HIV misdiagnosis in sub-Saharan Africa: performance of diagnostic algorithms at six testing sites

Lessons learnt from assessing and improving accuracy and positive predictive value of the national HIV testing algorithm in Nigeria

Background

HIV testing remains an entry point into HIV care and treatment services. In 2007, Nigeria adopted and implemented a two-test rapid HIV testing algorithm of three HIV rapid test kits, following the sequence: Alere Determine (first test), UnigoldTM (second test), and STAT-PAK® as the tie-breaker. Sub-analysis of the 2018 Nigeria HIV/AIDS Indicator and Impact Survey data showed significant discordance between the first and second tests, necessitating an evaluation of the algorithm. This manuscript highlights lessons learnt from that evaluation.

Intervention

A two-phased evaluation method was employed, including abstraction and analysis of retrospective HIV testing data from January 2017 to December 2019 from 24 selected sites supported by the United States President's Emergency Plan for AIDS Relief programme. A prospective evaluation of HIV testing was done among 2895 consecutively enrolled and consented adults, aged 15-64 years, accessing HIV testing services from three selected sites per state across the six geopolitical zones of Nigeria between July 2020 and September 2020. The prospective evaluation was performed both in the field and at the National Reference Laboratory under controlled laboratory conditions. Stakeholder engagements, strategic selection and training of study personnel, and integrated supportive supervision were employed to assure the quality of evaluation procedures and outcomes.

Lessons learnt

The algorithm showed higher sensitivity and specificity in the National Reference Laboratory compared with the field. The approaches to quality assurance were integral to the high-quality study outcomes.

Recommendations

We recommend comparison of testing algorithms under evaluation against a gold standard.

What this study adds

This study provides context-specific considerations in using World Health Organization recommendations to evaluate the Nigerian national HIV rapid testing algorithm.

Sensitivity and specificity of the new Bio-Rad HIV screening test, Access HIV combo V2

Diagnosing of human immunodeficiency virus (HIV) types 1 and 2 requires a screening with a highly sensitive and specific enzyme immunoassay and a low detection limit for the HIV-1 p24 antigen to minimize the diagnostic window. The objective of the study was to determine the sensitivity, specificity, and p24 limit of detection of the Access HIV combo V2 assay. Retrospective part of sensitivity: 452 HIV-1 positive samples from 403 chronic (9 different HIV-1 group M subtypes, 22 different HIV-1 group M CRFs, and 3 HIV-1 group O), 49 primary HIV-1 infections, 103 HIV-2 positive samples assessed at Pitié-Salpêtrière Hospital, 600 untyped HIV-1, 10 subtype-D, and 159 untyped HIV-2 samples assessed in Bio-Rad Laboratories. Prospective part of clinical specificity: all consecutive samples in two blood donor facilities and Pitié-Salpêtrière (6,570 patients) tested with Access HIV combo V2 and respectively Prism HIV O Plus (Abbott) or Architect HIV Ag/Ab Combo (Abbott) for Ag/Ab screening, and Procleix Ultrio (Gen Probe) for HIV RNA screening. Limit of detection for p24 antigen was assessed on recombinant virus-like particles (10 HIV-1 group M subtypes/CRFs, HIV-1 group O). Sensitivity [95% confidence interval (CI)] of Access HIV combo V2 was 100% (99.63-100) for HIV-1 chronic infection, 100% (98.55-100) for HIV-2 chronic infection, and 100% (93.00-100) for HIV-1 primary infection. Specificity (95% CI) was 99.98 (99.91-100). Limit of detection for p24 antigen was around 0.43 IU/mL [interquartile range (0.38-0.56)], and consistent across the 11 analyzed subtypes/CRFs. Hence, with both high sensitivity and specificity, Access HIV combo V2 is a suitable screening assay for HIV-1/2 infection.

IMPORTANCE

Bio-Rad is one of the leading human immunodeficiency virus (HIV) screening test manufacturers. This laboratory released in 2021 their new version of the Access combo HIV test. However, to date, there have been no studies regarding its performance, especially its limit of detection of the diverse p24 antigen. We present the sensitivity (chronic and primary HIV-1 infection and HIV-2 chronic infection), specificity (blood donors and hospitalized patients), and raw data for the p24/seroconversion panels the manufacturer gave to the European agencies.

Brief Report: Self-Reported HIV-Positive Status but Subsequent HIV-Negative Test Results in Population-Based HIV Impact Assessment Survey Participants-11 Sub-Saharan African Countries, 2015-2018

BACKGROUND

HIV testing is a critical step to accessing antiretroviral therapy (ART) because early diagnosis can facilitate earlier initiation of ART. This study presents aggregated data of individuals who self-reported being HIV-positive but subsequently tested HIV-negative during nationally representative Population-Based HIV Impact Assessment surveys conducted in 11 countries from 2015 to 2018.

