly-used methods for estimation of HIV incidence. We review the essential data required for estimation along with the advantages and disadvantages, mathematical structures and likelihood derivations of these methods. The methods include the classical back-calculation method, the method based on CD4+ T-cell depletion, the use of HIV case reporting data, the use of cohort study data, the use of serial or cross-sectional prevalence data, and biomarker approach. By outlining the mechanistic features of each method, we provide guidance for planning incidence estimation efforts, which may depend on national or regional factors as well as the availability of epidemiological or laboratory datasets.

Demographic change and HIV epidemic projections to 2050 for adolescents and young people aged 15-24

Background: Ending AIDS as a public health threat by 2030 is a significant challenge, as new HIV infections among adolescents and young people have not decreased fast enough to curb the epidemic. The combination of slow HIV response and increasing youth populations 15–24 could affect progress towards 2030 goals.

Objective: This analysis aimed to describe global and regional trends from 2010–2050 in the HIV epidemic among adolescents and young people by accounting for demographic projections and recent trends in HIV interventions.

Methods: 148 national HIV estimates files were used to project the HIV epidemic to 2050. Numbers of people living with HIV and new HIV infections were projected by sex and five-year age group. Along with demographic data, projections were based on three key assumptions: future trends in HIV incidence, antiretroviral treatment coverage, and coverage of antiretrovirals for prevention of mother-to-child transmission. Results represent nine geographic regions.

Results: While the number of adolescents and young people is projected to increase by 10% from 2010–2050, those living with HIV is projected to decrease by 61%. In Eastern and Southern Africa, which hosts the largest HIV epidemic, new HIV infections among adolescents and young people are projected to decline by 84% from 2010–2050. In West and Central Africa, which hosts the second-largest HIV epidemic, new infections are projected to decline by 35%.

Conclusions: While adolescents and young people living with HIV are living longer and ageing into adulthood, if current trends continue, the number of new HIV infections is not projected to decline fast enough to end AIDS as a health threat in this age group. Regional variations suggest that while progress in Eastern and Southern Africa could reduce the size of the epidemic by 2050, other regions exhibit slower rates of decline among adolescents and young people.

The Estimation and Projection Package Age-Sex Model and the r-hybrid model: new tools for estimating HIV incidence trends in sub-Saharan Africa

OBJECTIVES

Improve models for estimating HIV epidemic trends in sub-Saharan Africa (SSA).

DESIGN

Mathematical epidemic model fit to national HIV survey and ANC sentinel surveillance (ANC-SS) data.

METHODS

We modified EPP to incorporate age and sex stratification (EPP-ASM) to more accurately capture the shifting demographics of maturing HIV epidemics. Secondly, we developed a new functional form for the HIV transmission rate, termed 'r-hybrid', which combines a four-parameter logistic function for the initial epidemic growth, peak, and decline followed by a first-order random walk for recent trends after epidemic stabilization. We fitted the r-hybrid model along with previously developed r-spline and r-trend models to HIV prevalence data from household surveys and ANC-SS in 177 regions in 34 SSA countries. We used leave-one-out cross validation with household survey HIV prevalence to compare model predictions.

RESULTS

The r-hybrid and r-spline models typically provided similar HIV prevalence trends, but sometimes qualitatively different assessments of recent incidence trends because of different structural assumptions about the HIV transmission rate. The r-hybrid model had the lowest average continuous ranked probability score, indicating the best model predictions. Coverage of 95% posterior predictive intervals was 91.5% for the r-hybrid model, versus 87.2 and 85.5% for r-spline and r-trend, respectively.

CONCLUSION

The EPP-ASM and r-hybrid models improve consistency of EPP and Spectrum, improve the epidemiological assumptions underpinning recent HIV incidence estimates, and improve estimates and short-term projections of HIV prevalence trends. Countries that use general population survey and ANC-SS data to estimate HIV epidemic trends should consider using these tools.

Global variations in mortality in adults after initiating antiretroviral treatment: an updated analysis of the International epidemiology Databases to Evaluate AIDS cohort collaboration

BACKGROUND

UNAIDS models use data from the International epidemiology Databases to Evaluate AIDS (IeDEA) collaboration in setting assumptions about mortality rates after antiretroviral treatment (ART) initiation. This study aims to update these assumptions with new data, to quantify the extent of regional variation in ART mortality and to assess trends in ART mortality.

METHODS

Adult ART patients from Africa, Asia and the Americas were included if they had a known date of ART initiation during 2001-2017 and a baseline CD4 cell count. In cohorts that relied only on passive follow-up (no patient tracing or linkage to vital registration systems), mortality outcomes were imputed in patients lost to follow-up based on a meta-analysis of tracing study data. Poisson regression models were fitted to the mortality data.

RESULTS

464 048 ART patients were included. In multivariable analysis, mortality rates were lowest in Asia and highest in Africa, with no significant differences between African regions. Adjusted mortality rates varied significantly between programmes within regions. Mortality rates in the first 12 months after ART initiation were significantly higher during 2001-2006 than during 2010-2014, although the difference was more substantial in Asia and the Americas [adjusted incidence rate ratio (aIRR) 1.43, 95% CI: 1.22-1.66] than in Africa (aIRR 1.07, 95% CI: 1.04-1.11).

CONCLUSION

There is substantial variation in ART mortality between and within regions, even after controlling for differences in mortality by age, sex, baseline CD4 category and calendar period. ART mortality rates have declined substantially over time, although declines have been slower in Africa.

