Performance of HIV-1 DNA or HIV-1 RNA tests for early diagnosis of perinatal HIV-1 infection during anti-retroviral prophylaxis

Point-of-care isothermal nucleic acid amplification tests: progress and bottlenecks for extraction-free sample collection and preparation

INTRODUCTION

Suitable sample collection and preparation methods are essential to enable nucleic acid amplification testing at the point of care (POC). Strategies that allow direct isothermal nucleic acid amplification testing (iNAAT) of crude sample lysate without the need for nucleic acid extraction minimize time to result as well as the need for operator expertise and costly infrastructure.

AREAS COVERED

The authors review research to understand how sample matrix and preparation affect the design and performance of POC iNAATs. They focus on approaches where samples are directly combined with liquid reagents for preparation and amplification via iNAAT strategies. They review factors related to the type and method of sample collection, storage buffers, and lysis strategies. Finally, they discuss RNA targets and relevant regulatory considerations.

EXPERT OPINION

Limitations in sample preparation methods are a significant technical barrier preventing implementation of nucleic acid testing at the POC. The authors propose a framework for co-designing sample preparation and amplification steps for optimal performance with an extraction-free paradigm by considering a sample matrix and lytic strategy prior to an amplification assay and readout. In the next 5 years, the authors anticipate increasing priority on the co-design of sample preparation and iNAATs.

Optimised prevention of postnatal HIV transmission in Zambia and Burkina Faso (PROMISE-EPI): a phase 3, open-label, randomised controlled trial

BACKGROUND

Transmission through breastfeeding accounts for more than half of the unacceptably high number of new paediatric HIV infections worldwide. We hypothesised that, in addition to maternal antiretroviral therapy (ART), extended postnatal prophylaxis with lamivudine, guided by point-of-care assays for maternal viral load, could reduce postnatal transmission.

METHODS

We did a phase 3, open-label, randomised controlled trial at four health-care facilities in Zambia and four health-care facilities in Burkina Faso. Mothers with HIV and their breastfed infants without HIV attending the second visit of the Expanded Programme of Immunisation (EPI-2; infant age 6-8 weeks) were randomly assigned 1:1 to intervention or control groups. In the intervention group, maternal viral load was measured using Xpert HIV viral load assay at EPI-2 and at 6 months, with results provided immediately. Infants whose mothers had a viral load of 1000 copies per mL or higher were started on lamivudine syrup twice per day for 12 months or 1 month after breastfeeding discontinuation. The control group followed national guidelines for prevention of postnatal transmission of HIV. The primary outcome assessed by modified intention to treat was infant HIV infection at age 12 months, with HIV DNA point-of-care testing at 6 months and at 12 months. This trial is registered with ClinicalTrials.gov (NCT03870438).

FINDINGS

Between Dec 12, 2019 and Sept 30, 2021, 34 054 mothers were screened for HIV. Among them, 1506 mothers with HIV and their infants without HIV, including 1342 mother and infant pairs from Zambia and 164 from Burkina Faso, were eligible and randomly assigned 1:1 to the intervention (n=753) or control group (n=753). At baseline, the median age of the mothers was 30·6 years (IQR 26·0-34·7), 1480 (98·4%) of 1504 were receiving ART, and 169 (11·5%) of 1466 had a viral load ≥1000 copies/mL. There was one case of HIV transmission in the intervention group and six in the control group, resulting in a transmission incidence of 0·19 per 100 person-years (95% CI 0·005-1·04) in the intervention group and 1·16 per 100 person-years (0·43-2·53) in the control group, which did not reach statistical significance (p=0·066). HIV-free survival and serious adverse events were similar in both groups.

INTERPRETATION

Our intervention, initiated at EPI-2 and based on extended single-drug postnatal prophylaxis guided by point-of-care maternal viral load could be an important strategy for paediatric HIV elimination.

FUNDING

The EDCTP2 programme with the support of the UK Department of Health & Social Care.

Characterization of HIV-1 Reservoirs in Children and Adolescents: A Systematic Review and Meta-Analysis Toward Pediatric HIV Cure

OBJECTIVE

To conduct a comprehensive, systematic review of the profile of HIV-1 reservoirs in children and adolescents with perinatally acquired HIV infection.

STUDY DESIGN

Randomized and nonrandomized trials, cohort studies, and cross-sectional studies on HIV reservoirs in pediatric populations, published between 2002 and 2022, were included. Archived-drug resistance mutations (ADRMs) and the size of reservoirs were evaluated. Subgroup analyses were performed to characterize further the data, and the meta-analysis was done through random effect models.

RESULTS

Overall, 49 studies from 17 countries worldwide were included, encompassing 2356 perinatally infected participants (48.83% females). There are limited data on the quantitative characterization of viral reservoirs in sub-Saharan Africa, with sensitive methodologies such as droplet digital polymerase chain reaction rarely employed. The overall prevalence of ADRMs was 37.80% (95% CI 13.89-65.17), with 48.79% (95% CI 0-100) in Africa, 42.08% (95% CI 6.68-82.71) in America, 23.88% (95% CI 14.34-34.90) in Asia, and 20.00% (95% CI 10.72-31.17) in Europe, without any difference between infants and adolescents (P = .656). Starting antiretroviral therapy (ART) before 2 months of age limited the levels of HIV-1 DNA (P = .054). Participants with long-suppressed viremia (>5 years) had lower levels of HIV-1 DNA (P = .027). Pre- and post-ART CD4 ≤29% and pre-ART viremia ≥5Log were all found associated with greater levels of HIV-1 DNA (P = .038, P = .047, and P = .041, respectively).

CONCLUSIONS

The pooled prevalence of ADRMs is high in perinatally infected pediatric population, with larger proviral reservoir size driven by delayed ART initiation, a shorter period of viral suppression, and immunovirological failures. Thus, strategies for pediatric HIV functional cure should target children and adolescents with very early ART initiation, immunocompetence, and long-term viral suppression.

Virological safety of the UK blood supply in the era of individual risk assessments and HIV PrEP

A more individualised donor selection policy was implemented in the UK in 2021, which replaced the previous 3-month deferral for men who have sex with men (MSM). Other blood services have a variety of policies in place to ensure the virological safety of blood components, ranging from an indefinite ban on MSM, to a defined period of exclusion, or to an individualised risk assessment that is not based on gender or sexual orientation. Justification of these policies should be based on scientific evidence including assessment of lengths of virological window periods, infectious disease epidemiology within donor populations and donation screening assay sensitivities. Developments in molecular technology and assays which can detect both antibodies and antigens in the very early stages of infection have significantly reduced the risk in most developed countries. However, the increasing usage of pre-exposure prophylaxis (PrEP) to prevent acquisition of HIV infection after possible high-risk sexual contact within the UK blood donor population has been recently noted. It has brought with it new diagnostic challenges within blood screening, notably possible non-detection of HIV RNA and serological markers following PrEP use despite potential infectivity. The use of other testing strategies such as detection of HIV DNA and screening for non-declared PrEP usage should be investigated further.

Assessing the Variability of Cell-Associated HIV DNA Quantification through a Multicenter Collaborative Study

Reliable and accurate quantification of cell-associated HIV DNA (CA HIV DNA) is critical for early infant diagnosis, clinical management of patients under therapy, and to inform new therapeutics efficacy. The present study assessed the variability of CA HIV DNA quantification obtained from various assays and the value of using reference materials to help harmonize the measurements. Using a common set of reagents, our multicenter collaborative study highlights significant variability of CA HIV DNA quantification and lower limit of quantification across assays. The quantification of CA HIV DNA from a panel of infected PBMCs can be harmonized through cross-subtype normalization but assay calibration with the commonly used 8E5 cell line failed to reduce quantification variability between assays, demonstrating the requirement to thoroughly evaluate reference material candidates to help improve the comparability of CA HIV DNA diagnostic assay performance. IMPORTANCE Despite a global effort, HIV remains a major public health burden with an estimated 1.5 million new infections occurring in 2020. HIV DNA is an important viral marker, and its monitoring plays a critical role in the fight against HIV: supporting diagnosis in infants and underpinning clinical management of patients under therapy. Our study demonstrates that HIV DNA measurement of the same samples can vary significantly from one laboratory to another, due to heterogeneity in the assay, protocol, and reagents used. We show that when carefully selected, reference materials can reduce measurement variability and harmonize HIV DNA quantification across laboratories, which will help contribute to improved diagnosis and clinical management of patients living with HIV.

Association of Maternal Viral Load and CD4 Count With Perinatal HIV-1 Transmission Risk During Breastfeeding in the PROMISE Postpartum Component

BACKGROUND

Breastfeeding mothers with HIV infection not qualifying for antiretroviral therapy (ART) based on country-specific guidelines at the time of the Promoting Maternal-Infant Survival Everywhere trial and their uninfected neonates were randomized to maternal ART (mART) or infant nevirapine prophylaxis (iNVP) postpartum. HIV transmission proportions were similar (<1%) in the 2 arms. We assessed whether maternal viral load (MVL) and CD4 cell counts were associated with breastfeeding HIV transmission.

