The impact, cost and cost-effectiveness of oral pre-exposure prophylaxis in sub-Saharan Africa: a scoping review of modelling contributions and way forward

Leveraging international stakeholders' experiences with oral PrEP costs to accelerate implementation of the monthly dapivirine vaginal ring: A qualitative study

BACKGROUND

Costing and financing systematic implementation are recognized barriers to human immunodeficiency virus (HIV) prevention. In the absence of empiric implementation and economic data, perspectives from international stakeholders involved in developing and supporting daily oral pre-exposure prophylaxis (PrEP) policy, and programs can provide critical insights for developing costed plans to support and accelerate the rollout of novel long-acting PrEP (LA-PrEP) methods, such as the monthly dapivirine vaginal ring (PrEP ring).

METHODS

We interviewed stakeholders from purposively selected international organizations about anticipated PrEP-ring implementation costs, evidence gaps and key process steps for developing a costed rollout plan template (CRPT). We deductively analysed interviews.

RESULTS

The 27 stakeholders (11 donors, 10 nongovernmental, 4 academic/research, 2 multilateral) identified 10 cost-related themes: 7 for planning and implementation and 3 for financing, costing and budgeting. Planning and implementation cost considerations included: (1) actionable target setting; (2) multilevel communication strategies for awareness-raising, demand creation, client-level adherence and choice counselling; (3) human resources, encompassing task shifting and integration into non-HIV services; (4) supply chain costs, including commodities, manufacturing diversification, packaging and forecasting; (5) laboratory infrastructure and monitoring; (6) updated health information systems and metrics to monitor and evaluate multiple methods integrated into HIV, non-HIV and de-medicalized delivery settings; and (7) technical assistance and knowledge management. Themes for financing, costing and budgeting comprised: (8) cost and budget analyses, such as cost-effectiveness; (9) economic evidence gaps on service integration; and (10) innovative or co-financing for sustainable and equitable allocation of limited financial resources to support accelerated PrEP-ring delivery. We organized these themes within the CRPT.

CONCLUSIONS

The CRPT could expedite planning and enhance the pace and scale of optimized, systematic and sustainable delivery of PrEP methods. Further research is needed to evaluate use cases of the CRPT.

Awareness of, willingness to use, and experiences with Pre-exposure prophylaxis among youth in Nigeria

BACKGROUND

Youth (ages 14-24) in Nigeria have disproportionately high rates of new HIV infection. Pre-exposure prophylaxis could substantially reduce new infections among youth but has not been scaled up. This cross-sectional study aimed to assess Pre-exposure prophylaxis awareness, willingness to use, and prior use of Pre-exposure prophylaxis among youth in Nigeria.

METHODS

This is a secondary analysis of cross-sectional data from a quasi-experimental pilot study (clinical trial NCT04070287). The analysis focused on Pre-exposure prophylaxis awareness, willingness to use, and prior use among 324 youth recruited between September 2019 to March 2020. Descriptive statistics were calculated as frequencies and percentages for categorical variables and means and standard deviations for continuous variables.

RESULTS

Of the 324 participants, the mean age and standard deviation were 21.17 (± 2.20) years. The majority were 20-24 years old (75.9%) and male (57.7%). Only 30.7% used condoms consistently over three months. Regarding Pre-exposure prophylaxis awareness and willingness, 62.6% had never heard of Pre-exposure prophylaxis, and 158 (50.1%) reported willingness to use Pre-exposure prophylaxis. Only 10 (3.2%) reported having used Pre-exposure prophylaxis.

CONCLUSION

Nigerian youth have low awareness of and prior use of Pre-exposure prophylaxis. Given the gap between prior use and willingness to use Pre-exposure prophylaxis, our findings suggest missed opportunities to prevent new HIV infections among youth in Nigeria. Efforts to increase awareness and uptake of Pre-exposure prophylaxis among this population should consider youth-led Pre-exposure prophylaxis outreach efforts and effectively communicate the benefits of Pre-exposure prophylaxis to this population.

TRIAL REGISTRATION

NCT04070287, the Date of registration of the trial is 20-07-2019.

