Field evaluation of near point of care Cepheid GeneXpert HIV-1 Qual for early infant diagnosis

A qualitative systematic review of barriers and facilitators to the implementation of community-based molecular diagnostics for infectious diseases

BACKGROUND

Community-based molecular diagnostic testing for infectious diseases can bring equitable healthcare to resource-limited settings without hospital-based laboratories. Low-complexity molecular testing devices allow for unprecedented sensitivity and specificity for infectious disease diagnostics outside of a dedicated laboratory, which may facilitate timely initiation of therapeutics and other public health interventions in rural, remote and/or marginalized communities.

OBJECTIVE

To identify barriers and facilitators to the implementation of community-based molecular testing.

METHODS

A systematic search was conducted on MEDLINE Ovid, EMBASE, Web of Science, Cumulative Index to Nursing and Allied Health, Google Scholar, and reference lists. Original research that includes implementation of molecular testing systems at the community-level or at rural/remote health facilities with frontline healthcare workers and reports barriers and facilitators to implementation were included. Studies were assessed by the Critical Appraisal Skills Programme Qualitative Checklist and underwent inductive thematic analysis. The review protocol was registered to Prospero prior to conducting the review (CRD42023397800).

RESULTS

A total of 6 studies were included in the review. We found three main themes present across all six included studies: infrastructure, usability, and staffing considerations. Infrastructure emerged as a critical determinant, with challenges ranging from physical space constraints to issues with reliable electricity and internet connectivity. The usability of testing devices, encompassing factors like ease of use and testing quality, also played a pivotal role. Staffing considerations, including workload, training, and attitudes, significantly influenced implementation outcomes.

CONCLUSION

Our review highlights the importance of addressing infrastructural challenges, ensuring usability of testing devices, and adequately supporting staff through training and workload management to realize the full potential of this new opportunity. Future implementation should consider these factors to successfully integrate molecular diagnostics into community-level healthcare delivery, particularly in rural and remote areas.

Public health implications of diagnosing and treating acute HIV

PURPOSE OF REVIEW

The earliest months of HIV infection are characterized by high viral loads and elevated transmissibility, particularly during the acute (preseroconversion) phase. Transmission prevention during early HIV requires diagnostic tools that narrow the window between viral acquisition and reactive test, followed by rapid linkage to effective antiretroviral therapy (ART). Here, we review recent advances related to diagnosing and treating persons during early HIV, with a particular focus on acute HIV infection (AHI).

RECENT FINDINGS

Point-of-care (POC) fourth-generation antigen/antibody tests have mixed performance, often dependent on the pretest probability of early infection within the screened population. Risk score algorithms demonstrate the potential for prioritizing resource-intensive tests, such as POC HIV RNA, to those most likely to have AHI, but their predictive performance varies across populations, complicating implementation. Emerging and re-emerging infections, including SARS-CoV-2 and mpox, present opportunities for and challenges to symptom-driven AHI screening. Daily oral ART with standard first-line regimens quickly suppresses viremia during AHI, but long-acting injectable drugs are yet to be explored for this indication.

SUMMARY

Few practice-changing results related to diagnosing or treating persons with early HIV have been released in the last 18 months. Accurate POC HIV RNA tests could leapfrog fourth-generation POC assays, but they remain unavailable for routine use. Implementation science approaches are needed to guide use of evidence-based strategies for early HIV screening, and additional research on same-day ART linkage, including injectable ART, could produce dramatic impacts on forward transmission during this period.

Nucleic acid amplification testing using dried blood spots to confirm the diagnosis of HIV-1 in adults

BACKGROUND

The WHO HIV testing algorithm for high prevalence populations recommends the use of three different serologic assays, though this approach may lead to diagnostic misclassification. The study objective was to compare dried blood spot (DBS)-based HIV-1 nucleic acid detection methods to determine their suitability to confirm the diagnosis of HIV-1 in adults generally with suppressed or low-level plasma HIV-1 RNA.

METHODS

Four methods were evaluated: Cepheid Xpert HIV-1 Qual Assay (Xpert), Hologic Aptima HIV-1 Quant Dx assay (Aptima), Roche Cobas Ampliprep/Cobas TaqMan HIV-1 test, v.2.0 (CAP/CTM) with guanidinium-based sample pre-extraction buffer (SPEX), or CAP/CTM with phosphate-buffered saline (PBS). Testing was performed on 163 DBS samples collected from participants with HIV-1 in the AIDS Clinical Trial Group (ACTG) A5230 study (73 samples) and the Peninsula AIDS Research Cohort (PARC) study (90 samples).