METHODS

MVL was collected at entry (7-14 days postpartum) and at weeks 6, 14, 26, and 50 postpartum. CD4 cell counts were collected at entry and weeks 14, 26, 38, and 50 postpartum. Infant HIV-1 nucleic acid test was performed at weeks 1 and 6, every 4 weeks until week 26, and then every 12 weeks. The associations of baseline and time-varying MVL and CD4 cell counts with transmission risk were assessed using time-to-event analyses by randomized treatment arm.

RESULTS

Two thousand four hundred thirty-one mother-infant pairs were enrolled in the study. Baseline MVL (P = 0.11) and CD4 cell counts (P = 0.51) were not significantly associated with infant HIV-1 infection. Time-varying MVL was significantly associated with infant HIV-1 infection {hazard ratio [95% confidence interval (CI)]: 13.96 (3.12 to 62.45)} in the mART arm but not in the iNVP arm [hazard ratio (95% CI): 1.04 (0.20 to 5.39)]. Time-varying CD4 cell counts were also significantly associated with infant HIV-1 infection [hazard ratio (95% CI): 0.18 (0.03 to 0.93)] in the mART arm but not in the iNVP arm [hazard ratio (95% CI): 0.38 (0.08 to 1.77)].

CONCLUSIONS

In women receiving mART, increased MVL and decreased CD4 cell counts during breastfeeding were associated with increased risk of infant HIV-1 infection.

A new highly sensitive single-tube nested real-time PCR assay: Clinical utility in perinatal HIV-1 diagnosis

Real time PCR is one of the major tools for molecular diagnosis, however not always reaches the required sensitivity, especially in detecting early infectious disease. To overcome this problem, nested PCR is commonly performed, since it is highly sensitive, but it is time-consuming, prone to cross-contamination and difficult to standardize. Therefore, we developed a sensitive and specific single-tube nested real-time PCR (STN-real-time PCR) assay and evaluated its clinical utility on early infant HIV-1 diagnosis (EID). The STN-real-time PCR enables the simultaneous amplification of four HIV-1 specific amplicons by the use of an internal and external pair of primers targeting ltr/gag region, and another one corresponding to human albumin as an internal control. Thermocycling had different annealing temperatures to favor the sequential use of each pair of primers, and included an initial touchdown step to broaden specificity and increase sensitivity. Finally, HIV-1 was detected by melting curve analysis. A total of 234 samples collected retrospectively and prospectively from HIV-1 exposed infants aged <18 months were used to evaluate the performance of the assay and compare it with a routine diagnostic nested-multiplex PCR. The developed assay had a limit of detection of 3 copies of HIV-1 DNA per reaction and had a sensitivity of 31 % more than routine diagnostic nested-multiplex PCR when testing samples near delivery. In conclusion, we developed a new assay by turning a conventional nested-PCR into a faster, more sensitive and feasible STN-real-time PCR assay for EID and potentially useful for detection of pathogens with variable genomes and present in low copy numbers.

Early Diagnosis of HIV-1 and HIV-2 Using Cobas HIV-1/HIV-2 Qualitative Test: A Novel Qualitative Nucleic Acid Amplification Test for Plasma, Serum, and Dried Blood Spot Specimens

BACKGROUND

Nucleic acid amplification tests (NATs) minimize the time from HIV infection to diagnosis, reducing transmission during acute HIV. NATs are especially useful for diagnosing HIV in children younger than 18 months and discriminating between HIV-1 and HIV-2.

METHODS

We evaluated the performance of the cobas HIV-1/HIV-2 qualitative (cobas HIV-1/2 Qual) test for use on cobas 6800/8800 Systems. The results of adult plasma and serum samples and pediatric dried blood spots were compared with those of the recomLine HIV-1 & HIV-2 Immunoglobulin G serological test and COBAS AmpliPrep/COBAS TaqMan HIV-1 qualitative test, v2.0. Genotype inclusivity and limits of detection were determined, and sensitivity on seroconversion panels was compared with that in the Bio-Rad Geenius HIV 1/2 Confirmatory Assay, Abbott ARCHITECT HIV Ag/Ab Combo serological test, and cobas TaqScreen MPX, v2.0.

RESULTS

Concordance of cobas HIV-1/2 Qual test with the comparator serological test and COBAS AmpliPrep/COBAS TaqMan test was ≥99.6% with all sample types. Reactivity with all HIV genotypes was 100%. LOD in plasma samples was 14.8, 12.6, and 27.9 copies/mL for HIV-1 group M, HIV-1 group O, and HIV-2, respectively, with similar results for serum samples. LOD in dried blood spots was 255 copies/mL for HIV-1 and 984 copies/mL for HIV-2. HIV infection was detected 18.9 days and 8.5 days earlier than the confirmatory and serological assays, respectively, and at a similar time to the NAT.

CONCLUSIONS

The cobas HIV-1/2 Qual test enables early and accurate diagnoses of HIV-1 and HIV-2 in adults and children across sample types. The assay could help avert transmission during acute HIV, simplify HIV diagnostic algorithms, and promote the survival of HIV-infected children.

Indeterminate HIV PCR results within South Africa's early infant diagnosis programme, 2010-2019

OBJECTIVES

We describe the extent of, and variables associated with, indeterminate HIV-PCR results and final HIV status within South Africa's early infant diagnosis (EID) programme between 2010 and 2019.

METHODS

Retrospective analysis of routine paediatric HIV-PCR laboratory data from South Africa's National Health Laboratory Service Data Warehouse between 2010 and 2019. Final HIV status was determined by linking patient results (including HIV-PCR, HIV viral load, HIV serology and CD4 counts) using a probabilistic matching algorithm. Multivariate logistic regression was performed to determine variables associated with final HIV status among patients with an indeterminate HIV-PCR result.

RESULTS

Among 4 429 742 specimens registered for HIV-PCR testing from 3 816 166 patients, 113 209 (2.97%) tested positive and 22 899 (0.6%) tested indeterminate. As a proportion of HIV-detected results, 15.7% (23 896/151 832) of total and 31.5% (4900/15 566), 18.8% (11 400/60 794) and 10.1% (7596/75 472) among patients aged <7 days, 7 days-3 months and ≥3 months, respectively, were reported as indeterminate. Overall, 39.7% of patients with an indeterminate result had a linked HIV test to determine HIV status, of which 53.6% were positive with a median time to repeat testing of 30 days (interquartile range 15-69). Among patients who tested indeterminate, variables associated with a significantly higher odds of having a positive HIV status included testing indeterminate at birth (adjusted odds ratio (AOR) 0.63 (0.48-0.83) and 0.52 (0.39-0.69) for testing indeterminate at 7 days-3 months and ≥3 months respectively compared with birth), within a hospital (AOR 2.45 (1.99-3.03)), and in districts with an intra-uterine transmission rate ≥1.1% (AOR 3.14 (1.84-5.35)) (p < 0.001).

DISCUSSION

Indeterminate HIV-PCR results represent a considerable burden of missed diagnostic opportunities, diagnostic dilemmas and delays in making a definite diagnosis among HIV-infected infants within South Africa's EID programme. Alternative EID verification practices are urgently needed.

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.

Evaluation of the Aptima HIV-1 Quant Dx assay for HIV diagnosis at birth in South Africa

The increased coverage of antiretroviral therapy has resulted in a decrease in the positive predictive value (PPV) and diagnostic sensitivity of early infant diagnosis assays. To evaluate the diagnostic performance of the Aptima HIV-1 Quant DX assay (Aptima) in detecting HIV infection at birth. The study was a cross-sectional laboratory based evaluation using whole blood DBS specimens. Samples were collected from HIV-exposed neonates at birth at two paediatric facilities in Gauteng between 1st March 2018 - 31st January 2020. Performance of the Aptima compared to the Cobas® AmpliPrep/Cobas® TaqMan HIV-1 Qualitative Test v2.0 was calculated using a two-by-two table and reported as proportions with 95% confidence intervals. A total of 363 infants met the inclusion criteria of which 4 (1.1%) had an Aptima result discordant with CAP/CTM HIV status: two (50%) negative and two (50%) positive. The Aptima assay had a sensitivity of 93.75% (95% CI: 79.19%-99.23%), specificity of 99.4% (95% CI: 97.83%-99.93%), PPV of 93.75% (95% CI: 78.98%-98.36%), negative predictive value of 99.4% (95% CI: 97.73%-99.84%), and overall accuracy of 98.9% (95% CI: 97.2%-99.7%). The Aptima yielded an error code on 37 (10.19%) results, of which 35 (94.59%) were resolved on repeat testing. Of the 32 HIV-detected specimens, 20 had a plasma VL result available (18 on Abbott and 2 on Cobas). The absolute median difference was 0.66 log10 (IQR: 0.36-1.71). The Aptima demonstrated good EID performance and can be considered as a qualitative EID assay.

