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.

New HIV Infections Among Key Populations and Their Partners in 2010 and 2022, by World Region: A Multisources Estimation.

BACKGROUND: Previously, The Joint United Nations Programme on HIV/AIDS estimated proportions of adult new HIV infections among key populations (KPs) in the last calendar year, globally and in 8 regions. We refined and updated these, for 2010 and 2022, using country-level trend models informed by national data. METHODS: Infections among 15-49 year olds were estimated for sex workers (SWs), male clients of female SW, men who have sex with men (MSM), people who inject drugs (PWID), transgender women (TGW), and non-KP sex partners of these groups. Transmission models used were Goals (71 countries), AIDS Epidemic Model (13 Asian countries), Optima (9 European and Central Asian countries), and Thembisa (South Africa). Statistical Estimation and Projection Package fits were used for 15 countries. For 40 countries, new infections in 1 or more KPs were approximated from first-time diagnoses by the mode of transmission. Infection proportions among nonclient partners came from Goals, Optima, AIDS Epidemic Model, and Thembisa. For remaining countries and groups not represented in models, median proportions by KP were extrapolated from countries modeled within the same region. RESULTS: Across 172 countries, estimated proportions of new adult infections in 2010 and 2022 were both 7.7% for SW, 11% and 20% for MSM, 0.72% and 1.1% for TGW, 6.8% and 8.0% for PWID, 12% and 10% for clients, and 5.3% and 8.2% for nonclient partners. In sub-Saharan Africa, proportions of new HIV infections decreased among SW, clients, and non-KP partners but increased for PWID; elsewhere these groups' 2010-to-2022 differences were opposite. For MSM and TGW, the proportions increased across all regions. CONCLUSIONS: KPs continue to have disproportionately high HIV incidence.

Comparison of Empirically Derived and Model-Based Estimates of Key Population HIV Incidence and the Distribution of New Infections by Population Group in Sub-Saharan Africa.

BACKGROUND: The distribution of new HIV infections among key populations, including female sex workers (FSWs), gay men and other men who have sex with men (MSM), and people who inject drugs (PWID) are essential information to guide an HIV response, but data are limited in sub-Saharan Africa (SSA). We analyzed empirically derived and mathematical model-based estimates of HIV incidence among key populations and compared with the Joint United Nations Programme on HIV/AIDS (UNAIDS) estimates. METHODS: We estimated HIV incidence among FSW and MSM in SSA by combining meta-analyses of empirical key population HIV incidence relative to the total population incidence with key population size estimates (KPSE) and HIV prevalence. Dynamic HIV transmission model estimates of HIV incidence and percentage of new infections among key populations were extracted from 94 country applications of 9 mathematical models. We compared these with UNAIDS-reported distribution of new infections, implied key population HIV incidence and incidence-to-prevalence ratios. RESULTS: Across SSA, empirical FSW HIV incidence was 8.6-fold (95% confidence interval: 5.7 to 12.9) higher than total population female 15-39 year incidence, and MSM HIV incidence was 41.8-fold (95% confidence interval: 21.9 to 79.6) male 15-29 year incidence. Combined with KPSE, these implied 12% of new HIV infections in 2021 were among FSW and MSM (5% and 7% respectively). In sensitivity analysis varying KPSE proportions within 95% uncertainty range, the proportion of new infections among FSW and MSM was between 9% and 19%. Insufficient data were available to estimate PWID incidence rate ratios. Across 94 models, median proportion of new infections among FSW, MSM, and PWID was 6.4% (interquartile range 3.2%-11.7%), both much lower than the 25% reported by UNAIDS. CONCLUSION: Empirically derived and model-based estimates of HIV incidence confirm dramatically higher HIV risk among key populations in SSA. Estimated proportions of new infections among key populations in 2021 were sensitive to population size assumptions and were substantially lower than estimates reported by UNAIDS.

Differences in Breastfeeding Duration by Maternal HIV Status: A Pooled Analysis of Nationally Representative Surveys in Sub-Saharan Africa.

