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

Using queueing models as a decision support tool in allocating point-of-care HIV viral load testing machines in Kisumu County, Kenya

Point-of-care (POC) technologies-including HIV viral load (VL) monitoring-are expanding globally, including in resource-limited settings. Modelling could allow decision-makers to consider the optimal strategy(ies) to maximize coverage and access, minimize turnaround time (TAT) and minimize cost with limited machines. Informed by formative qualitative focus group discussions with stakeholders focused on model inputs, outputs and format, we created an optimization model incorporating queueing theory and solved it using integer programming methods to reflect HIV VL monitoring in Kisumu County, Kenya. We modelled three scenarios for sample processing: (1) centralized laboratories only, (2) centralized labs with 7 existing POC 'hub' facilities and (3) centralized labs with 7 existing and 1-7 new 'hub' facilities. We calculated total TAT using the existing referral network for scenario 1 and solved for the optimal referral network by minimizing TAT for scenarios 2 and 3. We conducted one-way sensitivity analyses, including distributional fairness in each sub-county. Through two focus groups, stakeholders endorsed the provisionally selected model inputs, outputs and format with modifications incorporated during model-building. In all three scenarios, the largest component of TAT was time spent at a facility awaiting sample batching and transport (scenarios 1-3: 78.7%, 89.9%, 91.8%) and waiting time at the testing site (18.7%, 8.7%, 7.5%); transportation time contributed minimally to overall time (2.6%, 1.3%, 0.7%). In scenario 1, the average TAT was 39.8 h (SD: 2.9), with 1077 h that samples spent cumulatively in the VL processing system. In scenario 2, the average TAT decreased to 33.8 h (SD: 4.8), totalling 430 h. In scenario 3, the average TAT decreased nearly monotonically with each new machine to 31.1 h (SD: 8.4) and 346 total hours. Frequency of sample batching and processing rate most impacted TAT, and inclusion of distributional fairness minimally impacted TAT. In conclusion, a stakeholder-informed resource allocation model identified optimal POC VL hub allocations and referral networks. Using existing-and adding new-POC machines could markedly decrease TAT, as could operational changes.

Challenges and Pragmatic Solutions for Assessing the Reliability of HIV-1 Viral Load Monitoring in Resource-Constrained Settings

INTRODUCTION

HIV-1 RNA detection is the most reliable method for monitoring treatment response among people living with HIV. Effective quality control measures that include internal quality control (IQC) are challenging in resource-constrained settings.

METHODS

We ascertained the utility of the kit low positive control (LPC) as an effective IQC to monitor the reliability of the HIV-1 viral load assay. Variations in LPC values were measured for 390 different runs over 10 years (2011-2021) and compared to in-house IQC data using Levey-Jennings control chart.

RESULTS

Overall, the Levey-Jennings analysis showed minimal variation (±0.5 log) for both the LPC and IQC data. The mean LPC value for first 20 runs (20 days) was 2.91. The mean LPC value for the 390 runs comprising 35 different lots was 3.01 ± 0.1 log.

CONCLUSION

Our decadal data reveal that Abbott RealTime HIV-1 assay (Abbott Molecular Inc., IL, USA) LPC exhibited no significant biological variation over 390 runs distributed over 10 years. Hence, assay LPC can supplant the IQC for monitoring assay trends as a stable and commutable material in resource-constrained settings.

Low Hepatitis C Virus Prevalence among Men Who Have Sex with Men Attending Public Health Services in The Netherlands

The hepatitis C virus (HCV) prevalence is high among men who have sex with men (MSM) with HIV in the Netherlands. Large reductions in HCV incidence among MSM with HIV, however, have occurred since treatment with direct-acting antivirals. Over the years, a broader understanding of the HCV epidemic has shown that HCV infections are not solely restricted to MSM with HIV, but they also occur among HIV-negative MSM. Currently, HCV testing among HIV-negative MSM is only provided for PrEP users and is not part of routine sexually transmitted infection (STI) screening among HIV-negative MSM who are not using PrEP. In this study, we screened 1885 HIV-negative MSM who did not participate in a PrEP program, with over 1966 STI screening visits at four different public health clinic sites. Among the 1885 MSM, only one person had a new HCV infection, resulting in a 0.05% (95% confidence interval 0.0-0.3) incidence. Based on our findings, we can conclude that systematic HCV testing at STI clinics may not yield significant benefits for this particular population.