Non Detection of HIV-1 Proviral DNA in PBMCs of the Neonates Born to Iranian HIV-Infected Mothers in PMTCT Program

Background: Early diagnosis of immunodeficiency virus-1 infection in children and access to treatment for this infection is critical in decreasing infant mortality. Objectives: The aim of the current survey was to determine the presence of HIV-1 genomic RNA in plasma and proviral DNA in peripheral blood mononuclear cell (PBMC) specimens of neonates born to HIV-infected mothers. Methods: From March 2014 to February 2018, 73 neonates born to HIV-1-infected mothers covered by the prevention of mother-to-child transmission (PMTCT) program were enrolled in this study to compare two different diagnostic methods. After the extraction of viral RNA of plasma and genomic DNA of PBMC specimens, HIV-1 RNA and proviral DNA was tested by amplification of the long terminal repeat (LTR) region of HIV-1 using real-time PCR. Results: Out of 73 evaluated infants, 41 infants (56.2%) were male. The average age of the mothers with HIV-1 infection was 30.7 ± 5.2 (range: 19–47) years. The results revealed that none of the infants were infected with HIV-1, and also all were negative for HIV-1 genomic RNA in plasma specimen and proviral DNA of HIV-1 in PMBC samples. During the present study, 20 infants born to HIV-1 positive mothers who were not included in the PMTCT project were accidentally identified. Four infants (20%) out of these 20 infants were infected with HIV, all were infected with CRF35-AD of HIV, and none carried variants with surveillance drug-resistant mutations. Conclusions: The results of the present study showed that two molecular methods of detecting HIV infection (presence of genomic RNA of HIV-1 in plasma and proviral DNA of HIV-1 in PBMC specimens) are completely in agreement with each other, and the PMTCT program is possibly an effective program.

Mini review: Prevention of mother-child transmission of HIV: 25 years of continuous progress toward the eradication of pediatric AIDS?

Prevention of mother-to-child transmission with antiretrovirals is extraordinarily effective. When medically well followed, a mother living with human immunodeficiency virus can now expect to avoid transmitting the virus to her child. Despite the immense difficulties inherent in the global implementation of this treatment, the virtual disappearance of pediatric AIDS can be considered in the long term.

Impact of breastfeeding, maternal antiretroviral treatment and health service factors on 18-month vertical transmission of HIV and HIV-free survival: results from a nationally representative HIV-exposed infant cohort, South Africa

BACKGROUND

We analysed the impact of breastfeeding, antiretroviral drugs and health service factors on cumulative (6 weeks to 18 months) vertical transmission of HIV (MTCT) and 'MTCT-or-death', in South Africa, and compared estimates with global impact criteria to validate MTCT elimination: (1) <5% final MTCT and (2) case rate ≤50 (new paediatric HIV infections/100 000 live births).

METHODS

9120 infants aged 6 weeks were enrolled in a nationally representative survey. Of 2811 HIV-exposed uninfected infants (HEU), 2644 enrolled into follow-up (at 3, 6, 9, 12, 15 and 18 months). Using Kaplan-Meier analysis and weighted survey domain-based Cox proportional hazards models, we estimated cumulative risk of MTCT and 'MTCT or death' and risk factors for time-to-event outcomes, adjusting for study design and loss-to-follow-up.

RESULTS

Cumulative (final) MTCT was 4.3% (95% CI 3.7% to 5.0%); case rate was 1290. Postnatal MTCT (>6 weeks to 18 months) was 1.7% (95% CI 1.2% to 2.4%). Cumulative 'MTCT-or-death' was 6.3% (95% CI 5.5% to 7.3%); 81% and 62% of cumulative MTCT and 'MTCT-or-death', respectively, occurred by 6 months. Postnatal MTCT increased with unknown maternal CD4-cell-count (adjusted HR (aHR 2.66 (1.5-5.6)), undocumented maternal HIV status (aHR 2.21 (1.0-4.7)) and exclusive (aHR 2.3 (1.0-5.2)) or mixed (aHR 3.7 (1.2-11.4)) breastfeeding. Cumulative 'MTCT-or death' increased in households with 'no refrigerator' (aHR 1.7 (1.1-2.9)) and decreased if infants used nevirapine at 6 weeks (aHR 0.4 (0.2-0.9)).

CONCLUSIONS

While the <5% final MTCT target was met, the case rate was 25-times above target. Systems are needed in the first 6 months post-delivery to optimise HEU health and fast-track ART initiation in newly diagnosed mothers.

Negative Diagnostic PCR Tests in School-Aged, HIV-Infected Children on Antiretroviral Therapy Since Early Life in Johannesburg, South Africa

BACKGROUND

Younger age at antiretroviral therapy (ART) initiation has been associated with smaller HIV reservoirs. We investigated whether younger age of ART initiation is associated with testing negative and weaker signal on a standard HIV diagnostic test in treated children.

METHODS

At exit from a longitudinal study at 2 sites in Johannesburg, South Africa, 316 school-aged, HIV-infected children on continuous ART started at a median age of 6.3 months, were tested with standard total nucleic acid PCR used for infant diagnosis. All negative results were repeated. Simultaneous viral load (VL) and CD4 T-cell counts/percentages, along with data collected over the prior 4 years, were used in multivariable regression to predict negative PCR results and higher cycle threshold (Ct) values (weaker signal).

RESULTS

Seven children (2.2%, 95% confidence interval: 0.6 to 3.8) in the full cohort had negative PCR results; all 7 were in a subset of 102 (6.9%, 95% confidence interval: 2.0 to 11.8) who had initiated ART at age 0-4 months and had VL <50 copies/mL at the time of PCR testing. Only one repeat tested as negative. Younger age at ART initiation, VL <50 copies/mL at time of test, sustained VL <400 copies/mL, lower CD4 T-cell counts, and ever treated with efavirenz were significant predictors of weaker signal on the diagnostic test.

CONCLUSIONS

In a small proportion of children who start ART in the first months of life and remain on continuous therapy, standard diagnostic HIV PCR tests may result as negative. Repeat testing may resolve uncertainty of diagnosis.

HIV Testing in Adults Presenting With Central Nervous System Infections

Background

Universal HIV testing in adults presenting to a health care setting was recommended by the Centers for Disease Control and Prevention (CDC) in 2006, but compliance in central nervous system (CNS) infections is unknown.

Methods

A multicenter study of adults presenting with CNS infections to 18 hospitals in Houston and New Orleans between 2000 and 2015 was done to characterize HIV testing and explore factors associated with a positive HIV test.

Results

A total of 1478 patients with a diagnosis of meningitis or encephalitis were identified; 180 were excluded because of known HIV diagnosis (n = 100) or were <17 years old (n = 80). Out of 1292 patients, 642 (49.7%) had HIV testing, and testing did not differ significantly before or after the CDC recommendations in 2006 (53% vs 48%; P = .068). An HIV test was more commonly done in patients who were non-Caucasian, had fever >38°C, or had seizures on presentation, and of those tested, non-Caucasian patients and those with photophobia were more likely to have a positive HIV test (P < .05). HIV testing also varied by type of CNS infection: community-acquired bacterial meningitis (98/130, 75.4%), encephalitis (174/255, 68.2%), aseptic meningitis (285/619, 46.0%), and health care–associated meningitis (85/288, 29.5%; P < .001).

Conclusions

Even though HIV testing should be done in all adults presenting with a CNS infection, testing remains ~50% and did not improve after the recommendation for universal testing by the CDC in 2006.

Use of an Indeterminate Range in HIV Early Infant Diagnosis: A Systematic Review and Meta-Analysis

BACKGROUND

Expanded access to HIV antiretrovirals has dramatically reduced mother-to-child transmission of HIV. However, there is increasing concern around false-positive HIV test results in perinatally HIV-exposed infants but few insights into the use of indeterminate range to improve infant HIV diagnosis.

METHODS

A systematic review and meta-analysis was conducted to evaluate the use of an indeterminate range for HIV early infant diagnosis. Published and unpublished studies from 2000 to 2018 were included. Study quality was evaluated using GRADE and QUADAS-2 criteria. A random-effects model compared various indeterminate ranges for identifying true and false positives.

RESULTS

The review identified 32 studies with data from over 1.3 million infants across 14 countries published from 2000 to 2018. Indeterminate results accounted for 16.5% of initial non-negative test results, and 76% of indeterminate results were negative on repeat testing. Most results were from Roche tests. In the random-effects model, an indeterminate range using a polymerase chain reaction cycle threshold value of ≥33 captured over 93% of false positives while classifying fewer than 9% of true positives as indeterminate.

CONCLUSIONS

Without the use of an indeterminate range, over 10% of infants could be incorrectly diagnosed as HIV positive if their initial test results are not confirmed. Use of an indeterminate range appears to lead to substantial improvements in the accuracy of early infant diagnosis testing and supports current recommendations to confirm all initial positive tests.