BACKGROUND: Breastfeeding improves child survival but is a source of mother-to-child HIV transmission among women with unsuppressed HIV infection. Estimated HIV incidence in children is sensitive to breastfeeding duration among mothers living with HIV (MLHIV). Breastfeeding duration may vary according to maternal HIV status. SETTING: Sub-Saharan Africa. METHODS: We analyzed pooled data from nationally representative household surveys conducted during 2003-2019 that included HIV testing and elicited breastfeeding practices. We fitted survival models of breastfeeding duration by country, year, and maternal HIV status for 4 sub-Saharan African regions (Eastern, Central, Southern, and Western). RESULTS: Data were obtained from 65 surveys in 31 countries. In 2010, breastfeeding in the first month of life ("initial breastfeeding") among MLHIV ranged from 69.1% (95% credible interval: 68-79.9) in Southern Africa to 93.4% (92.7-98.0) in Western Africa. Median breastfeeding duration among MLHIV was the shortest in Southern Africa at 15.6 (14.2-16.3) months and the longest in Eastern Africa at 22.0 (21.7-22.5) months. By comparison, HIV-negative mothers were more likely to breastfeed initially (91.0%-98.7% across regions) and for longer duration (median 18.3-24.6 months across regions). Initial breastfeeding and median breastfeeding duration decreased during 2005-2015 in most regions and did not increase in any region regardless of maternal HIV status. CONCLUSIONS: MLHIV in sub-Saharan Africa are less likely to breastfeed initially and stop breastfeeding sooner than HIV-negative mothers. Since 2020, UNAIDS-supported HIV estimates have accounted for this shorter breastfeeding exposure among HIV-exposed children. MLHIV need support to enable optimal breastfeeding practices and to adhere to antiretroviral therapy for HIV treatment and prevention of postnatal mother-to-child transmission.

Measuring HIV Acquisitions Among Partners of Key Populations: Estimates From HIV Transmission Dynamic Models.

BACKGROUND: Key populations (KPs), including female sex workers (FSWs), gay men and other men who have sex with men (MSM), people who inject drugs (PWID), and transgender women (TGW) experience disproportionate risks of HIV acquisition. The UNAIDS Global AIDS 2022 Update reported that one-quarter of all new HIV infections occurred among their non-KP sexual partners. However, this fraction relied on heuristics regarding the ratio of new infections that KPs transmitted to their non-KP partners to the new infections acquired among KPs (herein referred to as "infection ratios"). We recalculated these ratios using dynamic transmission models. SETTING: One hundred seventy-eight settings (106 countries). METHODS: Infection ratios for FSW, MSM, PWID, TGW, and clients of FSW were estimated from 12 models for 2020. RESULTS: Median model estimates of infection ratios were 0.7 (interquartile range: 0.5-1.0; n = 172 estimates) and 1.2 (0.8-1.8; n = 127) for acquisitions from FSW clients and transmissions from FSW to all their non-KP partners, respectively, which were comparable with the previous UNAIDS assumptions (0.2-1.5 across regions). Model estimates for female partners of MSM were 0.5 (0.2-0.8; n = 20) and 0.3 (0.2-0.4; n = 10) for partners of PWID across settings in Eastern and Southern Africa, lower than the corresponding UNAIDS assumptions (0.9 and 0.8, respectively). The few available model estimates for TGW were higher [5.1 (1.2-7.0; n = 8)] than the UNAIDS assumptions (0.1-0.3). Model estimates for non-FSW partners of FSW clients in Western and Central Africa were high (1.7; 1.0-2.3; n = 29). CONCLUSIONS: Ratios of new infections among non-KP partners relative to KP were high, confirming the importance of better addressing prevention and treatment needs among KP as central to reducing overall HIV incidence.

A quantitative assessment of the consistency of projections from five mathematical models of the HIV epidemic in South Africa: a model comparison study.