Updates to the Spectrum/AIM model for estimating key HIV indicators at national and subnational levels

Supplemental Digital Content is available in the text

Background:

The Spectrum/AIM model is used by national programs and UNAIDS to prepare annual estimates of the status of the HIV epidemic in 170 countries. The model and assumptions are updated regularly under the guidance of the UNAIDS Reference Group on Estimates, Modelling and Projections in response to new data, studies and program needs. This article describes the most recent updates for the 2018 round of estimates.

Methods:

New data on AIDS-related mortality from Europe and Brazil have been used to update mortality rates of those not on antiretroviral therapy (ART). Household survey data and new studies of pregnant women, mothers, and children have been used to improve estimates of the number of HIV-positive pregnant and breastfeeding women and pediatric ART initiation. New tools to estimate geographic variation in HIV prevalence have been used to prepare district estimates of key indicators.

Results:

The 2018 version of Spectrum includes: new estimates of non-ART AIDS-related mortality by CD4⁺ count that depend on ART coverage; a procedure to estimate country-specific patterns of HIV incidence by age by fitting to prevalence by age from household surveys; an updated estimate of postpartum transmission with ART started before pregnancy of 0.023% per month; an updated estimate of retention on treatment at delivery of 80% for all women on ART; a somewhat older pattern of ART initiation by age that has 26% of new pediatric patients initiating ART at 10–14 years of age, 18% at 2–4 years of age, and 26% at 5–9 years of age; and a new tool for estimating key HIV indicators at the district level.

Conclusion:

The new methods and data implemented in the 2018 version of Spectrum allow national programs more flexibility in describing their programs and are intended to improve the estimates of adult mortality and pediatric HIV indicators.

National HIV testing and diagnosis coverage in sub-Saharan Africa: a new modeling tool for estimating the 'first 90' from program and survey data

OBJECTIVE

HIV testing services (HTS) are a crucial component of national HIV responses. Learning one's HIV diagnosis is the entry point to accessing life-saving antiretroviral treatment and care. Recognizing the critical role of HTS, the Joint United Nations Programme on HIV/AIDS (UNAIDS) launched the 90-90-90 targets stipulating that by 2020, 90% of people living with HIV know their status, 90% of those who know their status receive antiretroviral therapy, and 90% of those on treatment have a suppressed viral load. Countries will need to regularly monitor progress on these three indicators. Estimating the proportion of people living with HIV who know their status (i.e. the 'first 90'), however, is difficult.

METHODS

We developed a mathematical model (henceforth referred to as 'Shiny90') that formally synthesizes population-based survey and HTS program data to estimate HIV status awareness over time. The proposed model uses country-specific HIV epidemic parameters from the standard UNAIDS Spectrum model to produce outputs that are consistent with other national HIV estimates. Shiny90 provides estimates of HIV testing history, diagnosis rates, and knowledge of HIV status by age and sex. We validate Shiny90 using both in-sample comparisons and out-of-sample predictions using data from three countries: Côte d'Ivoire, Malawi, and Mozambique.

RESULTS

In-sample comparisons suggest that Shiny90 can accurately reproduce longitudinal sex-specific trends in HIV testing. Out-of-sample predictions of the fraction of people living with HIV ever tested over a 4-to-6-year time horizon are also in good agreement with empirical survey estimates. Importantly, out-of-sample predictions of HIV knowledge of status are consistent (i.e. within 4% points) with those of the fully calibrated model in the three countries when HTS program data are included. The model's predictions of knowledge of status are higher than available self-reported HIV awareness estimates, however, suggesting - in line with previous studies - that these self-reports could be affected by nondisclosure of HIV status awareness.

CONCLUSION

Knowledge of HIV status is a key indicator to monitor progress, identify bottlenecks, and target HIV responses. Shiny90 can help countries track progress towards their 'first 90' by leveraging surveys of HIV testing behaviors and annual HTS program data.

Pediatric HIV Treatment Gaps in 7 East and Southern African Countries: Examination of Modeled, Survey, and Routine Program Data

BACKGROUND

Remarkable success in the prevention and treatment of pediatric HIV infection has been achieved in the past decade. Large differences remain between the estimated number of children living with HIV (CLHIV) and those identified through national HIV programs. We evaluated the number of CLHIV and those on treatment in Lesotho, Malawi, Swaziland, Tanzania, Uganda, Zambia, and Zimbabwe.

METHODS

We assessed the total number of CLHIV, CLHIV on antiretroviral treatment (ART), and national and regional ART coverage gaps using 3 data sources: (1) Joint United Nations Programme on HIV/AIDS model-based estimates and national program data used as input values in the models, (2) population-based HIV impact surveys (PHIA), and (3) program data from the President's Emergency Plan for AIDS Relief (PEPFAR)-supported clinics.

RESULTS

Across the 7 countries, HIV prevalence among children aged 0-14 years ranged from 0.4% (Uncertainty Bounds (UB) 0.2%-0.6%) to 2.8% (UB: 2.2%-3.4%) according to the PHIA surveys, resulting in estimates of 520,000 (UB: 460,000-580,000) CLHIV in 2016-2017 in the 7 countries. This compared with Spectrum estimates of pediatric HIV prevalence ranging from 0.5% (UB: 0.5%-0.6%) to 3.5% (UB: 3.0%-4.0%) representing 480,000 (UB: 390,000-550,000) CLHIV. CLHIV not on treatment according to the PEPFAR, PHIA, and Spectrum for the countries stood at 48% (UB: 25%-60%), 49% (UB: 37%-50%), and 38% (UB: 24%-47%), respectively. Of 78 regions examined across 7 countries, 33% of regions (PHIA data) or 41% of regions (PEPFAR data) had met the ART coverage target of 81%.