RESULTS

Xpert and SPEX CAP/CTM [96.9 % (158/163):95.7 % (156/163); P = 0.75) showed similar sensitivity. However, PBS CAP/CTM and Aptima demonstrated significantly lower sensitivity, 68.2 % (107/157) and 69.2 % (99/143), respectively, compared to Xpert and SPEX CAP/CTM (P < 0.0001 for all comparisons). Overall agreement between Xpert and SPEX CAP/CTM was 93.9 % (153/163), including 152 DBS samples in which both methods detected HIV-1 nucleic acids.

CONCLUSIONS

Xpert and SPEX CAP/CTM provide sensitive performance for the detection of HIV-1 nucleic acids using DBS collected from adults living with HIV-1, including those with suppressed virus loads. Given the cost and side-effects associated with inappropriate life-long antiretroviral therapy, these assays may play a role in diagnosing HIV-1 infection in individuals with suspected false-positive serologic testing.

The challenges of Chile to achieve control the HIV/AIDS pandemic the year 2030: A review

Chile is contending with the highest rates of new human immunodeficiency virus (HIV) cases in both Latin America and globally, despite substantial ongoing investments in treatment. This comprehensive study, derived from PUBMED and Google searches, ANID data, and various organizational reports, highlights key areas for improvement. Over the past decade, Chile's annual infection rate has risen, signaling an urgent need for detailed analysis and effective solutions. The study includes 44 references, comprising 32 scientific articles and 12 reports from entities like the WHO and the Pan American Health Organization. Data was meticulously collected through diverse means, such as scientific congresses, meetings with authorities, and direct data requests. Fourteen critical points are identified for addressing the HIV epidemic in Chile, spanning from legislative reforms to enhanced prevention campaigns. Key recommendations include universal diagnosis, decentralized healthcare, the availability of self-tests, and a focus on mental health and the impact of migration. Despite Chile's strong economic indicators, factors such as inadequate sexual education, outdated legislation, and centralized diagnostic processes contribute to the persistent increase in new cases. The study underscores the pressing need for enhanced investment in prevention policies. Chile faces significant challenges in meeting the 90/90/90 targets, yet there is optimism in aiming for the 95/95/95 strategy by 2030. Achieving success requires a global commitment, an emphasis on prevention, and collaborative efforts among authorities, healthcare providers, and patients. Overcoming these identified barriers is essential for Chile to reach its ambitious goal and ultimately end the HIV epidemic.

Process Evaluation of Services for HIV-Infected Post-Partum Women and HIV-Exposed Infants in Primary Health Care Blantyre Malawi

HIV testing among HIV-exposed infants (HEI) in Malawi is below global targets and, affected by low utilisation of health services after birth. We conducted a mixed methods evaluation of the implementation of services for early infant diagnosis (EID) of HIV against national guidelines in Blantyre, Malawi, to inform the development of strategies to improve EID services uptake. We estimated coverage of HEI enrolment in HIV care and HIV testing at 6 weeks through a retrospective data review. We qualitatively explored implementation gaps in EID services through process mapping of 8 mother-infant pairs (MIP); and investigated healthcare workers' (HCW) perspectives on the implementation gaps through group interviews with 16 HCWs. We analysed the quantitative data descriptively and conducted a thematic content analysis of qualitative data. Of 163 HEIs born at the study sites, 39 (24%) were enrolled in an HIV care clinic before post-natal discharge, and 85 (52%) received HIV testing by 6 weeks. The median time for MIP to receive EID services was 4 (1-8) hours. The implementation gaps observed during process mapping included: failure to identify and enrol HEI in HIV care clinic; lack of immunisation, counselling for HEI testing, HIV testing, drug refilling, and family planning; and different appointment dates for mother and infant. HCWs reported delays and gaps influencing optimal service provision including: lack of screening to identify MIP, limited supervision for student HCWs when providing services, inadequate capacity of point of care machines, challenges with integrating services, and role confusion. Use of unique identifiers for MIP and establishing a booking system to schedule appointments to suit point of care machine capacity were primary service improvement recommendations. This study identified suboptimal EID services in Malawi due to process, capacity, and system factors. Context-appropriate interventions accommodating systems thinking are needed to enhance service provision.

Evaluating the impact of point-of-care HIV viral load assessment on linkage to care in Baltimore, MD: a randomized controlled trial

BACKGROUND

Integration of a sensitive point-of-care (POC) HIV viral load (VL) test into screening algorithms may help detect acute HIV infection earlier, identify people with HIV (PWH) who are not virally suppressed, and facilitate earlier referral to antiretroviral therapy (ART), or evaluation for pre-exposure prophylaxis (PrEP). This report describes a randomized clinical trial sponsored by the Centers for Disease Control and Prevention (CDC): "Ending the HIV Epidemic Through Point-of-Care Technologies" (EHPOC). The study's primary aim is to evaluate the use of a POC HIV VL test as part of a testing approach and assess the impact on time to linkage to ART or PrEP. The study will recruit people in Baltimore, Maryland, including patients attending a hospital emergency department, patients attending an infectious disease clinic, and people recruited via community outreach. The secondary aim is to evaluate the performance characteristics of two rapid HIV antibody tests approved by the United States Food and Drug Administration (FDA).