METHOD

Survey participants aged 15 years or older were interviewed by trained personnel using a standard questionnaire to determine HIV testing history and self-reported HIV status. Home-based HIV testing and counseling using rapid diagnostic tests with return of results were performed by survey staff according to the respective national HIV testing services algorithms on venous blood samples. Laboratory-based confirmatory HIV testing for all participants identified as HIV-positives and self-reported positives, irrespective of HIV testing results, was conducted and included Geenius HIV-1/2 and DNA polymerase chain reaction if Geenius was negative or indeterminate.

RESULTS

Of the 16,630 participants who self-reported as HIV-positive, 16,432 (98.6%) were confirmed as HIV-positive and 198 (1.4%) were HIV-negative by subsequent laboratory-based testing. Participants who self-reported as HIV-positive but tested HIV-negative were significantly younger than 30 years, less likely to have received ART, and less likely to have received a CD4 test compared with participants who self-reported as HIV-positive with laboratory-confirmed infection.

CONCLUSIONS

A small proportion of self-reported HIV-positive individuals could not be confirmed as positive, which could be due to initial misdiagnosis, deliberate wrong self-report, or misunderstanding of the questionnaire. As universal ART access is expanding, it is increasingly important to ensure quality of HIV testing and confirmation of HIV diagnosis before ART initiation.

An Incognito Standardized Patient Approach for Measuring and Reducing Intersectional Healthcare Stigma

Background

Consistent evidence highlights the role of stigma in impairing healthcare access in people living with HIV (PLWH), men who have sex with men (MSM), and people with both identities. We developed an incognito standardized patient (SP) approach to obtain observations of providers to inform a tailored, relevant, and culturally appropriate stigma reduction training. Our pilot cluster randomized control trial assessed the feasibility, acceptability, and preliminary effects of an intervention to reduce HIV stigma, anti-gay stigma, and intersectional stigma.

Methods

Design of the intervention was informed by the results of a baseline round of incognito visits in which SPs presented standardized cases to consenting doctors. The HIV status and sexual orientation of each case was randomly varied, and stigma was quantified as differences in care across scenarios. Care quality was measured in terms of diagnostic testing, diagnostic effort, and patient-centered care. Impact of the training, which consisted of didactic, experiential, and discussion-based modules, was assessed by analyzing results of a follow-up round of SP visits using linear fixed effects regression models.

Results

Feasibility and acceptability among the 55 provider participants was high. We had a 87.3% recruitment rate and 74.5% completion rate of planned visits (N=238) with no adverse events. Every participant found the training content "highly useful" or "useful." Preliminary effects suggest that, relative to the referent case (HIV negative straight man), the intervention positively impacted testing for HIV negative MSM (0.05 percentage points [PP], 95% CI,-0.24, 0.33) and diagnostic effort in HIV positive MSM (0.23 standard deviation [SD] improvement, 95% CI, -0.92, 1.37). Patient-centered care only improved for HIV positive straight cases post-training relative to the referent group (SD, 0.57; 95% CI, -0.39, 1.53). All estimates lacked statistical precision, an expected outcome of a pilot RCT.

Conclusions

Our pilot RCT demonstrated high feasibility, acceptability, and several areas of impact for an intervention to reduce enacted healthcare stigma in a low-/middle-income country setting. The relatively lower impact of our intervention on care outcomes for PLWH suggests that future trainings should include more clinical content to boost provider confidence in the safe and respectful management of patients with HIV.

Perceived norms about male circumcision and personal circumcision status: a cross-sectional, population-based study in rural Uganda

Introduction

Over the past decade, 15 high-priority countries in eastern and southern Africa have promoted voluntary medical male circucmsion for HIV and STI prevention. Despite male circumcision prevalence in Uganda nearly doubling from 26% in 2011 to 43% in 2016, it remained below the target level by 2020. Little is known about perceived norms of male circumcision and their association with circumcision uptake among men.

Methods

We conducted a cross-sectional study targeting all adult residents across eight villages in Rwampara District, southwestern Uganda in 2020-2022. We compared what men and women reported as the adult male circumcision prevalence within their village (perceived norm: >50% (most), 10% to <50% (some), <10%, (few), or do not know) to the aggregated prevalence of circumcision as reported by men aged <50 years. We used a modified multivariable Poisson regression model to estimate the association between perceived norms about male circumcision uptake and personal circumcision status among men.

Results

Overall, 167 (38%) men < 50 years old were circumcised (and 27% of all men were circumcised). Among all 1566 participants (91% response rate), 189 (27%) men and 177 (20%) women underestimated the male circumcision prevalence, thinking that few men in their own village had been circumcised. Additionally, 10% of men and 25% of women reported not knowing the prevalence. Men who underestimated the prevalence were less likely to be circumcised (aRR = 0.51, 95% CI 0.37 to 0.83) compared to those who thought that some village men were circumcised, adjusting for perceived personal risk of HIV, whether any same-household women thought most men were circumcised, and other sociodemographic factors.

Conclusions

Across eight villages, a quarter of the population underestimated the local prevalence of male circumcision. Men who underestimated circumcision uptake were less likely to be circumcised. Future research should evaluate norms-based approaches to promoting male circumcision uptake. Strategies may include disseminating messages about the increasing prevalence of adult male circumcision uptake in Uganda and providing personalized normative feedback to men who underestimated local rates about how uptake is greater than they thought.