CONCLUSIONS

There are substantial gaps in the coverage of HIV treatment in CLHIV in the 7 countries studied according to all sources. There is continued need to identify, engage, and treat infants and children. Important inconsistencies in estimates across the 3 sources warrant in-depth investigation.

Simulation Modeling and Metamodeling to Inform National and International HIV Policies for Children and Adolescents

Objective and Approach:

Computer-based simulation models serve an important purpose in informing HIV care for children and adolescents. We review current model-based approaches to informing pediatric and adolescent HIV estimates and guidelines.

Findings:

Clinical disease simulation models and epidemiologic models are used to inform global and regional estimates of numbers of children and adolescents living with HIV and in need of antiretroviral therapy, to develop normative guidelines addressing strategies for diagnosis and treatment of HIV in children, and to forecast future need for pediatric and adolescent antiretroviral therapy formulations and commodities. To improve current model-generated estimates and policy recommendations, better country-level and regional-level data are needed about children living with HIV, as are improved data about survival and treatment outcomes for children with perinatal HIV infection as they age into adolescence and adulthood. In addition, novel metamodeling and value of information methods are being developed to improve the transparency of model methods and results, as well as to allow users to more easily tailor model-based analyses to their own settings.

Conclusions:

Substantial progress has been made in using models to estimate the size of the pediatric and adolescent HIV epidemic, to inform the development of guidelines for children and adolescents affected by HIV, and to support targeted implementation of policy recommendations to maximize impact. Ongoing work will address key limitations and further improve these model-based projections.

Monitoring viral load for the last mile: what will it cost?

INTRODUCTION

Routine viral load testing is the WHO-recommended method for monitoring HIV-infected patients on ART, and many countries are rapidly scaling up testing capacity at centralized laboratories. Providing testing access to the most remote populations and facilities (the "last mile") is especially challenging. Using a geospatial optimization model, we estimated the incremental costs of accessing the most remote 20% of patients in Zambia by expanding the transportation network required to bring blood samples from ART clinics to centralized laboratories and return results to clinics.

METHODS

The model first optimized a sample transportation network (STN) that can transport 80% of anticipated sample volumes to centralized viral load testing laboratories on a daily or weekly basis, in line with Zambia's 2020 targets. Data incorporated into the model included the location and infrastructure of all health facilities providing ART, location of laboratories, measured distances and drive times between the two, expected future viral load demand by health facility, and local cost estimates. We then continued to expand the modelled STN in 5% increments until 100% of all samples could be collected.

RESULTS AND DISCUSSION

The cost per viral load test when reaching 80% patient volumes using centralized viral load testing was a median of $18.99. With an expanded STN, the incremental cost per test rose to $20.29 for 80% to 85% and $20.52 for 85% to 90%. Above 90% coverage, the incremental cost per test increased substantially to $31.57 for 90% to 95% and $51.95 for 95% to 100%. The high numbers of kilometres driven per sample transported and large number of vehicles needed increase costs dramatically for reaching the clinics that serve the last 5% of patients.

CONCLUSIONS

Providing sample transport services to the most remote clinics in low- and middle-income countries is likely to be cost-prohibitive. Other strategies are needed to reduce the cost and increase the feasibility of making viral load monitoring available to the last 10% of patients. The cost of alternative methods, such as optimal point-of-care viral load equipment placement and usage, dried blood/plasma spot specimen utilization, or use of drones in geographically remote facilities, should be evaluated.

Optimizing viral load testing access for the last mile: Geospatial cost model for point of care instrument placement

INTRODUCTION

Viral load (VL) monitoring programs have been scaled up rapidly, but are now facing the challenge of providing access to the most remote facilities (the "last mile"). For the hardest-to-reach facilities in Zambia, we compared the cost of placing point of care (POC) viral load instruments at or near facilities to the cost of an expanded sample transportation network (STN) to deliver samples to centralized laboratories.

METHODS

We extended a previously described geospatial model for Zambia that first optimized a STN for centralized laboratories for 90% of estimated viral load volumes. Amongst the remaining 10% of volumes, facilities were identified as candidates for POC placement, and then instrument placement was optimized such that access and instrument utilization is maximized. We evaluated the full cost per test under three scenarios: 1) POC placement at all facilities identified for POC; 2)an optimized combination of both on-site POC placement and placement at facilities acting as POC hubs; and 3) integration into the centralized STN to allow use of centralized laboratories.

RESULTS

For the hardest-to-reach facilities, optimal POC placement covered a quarter of HIV-treating facilities. Scenario 2 resulted in a cost per test of $39.58, 6% less than the cost per test of scenario 1, $41.81. This is due to increased POC instrument utilization in scenario 2 where facilities can act as POC hubs. Scenario 3 was the most costly at $53.40 per test, due to high transport costs under the centralized model ($36 per test compared to $12 per test in scenario 2).

CONCLUSIONS

POC VL testing may reduce the costs of expanding access to the hardest-to-reach populations, despite the cost of equipment and low patient volumes. An optimal combination of both on-site placement and the use of POC hubs can reduce the cost per test by 6-35% by reducing transport costs and increasing instrument utilization.