BACKGROUND: Mathematical models are increasingly used to inform HIV policy and planning. Comparing estimates obtained using different mathematical models can test the robustness of estimates and highlight research gaps. As part of a larger project aiming to determine the optimal allocation of funding for HIV services, in this study we compare projections from five mathematical models of the HIV epidemic in South Africa: EMOD-HIV, Goals, HIV-Synthesis, Optima, and Thembisa. METHODS: The five modelling groups produced estimates of the total population, HIV incidence, HIV prevalence, proportion of people living with HIV who are diagnosed, ART coverage, proportion of those on ART who are virally suppressed, AIDS-related deaths, total deaths, and the proportion of adult males who are circumcised. Estimates were made under a "status quo" scenario for the period 1990 to 2040. For each output variable we assessed the consistency of model estimates by calculating the coefficient of variation and examining the trend over time. RESULTS: For most outputs there was significant inter-model variability between 1990 and 2005, when limited data was available for calibration, good consistency from 2005 to 2025, and increasing variability towards the end of the projection period. Estimates of HIV incidence, deaths in people living with HIV, and total deaths displayed the largest long-term variability, with standard deviations between 35 and 65% of the cross-model means. Despite this variability, all models predicted a gradual decline in HIV incidence in the long-term. Projections related to the UNAIDS 95-95-95 targets were more consistent, with the coefficients of variation below 0.1 for all groups except children. CONCLUSIONS: While models produced consistent estimates for several outputs, there are areas of variability that should be investigated. This is important if projections are to be used in subsequent cost-effectiveness studies.

Describing current use, barriers, and facilitators of patient portal messaging for research recruitment: Perspectives from study teams and patients at one institution.

Introduction: The electronic health record (EHR) and patient portal are used increasingly for clinical research, including patient portal recruitment messaging (PPRM). Use of PPRM has grown rapidly; however, best practices are still developing. In this study, we examined the use of PPRM at our institution and conducted qualitative interviews among study teams and patients to understand experiences and preferences for PPRM. Methods: We identified study teams that sent PPRMs and patients that received PPRMs in a 60-day period. We characterized these studies and patients, in addition to the patients' interactions with the PPRMs (e.g., viewed, responded). From these groups, we recruited study team members and patients for semi-structured interviews. A pragmatic qualitative inquiry framework was used by interviewers. Interviews were audio-recorded and analyzed using a rapid qualitative analysis exploratory approach. Results: Across ten studies, 35,037 PPRMs were sent, 33% were viewed, and 17% were responded to. Interaction rates varied across demographic groups. Six study team members completed interviews and described PPRM as an efficient and helpful recruitment method. Twenty-eight patients completed interviews. They were supportive of receiving PPRMs, particularly when the PPRM was relevant to their health. Patients indicated that providing more information in the PPRM would be helpful, in addition to options to set personalized preferences. Conclusions: PPRM is an efficient recruitment method for study teams and is acceptable to patients. Engagement with PPRMs varies across demographic groups, which should be considered during recruitment planning. Additional research is needed to evaluate and implement recommended changes by study teams and patients.

Applying mathematical modelling to estimate the impact of COVID-19-related VMMC service disruptions on new HIV infections in Zimbabwe.

BACKGROUND: The COVID-19 pandemic has overwhelmed health systems with knock on effects on diagnosis, treatment, and care. To mitigate the impact, the government of Zimbabwe enforced a strict lockdown beginning 30 March 2020 which ran intermittently until early 2021. In this period, the Ministry of Health and Childcare strategically prioritized delivery of services leading to partial and full suspension of services considered non-essential, including HIV prevention. As a result, Voluntary Medical Male Circumcision (VMMC) services were disrupted leading to an 80% decline in circumcisions conducted in 2020. Given the efficacy of VMMC, we quantified the potential effects of VMMC service disruption on new HIV infections in Zimbabwe. METHODS: We applied the GOALS model to evaluate the impact of COVID-19-related disruptions on reducing new HIV infections over 30-years. GOALS is an HIV simulation model that estimates number of new HIV infections based on sexual behaviours of population groups. The model is parameterized based on national surveys and HIV program data. We hypothesized three coverage scenarios by 2030: scenario I - pre-COVID trajectory: 80% VMMC coverage; Scenario II - marginal COVID-19 impact: 60% VMMC coverage, and scenario III - severe COVID-19 impact: 45% VMMC coverage. VMMC coverage between 2020 and 2030 was linearly interpolated to attain the estimated coverage and then held constant from 2030 to 2050, and discounted outcomes at 3%. RESULTS: Compared to the baseline scenario I, in scenario II, we estimated that the disruption of VMMC services would generate an average of 200 (176-224) additional new infections per year and 7,200 new HIV infections over the next 30 years. For scenario III, we estimated an average of 413 (389-437) additional new HIV infections per year and 15,000 new HIV infections over the next 30 years. The disruption of VMMC services could generate additional future HIV treatment costs ranging from $27 million to $55 million dollars across scenarios II and III, respectively. CONCLUSION: COVID-19 disruptions destabilized delivery of VMMC services which could contribute to an additional 7,200 new infections over the next 30 years. Unless mitigated, these disruptions could derail the national goals of reducing new infections by 2030.

