HIV testing in a high-incidence population: is antibody testing alone good enough?

Consensus recommendations for use of long-acting antiretroviral medications in the treatment and prevention of HIV-1: Endorsed by the American Academy of HIV Medicine, American College of Clinical Pharmacy, Canadian HIV and Viral Hepatitis Pharmacists Network, European AIDS Clinical Society, and Society of Infectious Diseases Pharmacists

Five long-acting (LA) antiretrovirals (ARVs) are currently available in a limited number of countries worldwide for HIV-1 prevention or treatment-cabotegravir, rilpivirine, lenacapavir, ibalizumab, and dapivirine. Implementing use of LA ARVs into routine clinical practice requires significant changes to the current framework of HIV-1 prevention, treatment, and service provision. Given the novelty, complexity, and interdisciplinary requirements needed to safely and optimally utilize LA ARVs, consensus recommendations on the use of LA ARVs will assist clinicians in optimizing use of these agents. The purpose of these recommendations is to provide guidance for the clinical use of LA ARVs for HIV-1 treatment and prevention. In addition, future areas of research are also identified and discussed.

STAMP-Based Digital CRISPR-Cas13a for Amplification-Free Quantification of HIV-1 Plasma Viral Loads

Quantification of HIV RNA in plasma is critical for identifying the disease progression and monitoring the effectiveness of antiretroviral therapy. While RT-qPCR has been the gold standard for HIV viral load quantification, digital assays could provide an alternative calibration-free absolute quantification method. Here, we reported a Self-digitization Through Automated Membrane-based Partitioning (STAMP) method to digitalize the CRISPR-Cas13 assay (dCRISPR) for amplification-free and absolute quantification of HIV-1 viral RNAs. The HIV-1 Cas13 assay was designed, validated, and optimized. We evaluated the analytical performances with synthetic RNAs. With a membrane that partitions ∼100 nL of reaction mixture (effectively containing 10 nL of input RNA sample), we showed that RNA samples spanning 4 orders of dynamic range between 1 fM (∼6 RNAs) to 10 pM (∼60k RNAs) could be quantified as fast as 30 min. We also examined the end-to-end performance from RNA extraction to STAMP-dCRISPR quantification using 140 μL of both spiked and clinical plasma samples. We demonstrated that the device has a detection limit of approximately 2000 copies/mL and can resolve a viral load change of 3571 copies/mL (equivalent to 3 RNAs in a single membrane) with 90% confidence. Finally, we evaluated the device using 140 μL of 20 patient plasma samples (10 positives and 10 negatives) and benchmarked the performance with RT-PCR. The STAMP-dCRISPR results agree very well with RT-PCR for all negative and high positive samples with Ct < 32. However, the STAMP-dCRISPR is limited in detecting low positive samples with Ct > 32 due to the subsampling errors. Our results demonstrated a digital Cas13 platform that could offer an accessible amplification-free quantification of viral RNAs. By further addressing the subsampling issue with approaches such as preconcentration, this platform could be further exploited for quantitatively determining viral load for an array of infectious diseases.

Point-of-Care Testing for Sexually Transmitted Infections

Point-of-care testing for sexually transmitted infections is essential for controlling transmission and preventing sequelae in high-risk populations. Since the World Health Organization published the ASSURED criteria, point-of-care testing has improved for use in large population screening and rapid testing that prevents loss of clinical follow-up. Recent advancements have been advantageous for low-resource areas allowing testing at a minimal cost without reliable electricity or refrigeration. Point-of-care nucleic acid detection and amplification techniques are recommended, but are often inaccessible in low-resource areas. Future advancements in point-of-care diagnostic testing should focus on improving antibody-based assays, monitoring viral loads, and detecting antimicrobial resistance.