Estimating HIV incidence from surveillance data indicates a second wave of infections in Brazil

Emerging evidence suggests that HIV incidence rates in Brazil, particularly among men, may be rising. Here we use Brazil's integrated health systems data to develop a mathematical model, reproducing the complex surveillance systems and providing estimates of HIV incidence, number of people living with HIV (PLHIV), reporting rates and ART initiation rates. An age-structured deterministic model with a flexible spline was used to describe the natural history of HIV along with reporting and treatment rates. Individual-level surveillance data for 1,077,295 cases (HIV/AIDS diagnoses, ART dispensations, CD4 counts and HIV/AIDS-related deaths) were used to calibrate the model using Bayesian inference. The results showed a second wave of infections occurring after 2001 and 56,000 (95% Credible Interval 43,000-71,000) new infections in 2015, 37,000 (95% CrI 28,000-54,000) infections in men and 16,000 (95% CrI 10,000-23,000) in women. The estimated number of PLHIV by end-2015 was 838,000 (95% CrI 675,000-1,083,000), with 80% (95% CrI 62-98%) of those individuals reported to the Ministry of Health. Women were more likely to be diagnosed and reported than men; 86.8% of infected women had been reported compared with 75.7% of men. Likewise, ART initiation rates for women were higher than those for men. The second wave contradicts previous estimates of HIV incidence trends in Brazil and there were persistent differences in the rates of accessing care between men and women. Nevertheless, the Brazilian HIV program has achieved high rates of detection and treatment, making considerable progress over the past ten years.

How are countries in sub-Saharan African monitoring the impact of programmes to prevent vertical transmission of HIV?

Ameena Goga and colleagues describe how five countries in sub-Saharan Africa are monitoring the effectiveness of national programmes to prevent vertical transmission of HIV

Evaluation of an HIV-Related Mortuary Surveillance System - Nairobi, Kenya, Two Sites, 2015

PROBLEM/CONDITION

Use of human immunodeficiency virus (HIV)-mortality surveillance data can help public health officials monitor, evaluate, and improve HIV treatment programs. Many high-income countries have high-coverage civil registration and vital statistics (CRVS) systems linked to case-based HIV surveillance on which to base HIV mortality estimates. However, in the absence of comprehensive CRVS systems in low- and medium-income countries, such as Kenya, mortuary surveillance can be used to understand the occurrence of HIV infection among cadavers. In 2015, a pilot HIV-related mortuary surveillance system was implemented in the two largest mortuaries in Nairobi, Kenya. CDC conducted an evaluation to assess performance attributes and identify strengths and weaknesses of the surveillance system pilot.

PERIOD COVERED

Data collection: January 29-March 3, 2015; evaluation: November 2015.

DESCRIPTION OF THE SYSTEM

The surveillance system objectives were to determine HIV positivity among cadavers at two mortuary sites in Nairobi, Kenya, and to determine annual cause-specific and HIV-specific mortality rates among the cadavers. Cadavers of persons aged ≥15 years at death admitted to either mortuary during a 33-day period were included. Demographic information and place and time of death were entered into a surveillance register. Cardiac blood was collected using transthoracic aspiration, and blood specimens were tested for HIV in a central laboratory. Causes of death were abstracted from mortuary and hospital records. Of the 807 cadavers brought to the mortuaries, 610 (75.6%) had an HIV test result available. The overall unadjusted HIV-positivity rate was 19.5% (119/610), which differed significantly by sex (14.6% among men versus 29.5% among women).

EVALUATION

The evaluation was conducted using CDC guidelines for evaluating public health surveillance systems. The attributes of simplicity, flexibility, data quality (completeness and validity), acceptability, sensitivity, predictive value positive, representativeness, timeliness, and stability were examined. The evaluation steps included review of the surveillance system documents, in-depth interviews with 20 key informants (surveillance system staff, including mortuary and laboratory staff, and stakeholders involved in funding or implementation), and review of the surveillance database.

RESULTS AND INTERPRETATION

Implementation of the pilot mortuary surveillance system was complex because of extensive paperwork and the need to collect and process specimens outside of business hours. However, the flexibility of the system accommodated multiple changes during implementation, including changes in specimen collection techniques and data collection tools. Acceptability was initially low among the mortuary staff but increased after concerns regarding workload were resolved. Timeliness of specimen collection could not be measured because time of death was rarely documented. Completeness of data available from the system was generally high except for cause of death (46.5%). Although the two largest mortuaries in Nairobi were included, the surveillance system might not be representative of the Nairobi population. One of the mortuaries was affiliated with the national referral hospital and included cadavers of admitted patients, some deaths might have occurred outside Nairobi, and data were collected for only 1 month.

PUBLIC HEALTH ACTIONS

Mortuary surveillance can provide data on HIV positivity among cadavers and HIV-related mortality, which are not available from other sources in most sub-Saharan African countries. Availability of these mortality data will help describe a country's progress toward achieving epidemic control and achieving Joint United Nations Programme on HIV/AIDS 95-95-95 targets. To understand HIV mortality in high-prevalence regions, the mortuary surveillance system is being replicated in Western Kenya. Although a low-cost system, its sustainability depends on external funding because mortuary surveillance is not yet incorporated into the national AIDS strategic framework in Kenya.