Implementation and resource needs for long-acting PrEP in low- and middle-income countries: a scoping review

INTRODUCTION

Several low- and middle-income countries (LMICs) are preparing to introduce long-acting pre-exposure prophylaxis (LAP). Amid multiple pre-exposure prophylaxis (PrEP) options and constrained funding, decision-makers could benefit from systematic implementation planning and aligned costs. We reviewed national costed implementation plans (CIPs) to describe relevant implementation inputs and activities (domains) for informing the costed rollout of LAP. We assessed how primary costing evidence aligned with those domains.

METHODS

We conducted a rapid review of CIPs for oral PrEP and family planning (FP) to develop a consensus of implementation domains, and a scoping review across nine electronic databases for publications on PrEP costing in LMICs between January 2010 and June 2022. We extracted cost data and assessed alignment with the implementation domains and the Global Health Costing Consortium principles.

RESULTS

We identified 15 implementation domains from four national PrEP plans and FP-CIP template; only six were in all sources. We included 66 full-text manuscripts, 10 reported LAP, 13 (20%) were primary cost studies-representing seven countries, and none of the 13 included LAP. The 13 primary cost studies included PrEP commodities (n = 12), human resources (n = 11), indirect costs (n = 11), other commodities (n = 10), demand creation (n = 9) and counselling (n = 9). Few studies costed integration into non-HIV services (n = 5), above site costs (n = 3), supply chains and logistics (n = 3) or policy and planning (n = 2), and none included the costs of target setting, health information system adaptations or implementation research. Cost units and outcomes were variable (e.g. average per person-year).

DISCUSSION

LAP planning will require updating HIV prevention policies, technical assistance for logistical and clinical support, expanding beyond HIV platforms, setting PrEP achievement targets overall and disaggregated by method, extensive supply chain and logistics planning and support, as well as updating health information systems to monitor multiple PrEP methods with different visit schedules. The 15 implementation domains were variable in reviewed studies. PrEP primary cost and budget data are necessary for new product introduction and should match implementation plans with financing.

CONCLUSIONS

As PrEP services expand to include LAP, decision-makers need a framework, tools and a process to support countries in planning the systematic rollout and costing for LAP.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Impact and cost-effectiveness of the national scale-up of HIV pre-exposure prophylaxis among female sex workers in South Africa: a modelling analysis

INTRODUCTION

In 2016, South Africa (SA) initiated a national programme to scale-up pre-exposure prophylaxis (PrEP) among female sex workers (FSWs), with ∼20,000 PrEP initiations among FSWs (∼14% of FSW) by 2020. We evaluated the impact and cost-effectiveness of this programme, including future scale-up scenarios and the potential detrimental impact of the COVID-19 pandemic.

METHODS

A compartmental HIV transmission model for SA was adapted to include PrEP. Using estimates on self-reported PrEP adherence from a national study of FSW (67.7%) and the Treatment and Prevention for FSWs (TAPS) PrEP demonstration study in SA (80.8%), we down-adjusted TAPS estimates for the proportion of FSWs with detectable drug levels (adjusted range: 38.0-70.4%). The model stratified FSW by low (undetectable drug; 0% efficacy) and high adherence (detectable drug; 79.9%; 95% CI: 67.2-87.6% efficacy). FSWs can transition between adherence levels, with lower loss-to-follow-up among highly adherent FSWs (aHR: 0.58; 95% CI: 0.40-0.85; TAPS data). The model was calibrated to monthly data on the national scale-up of PrEP among FSWs over 2016-2020, including reductions in PrEP initiations during 2020. The model projected the impact of the current programme (2016-2020) and the future impact (2021-2040) at current coverage or if initiation and/or retention are doubled. Using published cost data, we assessed the cost-effectiveness (healthcare provider perspective; 3% discount rate; time horizon 2016-2040) of the current PrEP provision.

RESULTS

Calibrated to national data, model projections suggest that 2.1% of HIV-negative FSWs were currently on PrEP in 2020, with PrEP preventing 0.45% (95% credibility interval, 0.35-0.57%) of HIV infections among FSWs over 2016-2020 or 605 (444-840) infections overall. Reductions in PrEP initiations in 2020 possibly reduced infections averted by 18.57% (13.99-23.29). PrEP is cost-saving, with $1.42 (1.03-1.99) of ART costs saved per dollar spent on PrEP. Going forward, existing coverage of PrEP will avert 5,635 (3,572-9,036) infections by 2040. However, if PrEP initiation and retention doubles, then PrEP coverage increases to 9.9% (8.7-11.6%) and impact increases 4.3 times with 24,114 (15,308-38,107) infections averted by 2040.

