Modern diagnostic technologies for HIV

Microfluidic systems for infectious disease diagnostics

Microorganisms, encompassing both uni- and multicellular entities, exhibit remarkable diversity as omnipresent life forms in nature. They play a pivotal role by supplying essential components for sustaining biological processes across diverse ecosystems, including higher host organisms. The complex interactions within the human gut microbiota are crucial for metabolic functions, immune responses, and biochemical signalling, particularly through the gut-brain axis. Viruses also play important roles in biological processes, for example by increasing genetic diversity through horizontal gene transfer when replicating inside living cells. On the other hand, infection of the human body by microbiological agents may lead to severe physiological disorders and diseases. Infectious diseases pose a significant burden on global healthcare systems, characterized by substantial variations in the epidemiological landscape. Fast spreading antibiotic resistance or uncontrolled outbreaks of communicable diseases are major challenges at present. Furthermore, delivering field-proven point-of-care diagnostic tools to the most severely affected populations in low-resource settings is particularly important and challenging. New paradigms and technological approaches enabling rapid and informed disease management need to be implemented. In this respect, infectious disease diagnostics taking advantage of microfluidic systems combined with integrated biosensor-based pathogen detection offers a host of innovative and promising solutions. In this review, we aim to outline recent activities and progress in the development of microfluidic diagnostic tools. Our literature research mainly covers the last 5 years. We will follow a classification scheme based on the human body systems primarily involved at the clinical level or on specific pathogen transmission modes. Important diseases, such as tuberculosis and malaria, will be addressed more extensively.

Barriers and enablers for implementation of digital-linked diagnostics models at point-of-care in South Africa: stakeholder engagement

The integration of digital technologies holds significant promise in enhancing accessibility to disease diagnosis and treatment at point-of-care (POC) settings. Effective implementation of such interventions necessitates comprehensive stakeholder engagements. This study presents the outcomes of a workshop conducted with key stakeholders, aiming to discern barriers and enablers in implementing digital-connected POC diagnostic models in South Africa. The workshop, a component of the 2022 REASSURED Diagnostics symposium, employed the nominal group technique (NGT) and comprised two phases: Phase 1 focused on identifying barriers, while Phase 2 centered on enablers for the implementation of digital-linked POC diagnostic models. Stakeholders identified limited connectivity, restricted offline functionality, and challenges related to load shedding or rolling electricity blackouts as primary barriers. Conversely, ease of use, subsidies provided by the National Health Insurance, and 24-h assistance emerged as crucial enablers for the implementation of digital-linked POC diagnostic models. The NGT workshop proved to be an effective platform for elucidating key barriers and enablers in implementing digital-linked POC diagnostic models. Subsequent research endeavors should concentrate on identifying optimal strategies for implementing these advanced diagnostic models in underserved populations.

Adherence, adverse drug reactions, and discontinuation associated with adverse drug reactions of HIV post-exposure prophylaxis: a meta-analysis based on cohort studies

Objective: Evaluate the profiles of post-exposure prophylaxis (PEP) adherence, adverse drug reactions (ADRs), and discontinuation associated with ADRs to provide information for further PEP program improvement and increase adherence to PEP.Methods: The Web of Science, PubMed, Embase, and the Cochrane Library were searched for cohort studies reporting data related to PEP adherence or ADRs (PROSPERO, CRD42022385073). Pooled estimates of adherence, the incidence of ADRs and discontinuation associated with ADRs, and their 95% confidence intervals (CI) were calculated separately for the included literature using random effects models. For substantial heterogeneity, meta-regression and subgroup analyses were conducted to explore sources of heterogeneity.Results: Overall adherence was 58.4% (95% CI: 50.9%-65.8%), with subgroup analysis showing differences in adherence across samples, with the highest adherence among men who had sex with men (MSM) (72.4%, 95% CI: 63.4%-81.3%) and the lowest adherence among survivors of sexual assault (SAs) (41.7%, 95% CI: 28.0%-55.3%). The incidence of ADRs was 60.3% (95% CI: 50.3%-70.3%), and the prevalence of PEP discontinuation associated with ADRs was 32.7% (95% CI: 23.7%-41.7%), with subgroup analyses revealing disparities in the prevalence of discontinuation associated with ADRs among samples with different drug regimens. Time trend analysis showed a slight downward trend in the incidence of ADRs and PEP discontinuation associated with ADRs.Conclusion: Adherence to PEP was less than 60% across samples, however, there was significant heterogeneity depending on the samples. SAs had the lowest adherence and the highest incidence of PEP discontinuation. Ongoing adherence education for participants, timely monitoring, and management of ADRs may improve adherence.

The contemporary immunoassays for HIV diagnosis: a concise overview

Recent advances in human immunodeficiency virus (HIV) diagnostics have improved the management of disease progression significantly, which have also boosted the efficacy of antiviral therapies. The detection of HIV at the earliest is very important. A highly recognized and effective virological biomarker for acute HIV infections is p24 antigen. This brief overview is based on advances of HIV diagnosis while focusing on the latest HIV testing technologies including HIV-specific antigens detecting assays of both anti-HIV antibodies and p24 antigen. In addition to other emerging molecular diagnostics for acute HIV infection, the utilization of p24 antigen has been summarized. Moreover, it has been explained how these immunoassays have reduced the window period for detection of HIV in the acute stage of infection.