Verification of dried blood spot as a sample type for HIV viral load and early infant diagnosis on Hologic Panther in Zambia

OBJECTIVE

Zambia has embarked on improving the diagnostic capacity by setting up high throughput and accurate machines in the testing process and introduction of dried blood spot (DBS) as a sample type. This was a cross sectional study to verify dried blood spot as a sample type for HIV viral load and early infant diagnosis (EID) on Hologic Panther platform and Evaluate the analytical performance (precision, linearity and measurement of uncertainty) of the Hologic Panther.

RESULTS

The specificity and sensitivity of EID performance of Aptima Quant Dx assay on Hologic panther machine against the gold standard machine COBAS Taqman (CAP/CTM) was 100% with an overall agreement of 100%. The quantitative HIV Viral Load (VL) accuracy had a positive correlation of (0.96) obtained against the gold standard (plasma samples) run on COBAS4800 platform. Analytical performance of the Hologic panther machine was evaluated; Precision low positive repeatability 3.50154 and within lab 2.268915 at mean 2.88 concentration and precision high positive repeatability 1.116955 and within lab 2.010677 at mean 5.09 concentration were obtained confirming manufacturers claims. Uncertainty of measurement for this study was found to be ± 71 copies/ml. Linearity studies were determined and all points were within acceptable limits. We therefore recommend DBS as a sample type alternative to plasma for the estimation of HIV-1 viral load and EID diagnosis on the Hologic panther machine.

Review of antiretroviral therapy coverage in 10 highest burden HIV countries in Africa: 2015-2020

Africa is responsible for two-thirds of the global total of new HIV infections. South Africa, Nigeria, Mozambique, Uganda, Tanzania, Zambia, Zimbabwe, Kenya, Malawi, and Ethiopia were responsible for 80% of HIV cases in Africa in 2014 according to the Joint United Nations Programme on HIV/AIDS (UNAIDS). This study assesses antiretroviral coverage strategies implemented by these countries after the initiation of the "Fast-Track strategy to end the AIDS epidemic by 2030." Data reported in this review were obtained from different e-bibliographic including PubMed, Google Scholar, and Research Gate. Key terms were "Antiretroviral therapy," "Antiretroviral treatment," "HIV treatment," "HIV medication," "HIV/AIDS therapy," "HIV/AIDS treatment" + each of the countries listed earlier. We also extracted data on antiretroviral therapy (ART) coverage from the UNAIDS database. About 50 papers published from 2015 to 2021 met the inclusion criteria. All 10 countries have experienced an increase in ART coverage from 2015 to 2020 with an average of 47.6% increment. Nigeria recorded the highest increase in the rate of ART coverage (72% increase) while Ethiopia had the least (30%). New strategies adopted to increase ART coverage and retention in most countries were community-based models and the use of mobile health technology rather than clinic-based. These strategies focus on promoting task shifting, door-to-door access to HIV services, and a long-term supply of antiretroviral medications. Most of these strategies are still in the piloting stage. However, some new strategies and frameworks have been adopted nationwide in countries like Mozambique, Tanzania, Zambia, Zimbabwe, Kenya, and Malawi. Identified challenges include lack of funding, inadequate testing and surveillance services, poor digital penetration, and cultural/religious beliefs. The adoption of community-based and digital health strategies could have contributed to increased ART coverage and retention. African countries should facilitate nationwide scaling of ART coverage strategies to attain the 95-95-95 goal by 2030.

SARS-CoV-2 diagnostic testing rates determine the sensitivity of genomic surveillance programs

The first step in SARS-CoV-2 genomic surveillance is testing to identify people who are infected. However, global testing rates are falling as we emerge from the acute health emergency and remain low in many low- and middle-income countries (mean = 27 tests per 100,000 people per day). We simulated COVID-19 epidemics in a prototypical low- and middle-income country to investigate how testing rates, sampling strategies and sequencing proportions jointly impact surveillance outcomes, and showed that low testing rates and spatiotemporal biases delay time to detection of new variants by weeks to months and can lead to unreliable estimates of variant prevalence, even when the proportion of samples sequenced is increased. Accordingly, investments in wider access to diagnostics to support testing rates of approximately 100 tests per 100,000 people per day could enable more timely detection of new variants and reliable estimates of variant prevalence. The performance of global SARS-CoV-2 genomic surveillance programs is fundamentally limited by access to diagnostic testing.