METHODS

The study will recruit people 18 years or older who have risk factors for HIV acquisition and are not on PrEP, or PWH who are not taking ART. Participants will be randomly assigned to either the control arm or the intervention arm. Participants randomized to the control arm will only receive the standard-of-care (SOC) HIV screening tests. Intervention arm participants will receive a POC HIV VL test in addition to the SOC HIV diagnostic screening tests. Follow up will consist of an interim phone survey conducted at week-4 and an in-person week-12 visit. Demographic and behavioral information, and oral fluid and blood specimens will be collected at enrollment and at week-12. Survey data will be captured in a Research Electronic Data Capture (REDCap) database. Participants in both arms will be referred for either ART or PrEP based on their HIV test results.

DISCUSSION

The EHPOC trial will explore a novel HIV diagnostic technology that can be performed at the POC and provide viral assessment. The study may help inform HIV testing algorithms and contribute to the evidence to support same day ART and PrEP recommendations.

TRIAL REGISTRATION

NIH ClinicalTrials.gov NCT04793750. Date: 11 March 2021.

'If I am on ART, my new-born baby should be put on treatment immediately': Exploring the acceptability, and appropriateness of Cepheid Xpert HIV-1 Qual assay for early infant diagnosis of HIV in Malawi

Early infant diagnosis of HIV (EID-HIV) is key to reducing paediatric HIV mortality. Traditional approaches for diagnosing HIV in exposed infants are usually unable to optimally contribute to EID. Point-of-care testing such as Cepheid Xpert HIV-1 Qual assay-1 (XPertHIV) are available and could improve EID-HIV in resource constrained and high HIV burden contexts. We investigated the acceptability and perceived appropriateness of XpertHIV for EID-HIV in Mulanje Hospital, Malawi. Qualitative cross-sectional study using semi-structured interviews (SSI) among caregivers and health care workers at Mulanje District Hospital. The qualitative study was nested within a larger diagnostic study that evaluated the performance of XpertHIV using whole-blood-sample in a resource limited and high burden setting. A total of 65 SSIs were conducted among caregivers (n = 60) and health care providers (n = 5). Data were coded using deductive and inductive approaches while thematic approach was used to analyse data. Point-of-care XPertHIV was perceived to be acceptable among caregivers and health care providers. Caregivers' motivations for accepting XPertHIV HIV-testing for their infants included perceived risk of HIV emanating from child's exposure and validation of caregiver's own HIV sero-status. Although concerns about pain of testing and blood sample volumes taken from an infant remained amplified, overall, both caregivers and health care providers felt XpertHIV was appropriate because of its quick result turn-around-time which decreased anxiety and stress, the prospect of early treatment initiation and reduction in hospital visits and related costs. Implementation of XpertHIV has a great potential to improve EID-HIV in Malawi because of its quick turn-around-time and associated benefits including overcoming access-related barriers. Scaled implementation of this diagnostic technology require a robust community engagement strategy for managing caregivers and community myths and misconceptions towards the amount of blood sample collected from infants.

The effect of the Xpert HIV-1 Qual test on early infant diagnosis of HIV in Myanmar and Papua New Guinea: a pragmatic, cluster-randomised, stepped-wedge, open-label trial

BACKGROUND

Despite proven benefits for child health, coverage of early infant diagnosis of HIV remains suboptimal in many settings. We aimed to assess the effect of a point-of-care early infant diagnosis test on time-to-results communication for infants vertically exposed to HIV.

METHODS

This pragmatic, cluster-randomised, stepped-wedge, open-label trial assessed the effect of the Xpert HIV-1 Qual early infant diagnosis test (Cepheid) on time-to-results communication, compared with standard care laboratory-based testing of dried blood spots using PCR. Hospitals were the unit of randomisation for one-way crossover from control to intervention phase. Each site had between 1 month and 10 months of control phase before transitioning to the intervention, with a total of 33 hospital-months in the control phase and 45 hospital-months in the intervention phase. We enrolled infants vertically exposed to HIV at six public hospitals: four in Myanmar and two in Papua New Guinea. Infants had to have mothers with confirmed HIV infection, be younger than 28 days, and required HIV testing to be eligible for enrolment. Health-care facilities providing prevention of vertical transmission services were eligible for participation. The primary outcome was communication of early infant diagnosis results to the infant's caregiver by 3 months of age, assessed by intention to treat. This completed trial was registered with the Australian and New Zealand Clinical Trials Registry, 12616000734460.