Evaluation of an HIV-Related Mortuary Surveillance System - Nairobi, Kenya, Two Sites, 2015

PROBLEM/CONDITION

Use of human immunodeficiency virus (HIV)-mortality surveillance data can help public health officials monitor, evaluate, and improve HIV treatment programs. Many high-income countries have high-coverage civil registration and vital statistics (CRVS) systems linked to case-based HIV surveillance on which to base HIV mortality estimates. However, in the absence of comprehensive CRVS systems in low- and medium-income countries, such as Kenya, mortuary surveillance can be used to understand the occurrence of HIV infection among cadavers. In 2015, a pilot HIV-related mortuary surveillance system was implemented in the two largest mortuaries in Nairobi, Kenya. CDC conducted an evaluation to assess performance attributes and identify strengths and weaknesses of the surveillance system pilot.

PERIOD COVERED

Data collection: January 29-March 3, 2015; evaluation: November 2015.

DESCRIPTION OF THE SYSTEM

The surveillance system objectives were to determine HIV positivity among cadavers at two mortuary sites in Nairobi, Kenya, and to determine annual cause-specific and HIV-specific mortality rates among the cadavers. Cadavers of persons aged ≥15 years at death admitted to either mortuary during a 33-day period were included. Demographic information and place and time of death were entered into a surveillance register. Cardiac blood was collected using transthoracic aspiration, and blood specimens were tested for HIV in a central laboratory. Causes of death were abstracted from mortuary and hospital records. Of the 807 cadavers brought to the mortuaries, 610 (75.6%) had an HIV test result available. The overall unadjusted HIV-positivity rate was 19.5% (119/610), which differed significantly by sex (14.6% among men versus 29.5% among women).

EVALUATION

The evaluation was conducted using CDC guidelines for evaluating public health surveillance systems. The attributes of simplicity, flexibility, data quality (completeness and validity), acceptability, sensitivity, predictive value positive, representativeness, timeliness, and stability were examined. The evaluation steps included review of the surveillance system documents, in-depth interviews with 20 key informants (surveillance system staff, including mortuary and laboratory staff, and stakeholders involved in funding or implementation), and review of the surveillance database.

RESULTS AND INTERPRETATION

Implementation of the pilot mortuary surveillance system was complex because of extensive paperwork and the need to collect and process specimens outside of business hours. However, the flexibility of the system accommodated multiple changes during implementation, including changes in specimen collection techniques and data collection tools. Acceptability was initially low among the mortuary staff but increased after concerns regarding workload were resolved. Timeliness of specimen collection could not be measured because time of death was rarely documented. Completeness of data available from the system was generally high except for cause of death (46.5%). Although the two largest mortuaries in Nairobi were included, the surveillance system might not be representative of the Nairobi population. One of the mortuaries was affiliated with the national referral hospital and included cadavers of admitted patients, some deaths might have occurred outside Nairobi, and data were collected for only 1 month.

PUBLIC HEALTH ACTIONS

Mortuary surveillance can provide data on HIV positivity among cadavers and HIV-related mortality, which are not available from other sources in most sub-Saharan African countries. Availability of these mortality data will help describe a country's progress toward achieving epidemic control and achieving Joint United Nations Programme on HIV/AIDS 95-95-95 targets. To understand HIV mortality in high-prevalence regions, the mortuary surveillance system is being replicated in Western Kenya. Although a low-cost system, its sustainability depends on external funding because mortuary surveillance is not yet incorporated into the national AIDS strategic framework in Kenya.

Impact of a borderless sample transport network for scaling up viral load monitoring: results of a geospatial optimization model for Zambia

INTRODUCTION

The World Health Organization recommends viral load (VL) monitoring at six and twelve months and then annually after initiating antiretroviral treatment for HIV. In many African countries, expansion of VL testing has been slow due to a lack of efficient blood sample transportation networks (STN). To assist Zambia in scaling up testing capacity, we modelled an optimal STN to minimize the cost of a national VL STN.

METHODS

The model optimizes a STN in Zambia for the anticipated 1.5 million VL tests that will be needed in 2020, taking into account geography, district political boundaries, and road, laboratory and facility infrastructure. We evaluated all-inclusive STN costs of two alternative scenarios: (1) optimized status quo: each district provides its own weekly or daily sample transport; and (2) optimized borderless STN: ignores district boundaries, provides weekly or daily sample transport, and reaches all Scenario 1 facilities.

RESULTS

Under both scenarios, VL testing coverage would increase to from 10% in 2016 to 91% in 2020. The mean transport cost per VL in Scenario 2 was $2.11 per test (SD $0.28), 52% less than the mean cost/test in Scenario 1, $4.37 (SD $0.69), comprising 10% and 19% of the cost of a VL respectively.

CONCLUSIONS

An efficient STN that optimizes sample transport on the basis of geography and test volume, rather than political boundaries, can cut the cost of sample transport by more than half, providing a cost savings opportunity for countries that face significant resource constraints.

Evaluation of Senegal's prevention of mother to child transmission of HIV (PMTCT) program data for HIV surveillance

Background

With the expansion of Prevention of Mother to Child Transmission (PMTCT) services in Senegal, there is growing interest in using PMTCT program data in lieu of conducting unlinked anonymous testing (UAT)-based ANC Sentinel Surveillance. For this reason, an evaluation was conducted in 2011–2012 to identify the gaps that need to be addressed while transitioning to using PMTCT program data for surveillance.