Facility-based HIV self-testing strategies may substantially and cost-effectively increase the number of men and youth tested for HIV in Malawi: results from an individual-based mathematical model

INTRODUCTION

Malawi is rapidly closing the gap in achieving the UNAIDS 95-95-95 targets, with 90% of people living with HIV in Malawi aware of their status. As we approach epidemic control, interventions to improve coverage will become more costly. There is, therefore, an urgent need to identify innovative and low-cost strategies to maintain and increase testing coverage without diverting resources from other HIV services. The objective of this study is to model different combinations of facility-based HIV testing modalities and determine the most cost-effective strategy to increase the proportion of men and youth testing for HIV.

METHODS

A data-driven individual-based model was parameterized with data from a community-representative survey (socio-demographic, health service utilization and HIV testing history) of men and youth in Malawi (data collected August 2019). In total, 79 different strategies for the implementation of HIV self-testing (HIVST) and provider-initiated-testing-and-counselling at the outpatient department (OPD) were evaluated. Outcomes included percent of men/youth tested for HIV in a 12-month period, cost-effectiveness and human resource requirements. The testing yield was assumed to be constant across the scenarios.

RESULTS

Facility-based HIVST offered year-round resulted in the greatest increase in the proportion of men and youth tested in the OPD (from 45% to 72%-83%), was considered cost-saving for HIVST kit priced at $1.00, and generally reduced required personnel as compared to the status quo. At higher HIVST kit prices, and more relaxed eligibility criteria, all scenarios that considered year-round HIVST in the OPD remained on the cost-effectiveness frontier.

CONCLUSIONS

Facility-based HIVST is a cost-effective strategy to increase the proportion of men/youth tested for HIV in Malawi and decreases the human resource requirements for HIV testing in the OPD-providing additional healthcare worker time for other priority healthcare activities.

SARS-CoV-2 diagnostic testing rates determine the sensitivity of genomic surveillance programs

The first step in SARS-CoV-2 genomic surveillance is testing to identify infected people. However, global testing rates are falling as we emerge from the acute health emergency and remain low in many low- and middle-income countries (LMICs) (mean = 27 tests/100,000 people/day). We simulated COVID-19 epidemics in a prototypical LMIC to investigate how testing rates, sampling strategies, and sequencing proportions jointly impact surveillance outcomes and showed that low testing rates and spatiotemporal biases delay time-to-detection of new variants by weeks-to-months and can lead to unreliable estimates of variant prevalence even when the proportion of samples sequenced is increased. Accordingly, investments in wider access to diagnostics to support testing rates of ~100 tests/100,000 people/day could enable more timely detection of new variants and reliable estimates of variant prevalence. The performance of global SARS-CoV-2 genomic surveillance programs is fundamentally limited by access to diagnostic testing.

Use of Physical Accessibility Modelling in Diagnostic Network Optimization: A Review

Diagnostic networks are complex systems that include both laboratory-tested and community-based diagnostics, as well as a specimen referral system that links health tiers. Since diagnostics are the first step before accessing appropriate care, diagnostic network optimization (DNO) is crucial to improving the overall healthcare system. The aim of our review was to understand whether the field of DNO, and especially route optimization, has benefited from the recent advances in geospatial modeling, and notably physical accessibility modeling, that have been used in numerous health systems assessment and strengthening studies. All publications published in English between the journal’s inception and 12 August 2021 that dealt with DNO, geographical accessibility and optimization, were systematically searched for in Web of Science and PubMed, this search was complemented by a snowball search. Studies from any country were considered. Seven relevant publications were selected and charted, with a variety of geospatial approaches used for optimization. This paucity of publications calls for exploring the linkage of DNO procedures with realistic accessibility modeling framework. The potential benefits could be notably better-informed travel times of either the specimens or population, better estimates of the demand for diagnostics through realistic population catchments, and innovative ways of considering disease epidemiology to inform DNO.