Challenges faced by the HIV testing system in low- and middle-income countries

Introduction

Determining the HIV status of some individuals remains challenging due to multidimensional factors such as flaws in diagnostic systems, technological challenges, and viral diversity. This report pinpoints challenges faced by the HIV testing system in Cameroon.

Case presentation

A 53-year-old male received a positive HIV result by a rapid testing algorithm in July 2016. Not convinced of his HIV status, he requested additional tests. In February 2017, he received a positive result using ImmunoComb^® II HIV 1 & 2 BiSpot and Roche cobas electrochemiluminescence assays. A sample sent to France in April 2017 was positive on the Bio-Rad GenScreen™ HIV 1/2, but serotyping was indeterminate, and viral load was < 20 copies/mL. The Roche electrochemiluminescence immunoassay and INNO-LIA HIV I/II Score were negative for samples collected in 2018. A sample collected in July 2019 and tested with VIDAS^® HIV Duo Ultra enzyme-linked fluorescent assay and Geenius™ HIV 1/2 Confirmatory Assay was positive, but negative with Western blot; CD4 count was 1380 cells/mm³ and HIV proviral DNA tested in France was 'target-not-detected'. Some rapid tests were still positive in 2020 and 2021. Serotyping remained indeterminate, and viral load was 'target-not-detected'. There were no self-reported exposure to HIV risk factors, and his wife was HIV-seronegative.

Management and outcome

Given that the patient remained asymptomatic with no evidence of viral replication, no antiretroviral therapy was initiated.

Conclusion

This case highlights the struggles faced by some individuals in confirming their HIV status and the need to update existing technologies and develop an algorithm for managing exceptional cases.

Evaluation of the Nigeria national HIV rapid testing algorithm

Human Immunodeficiency Virus (HIV) diagnosis remains the gateway to HIV care and treatment. However, due to changes in HIV prevalence and testing coverage across different geopolitical zones, it is crucial to evaluate the national HIV testing algorithm as false positivity due to low prevalence could be detrimental to both the client and the service delivery. Therefore, we evaluated the performance of the national HIV rapid testing algorithm using specimens collected from multiple HIV testing services (HTS) sites and compared the results from different HIV prevalence levels across the six geopolitical zones of Nigeria. The evaluation employed a dual approach, retrospective, and prospective. The retrospective evaluation focused on a desktop review of program data (n = 492,880) collated from patients attending routine HTS from six geopolitical zones of Nigeria between January 2017 and December 2019. The prospective component utilized samples (n = 2,895) collected from the field at the HTS and tested using the current national serial HIV rapid testing algorithm. These samples were transported to the National Reference Laboratory (NRL), Abuja, and were re-tested using the national HIV rapid testing algorithm and HIV-1/2 supplementary assays (Geenius to confirm positives and resolve discordance and multiplex assay). The retrospective component of the study revealed that the overall proportion of HIV positives, based on the selected areas, was 5.7% (28,319/492,880) within the study period, and the discordant rate between tests 1 and 2 was 1.1%. The prospective component of the study indicated no significant differences between the test performed at the field using the national HIV rapid testing algorithm and the re-testing performed at the NRL. The comparison between the test performed at the field using the national HIV rapid testing algorithm and Geenius HIV-1/2 supplementary assay showed an agreement rate of 95.2%, while that of the NRL was 99.3%. In addition, the comparison of the field results with HIV multiplex assay indicated a sensitivity of 96.6%, the specificity of 98.2%, PPV of 97.0%, and Kappa Statistic of 0.95, and that of the NRL with HIV multiplex assay was 99.2%, 99.4%, 99.0%, and 0.99, respectively. Results show that the Nigeria national serial HIV rapid testing algorithm performed very well across the target settings. However, the algorithm's performance in the field was lower than the performance outcomes under a controlled environment in the NRL. There is a need to target testers in the field for routine continuous quality improvement implementation, including refresher trainings as necessary.

Vaccine-Induced Seroreactivity Impacts the Accuracy of HIV Testing Algorithms in Sub-Saharan Africa: An Exploratory Study

The detection of vaccine-induced HIV antibody responses by rapid diagnostic tests (RDTs) may confound the interpretation of HIV testing results. We assessed the impact of vaccine-induced seroreactivity (VISR) on the diagnosis of HIV in sub-Saharan Africa. Samples collected from healthy participants of HIVIS and TaMoVac HIV vaccine trials after the final vaccination were analyzed for VISR using HIV testing algorithms used in Mozambique and Tanzania that employ two sequential RDTs. The samples were also tested for VISR using Enzygnost HIV Integral 4 ELISA and HIV western blot assays. Antibody titers to subtype C gp140 were determined using an in-house enzyme-linked immunosorbent assay (ELISA). The frequency of VISR was 93.4% (128/137) by Enzygnost HIV Integral 4 ELISA, and 66.4% (91/137) by western blot assay (WHO interpretation). The proportion of vaccine recipients that would have been misdiagnosed as HIV-positive in Mozambique was half of that in Tanzania: 26.3% (36/137) and 54.0% (74/137), respectively, p < 0.0001. In conclusion, the HIV RDTs and algorithms assessed here will potentially misclassify a large proportion of the HIV vaccine recipients if no other test is used. Increased efforts are needed to develop differential serological or molecular tools for use at the point of care.