Methods

We conducted analyses to assess HIV prevalence rates and agreements between Sentinel Surveillance and PMTCT HIV test results. Also, a data quality assessment of the PMTCT program registers and data was conducted during the Sentinel Surveillance period (December 2011 to March 2012) and 3 months prior. Finally, we also assessed selection bias, which was the percentage difference from the HIV prevalence among all women enrolled in the antenatal clinic and the HIV prevalence among women who accepted PMTCT HIV testing.

Results

The median site HIV prevalence using routine PMTCT HIV testing data was 1.1% (IQR: 1.0) while the median site prevalence from the UAT HIV Sentinel Surveillance data was at 1.0% (IQR: 1.6). The Positive per cent agreement (PPA) of the PMTCT HIV test results compared to those of the Sentinel Surveillance was 85.1% (95% CI 77.2–90.7%), and the percent-negative agreement (PNA) was 99.9% (95% CI 99.8–99.9%). The overall HIV prevalence according to UAT was the same as that found for women accepting a PMTCT HIV test and those who refused, with percent bias at 0.00%. For several key PMTCT variables, including “HIV test offered” (85.2%), “HIV test acceptance” (78.0%), or “HIV test done” (58.8%), the proportion of records in registers with combined complete and valid data was below the WHO benchmark of 90%.

Conclusions

The PPA of 85.1 was below the WHO benchmarks of 96.6%, while the combined data validity and completeness rates was below the WHO benchmark of 90% for many key PMTCT variables. These results suggested that Senegal will need to reinforce the quality of onsite HIV testing and improve program data collection practices in preparation for using PMTCT data for surveillance purposes.

Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017

BACKGROUND

The Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017) includes a comprehensive assessment of incidence, prevalence, and years lived with disability (YLDs) for 354 causes in 195 countries and territories from 1990 to 2017. Previous GBD studies have shown how the decline of mortality rates from 1990 to 2016 has led to an increase in life expectancy, an ageing global population, and an expansion of the non-fatal burden of disease and injury. These studies have also shown how a substantial portion of the world's population experiences non-fatal health loss with considerable heterogeneity among different causes, locations, ages, and sexes. Ongoing objectives of the GBD study include increasing the level of estimation detail, improving analytical strategies, and increasing the amount of high-quality data.

METHODS

We estimated incidence and prevalence for 354 diseases and injuries and 3484 sequelae. We used an updated and extensive body of literature studies, survey data, surveillance data, inpatient admission records, outpatient visit records, and health insurance claims, and additionally used results from cause of death models to inform estimates using a total of 68 781 data sources. Newly available clinical data from India, Iran, Japan, Jordan, Nepal, China, Brazil, Norway, and Italy were incorporated, as well as updated claims data from the USA and new claims data from Taiwan (province of China) and Singapore. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between rates of incidence, prevalence, remission, and cause of death for each condition. YLDs were estimated as the product of a prevalence estimate and a disability weight for health states of each mutually exclusive sequela, adjusted for comorbidity. We updated the Socio-demographic Index (SDI), a summary development indicator of income per capita, years of schooling, and total fertility rate. Additionally, we calculated differences between male and female YLDs to identify divergent trends across sexes. GBD 2017 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting.

FINDINGS

Globally, for females, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and haemoglobinopathies and haemolytic anaemias in both 1990 and 2017. For males, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and tuberculosis including latent tuberculosis infection in both 1990 and 2017. In terms of YLDs, low back pain, headache disorders, and dietary iron deficiency were the leading Level 3 causes of YLD counts in 1990, whereas low back pain, headache disorders, and depressive disorders were the leading causes in 2017 for both sexes combined. All-cause age-standardised YLD rates decreased by 3·9% (95% uncertainty interval [UI] 3·1-4·6) from 1990 to 2017; however, the all-age YLD rate increased by 7·2% (6·0-8·4) while the total sum of global YLDs increased from 562 million (421-723) to 853 million (642-1100). The increases for males and females were similar, with increases in all-age YLD rates of 7·9% (6·6-9·2) for males and 6·5% (5·4-7·7) for females. We found significant differences between males and females in terms of age-standardised prevalence estimates for multiple causes. The causes with the greatest relative differences between sexes in 2017 included substance use disorders (3018 cases [95% UI 2782-3252] per 100 000 in males vs s1400 [1279-1524] per 100 000 in females), transport injuries (3322 [3082-3583] vs 2336 [2154-2535]), and self-harm and interpersonal violence (3265 [2943-3630] vs 5643 [5057-6302]).

INTERPRETATION

Global all-cause age-standardised YLD rates have improved only slightly over a period spanning nearly three decades. However, the magnitude of the non-fatal disease burden has expanded globally, with increasing numbers of people who have a wide spectrum of conditions. A subset of conditions has remained globally pervasive since 1990, whereas other conditions have displayed more dynamic trends, with different ages, sexes, and geographies across the globe experiencing varying burdens and trends of health loss. This study emphasises how global improvements in premature mortality for select conditions have led to older populations with complex and potentially expensive diseases, yet also highlights global achievements in certain domains of disease and injury.

FUNDING

Bill & Melinda Gates Foundation.

Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017

BACKGROUND

The Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017) includes a comprehensive assessment of incidence, prevalence, and years lived with disability (YLDs) for 354 causes in 195 countries and territories from 1990 to 2017. Previous GBD studies have shown how the decline of mortality rates from 1990 to 2016 has led to an increase in life expectancy, an ageing global population, and an expansion of the non-fatal burden of disease and injury. These studies have also shown how a substantial portion of the world's population experiences non-fatal health loss with considerable heterogeneity among different causes, locations, ages, and sexes. Ongoing objectives of the GBD study include increasing the level of estimation detail, improving analytical strategies, and increasing the amount of high-quality data.