Unraveling HIV-1 diagnosis in special pediatric cases

BACKGROUND

Early HIV-1 diagnosis and initiation of antiretroviral treatment is essential to prevent AIDS, and reduce mortality in children. HIV-1 molecular diagnosis in children before 18 months of age require, two independent samples to confirm a result. However, some patients have discordant virologic results in different samples, raising uncertainty for a conclusive diagnosis. We defined these patients as "special pediatric cases".

OBJECTIVES

The aim of our study was to characterize the "special pediatric cases" among HIV-1 infected children diagnosed in a five-year period at our laboratory and evaluate the impact on the time to HIV-1 diagnosis.

STUDY DESIGN

A total of 44 perinatally HIV-1 infected infants with molecular diagnostic performed at the Pediatric Garrahan Hospital were analyzed from 2013 to 2017.

RESULTS

We identified eight "special pediatric cases". In the first samples, all of them had negative results by different DNA-PCR assays. Three infants had undetectable plasma viral load (pVL), four had low detectable pVL value, and one infant had no available pVL. All samples with detectable pVL, including those with low pVL (ie: 65copies/mL), had high pVL values at the end of the diagnosis. Considering the age of the HIV-1 infected children at the end of the diagnosis, five "special pediatric cases" (62 %) had a "late" positive diagnosis [mean (range) = 146 (89-268) days old].

CONCLUSIONS

These "special pediatric cases" are not as unusual as previously thought and are important diagnostic challenges. Also, this study add evidence to include the viral load assay in the molecular diagnostic algorithm for perinatal HIV-1 infection.

Accuracy and Operational Characteristics of Xpert Human Immunodeficiency Virus Point-of-Care Testing at Birth and Until Week 6 in Human Immunodeficiency Virus-exposed Neonates in Tanzania

Background

Point-of-care (PoC) systems for early infant diagnosis (EID) may improve timely infant human immunodeficiency virus (HIV) management. Experiences within African public health settings are limited.

Methods

We evaluated the accuracy and operational feasibility of the Xpert HIV-1 Qual for PoC-EID testing, using fresh blood and dried blood spots (DBS) samples at obstetric health facilities in Tanzania at birth and at postpartum weeks 1, 2, 3, and 6 in HIV-exposed infants. Test results were confirmed using TaqMan DBS HIV-deoxyribonucleic acid and/or plasma HIV-ribonucleic acid (RNA) testing.

Results

At week 6, 15 (2.5%) out of 614 infants were diagnosed with HIV; 10 (66.7%) of them at birth (median HIV-RNA 4570 copies/mL). At birth, the Xpert-PoC and Xpert-DBS were 100% sensitive (95% confidence intervals: PoC, 69.2–100%; DBS, 66.4–100%) and 100% specific (PoC, 92.1–100%; DBS, 88.4–100%). By week 3, 5 infants with intra/postpartum HIV-infection (median HIV-RNA 1 160 000 copies/mL) were all correctly diagnosed by Xpert. In 2 cases, Xpert-PoC testing correctly identified HIV-infection when DBS tests (Xpert and TaqMan) were negative, suggesting a greater sensitivity. In 2 infants with confirmed HIV at birth, all tests were negative at week 6, possibly because of viral suppression under nevirapine prophylaxis. Problems were reported in 183/2736 (6.7%) of Xpert-PoC tests, mostly related to power cuts (57.9%).

Conclusions

We demonstrated excellent Xpert HIV-1 Qual performance and good operational feasibility for PoC-EID testing at obstetric health facilities. Week 6 sensitivity issues were possibly related to nevirapine prophylaxis, supporting additional birth PoC-EID testing to avoid underdiagnosis.

Clinical Trials Registration

NCT02545296

Performance evaluation of the Aptima HIV-1 Quant Dx assay for detection of HIV in infants in Kenya

BACKGROUND

Early infant diagnosis (EID) of HIV-1 exposed infants enables timely initiation of antiretroviral therapy (ART), thereby allowing early diagnosis and treatment to slow disease progression and reduce mortality. Turn-around time to results, partially caused by low to medium throughput technology, remains a hindrance to early treatment. A major solution to this challenge is to incorporate high throughput and accurate technologies in the testing process. The Hologic Aptima Quant Dx Assay (Aptima) is a CE marked Real-Time TMA assay running on the high throughput Panther system.

OBJECTIVES

The objective of this study was to evaluate the performance of Aptima for EID using dried blood spots.

STUDY DESIGN

This was a cross-sectional prospective study of 2,048 infants seeking HIV services from health facilities in Western Kenya, Africa. Capillary Dried Blood Spot samples DBS were collected from infants with the consent of their mothers. The qualitative performance of Aptima was compared with the Roche COBAS Ampliprep/ COBAS Taqman HIV-1 Qualitative Test v2.0 (CAP/CTM), using these DBS. Demographic information of the participants was also collected.

RESULTS

A total of 1,975 successful comparisons between the two platforms were included in the analysis. The overall agreement between the assays was 99.65 %. The sensitivity and specificity of Aptima was 95.24 % (95 % CI 88.40-98.19 %) and 99.84 % (95 % CI 99.49-99.92 %) respectively.

CONCLUSIONS

Aptima assay has performance characteristics that are comparable to those of the Roche CAP/CTM for qualitative testing on DBS taken from infants. The two assays can therefore be used interchangeably for Early Infant Diagnosis of HIV.

Undetectable proviral deoxyribonucleic acid in an adolescent perinatally infected with human immunodeficiency virus-1C and on long-term antiretroviral therapy resulted in viral rebound following antiretroviral therapy termination: A case report with implications for clinical care

RATIONALE

Early initiation of antiretroviral therapy (ART) leads to long-term viral suppression, reduces proviral reservoir size, and prolongs time to rebound. Since human immunodeficiency virus (HIV) is a lifelong disease, diagnostic monitoring after confirmed infection is typically not performed; therefore, little is known about the impact of early initiation and long-term ART on the sensitivity of assays that detect HIV antibodies and viral nucleic acid in children and adolescents.

PATIENT CONCERNS

Here we report 1 case of diagnosed and confirmed perinatal HIV-1C infection with longstanding viral suppression, who subsequently had a negative HIV-1 deoxyribonucleic acid (DNA) test, undetectable antibodies to HIV-1, and high CD4+ T cell count after 14 years of ART.

DIAGNOSIS

The patient was diagnosed with HIV in 2002 at 1 and 2 months of age using DNA polymerase chain reaction. At 8 months old, his viral load was 1210 HIV ribonucleic acid (RNA) copies/mL and CD4 T cell count was 3768 cells/mm.

INTERVENTION

At the age of 9 months, highly active antiretroviral therapy comprising of zidovudine, nevirapine, and lamivudine was initiated. The patient remained on this treatment for 14 years 11 months and was virally suppressed.

OUTCOMES

At the age of 14 years 4 months, the participant decided to visit a local voluntary HIV testing center, where a rapid HIV test came out negative and the viral load was undetectable (<400 HIV-1 RNA copies/mL). These results led to termination of ART which led to viral rebound within 9 months.

LESSONS

As more people with early HIV infection initiate early ART in the context of "Test and Treat all" recommendations, aspects of this report may become more commonplace, with both clinical and public health implications. If the possibility of functional cure (or false-positive diagnosis) is being considered, decisions to terminate ART should be made cautiously and with expert guidance, and may benefit from highly sensitive quantification of the proviral reservoir.

Evolving complexities of infant HIV diagnosis within Prevention of Mother-to-Child Transmission programs

Early diagnosis of HIV infection among infants and children is critical as prompt initiation of antiretroviral therapy prevents morbidity and death. Yet despite advances in the accuracy and availability of infant HIV diagnostic testing, there are increasing challenges with making an early definitive diagnosis. These challenges relate primarily to advances in prevention of mother-to-child transmission (PMTCT) of HIV. Although PMTCT programs have proven to be highly effective in reducing infant HIV infection, infants who are HIV-infected may achieve virological suppression and loss of detectability of HIV nucleic acid prior to diagnosis because of antiretroviral drug exposure. Hence, false-negative and indeterminate HIV polymerase chain reaction (PCR) results can occur, especially among high-risk infants given multi-drug prophylactic regimens. However, the infant HIV diagnostic landscape is also complicated by the inevitable decline in the positive predictive value of early infant diagnosis (EID) assays. As PMTCT programs successfully reduce the mother-to-child transmission rate, the proportion of false-positive EID results will increase. Consequently, false-negative and false-positive HIV PCR results are increasingly likely despite highly accurate diagnostic assays. The problem is compounded by the seemingly intractable prevalence of maternal HIV within some settings, resulting in a considerable absolute burden of HIV-infected infants despite a low mother-to-child transmission rate.

HIV diagnostic challenges in breast-fed infants of mothers on antiretroviral therapy

BACKGROUND

Prompt initiation of antiretroviral therapy (ART) for HIV-infected infants is strongly recommended but diagnostic confirmation is important as committing children to life-long ART carries serious health and social implications.