Cost-effectiveness of voluntary medical male circumcision for HIV prevention across sub-Saharan Africa: results from five independent models.

BACKGROUND: Voluntary medical male circumcision (VMMC) has been a recommended HIV prevention strategy in sub-Saharan Africa since 2007, particularly in countries with high HIV prevalence. However, given the scale-up of antiretroviral therapy programmes, it is not clear whether VMMC still represents a cost-effective use of scarce HIV programme resources. METHODS: Using five existing well described HIV mathematical models, we compared continuation of VMMC for 5 years in men aged 15 years and older to no further VMMC in South Africa, Malawi, and Zimbabwe and across a range of setting scenarios in sub-Saharan Africa. Outputs were based on a 50-year time horizon, VMMC cost was assumed to be US$90, and a cost-effectiveness threshold of US$500 was used. FINDINGS: In South Africa and Malawi, the continuation of VMMC for 5 years resulted in cost savings and health benefits (infections and disability-adjusted life-years averted) according to all models. Of the two models modelling Zimbabwe, the continuation of VMMC for 5 years resulted in cost savings and health benefits by one model but was not as cost-effective according to the other model. Continuation of VMMC was cost-effective in 68% of setting scenarios across sub-Saharan Africa. VMMC was more likely to be cost-effective in modelled settings with higher HIV incidence; VMMC was cost-effective in 62% of settings with HIV incidence of less than 0·1 per 100 person-years in men aged 15-49 years, increasing to 95% with HIV incidence greater than 1·0 per 100 person-years. INTERPRETATION: VMMC remains a cost-effective, often cost-saving, prevention intervention in sub-Saharan Africa for at least the next 5 years. FUNDING: Bill & Melinda Gates Foundation for the HIV Modelling Consortium.

Early supplemental parenteral nutrition for the achievement of nutritional goals in subarachnoid hemorrhage patients: An observational cohort study.

PURPOSE: Enteral nutrition (EN) often fails to achieve nutritional goals in neurocritical care patients. We sought to investigate the safety and utility of supplemental parenteral nutrition (PN) in subarachnoid hemorrhage (SAH) patients. MATERIALS AND METHODS: Data of 70 consecutive patients with non-traumatic SAH admitted to the neurological intensive care unit of a tertiary referral center were prospectively collected and retrospectively analyzed. We targeted the provision of 20-25 kilocalories per kilogram bodyweight per day (kcal/kg/d) by enteral nutrition. Supplemental PN was given when this target could not be reached. Nutritional data were analyzed for up to 14 days of ICU stay. Hospital complications were tested for associations with impaired enteral feeding. The amounts of EN and PN were tested for associations with the level of protein delivery and functional outcome. Repeated measurements within subjects were handled utilizing generalized estimating equations. RESULTS: Forty (27 women and 13 men) of 70 screened patients were eligible for the analysis. Median age was 61 (IQR 49-71) years, 8 patients (20%) died in the hospital. Thirty-six patients (90%) received PN for a median duration of 8 (IQR 4-12) days. The provision of 20 kcal/kg by EN on at least 1 day of ICU stay was only achieved in 24 patients (60%). Hydrocephalus (p = 0.020), pneumonia (p = 0.037) and sepsis (p = 0.013) were associated with impaired enteral feeding. Neither the amount nor the duration of PN administration was associated with an increased risk of severe complications or poor outcome. Supplemental PN was associated with significantly increased protein delivery (p<0.001). In patients with sepsis or pneumonia, there was an association between higher protein delivery and good functional outcome (p<0.001 and p = 0.031), but not in the overall cohort (p = 0.08). CONCLUSIONS: Enteral feeding was insufficient to achieve nutritional goals in subarachnoid hemorrhage patients. Supplemental PN was safe and associated with increased protein delivery. A higher protein supply was associated with good functional outcome in patients who developed sepsis or pneumonia.

The case for prevention - Primary HIV prevention in the era of universal test and treat: A mathematical modeling study.