Screening and diagnostic testing protocols for HIV and Syphilis infections in health care setting in Qatar: Evaluation and recommendations

BACKGROUND

HIV and Syphilis are common STIs, which have become a concern and burden on healthcare systems, as many infections go untreated and lead to potentially serious complications. HIV is usually diagnosed with Western blot, PCR, and p24 antigen testing. Whereas, Syphilis is mainly diagnosed through clinical findings and serologic testing. The Medical Commission Department (MC) under MOPH is responsible for screening all newcomers to Qatar, aiming to keep the country free from serious infectious diseases.

OBJECTIVE

We aimed to evaluate the diagnostic efficiency of the protocols used in the MC for screening HIV and Syphilis infections.

METHODS

We conducted a retrospective study of samples analyzed by 4th Generation ARCHITECT® HIV Ag/Ab Combo and Rapid Plasma Reagin (RPR) between January to December 2019. ARCHITECT® HIV Ag/Ab Combo positive samples were confirmed by INNO-LIA™ HIVI/II and RT-PCR. RPR-reactive samples were confirmed by ARCHITECT® Syphilis Treponema pallidium Antibody (Syphilis TPA) assay.

RESULTS

For HIV, data were collected from 585,587 individuals, of which 595 (0.1%) were positive by the ARCHITECT® HIV Ag/Ab Combo (Analyzer A). When all initially positive sera were re-tested on newly collected blood samples using different ARCHITECT® HIV Ag/Ab Combo analyzer (analyzer B), 99.8% (594/595) of samples were also positive, suggesting high reproducibility. The positive predictive value (PPV) between ARCHITECT® HIV Ag/Ab Combo and the INNO-LIA™ HIVI/II confirmatory assay was 31.8%. The PPV between ARCHITECT® HIV Ag/Ab Combo and HIV-PCR assay was 26.8%. Retrospective data for Syphilis were collected from a total of 97,298 individuals who visited the MC, of which 198 (0.20%) were initially positive by RPR. The PPV between RPR and Syphilis TPA confirmatory assay was 36.6%.

CONCLUSION

Despite the high rate of false positivity using ARCHITECT® HIV Ag/Ab Combo and RPR screening assays, both assays have proven to be highly effective as screening testing methods.

Case Report: Erroneous HIV-1 Diagnosis in a Pregnant Woman Using CDC Diagnostic Algorithm

We describe a case of a pregnant cisgender woman diagnosed with human immunodeficiency virus (HIV)-1 using the current Centers for Disease Control and Prevention diagnostic algorithm who subsequently had her diagnosis overturned after additional testing outside of the algorithm, including an HIV-1 proviral deoxyribonucleic acid test that was negative.

Provider perspectives on the use of motivational interviewing and problem-solving counseling paired with the point-of-care nucleic acid test for HIV care

Aims

To evaluate provider perspectives on the use of a point-of-care nucleic acid test (POC NAT) and preferential opinions for motivational interviewing (MI) or problem-solving counseling (PSC) as an ultra-brief intervention for patients experiencing challenges to antiretroviral therapy (ART) adherence.

Methods

A qualitative study was conducted among providers at an HIV care clinic in Seattle, Washington. Ten in-depth interviews with HIV care providers were completed, which explored determinants of acceptability, feasibility and preferences for a combined adherence counseling and POC NAT intervention for patients living with HIV. Interviews were analyzed through consensus coding and the Five A’s Framework to inform thematic analysis.

Results

Providers favored the use of a combined adherence counseling technique and POC NAT for their non-adherent patients living with HIV. Providers believed the intervention was an improvement on current assessment and advising practices. However, concerns about extended wait times for the POC NAT results influenced perceptions about feasibility around clinic flow and incorporation into clinic practice. Providers believed that acceptability of POC NAT implementation would be enhanced by including a subset of patient populations whom tend to be in the clinic for longer periods, and in tandem face greater ART adherence challenges.