FINDINGS

In Myanmar, recruitment took place between Oct 1, 2016, and June 30, 2018; in Papua New Guinea, recruitment was between Dec 1, 2016, and Aug 31, 2018. A total of 393 caregiver-infant pairs were enrolled in the study across both countries. Independent of study time, the Xpert test reduced time to early infant diagnosis results communication by 60%, compared with the standard of care (adjusted time ratio 0·40, 95% CI 0·29-0·53, p<0·0001). In the control phase, two (2%) of 102 study participants received an early infant diagnosis test result by 3 months of age compared with 214 (74%) of 291 in the intervention phase. No safety and adverse events were reported related to the diagnostic testing intervention.

INTERPRETATION

This study reinforces the importance of scaling up point-of-care early infant diagnosis testing in resource-constrained and low HIV-prevalence settings, typical of the UNICEF East Asia and Pacific region.

FUNDING

National Health and Medical Research Council of Australia.

Evaluation of Simplified HCV Diagnostics in HIV/HCV Co-Infected Patients in Myanmar

To evaluate a decentralised testing model and simplified treatment protocol of hepatitis C virus (HCV) infection to facilitate treatment scale-up in Myanmar, this prospective, observational study recruited HIV-HCV co-infected outpatients receiving sofosbuvir/daclatasvir in Yangon, Myanmar. The study examined the outcomes and factors associated with a sustained virological response (SVR). A decentralised "hub-and-spoke" testing model was evaluated where fingerstick capillary specimens were transported by taxi and processed centrally. The performance of the Xpert HCV VL Fingerstick Assay in detecting HCV RNA was compared to the local standard of care ( plasma HCV RNA collected by venepuncture). Between January 2019 and February 2020, 162 HCV RNA-positive individuals were identified; 154/162 (95%) initiated treatment, and 128/154 (84%) returned for their SVR12 visit. A SVR was achieved in 119/154 (77%) participants in the intent-to-treat population and 119/128 (93%) participants in the modified-intent-to-treat population. Individuals receiving an antiretroviral therapy were more likely to achieve a SVR (with an odds ratio (OR) of 7.16, 95% CI 1.03-49.50), while those with cirrhosis were less likely (OR: 0.26, 95% CI 0.07-0.88). The sensitivity of the Xpert HCV VL Fingerstick Assay was 99.4% (95% CI 96.7-100.0), and the specificity was 99.2% (95% CI 95.9-99.9). A simplified treatment protocol using a hub-and-spoke testing model of fingerstick capillary specimens can achieve an SVR rate in LMIC comparable to well-resourced high-income settings.

Sensitive and Quantitative Point-of-Care HIV Viral Load Quantification from Blood Using a Power-Free Plasma Separation and Portable Magnetofluidic Polymerase Chain Reaction Instrument

Point-of-care (POC) HIV viral load (VL) tests are needed to enhance access to HIV VL testing in low- and middle-income countries (LMICs) and to enable HIV VL self-testing at home, which in turn have the potential to enhance the global management of the disease. While methods based on real-time reverse transcription-polymerase chain reaction (RT-PCR) are highly sensitive and quantitatively accurate, they often require bulky and expensive instruments, making applications at the POC challenging. On the other hand, although methods based on isothermal amplification techniques could be performed using low-cost instruments, they have shown limited quantitative accuracies, i.e., being only semiquantitative. Herein, we present a sensitive and quantitative POC HIV VL quantification method from blood that can be performed using a small power-free three-dimensional-printed plasma separation device and a portable, low-cost magnetofluidic real-time RT-PCR instrument. The plasma separation device, which is composed of a plasma separation membrane and an absorbent material, demonstrated 96% plasma separation efficiency per 100 μL of whole blood. The plasma solution was then processed in a magnetofluidic cartridge for automated HIV RNA extraction and quantification using the portable instrument, which completed 50 cycles of PCR in 15 min. Using the method, we achieved a limit of detection of 500 HIV RNA copies/mL, which is below the World Health Organization's virological failure threshold, and a good quantitative accuracy. The method has the potential for sensitive and quantitative HIV VL testing at the POC and at home self-testing.

A Randomized Trial of Point-of-Care Early Infant Human Immunodeficiency Virus (HIV) Diagnosis in Zambia

BACKGROUND

Point-of-care (POC) early infant diagnosis (EID) provides same-day results and the potential for immediate initiation of antiretroviral therapy (ART).

METHODS

We conducted a pragmatic trial at 6 public clinics in Zambia. HIV-exposed infants were individually randomized to either (1) POC EID (onsite testing with the Alere q HIV-1/2 Detect) or (2) enhanced standard of care (SOC) EID (off-site testing at a public laboratory). Infants with HIV were referred for ART and followed for 12 months. Our primary outcome was defined as alive, in care, and virally suppressed at 12 months.