Manually-Operated, Slider Cassette for Multiplexed Molecular Detection at the Point of Care

Effective control of epidemics, individualized medicine, and new drugs with virologic response-dependent dose and timing require, among other things, simple, inexpensive, multiplexed molecular detection platforms suitable for point of care and home use. Herein, we describe our progress towards developing such a platform that includes sample lysis, nucleic acid isolation, concentration, purification, and amplification. Our diagnostic device comprises a sliding component that houses the nucleic acid isolation membrane and a housing containing three amplification reaction chambers with dry stored reagents, blisters with buffers and wash solutions, and absorption pads to facilitate capillarity pull and waste storage. After sample introduction, the user slides the slider within the housing from one station to another to carry out various unit operations. The slider motion induces blisters to discharge their contents, effectuating washes, and eventual elution of captured nucleic acids into reaction chambers. The slider cassette mates with a processor that incubates isothermal amplification but can also be made to operate instrumentation-free. We demonstrate our cassette's utility for the co-detection of the human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). These three blood-borne pathogens co-infect many people worldwide with severe personal and public health consequences.

Bridging the gap between development of point-of-care nucleic acid testing and patient care for sexually transmitted infections

The incidence rates of sexually transmitted infections (STIs), including the four major curable STIs - chlamydia, gonorrhea, trichomoniasis and, syphilis - continue to increase globally, causing medical cost burden and morbidity especially in low and middle-income countries (LMIC). There have seen significant advances in diagnostic testing, but commercial antigen-based point-of-care tests (POCTs) are often insufficiently sensitive and specific, while near-point-of-care (POC) instruments that can perform sensitive and specific nucleic acid amplification tests (NAATs) are technically complex and expensive, especially for LMIC. Thus, there remains a critical need for NAAT-based STI POCTs that can improve diagnosis and curb the ongoing epidemic. Unfortunately, the development of such POCTs has been challenging due to the gap between researchers developing new technologies and healthcare providers using these technologies. This review aims to bridge this gap. We first present a short introduction of the four major STIs, followed by a discussion on the current landscape of commercial near-POC instruments for the detection of these STIs. We present relevant research toward addressing the gaps in developing NAAT-based STI POCT technologies and supplement this discussion with technologies for HIV and other infectious diseases, which may be adapted for STIs. Additionally, as case studies, we highlight the developmental trajectory of two different POCT technologies, including one approved by the United States Food and Drug Administration (FDA). Finally, we offer our perspectives on future development of NAAT-based STI POCT technologies.

Serological, Molecular and Culture-Based Diagnosis of Lentiviral Infections in Small Ruminants

Small ruminant lentiviruses (SRLVs) infections lead to chronic diseases and remarkable economic losses undermining health and welfare of animals and the sustainability of farms. Early and definite diagnosis of SRLVs infections is the cornerstone for any control and eradication efforts; however, a "gold standard" test and/or diagnostic protocols with extensive applicability have yet to be developed. The main challenges preventing the development of a universally accepted diagnostic tool with sufficient sensitivity, specificity, and accuracy to be integrated in SRLVs control programs are the genetic variability of SRLVs associated with mutations, recombination, and cross-species transmission and the peculiarities of small ruminants' humoral immune response regarding late seroconversion, as well as intermittent and epitope-specific antibody production. The objectives of this review paper were to summarize the available serological and molecular assays for the diagnosis of SRLVs, to highlight their diagnostic performance emphasizing on advantages and drawbacks of their application, and to discuss current and future perspectives, challenges, limitations and impacts regarding the development of reliable and efficient tools for the diagnosis of SRLVs infections.

An observed, prospective field study to evaluate the performance and acceptance of a blood-based HIV self-test in Canada

Background

Self testing for HIV is a targeted intervention with the potential to increase the access, uptake and frequency of HIV testing and more effectively reach the undiagnosed, especially in priority populations. The objectives of this study were to (1) evaluate the INSTI HIV self-test performance compared with laboratory reference testing, (2) document if intended users can perform the steps to use the HIV self-test device, and (3) document if intended users can successfully interpret contrived positive, negative, and invalid results. Study was intended to be submitted to Health Canada for review for regulatory approval purposes.

Methods

The study used a cross-sectional design and recruited consenting adults who were representative of intended users of HIV self-testing from four community sites across Ontario, Québec, and Manitoba between August 2019 and March 2020. The results of the observed HIV self-test were compared with results of the Abbott Architect HIV Ag/Ab Combo test. Usability outcomes for critical (e.g., lancing finger, blood droplet into bottle, shaking bottle four times) and noncritical self-test procedure steps were also determined.

Results

Overall, 77% (n = 522) of participants were between 18 and 45 years of age, 61% (n = 410) were male, 71% (n = 480) had some college or more education, and 45% (n = 307) were employed; identity for race and ethnicity: Caucasian (44%; n = 296), African, Caribbean or Black (17%; n = 113), Indigenous [First Nations, Métis or Inuit] (14%; n = 95), Asian (16%; n = 106), Latin American (7%; n = 46). Primary performance analysis on 678 completed HIV self-tests revealed a positive percent agreement of 100% (5/5, 95% CI: 43.6–97.0%) and a negative percent agreement of 99.5% (614/617, 95% CI: 98.6–99.8%) with the comparator method. The overall percent agreement of results interpretation between participant and observer was 93.5% (n = 633). For the 708 participants who took part in the usability study, the average success rate for steps determined to be “critical” for successful completion of the test was 92.4%. 97% (n = 670) of participants found the instructions easy to follow, and 95% (n = 655) of participants indicated that they would use the test again. Of the 404 participants who interpreted the strong positive, weak positive, negative, and invalid contrived results, successful interpretation ranged from 90.6% (for weak positive, n = 366) to 99.3% (for negative, n = 401).

Conclusions

The addition of a regulatory-approved self-test into the Canadian HIV testing landscape could significantly increase HIV testing rates. Having a blood-based HIV self-test approved in Canada can offer an accurate, acceptable, and simple alternative to facility-based HIV testing, particularly when impacted by Coronavirus pandemic restrictions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11418-z.