The early-stage comprehensive costs of routine PrEP implementation and scale-up in Zambia

Pre-exposure prophylaxis (PrEP) is an effective HIV prevention option, but cost-effectiveness is sensitive to implementation and program costs. Studies indicate that, in addition to direct delivery cost, PrEP provision requires substantial demand creation and client support to encourage PrEP initiation and persistence. We estimated the cost of providing PrEP in Zambia through different PrEP delivery models. Taking a guidelines-based approach for visits, labs and drugs, we estimated the annual cost of providing PrEP per client for five delivery models: one focused on key populations (men-who-have-sex-with-men (MSM) and female sex workers (FSW), one on adolescent girls and young women (AGYW), and three integrated programs (operated within HIV counselling and testing services at primary healthcare centres). Program start-up and support costs were based on program expenditure data and number of PrEP sites and clients in 2018. PrEP clinic visit costs were based on micro-costing at two PrEP delivery sites (2018 USD). Costs are presented in 2018 prices and inflated to 2021 prices. The annual cost/PrEP client varied by service delivery model, from $394 (AGYW) to $655 (integrated model). Cost differences were driven largely by client volume, which impacted the relative costs of program support and technical assistance assigned to each PrEP client. Direct service delivery costs ranged narrowly from $205-212/PrEP-client and were a key component in the cost of PrEP, representing 35-65% of total costs. The results show that, even when integrated into full service delivery models, accessing vulnerable, marginalised populations at substantial risk of HIV infection is likely to cost more than previously estimated due to the programmatic costs involved in community sensitization and client support. Improved data on individual client resource usage and outcomes is required to get a better understanding of the true resource utilization, expected outcomes and annual costs of different PrEP service delivery programs in Zambia.

Evaluating Point-of-Care Nucleic Acid Tests in Adult Human Immunodeficiency Virus Diagnostic Strategies: A Côte d'Ivoire Modeling Analysis

BACKGROUND

The World Health Organization (WHO) human immunodeficiency virus (HIV) diagnostic strategy requires 6 rapid diagnostic tests (RDTs). Point-of-care nucleic acid tests (POC NATs) are costlier, less sensitive, but more specific than RDTs.

METHODS

We simulated a 1-time screening process in Côte d'Ivoire (CI; undiagnosed prevalence: 1.8%), comparing WHO- and CI-recommended RDT-based strategies (RDT-WHO, RDT-CI) and an alternative: POC NAT to resolve RDT discordancy (NAT-Resolve). Costs included assays (RDT: $1.47; POC NAT: $27.92), antiretroviral therapy ($6-$22/month), and HIV care ($27-$38/month). We modeled 2 sensitivity/specificity scenarios: high-performing (RDT: 99.9%/99.1%; POC NAT: 95.0%/100.0%) and low-performing (RDT: 91.1%/82.9%; POC NAT: 93.3%/99.5%). Outcomes included true-positive (TP), false-positive (FP), true-negative (TN), or false-negative (FN) results; life expectancy; costs; and incremental cost-effectiveness ratios (ICERs: $/year of life saved [YLS]; threshold ≤$1720/YLS [per-capita gross domestic product]).

RESULTS

Model-projected impacts of misdiagnoses were 4.4 years lost (FN vs TP; range, 3.0-13.0 years) and a $5800 lifetime cost increase (FP vs TN; range, $590-$14 680). In the high-performing scenario, misdiagnoses/10 000 000 tested were lowest for NAT-Resolve vs RDT-based strategies (FN: 409 vs 413-429; FP: 14 vs 21-28). Strategies had similar life expectancy (228 months) and lifetime costs ($220/person) among all tested; ICERs were $3450/YLS (RDT-CI vs RDT-WHO) and $120 910/YLS (NAT-Resolve vs RDT-CI). In the low-performing scenario, misdiagnoses were higher (FN: 22 845-30 357; FP: 83 724-112 702) and NAT-Resolve was cost-saving.

CONCLUSIONS

We projected substantial clinical and economic impacts of misdiagnoses. Using POC NAT to resolve RDT discordancy generated the fewest misdiagnoses and was not cost-effective in high-performing scenarios, but may be an important adjunct to existing RDT-based strategies in low-performing scenarios.