METHODS

Two HIV-exposed infants in Johannesburg, South Africa were identified presenting with unusual trajectories of diagnostic nucleic acid amplification tests (NAAT) and viral load results.

RESULTS

Case 1 had repeat indeterminate NAAT results during the first 3 weeks of life; repeat testing thereafter was negative with undetectable viral load including after daily nevirapine prophylaxis ended. ART was not initiated at this time. Case 2 had a single positive NAAT result at 1 month of age that prompted initiation of ART. Subsequent results were negative and ART was discontinued. Repeat negative NAAT with viral load below the limit of quantification or undetectable continued to be obtained. Shortly after and around weaning, positive NAAT results with high viral load (7.1 and 6.03 log10 copies/ml for Cases 1 and 2, respectively) were observed in both children. Both mothers were treated with tenofovir, emtricitabine and efavirenz during breastfeeding. Testing with ultrasensitive assays on early samples conclusively revealed HIV-1 proviral DNA in Case 1. Testing with ultrasensitive assays after the early period but prior to weaning did not detect HIV in either infant.

CONCLUSION

We hypothesize that breast milk from the mothers of these two rare cases had HIV-specific or nonspecific factors that led to the undetectable results in already infected infants until breastfeeding ended. Our results raise the importance of repeat testing of HIV-exposed breast-fed infants after complete cessation of all breastfeeding.

A Clinical Score to Support Antiretroviral Management of HIV-exposed Infants on the Day of Birth

BACKGROUND

The benefits of combination antiretroviral (ARV) prophylaxis for infants whose HIV exposure is recognized near birth have been established, and the benefits of early ARV therapy are well known. Decisions about ARVs can be supported by the probability that the child has acquired HIV.

METHODS

Using 2005-2010 data from Enhanced Perinatal Surveillance of the Centers for Disease Control and Prevention, we developed a tool for use at birth to help predict HIV acquisition of HIV-exposed infants to support ARV management. A logistic regression model, fit using a fully Bayesian approach, was used to determine maternal variables predictive of infant HIV acquisition. We created a score index from these variables, established the sensitivity and specificity of each possible score, and determined the distribution of scores among infants, with and without HIV, in our study population.

RESULTS

Multivariable analysis of data from 8740 HIV-exposed infants (176 infected and 8564 uninfected) yielded 4 maternal variables in the perinatal HIV acquisition prediction model: sexually transmitted infection, substance use, last HIV viral load before delivery and ARV use. Using the regression coefficient estimates, we rescaled each possible score to make the maximum score equal to 100. For each score, sensitivity and specificity were determined; the area under the receiver operating characteristic curve was 0.79. Median index scores for infants with HIV and without HIV were 43 (first quartile 27 and third quartile 60), and 12 (first quartile, 0 and thirs quartile, 29), respectively.

CONCLUSIONS

Decisions to begin infants on 3 ARVs-whether considered therapeutic or prophylactic-can be supported by data available on the day of birth.

Non-nucleoside reverse transcriptase inhibitor levels among HIV-exposed uninfected infants at the time of HIV PCR testing - findings from a tertiary healthcare facility in Pretoria, South Africa

INTRODUCTION

To date, very little programmatic data has been published regarding serial antiretroviral (ARV) levels in infants exposed to maternal treatment and/or infant prophylaxis during the first months of life. Such data provide the opportunity to describe the proportion of infants exposed to virologically suppressive levels of ARVs and to gauge adherence to the prevention of mother-to-child transmission of HIV (PMTCT) programme.

METHODS

From August 2014 to January 2016, HIV-exposed infants born at Kalafong Provincial Tertiary Hospital in Pretoria, South Africa were enrolled as part of an observational cohort study. Plasma samples from HIV-exposed uninfected infants were obtained at birth, 6-weeks, 10-weeks and 14-weeks of age and quantitative efavirenz (EFV) and nevirapine (NVP) drug level testing performed using liquid chromatography-mass spectrometry, irrespective of maternal ARV regimen. Descriptive analysis of EFV and NVP levels in relation to self-reported maternal and infant ARV exposure was performed. EFV levels >500 ng/mL and NVP levels >100 ng/mL were reported based on studies suggesting that trough levels above these thresholds are associated with virological suppression and PMTCT respectively.

RESULTS

Among 66 infants exposed to maternal EFVin utero, 29 (44%) had virologically suppressive plasma EFV levels at birth, with a median level of 1665 ng/mL (IQR: 1094 to 3673). Among infants who were exclusively breastfed at 6-, 10- and 14 weeks, 13/48 (27%), 5/25 (25%) and 0/21 (0%) had virologically suppressive EFV levels. Among 64 infants whose mothers reported administering daily infant NVP at time of their 6-week HIV PCR test, only 45 (70%) had NVP levels above the minimum prophylactic trough level.

CONCLUSIONS

During the first 10-weeks after delivery, a quarter of breastfed infants born to women on an EFV-containing treatment regimen maintained virologically suppressive EFV plasma levels. This finding highlights the importance of both careful monitoring of ARV side effects and repeat HIV PCR after the first few months of life among HIV-exposed uninfected infants. As 30% of infants had inadequate NVP plasma levels at 6-weeks of age, adherence counselling to caregivers regarding infant prophylaxis needs to be enhanced to further reduce mother-to-child transmission of HIV.

Early infant diagnosis HIV-1 PCR cycle-threshold predicts infant viral load at birth

BACKGROUND

HIV-1 viral load (VL) has been found to be an independent predictor for disease progression among untreated HIV-infected children. However, qualitative polymerase chain reaction (PCR) assays are routinely used for early infant diagnosis (EID).

OBJECTIVES

To predict HIV-1 VL at birth using qualitative EID real-time PCR cycle-threshold (Ct) values.

STUDY DESIGN

This study was a secondary analysis of results from a cohort of intrauterine HIV-1 infected neonates. Neonates were enrolled at Rahima Moosa Mother & Child Hospital in Johannesburg, South Africa between June 2014 and November 2017. Laboratory EID HIV-1 PCR testing was performed at birth using COBAS AmpliPrep/COBAS TaqMan HIV-1 Qualitative Test v2.0 (EID CAP/CTM). Some infants had simultaneous EID point-of-care (POC) testing using Xpert HIV-1 Qualitative assay (EID Xpert). Neonates with a confirmed HIV-1 detected EID result and plasma HIV-1 RNA VL test were included in this analysis. Bland-Altman analysis was used to determine extent of agreement between Ct values of both EID assays. Multivariable linear regression models adjusting for time between EID and VL testing were used to describe the association between EID Ct values and VL and to predict VL at given EID Ct values.

RESULTS

Among 107 HIV-1 infected neonates included in the study, 59 had POC EID testing. Median VL was 28 400 copies per millilitre (cps/ml) (IQR: 1 918-218 358) - two neonates had VL < 100 cps/ml prior to antiretroviral therapy initiation. There was good correlation between Ct values of both EID assays (Spearman correlation coefficient 0.9, 95% CI: 0.8-1.0). The limits of agreement between EID CAP/CTM and Xpert Ct values were 4-11 cycles. For every one cycle increase in Ct value there was 0.3 log₁₀ RNA decrease (95% CI: -0.3 to -0.2) for both EID assays. An EID CAP/CTM Ct value ≤ 23 and an EID Xpert Ct value ≤ 31 predicted a VL of > 5.0 log₁₀ cps/ml in 82.2% (95% CI: 73.9-88.3) and 84.7% (95% CI: 73.7-91.8) of cases, respectively.

CONCLUSION

EID Ct values at birth predict VL and accurately identify infants with VL > 5.0 log₁₀ cps/ml.

Brief Report: Declining Baseline Viremia and Escalating Discordant HIV-1 Confirmatory Results Within South Africa's Early Infant Diagnosis Program, 2010-2016

OBJECTIVE

To describe baseline HIV-1 RNA viral load (VL) trends within South Africa's Early Infant Diagnosis program 2010-2016, with reference to prevention of mother-to-child transmission guidelines.

METHODS

HIV-1 total nucleic acid polymerase chain reaction (TNA PCR) and RNA VL data from 2010 to 2016 were extracted from the South African National Health Laboratory Service's central data repository. Infants with a positive TNA PCR and subsequent baseline RNA VL taken at age <7 months were included. Descriptive statistics were performed for quantified and lower-than-quantification limit (LQL) results per annum and age in months. Trend analyses were performed using log likelihood ratio tests. Multivariable linear regression was used to model the relationship between RNA VL and predictor variables, whereas logistic regression was used to identify predictors associated with LQL RNA VL results.