Background: As antiretroviral therapy (ART) has scaled up and HIV incidence has declined, some have questioned the continued utility of HIV prevention. This study examines the role and cost-effectiveness of HIV prevention in the context of "universal test and treat" (UTT) in three sub-Saharan countries with generalized HIV epidemics. Methods: Scenarios were created in Spectrum/Goals models for Lesotho, Mozambique, and Uganda with various combinations of voluntary medical male circumcision (VMMC); pre-exposure prophylaxis; and a highly effective, durable, hypothetical vaccine layered onto three different ART scenarios. One ART scenario held coverage constant at 2008 levels to replicate prevention modeling studies that were conducted prior to UTT. One scenario assumed scale-up to the UNAIDS treatment goals of 90-90-90 by 2025 and 95-95-95 by 2030. An intermediate scenario held ART constant at 2019 coverage. HIV incidence was visualized over time, and cost per HIV infection averted was assessed over 5-, 15-, and 30-year time frames, with 3% annual discounting. Findings: Each prevention intervention reduced HIV incidence beyond what was achieved by ART scale-up alone to the 90-90-90/95-95-95 goals, with near-zero incidence achievable by combinations of interventions covering all segments of the population. Cost-effectiveness of HIV prevention may decrease as HIV incidence decreases, but one-time interventions like VMMC and a durable vaccine may remain cost-effective and even cost-saving as ART is scaled up. Interpretation: Primary HIV prevention is still needed in the era of UTT. Combination prevention is more impactful than a single, highly effective intervention. Broad population coverage of primary prevention, regardless of cost-effectiveness, will be required in generalized epidemic countries to eradicate HIV.

Do not forget the children: a model-based analysis on the potential impact of COVID-19-associated interruptions in paediatric HIV prevention and care.

INTRODUCTION: The COVID-19 pandemic has affected women and children globally, disrupting antiretroviral therapy (ART) services and exacerbating pre-existing barriers to care for both pregnant women and paediatric populations. METHODS: We used the Spectrum modelling package and the CEPAC-Pediatric model to project the impact of COVID-19-associated care disruptions on three key populations in the 21 Global Plan priority countries in sub-Saharan Africa: (1) pregnant and breastfeeding women living with HIV and their children, (2) all children (aged 0-14 years) living with HIV (CLWH), regardless of their engagement in care and (3) CLWH who were engaged in care and on ART prior to the start of the pandemic. We projected clinical outcomes over the 12-month period of 1 March 2020 to 1 March 2021. RESULTS: Compared to a scenario with no care disruption, in a 3-month lockdown with complete service disruption, followed by 3 additional months of partial (50%) service disruption, a projected 755,400 women would have received PMTCT care (a 21% decrease), 187,800 new paediatric HIV infections would have occurred (a 77% increase) and 516,800 children would have received ART (a 35% decrease). For children on ART as of March 2020, we projected 507,200 would have experienced ART failure (an 80% increase). Additionally, a projected 88,400 AIDS-related deaths would have occurred (a 27% increase) between March 2020 and March 2021, with 51,700 of those deaths occurring among children engaged in care as of March 2020 (a 54% increase). CONCLUSIONS: While efforts will continue to curb morbidity and mortality stemming directly from COVID-19 itself, it is critical that providers also consider the immediate and indirect harms of this pandemic, particularly among vulnerable populations. Well-informed, timely action is critical to meet the health needs of pregnant women and children if the global community is to maintain momentum towards an AIDS-free generation.

The risks and benefits of providing HIV services during the COVID-19 pandemic.

INTRODUCTION: The COVID-19 pandemic has caused widespread disruptions including to health services. In the early response to the pandemic many countries restricted population movements and some health services were suspended or limited. In late 2020 and early 2021 some countries re-imposed restrictions. Health authorities need to balance the potential harms of additional SARS-CoV-2 transmission due to contacts associated with health services against the benefits of those services, including fewer new HIV infections and deaths. This paper examines these trade-offs for select HIV services. METHODS: We used four HIV simulation models (Goals, HIV Synthesis, Optima HIV and EMOD) to estimate the benefits of continuing HIV services in terms of fewer new HIV infections and deaths. We used three COVID-19 transmission models (Covasim, Cooper/Smith and a simple contact model) to estimate the additional deaths due to SARS-CoV-2 transmission among health workers and clients. We examined four HIV services: voluntary medical male circumcision, HIV diagnostic testing, viral load testing and programs to prevent mother-to-child transmission. We compared COVID-19 deaths in 2020 and 2021 with HIV deaths occurring now and over the next 50 years discounted to present value. The models were applied to countries with a range of HIV and COVID-19 epidemics. RESULTS: Maintaining these HIV services could lead to additional COVID-19 deaths of 0.002 to 0.15 per 10,000 clients. HIV-related deaths averted are estimated to be much larger, 19-146 discounted deaths per 10,000 clients. DISCUSSION: While there is some additional short-term risk of SARS-CoV-2 transmission associated with providing HIV services, the risk of additional COVID-19 deaths is at least 100 times less than the HIV deaths averted by those services. Ministries of Health need to take into account many factors in deciding when and how to offer essential health services during the COVID-19 pandemic. This work shows that the benefits of continuing key HIV services are far larger than the risks of additional SARS-CoV-2 transmission.