CONCLUSIONS

Our findings advocate for the expansion of PrEP to FSWs throughout SA to maximize its impact. This should include strategies to optimize retention and should target women in contact with FSW services.

Cost Utility of Supporting Family-Based Care to Prevent HIV and Deaths among Orphaned and Separated Children in East Africa: A Markov Model-Based Simulation

Purpose. Strengthening family-based care is a key policy response to the more than 15 million orphaned and separated children who have lost 1 or both parents in sub-Saharan Africa. This analysis estimated the cost-effectiveness of family-based care environments for preventing HIV and death in this population. Design. We developed a time-homogeneous Markov model to simulate the incremental cost per disability-adjusted life year (DALY) averted by supporting family-based environments caring for orphaned and separated children in western Kenya. Model parameters were based on data from the longitudinal OSCAR's Health and Well-Being Project and published literature. We used a societal perspective, annual cycle length, and 3% discount rate. Incremental cost-effectiveness ratios were simulated over 5- to 15-y horizons, comparing family-based settings to street-based "self-care." Parameter uncertainty was addressed via deterministic and probabilistic sensitivity analyses. Results. Under base-case assumptions, family-based environments prevented 422 HIV infections and 298 deaths in a simulated cohort of 1,000 individuals over 10 y. Compared with street-based self-care, family-based care had an incremental cost of $2,528 per DALY averted (95% confidence interval [CI]: 1,798, 2,599) and $2,355 per quality-adjusted life year gained (95% CI: 1,667, 2,413). The probability of family-based care being highly cost-effective was >80% at a willingness-to-pay (WTP) threshold of $2,250/DALY averted. Households receiving government cash transfers had minimally higher cost-effectiveness ratios than households without cash transfers but were still cost-effective at a WTP threshold of twice Kenya's GDP per capita. Conclusions. Compared with the status quo of street-based self-care, family-based environments offer a cost-effective approach for preventing HIV and death among orphaned children in lower-middle income countries. Decision makers should consider increasing resources to these environments in tandem with social protection programs.

Highlights

UNICEF and more than 200 other international organizations endorsed efforts to redirect services toward family-based care as part of the 2019 UN Resolution on the Rights of the Child; yet this study is one of the first to quantify the cost-effectiveness of family-based care environments serving some of the world's most vulnerable children.This health economic modeling analysis found that family-based environments would prevent 422 HIV infections and 298 deaths in a cohort of 1,000 orphaned and separated children over a 10-y time horizon.Compared with street-based "self-care," family-based care resulted in an incremental cost of $2,528 per DALY averted (95% CI: 1,798, 2,599) and $2,355 per quality-adjusted life year gained (95% CI: 1,667, 2,413) after 10 y.Annual per-child expenditures for children living in family-based care environments in sub-Saharan Africa could potentially be increased by at least 25% and remain highly cost-effective.

Estimating the budget impact of adopting tenofovir/emtricitabine for pre-exposure prophylaxis of HIV in the public health sector in Namibia (2021 - 2023)

BACKGROUND

Although Namibia started implementing pre-exposure prophylaxis (PrEP) of Human Immunodeficiency Virus (HIV) in 2016, no study to determine its budget impact has been conducted. This study, therefore, aimed to estimate the budget impact of adopting tenofovir/emtricitabine for PrEP of HIV for all eligible people in the public health sector in Namibia from 2021 to 2023.

METHODS

A country-specific model was developed for this budget impact analysis (BIA). PrEP has targeted all eligible people in Namibia who receive health services from the public sector. It was assumed that the adherence rate was 75% and PrEP effectiveness 60% in this study. Costs used in this study were taken from a study that included Namibian costs.

RESULTS

The BIA suggests that adopting PrEP may be cost saving as US$104 823, US$143 620, and US$182 452 of additional HIV care costs will potentially be saved in 2021, 2022, and 2023, respectively. Cost savings rely on high adherence rates, high PrEP effectiveness rates, low PrEP costs, and a small number of people living with HIV (PLHIV).

CONCLUSION

Further economic analysis could aid decision-making in Namibia, both to stress test assumptions in the BIA and conduct cost-effectiveness analysis to estimate the value for money of PrEP.