METHODS

We estimated incidence and prevalence for 354 diseases and injuries and 3484 sequelae. We used an updated and extensive body of literature studies, survey data, surveillance data, inpatient admission records, outpatient visit records, and health insurance claims, and additionally used results from cause of death models to inform estimates using a total of 68 781 data sources. Newly available clinical data from India, Iran, Japan, Jordan, Nepal, China, Brazil, Norway, and Italy were incorporated, as well as updated claims data from the USA and new claims data from Taiwan (province of China) and Singapore. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between rates of incidence, prevalence, remission, and cause of death for each condition. YLDs were estimated as the product of a prevalence estimate and a disability weight for health states of each mutually exclusive sequela, adjusted for comorbidity. We updated the Socio-demographic Index (SDI), a summary development indicator of income per capita, years of schooling, and total fertility rate. Additionally, we calculated differences between male and female YLDs to identify divergent trends across sexes. GBD 2017 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting.

FINDINGS

Globally, for females, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and haemoglobinopathies and haemolytic anaemias in both 1990 and 2017. For males, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and tuberculosis including latent tuberculosis infection in both 1990 and 2017. In terms of YLDs, low back pain, headache disorders, and dietary iron deficiency were the leading Level 3 causes of YLD counts in 1990, whereas low back pain, headache disorders, and depressive disorders were the leading causes in 2017 for both sexes combined. All-cause age-standardised YLD rates decreased by 3·9% (95% uncertainty interval [UI] 3·1-4·6) from 1990 to 2017; however, the all-age YLD rate increased by 7·2% (6·0-8·4) while the total sum of global YLDs increased from 562 million (421-723) to 853 million (642-1100). The increases for males and females were similar, with increases in all-age YLD rates of 7·9% (6·6-9·2) for males and 6·5% (5·4-7·7) for females. We found significant differences between males and females in terms of age-standardised prevalence estimates for multiple causes. The causes with the greatest relative differences between sexes in 2017 included substance use disorders (3018 cases [95% UI 2782-3252] per 100 000 in males vs s1400 [1279-1524] per 100 000 in females), transport injuries (3322 [3082-3583] vs 2336 [2154-2535]), and self-harm and interpersonal violence (3265 [2943-3630] vs 5643 [5057-6302]).

INTERPRETATION

Global all-cause age-standardised YLD rates have improved only slightly over a period spanning nearly three decades. However, the magnitude of the non-fatal disease burden has expanded globally, with increasing numbers of people who have a wide spectrum of conditions. A subset of conditions has remained globally pervasive since 1990, whereas other conditions have displayed more dynamic trends, with different ages, sexes, and geographies across the globe experiencing varying burdens and trends of health loss. This study emphasises how global improvements in premature mortality for select conditions have led to older populations with complex and potentially expensive diseases, yet also highlights global achievements in certain domains of disease and injury.

FUNDING

Bill & Melinda Gates Foundation.

Pushing the envelope through the Global Financing Facility: potential impact of mobilising additional support to scale-up life-saving interventions for women, children and adolescents in 50 high-burden countries

Introduction

The Global Financing Facility (GFF) was launched to accelerate progress towards the Sustainable Development Goals (SDGs) through scaled and sustainable financing for Reproductive, Maternal, Newborn, Child and Adolescent Health and Nutrition (RMNCAH-N) outcomes. Our objective was to estimate the potential impact of increased resources available to improve RMNCAH-N outcomes, from expanding and scaling up GFF support in 50 high-burden countries.

Methods

The potential impact of GFF was estimated for the period 2017–2030. First, two scenarios were constructed to reflect conservative and ambitious assumptions around resources that could be mobilised by the GFF model, based on GFF Trust Fund resources of US$2.6  billion. Next, GFF impact was estimated by scaling up coverage of prioritised RMNCAH-N interventions under these resource scenarios. Resource availability was projected using an Excel-based model and health impacts and costs were estimated using the Lives Saved Tool (V.5.69 b9).

Results

We estimate that the GFF partnership could collectively mobilise US$50–75  billion of additional funds for expanding delivery of life-saving health and nutrition interventions to reach coverage of at least 70% for most interventions by 2030. This could avert 34.7  million deaths—including preventable deaths of mothers, newborns, children and stillbirths—compared with flatlined coverage, or 12.4  million deaths compared with continuation of historic trends. Under-five and neonatal mortality rates are estimated to decrease by 35% and 34%, respectively, and stillbirths by 33%.

Conclusion

The GFF partnership through country- contextualised prioritisation and innovative financing could go a long way in increasing spending on RMNCAH-N and closing the existing resource gap. Although not all countries will reach the SDGs by relying on gains from the GFF platform alone, the GFF provides countries with an opportunity to significantly improve RMNCAH-N outcomes through achievable, well-directed changes in resource allocation.

Epidemiological metrics and benchmarks for a transition in the HIV epidemic

Peter Godfrey-Faussett and colleagues present six epidemiological metrics for tracking progress in reducing the public health threat of HIV.