Five years after Treat All implementation: Botswana's HIV response and future directions in the era of COVID-19.

BACKGROUND: As the relentless coronavirus disease-2019 (COVID-19) pandemic continues to spread across Africa, Botswana could face challenges maintaining the pathway towards control of its HIV epidemic. OBJECTIVE: Utilising the Spectrum GOALS module (GOALS-2021), the 5-year outcomes from the implementation of the Treat All strategy were analysed and compared with the original 2016 Investment Case (2016-IC) projections. Future impact of adopting the new Joint United Nations Programme on HIV/AIDS (UNAIDS) Global AIDS Strategy (2021-2026) targets and macroeconomic analysis estimating how the financial constraints from the COVID-19 pandemic could impact the available resources for Botswana's National HIV Response through 2030 were also considered. METHOD: Programmatic costs, population demographics, prevention and treatment outputs were determined. Previous 2016-IC data were uploaded for comparison, and inputs for the GOALS, AIM, DemProj, Resource Needs and Family Planning modules were derived from published reports, strategic plans, programmatic data and expert opinion. The economic projections were recalibrated with consideration of the impact of the COVID-19 pandemic. RESULTS: Decreases in HIV infections, incidence and mortality rates were achieved. Increases in laboratory costs were offset by estimated decreases in the population of people living with HIV (PLWH). Moving forward, young women and others at high risk must be targeted in HIV prevention efforts, as Botswana transitions from a generalised to a more concentrated epidemic. CONCLUSION: The Treat All strategy contributed positively to decreases in new HIV infections, mortality and costs. If significant improvements in differentiated service delivery, increases in human resources and HIV prevention can be realised, Botswana could become one of the first countries with a previously high-burdened generalised HIV epidemic to gain epidemic control, despite the demands of the COVID-19 pandemic.

Modeling the epidemiological impact of the UNAIDS 2025 targets to end AIDS as a public health threat by 2030.

BACKGROUND: UNAIDS has established new program targets for 2025 to achieve the goal of eliminating AIDS as a public health threat by 2030. This study reports on efforts to use mathematical models to estimate the impact of achieving those targets. METHODS AND FINDINGS: We simulated the impact of achieving the targets at country level using the Goals model, a mathematical simulation model of HIV epidemic dynamics that includes the impact of prevention and treatment interventions. For 77 high-burden countries, we fit the model to surveillance and survey data for 1970 to 2020 and then projected the impact of achieving the targets for the period 2019 to 2030. Results from these 77 countries were extrapolated to produce estimates for 96 others. Goals model results were checked by comparing against projections done with the Optima HIV model and the AIDS Epidemic Model (AEM) for selected countries. We included estimates of the impact of societal enablers (access to justice and law reform, stigma and discrimination elimination, and gender equality) and the impact of Coronavirus Disease 2019 (COVID-19). Results show that achieving the 2025 targets would reduce new annual infections by 83% (71% to 86% across regions) and AIDS-related deaths by 78% (67% to 81% across regions) by 2025 compared to 2010. Lack of progress on societal enablers could endanger these achievements and result in as many as 2.6 million (44%) cumulative additional new HIV infections and 440,000 (54%) more AIDS-related deaths between 2020 and 2030 compared to full achievement of all targets. COVID-19-related disruptions could increase new HIV infections and AIDS-related deaths by 10% in the next 2 years, but targets could still be achieved by 2025. Study limitations include the reliance on self-reports for most data on behaviors, the use of intervention effect sizes from published studies that may overstate intervention impacts outside of controlled study settings, and the use of proxy countries to estimate the impact in countries with fewer than 4,000 annual HIV infections. CONCLUSIONS: The new targets for 2025 build on the progress made since 2010 and represent ambitious short-term goals. Achieving these targets would bring us close to the goals of reducing new HIV infections and AIDS-related deaths by 90% between 2010 and 2030. By 2025, global new infections and AIDS deaths would drop to 4.4 and 3.9 per 100,000 population, and the number of people living with HIV (PLHIV) would be declining. There would be 32 million people on treatment, and they would need continuing support for their lifetime. Incidence for the total global population would be below 0.15% everywhere. The number of PLHIV would start declining by 2023.