RESULTS

Among 13,606 infants with a positive HIV-1 TNA PCR linked to a baseline RNA VL, median age of first PCR was 57 days and VL was 98 days. Thirteen thousand one hundred ninety-five (97.0%) infants had a quantified VL and 411 (3.0%) had an LQL result. A significant decline in median VL was observed between 2010 and 2016, from 6.3 log10 (interquartile range: 5.6-6.8) to 5.6 log10 (interquartile range: 4.2-6.5) RNA copies per milliliter, after controlling for age (P < 0.001), with younger age associated with lower VL (P < 0.001). The proportion of infants with a baseline VL <4 Log10 RNA copies per milliliter increased from 5.4% to 21.8%. Subsequent to prevention of mother-to-child transmission Option B implementation in 2013, the proportion of infants with an LQL baseline VL increased from 1.5% to 6.1% (P < 0.001).

CONCLUSIONS

Between 2010 and 2016, a significant decline in baseline viremia within South Africa's Early Infant Diagnosis program was observed, with loss of detectability among some HIV-infected infants.

The stability of HIV-1 nucleic acid in whole blood and improved detection of HIV-1 in alternative specimen types when compared to Dried Blood Spot (DBS) specimens

BACKGROUND

Commercially-available kits for HIV-1 detection include instructions for detecting HIV-1 in plasma and DBS, but don't support other specimen types.

OBJECTIVES

Show quantitative stability of HIV-1 total nucleic acid (TNA) in blood and improved HIV-1 detection in alternative specimen types.

STUDY DESIGN

Whole blood and DBS specimens, tested as part of an external quality assurance program for qualitative HIV-1 detection, were used to evaluated error rates (false negative [FN], false positive [FP] and indeterminant [IND] results) across assays (internally developed [IH], Roche Amplicor [RA], and Roche TaqMan Qual [TQ]) and specimen types (frozen whole blood [BLD], DBS and cell pellets [PEL]). A modified Roche TaqMan HIV-1 assay was used to quantify HIV-1 TNA.

RESULTS

Significantly higher error rates were noted in DBS across all of the assays (4% vs. 0% for DBS and PEL, IH, p = 0.005; 4% vs. 0.1% for DBS and PEL, RA, p < 0.001; 10% vs. 1% for DBS and PEL or BLD, TQ, p < 0.001). HIV TNA concentration is stable in BLD (day 1 vs. day 10, p = 0.39) and higher than DBS (p < 0.001).

CONCLUSIONS

Transporting refrigerated whole blood for centralized processing into alternative specimen types will improve the sensitivitiy of HIV-1 detection in samples with low virus loads.

Estimating the cost of diagnosing HIV at birth in Lesotho

Background

Infants with HIV infection, particularly those infected in utero, who do not receive antiretroviral therapy (ART) have high mortality in the first year of life. Virologic diagnostic testing is recommended by the World Health Organization between ages 4 and 6 weeks after birth. However, adding very early infant diagnosis (VEID) testing at birth has been suggested to enable earlier diagnosis and rapid treatment of in utero infection. We assessed the costs of adding VEID to the standard 6-week testing in Lesotho where coverage of PMTCT services is nearly universal.

Methods

Retrospective cost data were collected at eight health-care facilities in three districts participating in an observational prospective study that included birth testing as well as at the National Reference Laboratory in Lesotho, to investigate the cost-per-infection identified. Extrapolating to the national level, it was possible to estimate the impact of VEID on the identification of HIV-infected infants.

Results

The unit cost-per-VEID test in Lesotho in 2015 was $40.50. Major cost drivers were supplies/commodities (46%) and clinical labor (22%). In 2015, 66.3% of cohort study infants born at study facilities underwent VEID; one out of 199 infants had a positive HIV DNA PCR test at birth (0.5% potential in utero infection), yielding a cost of $8,060 per HIV-positive infant identified. Sensitivity analysis showed costs based on Lesotho costing data ranged from $810 to $16,194 per-infected child with varying in utero infection rates from 5% and 0.25%, respectively. With 11,157 HIV-exposed births nationally from pregnant women on PMTCT, 66.3% VEID coverage, and 0.5% in utero infection, 37 infants infected with HIV could have been identified at birth in 2015 and 8 early infant deaths potentially averted with immediate ART compared with waiting for 6-week testing.

Conclusion

If Lesotho costing data from this pilot study were applied to different epidemic circumstances, the cost-per-infected child identified by adding VEID birth testing to standard 6-week testing was lowest when in utero infection rates were high (when HIV prevalence is high and PMTCT coverage is low).

Early Infant Diagnosis Sample Management in Mashonaland West Province, Zimbabwe, 2017

Background

In 2016, Mashonaland West Province had 7.4% (520) dried blood spot (DBS) samples for early infant diagnosis (EID) rejected by the Zimbabwe National Microbiology Reference Laboratory (NMRL). The samples were suboptimal, delaying treatment initiation for HIV-infected children. EID is the entry point to HIV treatment services in exposed infants. We determined reasons for DBS sample rejections and suggested solutions.

Methods

A cause-effect analysis, modelled on Ishikawa, was used to identify factors impacting DBS sample quality. Interviewer-administered questionnaires and evaluation of sample collection process, using Standard Operating Procedure (SOP) was conducted. Rejected samples were reviewed. Epi Info™ was used to analyze findings.

Results

Eleven (73.3%) facilities did not adhere to SOP and (86.7%) did not evaluate DBS sample quality before sending for testing. Delayed feedback (up to 4 weeks) from NMRL extended EID delay for 14 (93.3%) of the facilities. Of the 53 participants, 62% knew valid sample identification. Insufficient samples resulted in most rejections (77.9%). Lack of training (94.3%) and ineffective supervision (69.8%) were also cited.

Conclusion

Sample rejections could have been averted through SOP adherence. Ineffective supervision, exacerbated by delayed communication of rejections, extended EID delay, disadvantaging potential ART beneficiaries. Following this study, enhanced quality control through perstage evaluations was recommended to enhance DBS sample quality.

Introduction of Routine HIV Birth Testing in the South African National Consolidated Guidelines

BACKGROUND

South Africa represents the first high-burden setting to introduce routine virologic testing at birth within its early infant diagnosis program, implemented in June 2015. National HIV birth testing coverage, intrauterine transmission rates and case rates for the first year since introduction of universal birth testing are reported.

METHODS

HIV polymerase chain reaction (PCR) test data from June 2015 to May 2016 were extracted from the National Health Laboratory Service's central data repository by year, month, age, result and geographic location. Birth testing was defined as all HIV PCR tests performed at <7 days of life; coverage as the proportion of all HIV-exposed neonates born who were tested at birth; estimated intrauterine transmission rate as the percentage of HIV PCR positive tests in HIV-exposed neonates tested and case rates as the number of HIV PCR positive tests per 100,000 total live births.

RESULTS

Between June 2015 and May 2016, the South African national monthly birth testing coverage increased from 39% (8636 tests) to 93% (20,479 tests). During this period, the number of positive tests at birth increased from 114 to 234 per month, equating to a national intrauterine transmission rate of 1.1% and a birth case rate of 247 per 100,000 live births.

CONCLUSIONS

Universal birth testing for all HIV-exposed neonates is rapidly being achieved in South Africa, facilitating earlier detection of intrauterine infected neonates. However, the successful linkage into care of HIV-infected neonates and their treatment outcomes remain to be assessed.

Similar HIV protection from four weeks of zidovudine versus nevirapine prophylaxis among formula-fed infants in Botswana

Background

The World Health Organization HIV guidelines recommend either infant zidovudine (ZDV) or nevirapine (NVP) prophylaxis for the prevention of intrapartum mother-to-child HIV transmission (MTCT) among formula-fed infants. No study has evaluated the comparative efficacy of infant prophylaxis with twice daily ZDV versus once daily NVP in exclusively formula-fed HIV-exposed infants.

Methods

Using data from the Mpepu Study, a Botswana-based clinical trial investigating whether prophylactic co-trimoxazole could improve infant survival, retrospective analyses of MTCT events and Division of AIDS (DAIDS) Grade 3 or Grade 4 occurrences of anaemia or neutropenia were performed among infants born full-term (≥ 37 weeks gestation), with a birth weight ≥ 2500 g and who were formula-fed from birth. ZDV infant prophylaxis was used from Mpepu Study inception. A protocol modification mid-way through the study led to the subsequent use of NVP infant prophylaxis.

Results

Among infants qualifying for this secondary retrospective analysis, a total of 695 (52%) infants received ZDV, while 646 (48%) received NVP from birth for at least 25 days but no more than 35 days. Confirmed intrapartum HIV infection occurred in two (0.29%) ZDV recipients and three (0.46%) NVP recipients (p = 0.68). Anaemia occurred in 19 (2.7%) ZDV versus 12 (1.9%) NVP (p = 0.36) recipients. Neutropenia occurred in 28 (4.0%) ZDV versus 21 (3.3%) NVP recipients (p = 0.47).

Conclusions

Both ZDV and NVP resulted in low intrapartum transmission rates and no significant differences in severe infant haematologic toxicity (DAIDS Grade 3 or Grade 4) among formula-fed full-term infants with a birthweight ≥ 2500 g.