Strengthening Existing Laboratory-Based Systems vs. Investing in Point-of-Care Assays for Early Infant Diagnosis of HIV: A Model-Based Cost-Effectiveness Analysis

Supplemental Digital Content is Available in the Text.

Background:

To improve early infant HIV diagnosis (EID) programs, options include replacing laboratory-based tests with point-of-care (POC) assays or investing in strengthened systems for sample transport and result return.

Setting:

We used the CEPAC-Pediatric model to examine clinical benefits and costs of 3 EID strategies in Zimbabwe for infants 6 weeks of age.

Methods:

We examined (1) laboratory-based EID (LAB), (2) strengthened laboratory-based EID (S-LAB), and (3) POC EID (POC). LAB/S-LAB and POC assays differed in sensitivity (LAB/S-LAB 100%, POC 96.9%) and specificity (LAB/S-LAB 99.6%, POC 99.9%). LAB/S-LAB/POC algorithms also differed in: probability of result return (79%/91%/98%), time until result return (61/53/1 days), probability of initiating antiretroviral therapy (ART) after positive result (52%/71%/86%), and total cost/test ($18.10/$30.47/$30.71). We projected life expectancy (LE) and average lifetime per-person cost for all HIV-exposed infants. We calculated incremental cost-effectiveness ratios (ICERs) from discounted (3%/year) LE and costs in $/year-of-life saved (YLS), defining cost effective as an ICER <$580/YLS (reflecting programs providing 2 vs. 1 ART regimens). In sensitivity analyses, we varied differences between S-LAB and POC in result return probability, result return time, ART initiation probability, and cost.

Results:

For infants who acquired HIV, LAB/S-LAB/POC led to projected one-year survival of 67.3%/69.9%/75.6% and undiscounted LE of 21.74/22.71/24.49 years. For all HIV-exposed infants, undiscounted LE was 63.35/63.38/63.43 years, at discounted lifetime costs of $200/220/240 per infant. In cost-effectiveness analysis, S-LAB was an inefficient use of resources; the ICER of POC vs. LAB was $830/YLS.

Conclusions:

Current EID programs will attain greater benefit from investing in POC EID rather than strengthening laboratory-based systems.

Participants on Dolutegravir Resuppress Human Immunodeficiency Virus RNA After Virologic Failure: Updated Data from the ADVANCE Trial

Following evidence of HIV RNA re-suppression on DTG-based regimens, we assess the re-suppressive capacity of ADVANCE participants on TAF/FTC+DTG, TDF/FTC+DTG, and TDF/FTC/EFV. Viraemic participants were able to re-suppress within 3 follow-up visits of protocol-defined virological failure (PDVF) in 77/121 (64%), 85/126 (67%), and 44/138 (32%) cases respectively (DTG regimens vs. TDF/FTC/EFV; P < 0.001).

The Development of a Standardized Quality Assessment Material to Support Xpert® HIV-1 Viral Load Testing for ART Monitoring in South Africa

The tiered laboratory framework for human immunodeficiency virus (HIV) viral load monitoring accommodates a range of HIV viral load testing platforms, with quality assessment critical to ensure quality patient testing. HIV plasma viral load testing is challenged by the instability of viral RNA. An approach using an RNA stabilizing buffer is described for the Xpert^® HIV-1 Viral Load (Cepheid) assay and was tested in remote laboratories in South Africa. Plasma panels with known HIV viral titres were prepared in PrimeStore molecular transport medium for per-module verification and per-instrument external quality assessment. The panels were transported at ambient temperatures to 13 testing laboratories during 2017 and 2018, tested according to standard procedures and uploaded to a web portal for analysis. A total of 275 quality assessment specimens (57 verification panels and two EQA cycles) were tested. All participating laboratories met study verification criteria (n = 171 specimens) with an overall concordance correlation coefficient (ρ_c) of 0.997 (95% confidence interval (CI): 0.996 to 0.998) and a mean bias of −0.019 log copies per milliliter (cp/mL) (95% CI: −0.044 to 0.063). The overall EQA ρ_c (n = 104 specimens) was 0.999 (95% CI: 0.998 to 0.999), with a mean bias of 0.03 log cp/mL (95% CI: 0.02 to 0.05). These panels are suitable for use in quality monitoring of Xpert^® HIV-1 VL and are applicable to laboratories in remote settings.