Conclusion

The GAIN Study will be the first project to evaluate the implementation of POC NAT in the U.S. Continued formative work is ongoing and may illustrate how best to address feasibility and concern around the two-hour time to result. The planned GAIN study will incorporate some of the findings found in this qualitative study and pilot this intervention, including a time-in-motion analyses of clinic flow, which may help reduce perceived wide-scale adaptation of POC NAT and ART adherence counselling among PLHW. Future work, including a shorter time to results and/or lower limit detection could make a significant improvement in the provision of HIV care.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

An improved HIV antigen/antibody prototype assay for earlier detection of acute HIV infection

BACKGROUND

Early detection of acute HIV infection by HIV antigen/antibody assays depends on antigen sensitivity. Maintaining consistently high sensitivity across diverse HIV strains is critical to ensure equal detection.

OBJECTIVES

The performance of an improved HIV antigen/antibody prototype, HIV Combo Next, was evaluated for detection of genetically-diverse HIV strains and seroconversion samples.

STUDY DESIGN

Antigen sensitivity of the prototype was evaluated and compared to five FDA-approved HIV antigen/antibody assays using World Health Organization (WHO) HIV p24 antigen standard and reference panels, 17 virus isolates and 9 seroconversion panels. Antibody sensitivity and assay specificity of the prototype were also assessed with 1062 disease-staged and genotyped samples, and samples from 3000 blood donors and 955 individuals with low-risk for HIV infection.

RESULTS

Compared with other assays evaluated, the prototype demonstrated the best analytical sensitivity for WHO antigen standard, reference panels including 12 HIV-1 variants (0.04 - 0.25 IU/ml) and one HIV-2 variant, and 17 HIV virus isolates including HIV-1 group M, N, P and O and HIV-2 (0.3 -16 pg/ml). The enhanced sensitivity was also observed for seroconversion samples, detecting more PCR-positive samples with detection up to 7 days earlier than the other assays. Improvement in antigen sensitivity did not compromise antibody sensitivity or assay specificity, detecting all HIV disease-staged and genotyped samples, with assay specificity of 99.97% for blood donors and 99.68% for the low-risk population.

CONCLUSIONS

These data indicate that the new prototype HIV Combo Next assay will be of diagnostic value, providing improved early detection for acute HIV infection from divergent HIV strains.

Analytical Performance Characteristics of a New Transcription-Mediated Amplification Assay for Treponema pallidum

This study evaluated the performance characteristics of a new research-use-only transcription-mediated amplification (TMA) assay for the detection of rRNA from Treponema pallidum. Analytical sensitivity determined using dark-field microscopy-quantitated T. pallidum was 1.4 organisms/ml (95% confidence interval [CI], 0.7 to 6.33 organisms/ml). Dilution of in vitro-transcribed (IVT) T. pallidum RNA in Aptima sample transport medium (STM) yielded 100% positivity (n = 3) at 10 copies/ml (4 copies/reaction). Analytical specificity testing of nontarget microorganisms (n = 59), including the closely related nonsyphilis treponemes Treponema denticola and Treponema phagedenis, yielded 0% positivity. TMA testing of mucosal swab specimens collected from men who have sex with men (MSM) attending a sexually transmitted disease clinic yielded 1.8% (17/944) positive results. A collection of 56 serum specimens obtained from a separate cohort of patients with known rapid plasma reagin (RPR) statuses and clinical diagnoses of syphilis was 19.6% (11/56) TMA positive overall and 29.7% (11/37) positive among subjects with syphilis diagnoses, including 8 (36.3%) of 22 persons with primary or secondary syphilis, 2 (20%) of 10 persons with early latent syphilis, and 1 (20%) of 5 persons with late latent or unstaged syphilis. None (0%) of the 18 RPR-positive sera from patients with histories of treated syphilis were TMA positive. These results show that TMA is an analytically sensitive and specific method for the detection of T. pallidum rRNA and is compatible with serum specimens in addition to pharyngeal and rectal mucocutaneous swab specimens. Automated real-time TMA testing for T. pallidum may be useful as an adjunctive method with serology for screening and diagnostic testing of selected patient populations for syphilis.