Differentiating clearly positive from indeterminate results: A review of irreproducible HIV-1 PCR positive samples from South Africa's Early Infant Diagnosis Program, 2010-2015

We describe the extent of and variables associated with irreproducible HIV-1 PCR positive results within South Africa's Early Infant Diagnosis (EID) program from 2010 to 2015 and propose criteria for differentiating indeterminate from clearly positive results using the COBAS® AmpliPrep/COBAS® TaqMan HIV-1 Qualitative Test version 2.0 (CAP/CTM Qual v2.0). Fourteen percent of specimens with an instrument-positive result that were repeat-tested yielded a negative result for which cycle threshold (Ct) proved to be the only predictive variable. A Ct <33.0 was found to be the most accurate threshold value for differentiating clearly positive from irreproducible cases, correctly predicting 96.8% of results. Among 70 patients with an irreproducible positive result linked to a follow up HIV-1 PCR test, 67 (95.7%) were negative and 3 (4.3%) were instrument-positive. Criteria differentiating clearly positive from indeterminate results need to be retained within EID services and infants with indeterminate results closely monitored and final HIV status determined.

Prevalence and outcomes of HIV-1 diagnostic challenges during universal birth testing - an urban South African observational cohort

Introduction: HIV‐1 polymerase chain reaction (PCR) testing at birth aims to facilitate earlier initiation of antiretroviral therapy (ART) for HIV‐infected neonates. Data from two years of universal birth testing implementation in a high‐burden South African urban setting are presented to demonstrate the prevalence and outcomes of diagnostic challenges in this context.

Methods: HIV‐exposed neonates born at Rahima Moosa Mother and Child Hospital between 5 June 2014 and 31 August 2016 were routinely screened at birth for HIV‐1 on whole blood samples using the COBAS® AmpliPrep/COBAS® TaqMan (CAP/CTM) HIV‐1 Qualitative Test, version 2.0 (Roche Molecular Systems, Inc., Branchburg, NJ, USA). Virological results were interpreted according to standard operating procedures with the South African National Health Laboratory Service. All neonates with non‐negative results were actively followed‐up and categorized according to HIV infection status as positive, negative, uncertain and lost to follow‐up (LTFU).

Results: 104 (1.8%) of 5743 HIV‐exposed neonates received a non‐negative birth PCR result, for which laboratory data were available for 102 (98%) cases – 78 (76%) tested positive and 24 (24%) indeterminate. HIV infection status was confirmed positive in 83 (81%) infants, negative in 8 (8%), uncertain in 5 (5%) and LTFU in 6 (6%) cases. The positive predictive value (excluding cases of uncertain diagnosis and inadequate testing) following a non‐negative HIV‐1 PCR screening test at birth was 0.91 (83/91; 95% confidence interval: 0.85–0.96). Neonates testing positive at birth had significantly higher viral load (VL) results than those testing indeterminate at birth of 4.5 and 3.0 log copies/ml (p = 0.0007), respectively. Similarly, mothers of neonates with positive as compared to indeterminate birth test results had higher VLs of 4.5 and 2.7 log copies/ml (p = 0.0013), respectively. Half of neonates with an indeterminate birth test were shown to be HIV‐infected on subsequent confirmatory testing, with time to final diagnosis 30 days longer for these neonates (p < 0.0001).

Conclusion: Indeterminate HIV‐1 PCR results accounted for a quarter of non‐negative results at birth and were associated with a high risk of infection in comparison to the risk of in utero transmission. Indeterminate birth results with positive HIV PCR results on repeat testing were associated with later final diagnosis. The HIV‐1 status remains uncertain in a minority of cases because of repeatedly indeterminate results, highlighting the need for more sensitive and specific virological tests.

Time to first positive HIV-1 DNA PCR may differ with antiretroviral regimen in infants infected with non-B subtype HIV-1

OBJECTIVE

To evaluate the association of type and timing of prophylactic maternal and infant antiretroviral regimen with time to first positive HIV-1 DNA PCR test, in nonbreastfed HIV-infected infants, from populations infected predominantly with HIV-1 non-B subtype virus.

DESIGN

Analysis of combined data on nonbreastfed HIV-infected infants from prospective cohorts in Botswana, Thailand, and the United Kingdom (N = 405).

METHODS

Parametric models appropriate for interval-censored outcomes estimated the time to first positive PCR according to maternal or infant antiretroviral regimen category and timing of maternal antiretroviral initiation, with adjustment for covariates.

RESULTS

Maternal antiretroviral regimens included: no antiretrovirals (n = 138), single-nucleoside analog reverse transcriptase inhibitor (n = 165), single-dose nevirapine with zidovudine (n = 66), and combination prophylaxis with 3 or more antiretrovirals [combination antiretroviral therapy (cART), n = 36]. Type of maternal/infant antiretroviral regimen and timing of maternal antiretroviral initiation were each significantly associated with time to first positive PCR (multivariate P < 0.0001). The probability of a positive test with no antiretrovirals compared with the other regimen/timing groups was significantly lower at 1 day after birth, but did not differ significantly after age 14 days. In a subgroup of 143 infants testing negative at birth, infant cART was significantly associated with longer time to first positive test (multivariate P = 0.04).

CONCLUSION

Time to first positive HIV-1 DNA PCR in HIV-1-infected nonbreastfed infants (non-B HIV subtype) may differ according to maternal/infant antiretroviral regimen and may be longer with infant cART, which may have implications for scheduling infant HIV PCR-diagnostic testing and confirming final infant HIV status.

The value of confirmatory testing in early infant HIV diagnosis programmes in South Africa: A cost-effectiveness analysis

BACKGROUND

The specificity of nucleic acid amplification tests (NAATs) used for early infant diagnosis (EID) of HIV infection is <100%, leading some HIV-uninfected infants to be incorrectly identified as HIV-infected. The World Health Organization recommends that infants undergo a second NAAT to confirm any positive test result, but implementation is limited. Our objective was to determine the impact and cost-effectiveness of confirmatory HIV testing for EID programmes in South Africa.

METHOD AND FINDINGS

Using the Cost-effectiveness of Preventing AIDS Complications (CEPAC)-Pediatric model, we simulated EID testing at age 6 weeks for HIV-exposed infants without and with confirmatory testing. We assumed a NAAT cost of US$25, NAAT specificity of 99.6%, NAAT sensitivity of 100% for infants infected in pregnancy or at least 4 weeks prior to testing, and a mother-to-child transmission (MTCT) rate at 12 months of 4.9%; we simulated guideline-concordant rates of testing uptake, result return, and antiretroviral therapy (ART) initiation (100%). After diagnosis, infants were linked to and retained in care for 10 years (false-positive) or lifelong (true-positive). All parameters were varied widely in sensitivity analyses. Outcomes included number of infants with false-positive diagnoses linked to ART per 1,000 ART initiations, life expectancy (LE, in years) and per-person lifetime HIV-related healthcare costs. Both without and with confirmatory testing, LE was 26.2 years for HIV-infected infants and 61.4 years for all HIV-exposed infants; clinical outcomes for truly infected infants did not differ by strategy. Without confirmatory testing, 128/1,000 ART initiations were false-positive diagnoses; with confirmatory testing, 1/1,000 ART initiations were false-positive diagnoses. Because confirmatory testing averted costly HIV care and ART in truly HIV-uninfected infants, it was cost-saving: total cost US$1,790/infant tested, compared to US$1,830/infant tested without confirmatory testing. Confirmatory testing remained cost-saving unless NAAT cost exceeded US$400 or the HIV-uninfected status of infants incorrectly identified as infected was ascertained and ART stopped within 3 months of starting. Limitations include uncertainty in the data used in the model, which we examined with sensitivity and uncertainty analyses. We also excluded clinical harms to HIV-uninfected infants incorrectly treated with ART after false-positive diagnosis (e.g., medication toxicities); including these outcomes would further increase the value of confirmatory testing.

CONCLUSIONS

Without confirmatory testing, in settings with MTCT rates similar to that of South Africa, more than 10% of infants who initiate ART may reflect false-positive diagnoses. Confirmatory testing prevents inappropriate HIV diagnosis, is cost-saving, and should be adopted in all EID programmes.

Multicountry Validation of SAMBA - A Novel Molecular Point-of-Care Test for HIV-1 Detection in Resource-Limited Setting

INTRODUCTION

Early diagnosis of HIV-1 infection and the prompt initiation of antiretroviral therapy are critical to achieving a reduction in the morbidity and mortality of infected infants. The Simple AMplification-Based Assay (SAMBA) HIV-1 Qual Whole Blood Test was developed specifically for early infant diagnosis and prevention of mother-to-child transmission programs implemented at the point-of-care in resource-limited settings.

METHODS

We have evaluated the performance of this test run on the SAMBA I semiautomated platform with fresh whole blood specimens collected from 202 adults and 745 infants in Kenya, Uganda, and Zimbabwe. Results were compared with those obtained with the Roche COBAS AmpliPrep/COBAS TaqMan (CAP/CTM) HIV-1 assay as performed with fresh whole blood or dried blood spots of the same subjects, and discrepancies were resolved with alternative assays.