Risk heterogeneity in compartmental HIV transmission models of ART as prevention in Sub-Saharan Africa: A scoping review

BACKGROUND

Transmission models provide complementary evidence to clinical trials about the potential population-level incidence reduction attributable to ART (ART prevention impact). Different modelling assumptions about risk heterogeneity may influence projected ART prevention impacts. We sought to review representations of risk heterogeneity in compartmental HIV transmission models applied to project ART prevention impacts in Sub-Saharan Africa.

METHODS

We systematically reviewed studies published before January 2020 that used non-linear compartmental models of sexual HIV transmission to simulate ART prevention impacts in Sub-Saharan Africa. We summarized data on model structure/assumptions (factors) related to risk and intervention heterogeneity, and explored multivariate ecological associations of ART prevention impacts with modelled factors.

RESULTS

Of 1384 search hits, 94 studies were included. 64 studies considered sexual activity stratification and 39 modelled at least one key population. 21 studies modelled faster/slower ART cascade transitions (HIV diagnosis, ART initiation, or cessation) by risk group, including 8 with faster and 4 with slower cascade transitions among key populations versus the wider population. In ecological analysis of 125 scenarios from 40 studies (subset without combination intervention), scenarios with risk heterogeneity that included turnover of higher risk groups were associated with smaller ART prevention benefits. Modelled differences in ART cascade across risk groups also influenced the projected ART benefits, including: ART prioritized to key populations was associated with larger ART prevention benefits. Of note, zero of these 125 scenarios considered lower ART coverage among key populations.

CONCLUSION

Among compartmental transmission models applied to project ART prevention impacts in Sub-Saharan Africa, representations of risk heterogeneity and projected impacts varied considerably. Inclusion/exclusion of risk heterogeneity with turnover, and intervention heterogeneity across risk groups could influence the projected impacts of ART scale-up. These findings highlight a need to capture risk heterogeneity with turnover and cascade heterogeneity when projecting ART prevention impacts.

Cost-effectiveness of easy-access, risk-informed oral pre-exposure prophylaxis in HIV epidemics in sub-Saharan Africa: a modelling study

BACKGROUND

Approaches that allow easy access to pre-exposure prophylaxis (PrEP), such as over-the-counter provision at pharmacies, could facilitate risk-informed PrEP use and lead to lower HIV incidence, but their cost-effectiveness is unknown. We aimed to evaluate conditions under which risk-informed PrEP use is cost-effective.

METHODS

We applied a mathematical model of HIV transmission to simulate 3000 setting-scenarios reflecting a range of epidemiological characteristics of communities in sub-Saharan Africa. The prevalence of HIV viral load greater than 1000 copies per mL among all adults (HIV positive and negative) varied from 1·1% to 7·4% (90% range). We hypothesised that if PrEP was made easily available without restriction and with education regarding its use, women and men would use PrEP, with sufficient daily adherence, during so-called seasons of risk (ie, periods in which individuals are at risk of acquiring infection). We refer to this as risk-informed PrEP. For each setting-scenario, we considered the situation in mid-2021 and performed a pairwise comparison of the outcomes of two policies: immediate PrEP scale-up and then continuation for 50 years, and no PrEP. We estimated the relationship between epidemic and programme characteristics and cost-effectiveness of PrEP availability to all during seasons of risk. For our base-case analysis, we assumed a 3-monthly PrEP cost of US$29 (drug $11, HIV test $4, and $14 for additional costs necessary to facilitate education and access), a cost-effectiveness threshold of $500 per disability-adjusted life-year (DALY) averted, an annual discount rate of 3%, and a time horizon of 50 years. In sensitivity analyses, we considered a cost-effectiveness threshold of $100 per DALY averted, a discount rate of 7% per annum, the use of PrEP outside of seasons of risk, and reduced uptake of risk-informed PrEP.

FINDINGS

In the context of PrEP scale-up such that 66% (90% range across setting-scenarios 46-81) of HIV-negative people with at least one non-primary condomless sex partner take PrEP in any given period, resulting in 2·6% (0·9-6·0) of all HIV negative adults taking PrEP at any given time, risk-informed PrEP was predicted to reduce HIV incidence by 49% (23-78) over 50 years compared with no PrEP. PrEP was cost-effective in 71% of all setting-scenarios, and cost-effective in 76% of setting-scenarios with prevalence of HIV viral load greater than 1000 copies per mL among all adults higher than 2%. In sensitivity analyses with a $100 per DALY averted cost-effectiveness threshold, a 7% per year discount rate, or with PrEP use that was less well risk-informed than in our base case, PrEP was less likely to be cost-effective, but generally remained cost-effective if the prevalence of HIV viral load greater than 1000 copies per mL among all adults was higher than 3%. In sensitivity analyses based on additional setting-scenarios in which risk-informed PrEP was less extensively used, the HIV incidence reduction was smaller, but the cost-effectiveness of risk-informed PrEP was undiminished.