Analytical Performance Characteristics of a New Transcription-Mediated Amplification Assay for Treponema pallidum

This study evaluated the performance characteristics of a new research-use-only transcription-mediated amplification (TMA) assay for the detection of rRNA from Treponema pallidum. Analytical sensitivity determined using dark-field microscopy-quantitated T. pallidum was 1.4 organisms/ml (95% confidence interval [CI], 0.7 to 6.33 organisms/ml). Dilution of in vitro-transcribed (IVT) T. pallidum RNA in Aptima sample transport medium (STM) yielded 100% positivity (n = 3) at 10 copies/ml (4 copies/reaction). Analytical specificity testing of nontarget microorganisms (n = 59), including the closely related nonsyphilis treponemes Treponema denticola and Treponema phagedenis, yielded 0% positivity. TMA testing of mucosal swab specimens collected from men who have sex with men (MSM) attending a sexually transmitted disease clinic yielded 1.8% (17/944) positive results. A collection of 56 serum specimens obtained from a separate cohort of patients with known rapid plasma reagin (RPR) statuses and clinical diagnoses of syphilis was 19.6% (11/56) TMA positive overall and 29.7% (11/37) positive among subjects with syphilis diagnoses, including 8 (36.3%) of 22 persons with primary or secondary syphilis, 2 (20%) of 10 persons with early latent syphilis, and 1 (20%) of 5 persons with late latent or unstaged syphilis. None (0%) of the 18 RPR-positive sera from patients with histories of treated syphilis were TMA positive. These results show that TMA is an analytically sensitive and specific method for the detection of T. pallidum rRNA and is compatible with serum specimens in addition to pharyngeal and rectal mucocutaneous swab specimens. Automated real-time TMA testing for T. pallidum may be useful as an adjunctive method with serology for screening and diagnostic testing of selected patient populations for syphilis.

Correlates of HIV self-testing among female sex workers in China: implications for expanding HIV screening

Background

Human immunodeficiency virus (HIV) self-testing may help improve test uptake among female sex workers. China has implemented many HIV self-testing programs among men who have sex with men, creating an opportunity for promotion among female sex workers. However, there is a limited literature on examining HIV self-testing among female sex workers. This study aimed to examine HIV self-testing experiences and its determinants among female sex workers in China.

Methods

A venue-based, cross-sectional study was conducted among Chinese female sex workers in 2019. Participants completed a survey including social-demographic characteristics, sexual behaviors, and HIV self-testing history, the distribution of which were analyzed using descriptive analysis. Multivariable logistic regression was conducted to identify associations with HIV self-testing.

Results

Among 1287 Chinese female sex workers, 1072 (83.3%, 95% confidence interval [CI] 81.2–85.3%) had ever tested for HIV, and 103 (8.0%, 95% CI 6.6–9.6%) had ever used HIV self-testing. More than half reported that the self-test was their first HIV test (59.2%, 61/103), around one-fifth reported HIV self-testing results influenced the price of sex (21.4%, 22/103). A minority of individuals reported ever experiencing pressure to undertake HIV self-testing (6.8%, 7/103). After adjusting for covariates, HIV self-testing was positively associated with receiving anal sex in the past month (adjusted odds ratio [aOR] = 2.2, 95% CI 1.4–3.5), using drugs before or during sex (aOR = 2.8, 95% CI 1.8–4.5), injecting drugs in the past 6 months (aOR = 2.6, 95% CI 1.2–6.0), being diagnosed with other sexually transmitted infections (aOR = 1.6, 95% CI 1.0–2.5), tested for other sexually transmitted infections in the past six months (aOR = 3.4, 95% CI 2.1–5.5), ever tested in the hospital (aOR = 3.4, 95% CI 2.0–5.6), and ever tested in the community (aOR = 1.5, 95% CI 1.2–1.9).

Conclusions

Our findings suggest that HIV self-testing could expand overall HIV testing uptake, increase HIV testing frequency, reach sub-groups of high-risk female sex workers and has limited potential harms among female sex workers. HIV self-testing should be incorporated among Chinese female sex workers as a complement to facility-based HIV testing services.