Costs of Point-of-Care Viral Load Testing for Adults and Children Living with HIV in Kenya

BACKGROUND

The number of people living with HIV (PLHIV) in need of treatment monitoring in low-and-middle-income countries is rapidly expanding, straining existing laboratory capacity. Point-of-care viral load (POC VL) testing can alleviate the burden on centralized laboratories and enable faster delivery of results, improving clinical outcomes. However, implementation costs are uncertain and will depend on clinic testing volume. We sought to estimate the costs of decentralized POC VL testing compared to centralized laboratory testing for adults and children receiving HIV care in Kenya.

METHODS

We conducted microcosting to estimate the per-patient costs of POC VL testing compared to known costs of centralized laboratory testing. We completed time-and-motion observations and stakeholder interviews to assess personnel structures, staff time, equipment costs, and laboratory processes associated with POC VL administration. Capital costs were estimated using a 5 year lifespan and a 3% annual discount rate.

RESULTS

We estimated that POC VL testing cost USD $24.25 per test, assuming a clinic is conducting 100 VL tests per month. Test cartridge and laboratory equipment costs accounted for most of the cost (62% and 28%, respectively). Costs varied by number of VL tests conducted at the clinic, ranging from $54.93 to $18.12 per test assuming 20 to 500 VL tests per month, respectively. A VL test processed at a centralized laboratory was estimated to cost USD $25.65.

CONCLUSION

POC VL testing for HIV treatment monitoring can be feasibly implemented in clinics within Kenya and costs declined with higher testing volumes. Our cost estimates are useful to policymakers in planning resource allocation and can inform cost-effectiveness analyses evaluating POC VL testing.

Bringing Data Analytics to the Design of Optimized Diagnostic Networks in Low- and Middle-Income Countries: Process, Terms and Definitions

Diagnostics services are an essential component of healthcare systems, advancing universal health coverage and ensuring global health security, but are often unavailable or under-resourced in low- and middle-income (LMIC) countries. Typically, diagnostics are delivered at various tiers of the laboratory network based on population needs, and resource and infrastructure constraints. A diagnostic network additionally incorporates screening and includes point-of-care testing that may occur outside of a laboratory in the community and clinic settings; it also emphasizes the importance of supportive network elements, including specimen referral systems, as being critical for the functioning of the diagnostic network. To date, design and planning of diagnostic networks in LMICs has largely been driven by infectious diseases such as TB and HIV, relying on manual methods and expert consensus, with a limited application of data analytics. Recently, there have been efforts to improve diagnostic network planning, including diagnostic network optimization (DNO). The DNO process involves the collection, mapping, and spatial analysis of baseline data; selection and development of scenarios to model and optimize; and lastly, implementing changes and measuring impact. This review outlines the goals of DNO and steps in the process, and provides clarity on commonly used terms.

Cost-effectiveness of point-of-care testing with task-shifting for HIV care in South Africa: a modelling study

BACKGROUND

The number of people on antiretroviral therapy (ART) requiring treatment monitoring in low-resource settings is rapidly increasing. Point-of-care (POC) testing for ART monitoring might alleviate burden on centralised laboratories and improve clinical outcomes, but its cost-effectiveness is unknown.

METHODS

We used cost and effectiveness data from the STREAM trial in South Africa (February, 2017-October, 2018), which evaluated POC testing for viral load, CD4 count, and creatinine, with task shifting from professional to lower-cadre registered nurses compared with laboratory-based testing without task shifting (standard of care). We parameterised an agent-based network model, EMOD-HIV, to project the impact of implementing this intervention in South Africa over 20 years, simulating approximately 175 000 individuals per run. We assumed POC monitoring increased viral suppression by 9 percentage points, enrolment into community-based ART delivery by 25 percentage points, and switching to second-line ART by 1 percentage point compared with standard of care, as reported in the STREAM trial. We evaluated POC implementation in varying clinic sizes (10-50 patient initiating ART per month). We calculated incremental cost-effectiveness ratios (ICERs) and report the mean and 90% model variability of 250 runs, using a cost-effectiveness threshold of US$500 per disability-adjusted life-year (DALY) averted for our main analysis.