INTERPRETATION

Under the assumption that making PrEP easily accessible for all adults in sub-Saharan Africa in the context of community education leads to risk-informed use, PrEP is likely to be cost-effective in settings with prevalence of HIV viral load greater than 1000 copies per mL among all adults higher than 2%, suggesting the need for implementation of such approaches, with ongoing evaluation.

FUNDING

US Agency for International Development, US President's Emergency Plan for AIDS Relief, and Bill & Melinda Gates Foundation.

The Costs of Creatinine Testing in the Context of a HIV Pre-Exposure Prophylaxis Demonstration Project in Eswatini

HIV treatment and prevention as well as other chronic disease care can require regular kidney function assessment based on a creatinine test. To assess the costs of creatinine testing in a public health care system, we conducted activity-based costing during a HIV pre-exposure prophylaxis (PrEP) demonstration project in the Hhohho region of Eswatini. Resource use was assessed by a laboratory technician and valued with government procurement prices, public sector salaries, and own cost estimates. Obtaining a blood sample in a clinic and performing a creatinine test in a high-throughput referral laboratory (> 660,000 blood tests, including > 120,000 creatinine tests, in 2018) were estimated to have cost, on average, $1.98 in 2018. Per test, $1.95 were variable costs ($1.38 personnel, ¢39 consumables, and ¢18 other costs) and ¢2.6 were allocated semi-fixed costs (¢1.1 laboratory equipment, ¢0.85 other, ¢0.45 consumables, and ¢1.3 personnel costs). Simulating different utilization of the laboratory indicated that semi-fixed costs of the laboratory (e.g., equipment purchase or daily calibration of the chemistry analyzer) contributed less than variable costs (e.g., per-test personnel time and test reagents) to the average creatinine test cost when certain minimum test numbers can be maintained. Our findings suggest, first, lower creatinine testing costs than previously used in cost and cost-effectiveness analyses of HIV services and, second, that investment in laboratory equipment imposed a relatively small additional cost on each performed test in the high-throughput referral laboratory.

PrEP for key populations: results from the first PrEP demonstration project in the Democratic Republic of the Congo

Oral pre-exposure prophylaxis (PrEP) is recommended for persons at substantial risk for HIV, including female sex workers (FSW), men who have sex with men (MSM), people who inject drugs (PWID), and transgender women (TGW). We report on a PrEP demonstration project at seven clinics in the Democratic Republic of the Congo. Routinely collected data were abstracted to assess PrEP uptake, scheduled visit attendance, and self-reported adherence. Between February and May 2018, 469 eligible clients were offered daily oral PrEP; 75.1% accepted: 78.7% FSW, 20.5% MSM, and 0.9% TGW. Two percent also identified as PWID. Attendance was 64.5% at one-month visits; 82.1% at three-month visits; and among 47.7% of clients who initiated PrEP at least six months before data abstraction, 85.8% at six-month visits. Among 66.3% of clients with at least one adherence assessment, 39% self-reported low adherence. Results demonstrate the acceptability of PrEP delivered in healthcare settings serving FSW, MSM, PWID, and TGW.

Risk scores for predicting HIV incidence among adult heterosexual populations in sub-Saharan Africa: a systematic review and meta-analysis

Introduction

Several HIV risk scores have been developed to identify individuals for prioritized HIV prevention in sub‐Saharan Africa. We systematically reviewed HIV risk scores to: (1) identify factors that consistently predicted incident HIV infection, (2) review inclusion of community‐level HIV risk in predictive models and (3) examine predictive performance.

Methods

We searched nine databases from inception until 15 February 2021 for studies developing and/or validating HIV risk scores among the heterosexual adult population in sub‐Saharan Africa. Studies not prospectively observing seroconversion or recruiting only key populations were excluded. Record screening, data extraction and critical appraisal were conducted in duplicate. We used random‐effects meta‐analysis to summarize hazard ratios and the area under the receiver‐operating characteristic curve (AUC‐ROC).