Performance evaluation of the Asante Rapid Recency Assay for verification of HIV diagnosis and detection of recent HIV-1 infections: Implications for epidemic control

We previously described development of a rapid test for recent infection (RTRI) that can diagnose HIV infection and detect HIV-1 recent infections in a single device. This technology was transferred to a commercial partner as Asante Rapid Recency Assay (ARRA). We evaluated performance of the ARRA kits in the laboratory using a well-characterized panel of specimens. The plasma specimen panel (N = 1500) included HIV-1 (N = 570), HIV-2 (N = 10), and HIV-negatives (N = 920) representing multiple subtypes and geographic locations. Reference diagnostic data were generated using the Bio-Rad HIV-1-2-O EIA/Western blot algorithm with further serotyping performed using the Multispot HIV-1/2 assay. The LAg-Avidity EIA was used to generate reference data on recent and long-term infection for HIV-1 positive specimens at a normalized optical density (ODn) cutoff of 2.0 corresponding to a mean duration of about 6 months. All specimens were tested with ARRA according to the manufacturer's recommendations. Test strips were also read for line intensities using a reader and results were correlated with visual interpretation. ARRA's positive verification line (PVL) correctly classified 575 of 580 HIV-positive and 910 of 920 negative specimens resulting in a sensitivity of 99.1% (95% CI: 98.0-99.6) and specificity of 98.9% (95% CI: 98.1-99.4), respectively. The reader-based classification was similar for PVL with sensitivity of 99.3% (576/580) and specificity of 98.8% (909/920). ARRA's long-term line (LTL) classified 109 of 565 HIV-1 specimens as recent and 456 as long-term compared to 98 as recent and 467 as long-term (LT) by LAg-Avidity EIA (cutoff ODn = 2.0), suggesting a mean duration of recent infection (MDRI) close to 6 months. Agreement of ARRA with LAg recent cases was 81.6% (80/98) and LT cases was 93.8% (438/467), with an overall agreement of 91.7% (kappa = 0.72). The reader (cutoff 2.9) classified 109/566 specimens as recent infections compared to 99 by the LAg-Avidity EIA for recency agreement of 81.8% (81/99), LT agreement of 9% (439/467) with overall agreement of 91.9% (kappa = 0.72). The agreement between visual interpretation and strip reader was 99.9% (95% CI: 99.6-99.9) for the PVL and 98.1% (95% CI: 96.6-98.9) for the LTL. ARRA performed well with HIV diagnostic sensitivity >99% and specificity >98%. Its ability to identify recent infections is comparable to the LA-Avidity EIA corresponding to an MDRI of about 6 months. This point-of-care assay has implications for real-time surveillance of new infections among newly diagnosed individuals for targeted prevention and interrupting ongoing transmission thus accelerating epidemic control.

HIV-1 diagnosis using dried blood spots from patients in Kinshasa, DRC: a tool to detect misdiagnosis and achieve World Health Organization 2030 targets

INTRODUCTION

Currently, only 54% of the population of the Democratic Republic of the Congo (DRC) know their HIV status. The aim of this study was to detect HIV misdiagnosis from rapid diagnostic tests (RDT) and to evaluate serological immunoassays using dried blood spots (DBS) from patients in Kinshasa, DRC.

METHODS

Between 2016 and 2018, 365 DBS samples were collected from 363 individuals and shipped to Spain. The samples were from people with a new HIV positive (n = 123) or indeterminate (n = 23) result, known HIV-positive patients (n = 157), and a negative control group (n = 62). HIV serology was performed using Elecsys HIV combi PT (Roche), VIDAS HIV Duo Quick (BioMérieux), and Geenius (Bio-Rad). In addition, HIV RNA detection was performed in all samples using the COBAS AmpliPrep/COBAS Taqman HIV-1 Test 2.0 (Roche).

RESULTS

Overall, 272 samples were found to be positive and 93 to be negative for HIV serology. The sensitivity was 100% for both Elecsys and VIDAS techniques, but specificity was slightly higher for the VIDAS test: 100% (96.1-100%) vs 98.9% (94.1-99.9%). Of the 23 indeterminate cases using RDT, only three cases were true-positives with a detectable viral load. Eleven samples out of the 280 classified as positive by RDT corresponded to nine patients who had received a false diagnosis of HIV through RDT (3.9%); six of them had been on antiretroviral therapy for at least 2 years.

CONCLUSIONS

Elecsys HIV combi PT and VIDAS HIV Duo Quick immunoassays showed high sensitivity and specificity when using DBS. RDT-based serological diagnosis can lead to HIV misdiagnosis with personal and social consequences in sub-Saharan Africa.