Disease progression and mortality with untreated HIV infection: evidence synthesis of HIV seroconverter cohorts, antiretroviral treatment clinical cohorts and population-based survey data.

INTRODUCTION: Model-based estimates of key HIV indicators depend on past epidemic trends that are derived based on assumptions about HIV disease progression and mortality in the absence of antiretroviral treatment (ART). Population-based HIV Impact Assessment (PHIA) household surveys conducted between 2015 and 2018 found substantial numbers of respondents living with untreated HIV infection. CD4 cell counts measured in these individuals provide novel information to estimate HIV disease progression and mortality rates off ART. METHODS: We used Bayesian multi-parameter evidence synthesis to combine data on (1) cross-sectional CD4 cell counts among untreated adults living with HIV from 10 PHIA surveys, (2) survival after HIV seroconversion in East African seroconverter cohorts, (3) post-seroconversion CD4 counts and (4) mortality rates by CD4 count predominantly from European, North American and Australian seroconverter cohorts. We used incremental mixture importance sampling to estimate HIV natural history and ART uptake parameters used in the Spectrum software. We validated modelled trends in CD4 count at ART initiation against ART initiator cohorts in sub-Saharan Africa. RESULTS: Median untreated HIV survival decreased with increasing age at seroconversion, from 12.5 years [95% credible interval (CrI): 12.1-12.7] at ages 15-24 to 7.2 years (95% CrI: 7.1-7.7) at ages 45-54. Older age was associated with lower initial CD4 counts, faster CD4 count decline and higher HIV-related mortality rates. Our estimates suggested a weaker association between ART uptake and HIV-related mortality rates than previously assumed in Spectrum. Modelled CD4 counts in untreated people living with HIV matched recent household survey data well, though some intercountry variation in frequencies of CD4 counts above 500 cells/mm3 was not explained. Trends in CD4 counts at ART initiation were comparable to data from ART initiator cohorts. An alternate model that stratified progression and mortality rates by sex did not improve model fit appreciably. CONCLUSIONS: Synthesis of multiple data sources results in similar overall survival as previous Spectrum parameter assumptions but implies more rapid progression and longer survival in lower CD4 categories. New natural history parameter values improve consistency of model estimates with recent cross-sectional CD4 data and trends in CD4 counts at ART initiation.

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.

Naomi: a new modelling tool for estimating HIV epidemic indicators at the district level in sub-Saharan Africa.

INTRODUCTION: HIV planning requires granular estimates for the number of people living with HIV (PLHIV), antiretroviral treatment (ART) coverage and unmet need, and new HIV infections by district, or equivalent subnational administrative level. We developed a Bayesian small-area estimation model, called Naomi, to estimate these quantities stratified by subnational administrative units, sex, and five-year age groups. METHODS: Small-area regressions for HIV prevalence, ART coverage and HIV incidence were jointly calibrated using subnational household survey data on all three indicators, routine antenatal service delivery data on HIV prevalence and ART coverage among pregnant women, and service delivery data on the number of PLHIV receiving ART. Incidence was modelled by district-level HIV prevalence and ART coverage. Model outputs of counts and rates for each indicator were aggregated to multiple geographic and demographic stratifications of interest. The model was estimated in an empirical Bayes framework, furnishing probabilistic uncertainty ranges for all output indicators. Example results were presented using data from Malawi during 2016-2018. RESULTS: Adult HIV prevalence in September 2018 ranged from 3.2% to 17.1% across Malawi's districts and was higher in southern districts and in metropolitan areas. ART coverage was more homogenous, ranging from 75% to 82%. The largest number of PLHIV was among ages 35 to 39 for both women and men, while the most untreated PLHIV were among ages 25 to 29 for women and 30 to 34 for men. Relative uncertainty was larger for the untreated PLHIV than the number on ART or total PLHIV. Among clients receiving ART at facilities in Lilongwe city, an estimated 71% (95% CI, 61% to 79%) resided in Lilongwe city, 20% (14% to 27%) in Lilongwe district outside the metropolis, and 9% (6% to 12%) in neighbouring Dowa district. Thirty-eight percent (26% to 50%) of Lilongwe rural residents and 39% (27% to 50%) of Dowa residents received treatment at facilities in Lilongwe city. CONCLUSIONS: The Naomi model synthesizes multiple subnational data sources to furnish estimates of key indicators for HIV programme planning, resource allocation, and target setting. Further model development to meet evolving HIV policy priorities and programme need should be accompanied by continued strengthening and understanding of routine health system data.