Results

From 1563 initial search records, we identified 14 risk scores in 13 studies. Seven studies were among sexually active women using contraceptives enrolled in randomized‐controlled trials, three among adolescent girls and young women (AGYW) and three among cohorts enrolling both men and women. Consistently identified HIV prognostic factors among women were younger age (pooled adjusted hazard ratio: 1.62 [95% confidence interval: 1.17, 2.23], compared to above 25), single/not cohabiting with primary partners (2.33 [1.73, 3.13]) and having sexually transmitted infections (STIs) at baseline (HSV‐2: 1.67 [1.34, 2.09]; curable STIs: 1.45 [1.17; 1.79]). Among AGYW, only STIs were consistently associated with higher incidence, but studies were limited (n = 3). Community‐level HIV prevalence or unsuppressed viral load strongly predicted incidence but was only considered in 3 of 11 multi‐site studies. The AUC‐ROC ranged from 0.56 to 0.79 on the model development sets. Only the VOICE score was externally validated by multiple studies, with pooled AUC‐ROC 0.626 [0.588, 0.663] (I²: 64.02%).

Conclusions

Younger age, non‐cohabiting and recent STIs were consistently identified as predicting future HIV infection. Both community HIV burden and individual factors should be considered to quantify HIV risk. However, HIV risk scores had only low‐to‐moderate discriminatory ability and uncertain generalizability, limiting their programmatic utility. Further evidence on the relative value of specific risk factors, studies populations not restricted to “at‐risk” individuals and data outside South Africa will improve the evidence base for risk differentiation in HIV prevention programmes.

PROSPERO Number

CRD42021236367

HIV PrEP is more than ART-lite: Longitudinal study of real-world PrEP services data identifies missing measures meaningful to HIV prevention programming

INTRODUCTION

Evidence indicates HIV oral pre-exposure prophylaxis (PrEP) is highly efficacious and effective. Substantial early discontinuation rates are reported by many programs, which may be misconstrued as program failure. However, PrEP use may be non-continuous and still effective, since HIV risk fluctuates. Real-world PrEP use phenomena, like restarting and cyclical use, and the temporal characteristics of these use patterns are not well described. The objective of our study was to characterize and identify predictors of use patterns observed in large PrEP scale-up programs in Africa.

METHODS

We analysed demographic and clinical data routinely collected during client visits between 2017 and 2019 in three Jhpiego-supported programs in Kenya, Lesotho and Tanzania. We characterized duration on/off PrEP and, using ordinal regression, modelled the likelihood of spending additional time off and identified factors associated with increasing cycle number. The Andersen-Gill model was used to identify predictors of time to PrEP discontinuation. To analyse factors associated with a client's first return following initiation, we used a two-step Heckman probit.

RESULTS

Among 47,532 clients initiating PrEP, approximately half returned for follow-up. With each increase in cycle number, time off PrEP between use cycles decreased. The Heckman first-step model showed an increased probability of returning versus not by older age groups and among key and vulnerable population groups versus the general population; in the second-step model older age groups and key and vulnerable populations were less likely in Kenya, but more likely in Lesotho, to return on-time (refill) versus delayed (restarting).

CONCLUSIONS

PrEP users frequently cycle on and off PrEP. Early discontinuation and delays in obtaining additional prescriptions were common, with broad predictive variability noted. Time off PrEP decreased with cycle number in all countries, suggesting normalization of use with experience. More nuanced measures of use are needed than exist for HIV treatment if effective use of PrEP is to be meaningfully measured. Providers should be equipped with measures and counselling messages that recognize non-continuous and cyclical use patterns so that clients are supported to align fluctuating risk and use, and can readily restart PrEP after stopping, in effect empowering them further to make their own prevention choices.

HIV supply chains in low- and middle-income countries: overview and research opportunities

Purpose

Despite HIV being reported as one of the major global health issues, availability and accessibility of HIV services and supplies remain limited, especially in low- and middle-income countries. The effective and efficient operation of HIV supply chains is critical to tackle this problem. The purpose of this paper is to give an introduction to HIV supply chains in low- and middle-income countries and identify research opportunities for the operations research/operations management (OR/OM) community.