Reconfirming HIV serostatus in three West African Military ART clinics

BACKGROUND

HIV rapid diagnostic test (RDT) algorithms have been successfully employed worldwide to accelerate critically important HIV testing. Deviations from the algorithm and processing errors have been associated with inaccurate algorithm results. Positive RDT algorithm results should be confirmed prior to HIV clinic enrollment, but compliance varies. We sought to retest HIV status of patients in three West African military HIV clinics.

SETTING

Military HIV clinics in Lome, Togo; Freetown, Sierra Leone; and Monrovia, Liberia METHODS: Patients coming for routine HIV clinic visits were approached for enrollment. Consenting participants completed a 15-minute questionnaire and provided blood samples for both national and WHO-recommended HIV RDT algorithms, and HIV ELISA (plus HIV PCR if HIV ELISA negative).

RESULTS

In total, 817 participants provided data: 374 in Togo, 360 in Sierra Leone, and 83 in Liberia. One participant from Liberia was HIV-negative (although follow-up testing was positive). Two of 807 participants on antiretroviral treatment (ART) had inconclusive algorithms, while 2 of 10 participants not on ART had algorithms, for 4 total based on the WHO-approved algorithm. Using the national algorithms, only 3 were inconclusive. A substantial proportion of the cohort had taken ART for over 6 years (25-46%, depending on the site).

CONCLUSION

HIV RDT retesting in three military HIV clinics did not uncover significant numbers of misclassified HIV patients. There was no significant difference between national and WHO-recommended RDT algorithms, although the study was underpowered to detect a difference. Antiretroviral treatment was not associated with increased rates of inconclusive RDT algorithm results.

HIV testing approaches to reach the first UNAIDS 95% target in sub-Saharan Africa

HIV testing is a crucial first step to accessing HIV prevention and treatment services and to achieving the UNAIDS target of 95% of people living with HIV being aware of their status by 2030. Combined implementation of facility-based and community-based approaches has helped to achieve high levels of HIV testing coverage in many countries including those in sub-Saharan Africa. Approaches such as index testing and self-testing help to reach individuals at higher risk of acquiring HIV, men, and those less likely to use health facilities or community-based services. However, as the proportion of people living with HIV who are aware of their HIV status has risen, the challenge of reaching those who remain undiagnosed or those who are at high risk of acquiring HIV has grown. Demand generation and novel testing approaches will be necessary to reach undiagnosed people living with HIV and to promote frequent retesting among key and priority populations.

Challenges in transfusion-transmitted infection screening in Sub-Saharan Africa

In Sub-Saharan Africa, high clinical demand for transfusion faces endemic bloodborne infections and limited resources. Blood screening for transfusion-transmitted bloodborne pathogens is the cornerstone of blood safety. Although there have been substantial improvements over the years, challenges in transfusion-transmitted infection screening that have been identified repeatedly long ago still need to be addressed. Affordability and sustainability of state-of-the-art quality assessed serological and molecular assays, and associated confirmation strategies remain of real concern. In addition, limited resources and infrastructures hamper the development of adequate facilities, quality management, and staff qualification, and exacerbate shortage of reagents and equipment maintenance. It is also important to maintain effort in constituting pools of repeat voluntary non-remunerated donors. Alternative strategies for blood screening that take into account local circumstances might be desirable but they should rely on appropriate field evaluation and careful economic assessment rather than dogma established from high-resource settings.

Successes and gaps in the HIV cascade of care of a high HIV prevalence setting in Zimbabwe: a population-based survey

INTRODUCTION

Gutu, a rural district in Zimbabwe, has been implementing comprehensive HIV care with the support of Médecins Sans Frontières (MSF) since 2011, decentralizing testing and treatment services to all rural healthcare facilities. We evaluated HIV prevalence, incidence and the cascade of care, in Gutu District five years after MSF began its activities.

METHODS

A cross-sectional study was implemented between September and December 2016. Using multistage cluster sampling, individuals aged ≥15 years living in the selected households were eligible. Individuals who agreed to participate were interviewed and tested for HIV at home. All participants who tested HIV-positive had their HIV-RNA viral load (VL) measured, regardless of their antiretroviral therapy (ART) status, and those not on ART with HIV-RNA VL ≥ 1000 copies/mL had Limiting-Antigen-Avidity EIA Assay for cross-sectional estimation of population-level HIV incidence.

RESULTS

Among 5439 eligible adults ≥15 years old, 89.0% of adults were included in the study and accepted an HIV test. The overall prevalence was 13.6% (95%: Confidence Interval (CI): 12.6 to 14.5). Overall HIV-positive status awareness was 87.4% (95% CI: 84.7 to 89.8), linkage to care 85.5% (95% CI: 82.5 to 88.0) and participants in care 83.8% (95% CI: 80.7 to 86.4). ART coverage among HIV-positive participants was 83.0% (95% CI: 80.0 to 85.7). Overall, 71.6% (95% CI 68.0 to 75.0) of HIV-infected participants had a HIV-RNA VL < 1000 copies/mL. Women achieved higher outcomes than men in the five stages of the cascade of care. Viral Load Suppression (VLS) among participants on ART was 83.2% (95% CI: 79.7 to 86.2) and was not statistically different between women and men (p = 0.98). The overall HIV incidence was estimated at 0.35% (95% CI 0.00 to 0.70) equivalent to 35 new cases/10,000 person-years.