RESULTS

Between March 2016 and November 2018, we randomized 4000 HIV-exposed infants to POC (n=1989) or SOC (n=2011). All but 2 infants in the POC group received same-day results, while the median time to result in the SOC group was 27 (interquartile range: 22-30) days. Eighty-one (2%; 95% confidence interval [CI]: 1.6-2.5%) infants were diagnosed with HIV. Although ART initiation was high, there were 15 (19%) deaths, 15 (19%) follow-up losses, and 31 (38%) virologic failures. By 12 months, only 20 of 81 (25%; 95% CI: 15-34%) infants with HIV were alive, in care, and virally suppressed: 13 (30%; 16-43%) infants in the POC group vs 7 (19%; 6-32%) in the SOC group (RR: 1.56; .7-3.50).

CONCLUSIONS

POC EID eliminated diagnostic delays and accelerated ART initiation but did not translate into definitive improvement in 12-month outcomes. In settings where centralized EID is well functioning, POC EID is unlikely to improve pediatric HIV outcomes.

CLINICAL TRIALS REGISTRATION

This trial is registered at https://clinicaltrials.gov (NCT02682810).

Evaluation of SAMBA II: A Qualitative and Semiquantitative HIV Point-of-Care Nucleic Acid Test

BACKGROUND

Point-of-care (POC) nucleic acid tests (NATs) have potential to diagnose acute HIV infection and monitor persons taking pre-exposure prophylaxis or antiretroviral therapy (ART). POC NATs have not yet been evaluated in the US.

METHODS

From June 2018-March 2019, we conducted a cross-sectional evaluation of the Simple Amplification-Based Assay version II (SAMBA II) POC NAT. People with HIV (PWH) and persons testing for HIV were tested with the SAMBA II qualitative (Qual) whole blood (WB) test. From April-September 2019, the Qual test was used on persons who were ART-naive, and SAMBA II Semi-quantitative (Semi-Q) WB was used with ART-experienced PWH. Both were performed on unprocessed venipuncture (VP) and, when indicated by protocol, fingerstick (FS) WB and plasma. SAMBA results were compared with Abbott RealTime HIV-1 polymerase chain reaction results on plasma. We calculated sensitivity, specificity, and concordance between tests.

RESULTS

SAMBA was used in 330 visits among 280 participants: 202 (61.2%) visits from PWH, and 128 (38.8%) from HIV-negative persons. Qual test sensitivity with ART-naive participants was 91.4% [32/35, 95% confidence interval (CI): 77.6% to 97.0%] using VP WB and 100% (27/27, 95% CI: 87.5% to 100%) using FS WB. Specificity was 100% using both specimen types. Concordance between the gold standard and Semi-Q at 1000 copies/mL among PWH on ART was 97.7% (86/88, 95% CI: 92.1% to 99.4%) and 100% (30/30, 95% CI: 88.7% to 100%) using VP and FS WB, respectively.

CONCLUSIONS

The SAMBA II POC NATs showed high sensitivity, specificity, and concordance with the gold standard assay, indicating its potential use in diagnostics and monitoring. Future work will evaluate POC NAT implementation in the US.

Operational experiences associated with the implementation of near point-of-care early infant diagnosis of HIV in Myanmar: a qualitative study

Background

Timely diagnosis and early initiation of life-saving antiretroviral therapy are critical factors in preventing mortality among HIV-infected infants. However, resource-limited settings experience numerous challenges associated with centralised laboratory-based testing, including low rates of testing, complex sample referral pathways and unacceptably long turnaround times for results. Point-of-care (POC) HIV testing for HIV-exposed infants can enable same-day communication of results and early treatment initiation for HIV-infected infants. However, complex operational issues and service integration can limit utility and must be well understood prior to implementation.

We explored and documented the challenges and enabling factors in implementing the POC Xpert® HIV-1 Qual test (Cepheid, Sunnyvale, CA, USA) for early infant diagnosis (EID) as part of routine services in four public hospitals in Myanmar.

Methods

This sub-study was part of a randomised controlled stepped-wedge trial (Australian and New Zealand Clinical Trials Registry, number 12616000734460) designed to investigate the impact of POC testing for EID in Myanmar and Papua New Guinea. Infants recruited during the intervention phase underwent POC testing at the participating hospitals as part of routine care. Semi-structured interviews with 23 caregivers, 12 healthcare providers and 10 key informants were used to explore experiences of POC-EID testing. The research team and hospital staff documented and discussed implementation challenges throughout the study.