RESULTS

The performance of the SAMBA and CAP/CTM assays evaluated at 5 laboratories in the 3 countries was similar for both adult and infant samples. The clinical sensitivity, specificity, positive predictive value, and negative predictive value for the SAMBA test were 100%, 99.2%, 98.7%, and 100%, respectively, with adult samples, and 98.5%, 99.8%, 99.7%, and 98.8%, respectively, with infant samples.

DISCUSSION

Our data suggest that the SAMBA HIV-1 Qual Whole Blood Test would be effective for early diagnosis of HIV-1 infection in infants at point-of-care settings in sub-Saharan Africa.

Performance of Virological Testing for Early Infant Diagnosis: A Systematic Review

BACKGROUND

Improved access to both maternal antiretroviral therapy and infant prophylaxis may have an impact on the performance of virological assays for diagnosis of HIV infection in infants. This systematic review was performed to assess the diagnostic accuracy of virological testing at birth as well as the performance of virological testing on dried blood spots at 6 weeks among HIV- and antiretroviral (ARV)-exposed infants.

METHODS

A systematic review was performed for studies published between January 1, 2009 and January 30, 2015. The search strategy included studies related to HIV, nucleic acid amplification tests, and newborns/infants and queried PubMed, Embase, the Cochrane Library, LILACS as well as several conference proceedings. Two independent reviewers collected studies and extracted data. The final analysis includes summary estimates of the sensitivities and specificities of the virological assays assessed. The GRADE approach was used to assess the overall quality of evidence and Quality Assessment of Diagnostic Accuracy Studies was used to evaluate the risk of bias in the studies.

RESULTS

A total of 2243 records were screened with a final selection of 5 manuscripts. To assess the test characteristics of virological testing at birth, 2 studies were used to calculate a pooled sensitivity of 69.3% (95% confidence interval: 61.1 to 77.4) and a specificity of 99.9% (98.6-100%). The quality of evidence to support the sensitivity of assays at birth was low, whereas the quality of evidence for the specificity of such tests was intermediate-high. In terms of the performance of virological testing on dried blood spots for HIV- and ARV-exposed infants, 3 studies were used to calculate a pooled sensitivity of 99.4% (98.3-100.00%) and specificity of 99.6% (99.1-100.00%). The quality of evidence for both outcomes was low.

CONCLUSION

The performance of polymerase chain reaction at birth demonstrates low sensitivity and high specificity, reflecting the difficulty of detecting intrapartum infections at birth and transmission dynamics. In addition, there is no evidence to suggest poor performance of virological testing on dried blood spots for ARV-exposed infants. Overall, given the very limited and low-quality evidence, further research is needed to assess the accuracy of polymerase chain reaction at different time points and in the context of more effective prevention of mother-to-child transmission interventions.

Moving forward with treatment options for HIV-infected children

INTRODUCTION

Current international guidelines recommend to treat all HIV-1 infected patients regardless of CD4 cell count. Despite the remarkable worldwide progress for universal access to antiretroviral during the last decade, the pediatric population remains fragile due to lack of randomized studies, inappropriate antiretroviral formulations, adherence difficulties, drug toxicity and development of resistance.

AREAS COVERED

This review summarizes the latest recommendations and advances for the treatment of HIV-infected children and highlights the potential complications of a lifelong antiretroviral treatment initiated early in life.

EXPERT OPINION

International guidelines recommend to start combination antiretroviral therapy (cART) as fast as possible in all children diagnosed with HIV-1. The principal goal is to improve survival and reduce mortality as well as rapidly decrease HIV reservoirs. This remains a challenge in resource-limited settings were diagnostic tools and treatment access may be limited. Different new strategies are in the pipeline such as immunotherapy in combination with very early cART initiation to seek remission or functional cure. For the time being and awaiting for long term remission or cure, there is a need for further pharmacokinetics studies, more pediatric formulations with improved palatability and implementation of randomized trials for the newer antiretroviral drugs.

Optimizing Infant HIV Diagnosis in Resource-Limited Settings: Modeling the Impact of HIV DNA PCR Testing at Birth

BACKGROUND

Early antiretroviral therapy (ART) initiation in HIV-infected infants significantly improves survival but is often delayed in resource-limited settings. Adding HIV testing of infants at birth to the current recommendation of testing at age 4-6 weeks may improve testing rates and decrease time to ART initiation. We modeled the benefit of adding HIV testing at birth to the current 6-week testing algorithm.

METHODS

Microsoft Excel was used to create a decision-tree model of the care continuum for the estimated 1,400,000 HIV-infected women and their infants in sub-Saharan Africa in 2012. The model assumed average published rates for facility births (42.9%), prevention of mother-to-child HIV transmission utilization (63%), mother-to-child-transmission rates based on prevention of mother-to-child HIV transmission regimen (5%-40%), return of test results (41%), enrollment in HIV care (52%), and ART initiation (54%). We conducted sensitivity analyses to model the impact of key variables and applied the model to specific country examples.

RESULTS

Adding HIV testing at birth would increase the number of infants on ART by 204% by age 18 months. The greatest increase is seen in early ART initiations (543% by age 3 months). The increase would lead to a corresponding increase in survival at 12 months of age, with 5108 fewer infant deaths (44,550, versus 49,658).

CONCLUSION

Adding HIV testing at birth has the potential to improve the number and timing of ART initiation of HIV-infected infants, leading to a decrease in infant mortality. Using this model, countries should investigate a combination of HIV testing at birth and during the early infant period.

Total HIV-1 DNA, a Marker of Viral Reservoir Dynamics with Clinical Implications

HIV-1 DNA persists in infected cells despite combined antiretroviral therapy (cART), forming viral reservoirs. Recent trials of strategies targeting latent HIV reservoirs have rekindled hopes of curing HIV infection, and reliable markers are thus needed to evaluate viral reservoirs. Total HIV DNA quantification is simple, standardized, sensitive, and reproducible. Total HIV DNA load influences the course of the infection and is therefore clinically relevant. In particular, it is predictive of progression to AIDS and death, independently of HIV RNA load and the CD4 cell count. Baseline total HIV DNA load is predictive of the response to cART. It declines during cART but remains quantifiable, at a level that reflects both the history of infection (HIV RNA zenith, CD4 cell count nadir) and treatment efficacy (residual viremia, cumulative viremia, immune restoration, immune cell activation). Total HIV DNA load in blood is also predictive of the presence and severity of some HIV-1-associated end-organ disorders. It can be useful to guide individual treatment, notably, therapeutic de-escalation. Although it does not distinguish between replication-competent and -defective latent viruses, the total HIV DNA load in blood, tissues, and cells provides insights into HIV pathogenesis, probably because all viral forms participate in host cell activation and HIV pathogenesis. Total HIV DNA is thus a biomarker of HIV reservoirs, which can be defined as all infected cells and tissues containing all forms of HIV persistence that participate in pathogenesis. This participation may occur through the production of new virions, creating new cycles of infection and disseminating infected cells; maintenance or amplification of reservoirs by homeostatic cell proliferation; and viral transcription and synthesis of viral proteins without new virion production. These proteins can induce immune activation, thus participating in the vicious circle of HIV pathogenesis.

On the duration of the period between exposure to HIV and detectable infection

HIV infection cannot be detected immediately after exposure because plasma viral loads are too small initially. The duration of this phase of infection (the "eclipse period") is difficult to estimate because precise dates of exposure are rarely known. Therefore, the reliability of clinical HIV testing during the first few weeks of infection is unknown, creating anxiety among HIV-exposed individuals and their physicians. We address this by fitting stochastic models of early HIV infection to detailed viral load records for 78 plasma donors, taken during the period of exposure and infection. We first show that the classic stochastic birth-death model does not satisfactorily describe early infection. We therefore apply a different stochastic model that includes infected cells and virions separately. Since every plasma donor in our data eventually becomes infected, we must condition the model to reflect this bias, before fitting to the data. Applying our best estimates of unknown parameter values, we estimate the mean eclipse period to be 8-10 days. We further estimate the reliability of a negative test t days after potential exposure.

Infectious Diseases of Poverty in Children: A Tale of Two Worlds

"Infectious diseases of poverty" (IDoP) describes infectious diseases that are more prevalent among poor and vulnerable populations, namely human immunodeficiency virus (HIV) infection, tuberculosis (TB), malaria, and neglected tropical diseases (NTDs). In 2013, 190,000 children died of HIV-related causes and there were 550,000 cases and 80,000 TB deaths in children. Children under age 5 account for 78% of malaria deaths annually. NTDs remain a public health challenge in low- and middle-income countries. This article provides an overview of the major IDoP that affect children. Clinicians must be familiar with the epidemiology and clinical manifestations to ensure prompt diagnosis and treatment.