CONCLUSIONS

Our study provides population-level evidence that achievement of HIV cascade of care coverage overall and among women is feasible in a context with broad access to services and implementation of a decentralized model of care. However, the VLS was relatively low even among participants on ART. Quality care remains the most critical gap in the cascade of care to further reduce mortality and HIV transmission.

Point-of-care viral load testing among adolescents and youth living with HIV in Haiti: a protocol for a randomised trial to evaluate implementation and effect

INTRODUCTION

Adolescents living with HIV have poor antiretroviral therapy (ART) adherence and viral suppression outcomes. Viral load (VL) monitoring could reinforce adherence but standard VL testing requires strong laboratory capacity often only available in large central laboratories. Thus, coordinated transport of samples and results between the clinic and laboratory is required, presenting opportunities for delayed or misplaced results. Newly available point-of-care (POC) VL testing systems return test results the same day and could simplify VL monitoring so that adolescents receive test results faster which could strengthen adherence counselling and improve ART adherence and viral suppression.

METHODS AND ANALYSIS

This non-blinded randomised clinical trial is designed to evaluate the implementation and effectiveness of POC VL testing compared with standard laboratory-based VL testing among adolescents and youth living with HIV in Haiti. A total of 150 participants ages 10-24 who have been on ART for >6 months are randomised 1:1 to intervention or standard arms. Intervention arm participants receive a POC VL test (Cepheid Xpert HIV-1 Viral Load system) with same-day result and immediate ART adherence counselling. Standard care participants receive a laboratory-based VL test (Abbott m2000sp/m2000rt) with the result available 1 month later, at which time they receive ART adherence counselling. VL testing is repeated 6 months later for both arms. The primary objective is to describe the implementation of POC VL testing compared with standard laboratory-based VL testing. The secondary objective is to evaluate the effect of POC VL testing on VL suppression at 6 months and participant comprehension of the correlation between VL and ART adherence.

ETHICS AND DISSEMINATION

This study is approved by GHESKIO, Weill Cornell Medicine and Columbia University ethics committees. This trial will provide critical data to understand if and how POC VL testing may impact adolescent ART adherence and viral suppression. If effective, POC VL testing could routinely supplement standard laboratory-based VL testing among high-risk populations living with HIV.

TRIAL REGISTRATION NUMBER

NCT03288246.

The use of the GeeniusTM HIV-1/2 Rapid confirmatory test for the enrolment of patients and blood donors in the WHO Universal Test and Treat Strategy in Cameroon, Africa

BACKGROUND AND OBJECTIVE

In the WHO Universal test and treat strategy, false-positive HIV blood donors and patients may be unnecessarily put under antiretroviral treatment and false-negative subjects may be lost to follow-up. This study assessed the false positivity rate of the Cameroonian national HIV screening testing algorithm and the benefit of a confirmation test in the enrolment of patients and donors in the HIV care programme.

METHODS

We included initial HIV reactive blood donors and patients in a cross-sectional study conducted in two Cameroonian hospitals. Samples were retested according to the Cameroon national algorithm for HIV diagnosis. A positive or discordant sample was retested with the Geenius Bio-Rad HIV 1&2 (Bio-Rad, Marnes-la-Coquette, France) for confirmation. The Geenius HIV-1-positive results with 'poor' profiles were retested for RNA as well as the Geenius indeterminate results.

RESULTS

Of the 356 participants, 190/225 (84·4%) patients and 76/131 (58%) blood donors were declared positive with the national algorithm; 257 participants (96·6%) were confirmed HIV-1-positive. The study revealed that about 34/1000 blood donors and patients are false-positive and unnecessarily put on treatment; 89/1000 blood donors and patients declared discordant could have been included immediately in the HIV care programme if confirmatory testing was performed. The second test of the algorithm had a false-negative rate of 3%. Eleven samples (3·1%) were Geenius poor positive and NAT negative.

CONCLUSION

The universal test and treat strategy may identify and refer more individuals to HIV care if a third rapid confirmatory test is performed for discordant cases.

Diagnostic Performances of Three Rapid Diagnostic Tests for Detecting HIV Infections in Mali

Diagnosis of HIV infections in resource-limited countries like Mali is based on Rapid Diagnostic Tests (RDTs). The RDTs are diagnostic assays designed for use at the Point-Of-Care (POC), which is quick, cost-effective and easy to perform. However, in these countries, the tests are commonly used without any initial evaluation or monitoring of their performance despite high levels of HIV strain diversity and rapid evolution of the virus. In this study, the reliability and accuracy of HIV RDTs (Determine™, Multispot™, SD Bioline™) used in Mali, where HIV-1 and HIV-2 co-exist, were evaluated from August 2004 to November 2017. A total of 1303 samples from new HIV-suspect patients in Bamako were tested for HIV-1 and HIV-2 using the RDT Determine™, followed by ELISA and Western Blot (WB). The Determine™ test showed a robust diagnostic sensitivity of 98.7% [CI 95: 97.59-99.37] and a diagnostic specificity of 99.2% [CI 95: 98.22-99.67]. The Multispot™ assay showed a diagnostic sensitivity of 98.77% [CI 95: 97.59-99.37] and a diagnostic specificity of 99.2% [CI 95: 98.22-99.67]. The diagnostic sensitivity and specificity of SD Bioline™ HIV-1/2 were 100% [CI 95:72.25-100] and 88.89% [CI 95: 56.50- 98.71], respectively. These data indicate excellent performance for HIV RDTs in Mali and we recommend the use of Determine™ HIV-1/2 for HIV screening and Multispot™ for discriminating HIV-2 from HIV-1 infections.