Results

Overall, caregivers and healthcare workers were satisfied with the short turnaround time of the POC test. Occasional delays in POC testing were mostly attributable to late receipt of samples by laboratory technicians and communication constraints among healthcare staff. Hospital staff valued technical assistance from the research group and the National Health Laboratory. Despite staff shortages and infrastructure challenges such as unreliable electricity supply and cramped space, healthcare workers and caregivers found the implementation of the POC test to be feasible at pilot sites.

Conclusions

As plans for national scale-up evolve, there needs to be a continual focus on staff training, communication pathways and infrastructure. Other models of care, such as allowing non-laboratory-trained personnel to perform POC testing, and cost effectiveness should also be evaluated.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-021-06797-3.

Point-of-care tests detecting HIV nucleic acids for diagnosis of HIV-1 or HIV-2 infection in infants and children aged 18 months or less

BACKGROUND

The standard method of diagnosing HIV in infants and children less than 18 months is with a nucleic acid amplification test reverse transcriptase polymerase chain reaction test (NAT RT-PCR) detecting viral ribonucleic acid (RNA). Laboratory testing using the RT-PCR platform for HIV infection is limited by poor access, logistical support, and delays in relaying test results and initiating therapy in low-resource settings. The use of rapid diagnostic tests at or near the point-of-care (POC) can increase access to early diagnosis of HIV infection in infants and children less than 18 months of age and timely initiation of antiretroviral therapy (ART).

OBJECTIVES

To summarize the diagnostic accuracy of point-of-care nucleic acid-based testing (POC NAT) to detect HIV-1/HIV-2 infection in infants and children aged 18 months or less exposed to HIV infection.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (until 2 February 2021), MEDLINE and Embase (until 1 February 2021), and LILACS and Web of Science (until 2 February 2021) with no language or publication status restriction. We also searched conference websites and clinical trial registries, tracked reference lists of included studies and relevant systematic reviews, and consulted experts for potentially eligible studies.

SELECTION CRITERIA

We defined POC tests as rapid diagnostic tests conducted at or near the patient site. We included any primary study that compared the results of a POC NAT to a reference standard of laboratory NAT RT-PCR or total nucleic acid testing to detect the presence or absence of HIV infection denoted by HIV viral nucleic acids in infants and children aged 18 months or less who were exposed to HIV-1/HIV-2 infection. We included cross-sectional, prospective, and retrospective study designs and those that provided sufficient data to create the 2 × 2 table to calculate sensitivity and specificity. We excluded diagnostic case control studies with healthy controls.

DATA COLLECTION AND ANALYSIS

We extracted information on study characteristics using a pretested standardized data extraction form. We used the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies) tool to assess the risk of bias and applicability concerns of the included studies. Two review authors independently selected and assessed the included studies, resolving any disagreements by consensus. The unit of analysis was the participant. We first conducted preliminary exploratory analyses by plotting estimates of sensitivity and specificity from each study on forest plots and in receiver operating characteristic (ROC) space. For the overall meta-analyses, we pooled estimates of sensitivity and specificity using the bivariate meta-analysis model at a common threshold (presence or absence of infection).

MAIN RESULTS

We identified a total of 12 studies (15 evaluations, 15,120 participants). All studies were conducted in sub-Saharan Africa. The ages of included infants and children in the evaluations were as follows: at birth (n = 6), ≤ 12 months (n = 3), ≤ 18 months (n = 5), and ≤ 24 months (n = 1). Ten evaluations were field evaluations of the POC NAT test at the point of care, and five were laboratory evaluations of the POC NAT tests.The POC NAT tests evaluated included Alere q HIV-1/2 Detect qualitative test (recently renamed m-PIMA q HIV-1/2 Detect qualitative test) (n = 6), Xpert HIV-1 qualitative test (n = 6), and SAMBA HIV-1 qualitative test (n = 3). POC NAT pooled sensitivity and specificity (95% confidence interval (CI)) against laboratory reference standard tests were 98.6% (96.1 to 99.5) (15 evaluations, 1728 participants) and 99.9% (99.7 to 99.9) (15 evaluations, 13,392 participants) in infants and children ≤ 18 months. Risk of bias in the included studies was mostly low or unclear due to poor reporting. Five evaluations had some concerns for applicability for the index test, as they were POC tests evaluated in a laboratory setting, but there was no difference detected between settings in sensitivity (-1.3% (95% CI -4.1 to 1.5)); and specificity results were similar.

AUTHORS' CONCLUSIONS

For the diagnosis of HIV-1/HIV-2 infection, we found the sensitivity and specificity of POC NAT tests to be high in infants and children aged 18 months or less who were exposed to HIV infection.