Design/methodology/approach

First, the authors review a combination of the scientific and grey literature, including both qualitative and quantitative papers, to give an overview of HIV supply chain operations in low- and middle-income countries and the challenges that are faced by organizing such supply chains. The authors then classify and discuss the relevant OR/OM literature based on seven classification criteria: decision level, methodology, type of HIV service modeled, challenges, performance measures, real-life applicability and countries covered. Because research on HIV supply chains in low- and middle-income countries is limited in the OR/OM field, this part also includes papers focusing on HIV supply chain modeling in high-income countries.

Findings

The authors conclude this study by identifying several tendencies and gaps and by proposing future research directions for OR/OM research.

Originality/value

To the best of the authors’ knowledge, this paper is the first literature review addressing this specific topic from an OR/OM perspective.

Mathematical Model Impact Analysis of a Real-Life Pre-exposure Prophylaxis and Treatment-As-Prevention Study Among Female Sex Workers in Cotonou, Benin

BACKGROUND

Daily pre-exposure prophylaxis (PrEP) and treatment-as-prevention (TasP) reduce HIV acquisition and transmission risk, respectively. A demonstration study (2015-2017) assessed TasP and PrEP feasibility among female sex workers (FSW) in Cotonou, Benin.

SETTING

Cotonou, Benin.

METHODS

We developed a compartmental HIV transmission model featuring PrEP and antiretroviral therapy (ART) among the high-risk (FSW and clients) and low-risk populations, calibrated to historical epidemiological and demonstration study data, reflecting observed lower PrEP uptake, adherence and retention compared with TasP. We estimated the population-level impact of the 2-year study and several 20-year intervention scenarios, varying coverage and adherence independently and together. We report the percentage [median, 2.5th-97.5th percentile uncertainty interval (95% UI)] of HIV infections prevented comparing the intervention and counterfactual (2017 coverages: 0% PrEP and 49% ART) scenarios.

RESULTS

The 2-year study (2017 coverages: 9% PrEP and 83% ART) prevented an estimated 8% (95% UI 6-12) and 6% (3-10) infections among FSW over 2 and 20 years, respectively, compared with 7% (3-11) and 5% (2-9) overall. The PrEP and TasP arms prevented 0.4% (0.2-0.8) and 4.6% (2.2-8.7) infections overall over 20 years, respectively. Twenty-year PrEP and TasP scale-ups (2035 coverages: 47% PrEP and 88% ART) prevented 21% (17-26) and 17% (10-27) infections among FSW, respectively, and 5% (3-10) and 17% (10-27) overall. Compared with TasP scale-up alone, PrEP and TasP combined scale-up prevented 1.9× and 1.2× more infections among FSW and overall, respectively.

CONCLUSIONS

The demonstration study impact was modest, and mostly from TasP. Increasing PrEP adherence and coverage improves impact substantially among FSW, but little overall. We recommend TasP in prevention packages.

The impact of self-selection based on HIV risk on the cost-effectiveness of preexposure prophylaxis in South Africa

OBJECTIVES

We explored the impact and cost-effectiveness of preexposure prophylaxis (PrEP) provision to different populations in South Africa, with and without effective self-selection by individuals at highest risk of contracting HIV (through concurrent partnerships and/or commercial sex).

DESIGN AND METHODS

We used a previously developed HIV transmission model to analyse the epidemiological impact of PrEP provision to adolescents, young adults, pregnant women, female sex workers (FSWs) and (MSM), and data from South African PrEP programmes to estimate the cost and cost-effectiveness of PrEP (cost in 2019 USD per HIV infection averted over 20 years, 2019, 38). PrEP uptake followed data from early implementation sites, scaled-up linearly over 3 years, with target coverage set to 18% for adolescents, young adults and pregnant women, 30% for FSW and 54% for MSM.

RESULTS

The annual cost of PrEP provision ranges between $75 and $134 per person. PrEP provision adolescents and young adults, regardless of risk behaviour, will each avert 3.2--4.8% of HIV infections over 20 years; provision to high-risk individuals only has similar impact at lower total cost. The incremental cost per HIV infection averted is lower in high-risk vs. all-risk sub-populations within female adolescents ($507 vs. $4537), male adolescents ($2108 vs. $5637), young women ($1592 vs. $10 323) and young men ($2605 vs. $7715), becoming cost saving within 20 years for high-risk adolescents, young women, MSM and FSWs.

CONCLUSION

PrEP is an expensive prevention intervention but uptake by those at the highest risk of HIV infection will make it more cost-effective, and cost-saving after 14-18 years.