High rate of hepatitis C virus and human immunodeficiency virus false-positive results in serologic screening in sub-Saharan Africa: adverse impact on the blood supply

BACKGROUND

False positivity in blood screening may cause unnecessary deferral of healthy donors and exacerbate blood shortages. An international multicenter study was conducted to estimate the frequency of HCV and HIV false seropositivity in seven African countries (Burundi, Cameroon, Democratic Republic of Congo, Madagascar, Mali, Mauritania, and Niger).

STUDY DESIGN AND METHODS

Blood donations were tested for hepatitis C virus (HCV) and human immunodeficiency virus (HIV) with rapid detection tests (RDTs), third-generation enzyme immunoassays (EIAs), or fourth-generation EIAs. HCV (456/16,613 [2.74%]) and HIV (249/16,675 [1.49%]) reactive samples were then confirmed with antigen/antibody assays, immunoblots, and nucleic acid testing. Partial viral sequences were analyzed when possible.

RESULTS

The HCV reactivity rate with RDTs was significantly lower than with EIAs (0.55% vs. 3.52%; p < 0.0001). The HIV reactivity rate with RDTs was lower than with third-generation EIAs (1.02% vs. 2.38%; p < 0.0001) but similar to a fourth-generation assay (1.09%). Only 16.0% (57/357) and 21.5% (38/177) of HCV and HIV initial reactive samples, respectively, were repeatedly reactive. HCV and HIV infections were confirmed in 13.2% and 13.7%, respectively, of repeated reactive donations. The predominant HCV genotype 2 and 4 strains in West and Central Africa showed high genetic variability. HIV-1 subtype CRF02_AG was most prevalent.

CONCLUSION

High rates (>80%) of unconfirmed anti-HCV and anti-HIV reactivity observed in several sub-Saharan countries highlights the need for better testing and confirmatory strategies for donors screening in Africa. Without confirmatory testing, HCV and HIV prevalence in African blood donors has probably been overestimated.

Cost implications of HIV retesting for verification in Africa

INTRODUCTION

HIV misdiagnosis leads to severe individual and public health consequences. Retesting for verification of all HIV-positive cases prior to antiretroviral therapy initiation can reduce HIV misdiagnosis, yet this practice has not been not widely implemented.

METHODS

We evaluated and compared the cost of retesting for verification of HIV seropositivity (retesting) to the cost of antiretroviral treatment (ART) for misdiagnosed cases in the absence of retesting (no retesting), from the perspective of the health care system. We estimated the number of misdiagnosed cases based on a review of misdiagnosis rates, and the number of positives persons needing ART initiation by 2020. We presented the total and per person costs of retesting as compared to no retesting, over a ten-year horizon, across 50 countries in Africa grouped by income level. We conducted univariate sensitivity analysis on all model input parameters, and threshold analysis to evaluate the parameter values where the total costs of retesting and the costs no retesting are equivalent. Cost data were adjusted to 2017 United States Dollars.

RESULTS AND DISCUSSION

The estimated number of misdiagnoses, in the absence of retesting was 156,117, 52,720 and 29,884 for lower-income countries (LICs), lower-middle income countries (LMICs), and upper middle-income countries (UMICs), respectively, totaling 240,463 for Africa. Under the retesting scenario, costs per person initially diagnosed were: $40, $21, and $42, for LICs, LMICs, and UMICs, respectively. When retesting for verification is implemented, the savings in unnecessary ART were $125, $43, and $75 per person initially diagnosed, for LICs, LMICs, and UMICs, respectively. Over the ten-year horizon, the total costs under the retesting scenario, over all country income levels, was $475 million, and was $1.192 billion under the no retesting scenario, representing total estimated savings of $717 million in HIV treatment costs averted.

CONCLUSIONS

Results show that to reduce HIV misdiagnosis, countries in Africa should implement the WHO's recommendation of retesting for verification prior to ART initiation, as part of a comprehensive quality assurance program for HIV testing services.