Successful Use of Near Point-of-Care Early Infant Diagnosis in NAMPHIA to Improve Turnaround Times in a National Household Survey

BACKGROUND

In the population-based HIV impact assessment surveys, early infant diagnosis (EID) was provided to infants <18 months without a prior diagnosis. For the Namibia population-based HIV impact assessment (NAMPHIA), the GeneXpert platform was assessed for the feasibility of near POC EID testing compared with the standard Roche COBAS AmpliPrep/COBAS TaqMan (CAP/CTM) platform. Quality assurance measures and turnaround time were compared to improve EID results reporting.

METHODS

NAMPHIA participants were screened for HIV exposure using Determine HIV-1/2 rapid test; samples reactive on Determine received EID testing on the GeneXpert instrument and Xpert HIV-1 Qual assay using whole blood. Results were confirmed at the Namibia Institute of Pathology using dried blood spots on the Roche CAP/CTM platform per national guidelines.

RESULTS

Of the 762 screened infants, 61 (8.0%) were Determine-reactive and considered HIV-exposed. Of the 61 exposed infants, 2 were found to be HIV-infected whereas 59 were negative on both GeneXpert and Roche platforms, achieving 100% concordance. Average turnaround time was 3.4 days for the Xpert HIV-1 Qual assay, and average time from collection to testing was 1.0 days for GeneXpert compared with 10.7 days for Roche. No samples failed using GeneXpert whereas 1 sample failed using Roche and was repeated.

CONCLUSION

Quality POC EID testing is feasible in a national survey through extensive training and external quality assurance measures. The use of decentralized POC EID for national testing would provide rapid diagnosis and improve TATs which may prevent loss to follow-up, ensure linkage to care, and improve clinical outcomes for infants.

Modeling the cost-effectiveness of point-of-care platforms for infant diagnosis of HIV in sub-Saharan African countries

BACKGROUND

Early infant diagnosis of HIV (EID) improves child survival through earlier initiation of antiretroviral therapy (ART). In many settings, ART initiation is hindered by delays in testing performed in centralized labs. Point-of-care (PoC) platforms offer opportunities to improve the timeliness of ART initiation.

METHODS

We used a mathematical model to estimate the costs and performance of on-site PoC testing using three platforms (m-PIMA, GeneXpert IV, and GeneXpert Edge) compared with the standard of care (SoC). Primary outcomes included ART initiation within 60 days of sample collection, HIV-related mortality before ART initiation, and incremental cost-effectiveness ratios (ICERs).

RESULTS

PoC testing significantly increased ART initiation within 60 days (from 19% with SoC to 82-84% with PoC) and decreased HIV-related mortality (from 23% with SoC to 5% with PoC). ART initiation and mortality were similar across PoC platforms. When only used for EID and with high coverage of prevention of mother-to-child transmission (PMTCT) programs, ICERs for PoC testing compared with the SoC ranged from $430 to $1097 per additional infant on ART within 60 days and from $1527 to $3888 per death averted. PoC-based testing was more cost-effective in settings with lower PMTCT coverage, greater delays in the SoC, and when PoC instruments could be integrated with other disease programs.

CONCLUSION

Our findings illustrate that PoC platforms can dramatically improve the timeliness of EID and linkage to HIV care. The cost-effectiveness of PoC platforms depends on the cost of PoC testing, existing access to diagnostic testing, and the ability to integrate PoC testing with non-EID programs.

Microfluidic Point-of-Care Testing: Commercial Landscape and Future Directions

Point-of-care testing (POCT) allows physicians to detect and diagnose diseases at or near the patient site, faster than conventional lab-based testing. The importance of POCT is considerably amplified in the trying times of the COVID-19 pandemic. Numerous point-of-care tests and diagnostic devices are available in the market including, but not limited to, glucose monitoring, pregnancy and infertility testing, infectious disease testing, cholesterol testing and cardiac markers. Integrating microfluidics in POCT allows fluid manipulation and detection in a singular device with minimal sample requirements. This review presents an overview of two technologies - (a.) Lateral Flow Assay (LFA) and (b.) Nucleic Acid Amplification - upon which a large chunk of microfluidic POCT diagnostics is based, some of their applications, and commercially available products. Apart from this, we also delve into other microfluidic-based diagnostics that currently dominate the in-vitro diagnostic (IVD) market, current testing landscape for COVID-19 and prospects of microfluidics in next generation diagnostics.

Programmatic evaluation of feasibility and efficiency of at birth and 6-week, point of care HIV testing in Kenyan infant

Background

Testing infants at birth and with more efficient point of care (POC) HIV diagnostic can streamline EID and expedite infant ART initiation. We evaluated the implementation of at birth and 6-week POC testing to assess the effectiveness and feasibility when implemented by existing hospital staff in Kenya.