FINDINGS

POC testing at 70% coverage of patients on ART was projected to reduce HIV infections by 4·5% (90% model variability 1·6 to 7·6) and HIV-related deaths by 3·9% (2·0 to 6·0). In clinics with 30 ART initiations per month, the intervention had an ICER of $197 (90% model variability -27 to 863) per DALY averted; results remained cost-effective when varying background viral suppression, ART dropout, intervention effectiveness, and reduction in HIV transmissibility. At higher clinic volumes (≥40 ART initiations per month), POC testing was cost-saving and at lower clinic volumes (20 ART initiations per month) the ICER was $734 (93 to 2569). A scenario that assumed POC testing did not increase enrolment into community ART delivery produced ICERs that exceeded the cost-effectiveness threshold for all clinic volumes.

INTERPRETATION

POC testing is a promising strategy to cost-effectively improve patient outcomes in moderately sized clinics in South Africa. Results are most sensitive to changes in intervention impact on enrolment into community-based ART delivery.

FUNDING

National Institutes of Health.

Point of Care Diagnostics in Resource-Limited Settings: A Review of the Present and Future of PoC in Its Most Needed Environment

Point of care (PoC) diagnostics are at the focus of government initiatives, NGOs and fundamental research alike. In high-income countries, the hope is to streamline the diagnostic procedure, minimize costs and make healthcare processes more efficient and faster, which, in some cases, can be more a matter of convenience than necessity. However, in resource-limited settings such as low-income countries, PoC-diagnostics might be the only viable route, when the next laboratory is hours away. Therefore, it is especially important to focus research into novel diagnostics for these countries in order to alleviate suffering due to infectious disease. In this review, the current research describing the use of PoC diagnostics in resource-limited settings and the potential bottlenecks along the value chain that prevent their widespread application is summarized. To this end, we will look at literature that investigates different parts of the value chain, such as fundamental research and market economics, as well as actual use at healthcare providers. We aim to create an integrated picture of potential PoC barriers, from the first start of research at universities to patient treatment in the field. Results from the literature will be discussed with the aim to bring all important steps and aspects together in order to illustrate how effectively PoC is being used in low-income countries. In addition, we discuss what is needed to improve the situation further, in order to use this technology to its fullest advantage and avoid “leaks in the pipeline”, when a promising device fails to take the next step of the valorization pathway and is abandoned.

Accelerating progress towards the elimination of mother-to-child transmission of HIV: a narrative review

INTRODUCTION

Findings from biomedical, behavioural and implementation studies provide a rich foundation to guide programmatic efforts for the prevention of mother-to-child HIV transmission (PMTCT).

METHODS

We summarized the current evidence base to support policy makers, programme managers, funding agencies and other stakeholders in designing and optimizing PMTCT programmes. We searched the scientific literature for PMTCT interventions in the era of universal antiretroviral therapy for pregnant and breastfeeding women (i.e. 2013 onward). Where evidence was sparse, relevant studies from the general HIV treatment literature or from prior eras of PMTCT programme implementation were also considered. Studies were organized into six categories: HIV prevention services for women, timely access to HIV testing, timely access to ART, programme retention and adherence support, timely engagement in antenatal care and services for infants at highest risk of HIV acquisition. These were mapped to specific missed opportunities identified by the UNAIDS Spectrum model and embedded in UNICEF operational guidance to optimize PMTCT services.

RESULTS AND DISCUSSION

From May to November 2019, we identified numerous promising, evidence-based strategies that, properly tailored and adopted, could contribute to population reductions in vertical HIV transmission. These spanned the HIV and maternal and child health literature, emphasizing the importance of continued alignment and integration of services. We observed overlap between several intervention domains, suggesting potential for synergies and increased downstream impact. Common themes included integration of facility-based healthcare; decentralization of health services from facilities to communities; and engagement of partners, peers and lay workers for social support. Approaches to ensure early HIV diagnosis and treatment prior to pregnancy would strengthen care across the maternal lifespan and should be promoted in the context of PMTCT.

CONCLUSIONS

A wide range of effective strategies exist to improve PMTCT access, uptake and retention. Programmes should carefully consider, prioritize and plan those that are most appropriate for the local setting and best address existing gaps in PMTCT health services.

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.