A Commitment to HIV Diagnostic Accuracy - a comment on "Towards more accurate HIV testing in sub-Saharan Africa: a multi-site evaluation of HIV RDTs and risk factors for false positives 'and' HIV misdiagnosis in sub-Saharan Africa: a performance of diagnostic algorithms at six testing sites"

As part of the global response to the HIV/AIDS epidemic, the U.S. President's Emergency Plan for AIDS Relief (PEPFAR) is committed to the provision of high-quality services and ensuring testing accuracy. Two recently published papers focusing on HIV testing and misdiagnosis in sub-Saharan Africa by Kosack et al. report on evaluations of HIV rapid diagnostic tests (RDTs) and found lower than expected specificity and sensitivity on some tests when used in certain geographic locations. The magnitude of PEPFAR's global HIV response has been possible due to the extensive use of RDTs, which have made HIV diagnosis accessible all over the world. We take the opportunity to address concerns raised about the potential implications that these findings could have on real-world HIV testing accuracy. PEPFAR supported countries adhere to the normative guidance by World Health Organization (WHO) supporting algorithms which require sequential positive tests for diagnostic accuracy. An analysis of Médecins Sans Frontières (MSF) RDT site-specific data applied to PEPFAR in-country protocols demonstrate a variation in the diagnostic accuracy of the testing algorithms, but with a very small population-level effect. The data demonstrate, with the use of these algorithms, that the RDT outcomes found in the study by Kosack et al. would be largely mitigated and would not be expected to have a significant impact on diagnostic accuracy and overall programming in most countries. Avoiding any misdiagnosis is a priority for PEPFAR, and it remains vital to gain a deeper understanding of the causes and the extent of diagnostic errors and any misclassification. Extensive quality control mechanisms and continued research are essential. With a focus on epidemic control and ensuring diagnostic accuracy, PEPFAR recommends that all countries use WHO pre-qualified RDTs within the recommended strategies and algorithms for HIV testing. We also support validation of HIV testing algorithms using in-country specimens to determine optimal performance, and the reverification testing of all people diagnosed with HIV prior to starting treatment as an essential quality assurance measure.

Evaluation of HIV-1 rapid tests and identification of alternative testing algorithms for use in Uganda

Introduction

The World Health Organization recommends that countries conduct two phase evaluations of HIV rapid tests (RTs) in order to come up with the best algorithms. In this report, we present the first ever such evaluation in Uganda, involving both blood and oral based RTs. The role of weak positive (WP) bands on the accuracy of the individual RT and on the algorithms was also investigated.

Methods

In total 11 blood based and 3 oral transudate kits were evaluated. All together 2746 participants from seven sites, covering the four different regions of Uganda participated. Two enzyme immunoassays (EIAs) run in parallel were used as the gold standard. The performance and cost of the different algorithms was calculated, with a pre-determined price cut-off of either cheaper or within 20% price of the current algorithm of Determine + Statpak + Unigold. In the second phase, the three best algorithms selected in phase I were used at the point of care for purposes of quality control using finger stick whole blood.

Results

We identified three algorithms; Determine + SD Bioline + Statpak; Determine + Statpak + SD Bioline, both with the same sensitivity and specificity of 99.2% and 99.1% respectively and Determine + Statpak + Insti, with sensitivity and specificity of 99.1% and 99% respectively as having performed better and met the cost requirements. There were 15 other algorithms that performed better than the current one but rated more than the 20% price. None of the 3 oral mucosal transudate kits were suitable for inclusion in an algorithm because of their low sensitivities. Band intensity affected the performance of individual RTs but not the final algorithms.

Conclusion

We have come up with three algorithms we recommend for public or Government procurement based on accuracy and cost. In case one algorithm is preferred, we recommend to replace Unigold, the current tie breaker with SD Bioline. We further recommend that all the 18 algorithms that have shown better performance than the current one are made available to the private sector where cost may not be a limiting factor.

Designing HIV Testing Algorithms Based on 2015 WHO Guidelines Using Data from Six Sites in Sub-Saharan Africa

Our objective was to evaluate the performance of HIV testing algorithms based on WHO recommendations, using data from specimens collected at six HIV testing and counseling sites in sub-Saharan Africa (Conakry, Guinea; Kitgum and Arua, Uganda; Homa Bay, Kenya; Douala, Cameroon; Baraka, Democratic Republic of Congo). A total of 2,780 samples, including 1,306 HIV-positive samples, were included in the analysis. HIV testing algorithms were designed using Determine as a first test. Second and third rapid diagnostic tests (RDTs) were selected based on site-specific performance, adhering where possible to the WHO-recommended minimum requirements of ≥99% sensitivity and specificity. The threshold for specificity was reduced to 98% or 96% if necessary. We also simulated algorithms consisting of one RDT followed by a simple confirmatory assay. The positive predictive values (PPV) of the simulated algorithms ranged from 75.8% to 100% using strategies recommended for high-prevalence settings, 98.7% to 100% using strategies recommended for low-prevalence settings, and 98.1% to 100% using a rapid test followed by a simple confirmatory assay. Although we were able to design algorithms that met the recommended PPV of ≥99% in five of six sites using the applicable high-prevalence strategy, options were often very limited due to suboptimal performance of individual RDTs and to shared falsely reactive results. These results underscore the impact of the sequence of HIV tests and of shared false-reactivity data on algorithm performance. Where it is not possible to identify tests that meet WHO-recommended specifications, the low-prevalence strategy may be more suitable.