Methods

Four government hospitals were randomly assigned to receive a GeneXpert HIV-1 Qual (n = 2) or Alere m-PIMA (n = 2) machine for POC testing. All HIV-exposed infants enrolled were eligible to receive POC testing at birth and 6-weeks of age. The primary outcome was repeat POC testing, defined as testing both at birth and 6-weeks of age. Secondary outcomes included predictors of repeat POC testing, POC efficiency (turnaround times of key services), and operations (failed POC results, missed opportunities).

Results

Of 626 enrolled infants, 309 (49.4%) received repeat POC testing, 115 (18.4%) were lost to follow up after an at-birth test, 120 (19.2%) received POC testing at 6-weeks only, 80 (12.8%) received no POC testing, and 2 (0.3%) received delayed POC testing (>12 weeks of age). Three (0.4%) were identified as HIV-positive. Of the total 853 POC tests run at birth (n = 424) or 6-weeks (n = 429), 806 (94.5%) had a valid result documented and 792 (98.3%) results had documented maternal notification. Mean time from sample collection to notification was 1.08 days, with 751 (94.8%) notifications on the same day as sample collection. Machine error rates at birth and 6-weeks were 8.5% and 2.5%, respectively. A total of 198 infants presented for care (48 at birth; 150 at 6-weeks) without receiving a POC test, representing missed opportunities for testing.

Discussion

At birth POC testing can streamline infant HIV diagnosis, expedite ART initiation and can be implemented by existing hospital staff. However, maternal disengagement and missed opportunities for testing must be addressed to realize the full benefits of at birth POC testing.

Enzyme-Assisted Nucleic Acid Detection for Infectious Disease Diagnostics: Moving toward the Point-of-Care

Driven by complex and interconnected factors, including population growth, climate change, and geopolitics, infectious diseases represent one of the greatest healthcare challenges of the 21st century. Diagnostic technologies are the first line of defense in the fight against infectious disease, providing critical information to inform epidemiological models, track diseases, decide treatment choices, and ultimately prevent epidemics. The diagnosis of infectious disease at the genomic level using nucleic acid disease biomarkers has proven to be the most effective approach to date. Such methods rely heavily on enzymes to specifically amplify or detect nucleic acids in complex samples, and significant effort has been exerted to harness the power of enzymes for in vitro nucleic acid diagnostics. Unfortunately, significant challenges limit the potential of enzyme-assisted nucleic acid diagnostics, particularly when translating diagnostic technologies from the lab toward the point-of-use or point-of-care. Herein, we discuss the current state of the field and highlight cross-disciplinary efforts to solve the challenges associated with the successful deployment of this important class of diagnostics at or near the point-of-care.

Point-of-care HIV maternal viral load and early infant diagnosis testing around time of delivery at tertiary obstetric units in South Africa: a prospective study of coverage, results return and turn-around times

INTRODUCTION

Maternal viral load monitoring (mVL) and early infant diagnosis (EID) are necessary to achieve elimination of mother-to-child transmission of HIV. Point-of-care testing can achieve better outcomes compared to centralized laboratory testing (CLT). We describe the first implementation of point-of-care (POC) mVL and EID testing around delivery at four high volume tertiary obstetric units (TOUs) in Gauteng, South Africa.

METHODS

Prospective study of pregnant women living with HIV (WLHIV) and their infants. During the period 1 June 2018 to 31 March 2019, routine staff collected blood specimens from women and their infants around delivery. Specimen collection occurred throughout the week while dedicated POC operators, conducted testing during working hours on weekdays. Descriptive statistics and multivariable Poisson regression with robust error variance were used to describe outcomes and associated factors. Outcomes determined were (i) coverage of mVL and EID testing defined as a proportion of live births to WLHIV admitted at each facility (ii) results returned prior to discharge (iii) turn-around time (TAT) and iv) performance of POC testing compared to CLT.

RESULTS

In total, 8147 live births to pregnant WLHIV were recorded in the implementation period. Of these, 2912 mVL and 5074 EID specimens were included in the analysis, with 131 (4.5%) mVL and 715 (14.1%) EID specimens having initial invalid/error results. Overall coverage of POC mVL and EID testing was 35.6% (range 20.9% to 60.1%) and 61.9% (range 47.0% to 88.0%) respectively. Proportions of POC tested mothers and infants with results returned prior to discharge were 74.3% (range 39.0% to 95.7%) and 73.0% (range 50.0 to 97.9%). Return of results was independently associated with TOU, after-hours specimen collection, having an initial invalid or error result and period of implementation. Overall TAT for specimens collected from mother-infant pairs where both had POC testing, during weekdays was longer for EID compared to mVL testing (median 3.3 hours vs. 2.9 hours, p-value sign test <0.001). POC results were comparable to those from laboratory testing.

CONCLUSION

Accurate and timely POC mVL and EID testing around delivery was implemented with variable success across TOUs. Further scale up would need to address health system factors at facility level and high analytical error rates.