Ending AIDS as a public health threat by 2030: Time to reset targets for 2025.

Paul De Lay and co-authors introduce a Collection on the design of targets for ending the AIDS epidemic.

Blood glucose response after oral lactulose intake in type 2 diabetic individuals.

BACKGROUND: Lactulose is approved for the symptomatic treatment of constipation, a gastrointestinal (GI) complication common in individuals with diabetes. Lactulose products contain carbohydrate impurities (e.g., lactose, fructose, galactose), which occur during the lactulose manufacturing process. These impurities may affect the blood glucose levels of individuals with type 2 diabetes mellitus (T2DM) using lactulose for the treatment of mild constipation. A previous study in healthy subjects revealed no increase in blood glucose levels after oral lactulose intake. However, it is still unclear whether the intake of lactulose increases blood glucose levels in individuals with diabetes. AIM: To evaluate the blood glucose profile after oral lactulose intake in mildly constipated, non-insulin-dependent subjects with T2DM in an outpatient setting. METHODS: This prospective, double-blind, randomized, controlled, single-center trial was conducted at the Clinical Research Center at the Medical University of Graz, Austria, in 24 adult Caucasian mildly constipated, non-insulin-dependent subjects with T2DM. Eligible subjects were randomized and assigned to one of six treatment sequences, each consisting of four treatments stratified by sex using an incomplete block design. Subjects received a single dose of 20 g or 30 g lactulose (crystal and liquid formulation), water as negative control or 30 g glucose as positive control. Capillary blood glucose concentrations were measured over a period of 180 min post dose. The primary endpoint was the baseline-corrected area under the curve of blood glucose concentrations over the complete assessment period [AUCbaseline_c (0-180 min)]. Quantitative comparisons were performed for both lactulose doses and formulations vs water for the equal lactulose dose vs glucose, as well as for liquid lactulose vs crystal lactulose. Safety parameters included GI tolerability, which was assessed at 180 min and 24 h post dose, and adverse events occurring up to 24 h post dose. RESULTS: In 24 randomized and analyzed subjects blood glucose concentration-time curves after intake of 20 g and 30 g lactulose were almost identical to those after water intake for both lactulose formulations despite the different amounts of carbohydrate impurities (≤ 3.0% for crystals and approx. 30% for liquid). The primary endpoint [AUCbaseline_c (0-180 min)] was not significantly different between lactulose and water regardless of lactulose dose and formulation. Also with regard to all secondary endpoints lactulose formulations showed comparable results to water with one exception concerning maximum glucose level. A minor increase in maximum blood glucose was observed after the 30 g dose, liquid lactulose, in comparison to water with a mean treatment difference of 0.63 mmol/L (95% confidence intervals: 0.19, 1.07). Intake of 30 g glucose significantly increased all blood glucose endpoints vs 30 g liquid and crystal lactulose, respectively (all P < 0.0001). No differences in blood glucose response were observed between the different lactulose formulations. As expected, lactulose increased the number of bowel movements and was generally well tolerated. Subjects experienced only mild to moderate GI symptoms due to the laxative action of lactulose. CONCLUSION: Blood glucose AUCbaseline_c (0-180 min) levels in mildly constipated, non-insulin dependent subjects with T2DM are not affected by the carbohydrate impurities contained in 20 g and 30 g crystal or liquid lactulose formulations.