Population-level HIV incidence estimates using a combination of synthetic cohort and recency biomarker approaches in KwaZulu-Natal, South Africa

Introduction

There is a notable absence of consensus on how to generate estimates of population-level incidence. Incidence is a considerably more sensitive indicator of epidemiological trends than prevalence, but is harder to estimate. We used a novel hybrid method to estimate HIV incidence by age and sex in a rural district of KwaZulu-Natal, South Africa.

Methods

Our novel method uses an ‘optimal weighting’ of estimates based on an implementation of a particular ‘synthetic cohort’ approach (interpreting the age/time structure of prevalence, in conjunction with estimates of excess mortality) and biomarkers of ‘recent infection’ (combining Lag-Avidity, Bio-Rad Avidity and viral load results to define recent infection, and adapting the method for age-specific incidence estimation). Data were obtained from a population-based cross-sectional HIV survey conducted in Mbongolwane and Eshowe health service areas in 2013.

Results

Using the combined method, we find that age-specific HIV incidence in females rose rapidly during adolescence, from 1.33 cases/100 person-years (95% CI: 0.98,1.67) at age 15 to a peak of 5.01/100PY (4.14,5.87) at age 23. In males, incidence was lower, 0.34/100PY (0.00-0.74) at age 15, and rose later, peaking at 3.86/100PY (2.52-5.20) at age 30. Susceptible population-weighted average incidence in females aged 15-29 was estimated at 3.84/100PY (3.36-4.40), in males aged 15-29 at 1.28/100PY (0.68-1.50) and in all individuals aged 15-29 at 2.55/100PY (2.09-2.76). Using the conventional recency biomarker approach, we estimated HIV incidence among females aged 15-29 at 2.99/100PY (1.79-4.36), among males aged 15-29 at 0.87/100PY (0.22-1.60) and among all individuals aged 15-59 at 1.66/100PY (1.13-2.27).

Discussion

HIV incidence was very high in women aged 15-30, peaking in the early 20s. Men had lower incidence, which peaked at age 30. The estimates obtained from the hybrid method are more informative than those produced by conventional analysis of biomarker data, and represents a more optimal use of available data than either the age-continuous biomarker or synthetic cohort methods alone. The method is mainly useful at younger ages, where excess mortality is low and uncertainty in the synthetic cohort estimates is reasonably small.

Conclusion

Application of this method to large-scale population-based HIV prevalence surveys is likely to result in improved incidence surveillance over methods currently in wide use. Reasonably accurate and precise age-specific estimates of incidence are important to target better prevention, diagnosis and care strategies.

Low Case Finding Among Men and Poor Viral Load Suppression Among Adolescents Are Impeding Namibia's Ability to Achieve UNAIDS 90-90-90 Targets

Background

In 2015, Namibia implemented an Acceleration Plan to address the high burden of HIV (13.0% adult prevalence and 216 311 people living with HIV [PLHIV]) and achieve the UNAIDS 90-90-90 targets by 2020. We provide an update on Namibia's overall progress toward achieving these targets and estimate the percent reduction in HIV incidence since 2010.

Methods

Data sources include the 2013 Namibia Demographic and Health Survey (2013 NDHS), the national electronic patient monitoring system, and laboratory data from the Namibian Institute of Pathology. These sources were used to estimate (1) the percentage of PLHIV who know their HIV status, (2) the percentage of PLHIV on antiretroviral therapy (ART), (3) the percentage of patients on ART with suppressed viral loads, and (4) the percent reduction in HIV incidence.

Results

In the 2013 NDHS, knowledge of HIV status was higher among HIV-positive women 91.8% (95% confidence interval [CI], 89.4%-93.7%) than HIV-positive men 82.5% (95% CI, 78.1%-86.1%). At the end of 2016, an estimated 88.3% (95% CI, 86.3%-90.1%) of PLHIV knew their status, and 165 939 (76.7%) PLHIV were active on ART. The viral load suppression rate among those on ART was 87%, and it was highest among ≥20-year-olds (90%) and lowest among 15-19-year-olds (68%). HIV incidence has declined by 21% since 2010.

Conclusions

With 76.7% of PLHIV on ART and 87% of those on ART virally suppressed, Namibia is on track to achieve UNAIDS 90-90-90 targets by 2020. Innovative strategies are needed to improve HIV case identification among men and adherence to ART among youth.

Modeling of the HIV epidemic and continuum of care in French Guiana

Background

In order to compute the continuum of care for French Guiana, it is necessary to estimate the total number of persons living with HIV. The main objective was to determine how many persons were infected with HIV and how many were unaware of it.

Methods

We used 2 different models to calculate the total number of persons infected with HIV: Spectrum’s AIM module using CSAVR to compute incidence from case registration and vital statistics; and the ECDC model from the French Guiana HIV cohort data.

Result

The present results show that both models led to similar results regarding the incident number of cases (i.e. for 2016 174 versus 161) and the total HIV population (in 2016 3206 versus 3539) respectively. The ECDC modeling tool showed that the proportion of undiagnosed HIV infections declined from 50% in 1990 to 15% in 2015. This amounted to a stable or slightly increasing total number of undiagnosed patients of 520.

Conclusions

The estimations of the total HIV population by both models show that the HIV population is still growing. The incidence rate declined in 2000 and the decline of the number of newly acquired HIV infections, after a decline after 2003 is offset by population growth. The proportion of undiagnosed infections has declined to 15% but the number of undiagnosed infections remains stable. The HIV cascade shows that despite good results for treatment in care, reaching the 90*90*90 UNAIDS target may be difficult because a significant proportion of patients are lost to follow-up.