Prospective Evaluation of HIV Testing Technologies in a Clinical Setting: Protocol for Project DETECT

BACKGROUND

HIV testing guidelines provided by the Centers for Disease Control and Prevention (CDC) are continually changing to reflect advancements in new testing technology. Evaluation of existing and new point-of-care (POC) HIV tests is crucial to inform testing guidelines and provide information to clinicians and other HIV test providers. Characterizing the performance of POC HIV tests using unprocessed specimens can provide estimates for the window period of detection, or the time from HIV acquisition to test positivity, which allows clinicians and other HIV providers to select the appropriate POC HIV tests for persons who may be recently infected with HIV.

OBJECTIVE

This paper describes the protocols and procedures used to evaluate the performance of the newest POC tests and determine their sensitivity during early HIV infection.

METHODS

Project DETECT is a CDC-funded study that is evaluating POC HIV test performance. Part 1 is a cross-sectional, retrospective study comparing behavioral characteristics and HIV prevalence of the overall population of the Public Health-Seattle & King County (PHSKC) Sexually Transmitted Disease (STD) Clinic to Project DETECT participants enrolled in part 2. Part 2 is a cross-sectional, prospective study evaluating POC HIV tests in real time using unprocessed whole blood and oral fluid specimens. A POC nucleic acid test (NAT) was added to the panel of HIV tests in June 2018. Part 3 is a longitudinal, prospective study evaluating seroconversion sensitivity of POC HIV tests through serial follow-up testing. For comparison, HIV-1 RNA and HIV-1/HIV-2 antigen/antibody tests are also performed for participants enrolled in part 2 or 3. A behavioral survey that collects information about demographics, history of HIV testing, STD history, symptoms of acute HIV infection, substance use, sexual behaviors in the aggregate and with recent partners, and use of pre-exposure prophylaxis and antiretroviral therapy is completed at each part 2 or 3 visit.

RESULTS

Between September 2015 and March 2019, there were 14,990 Project DETECT-eligible visits (part 1) to the PHSKC STD Clinic resulting in 1819 part 2 Project DETECT study visits. The longitudinal study within Project DETECT (part 3) enrolled 27 participants with discordant POC test results from their part 2 visit, and 10 (37%) were followed until they had fully seroconverted with concordant positive POC test results. Behavioral survey data and HIV test results, sensitivity, and specificity will be presented elsewhere.

CONCLUSIONS

Studies such as Project DETECT are critical for evaluating POC HIV test devices as well as describing characteristics of persons at risk for HIV acquisition in the United States. HIV tests in development, including POC NATs, will provide new opportunities for HIV testing programs.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR1-10.2196/16332.

Screening for Human Immunodeficiency Virus Infection by Use of a Fourth-Generation Antigen/Antibody Assay and Dried Blood Spots: In-Depth Analysis of Sensitivity and Performance Assessment in a Cross-Sectional Study

We evaluated the performance of a fourth-generation antigen/antibody (Ag/Ab) assay for detecting HIV-1 infection on dried blood spots (DBS) both in a conventional laboratory environment and in an epidemiological survey corresponding to a real-life situation. Although a 2-log loss of sensitivity compared to that with plasma was observed when using DBS in an analytical analysis, the median delay of positivity between DBS and crude serum during the early phase postacute infection was 7 days. The performance of the fourth-generation assay on DBS was approximately similar to that of a third-generation (antibody only) assay using crude serum samples. Among 2,646 participants of a cross-sectional study in a population of men having sex with men, 428 DBS were found reactive, but negative results were obtained from 5 DBS collected from individuals who self-reported a positive HIV status, confirmed by detection of antiretroviral (ARV) drugs in their DBS. The data generated allowed us to estimate a sensitivity of 98.8% of the fourth-generation assay/DBS strategy in a high-risk population, even including a broad majority of individuals on ARV treatment among those HIV positive. Our study brings additional proofs that DBS testing using a fourth-generation immunoassay is a reliable strategy able to provide alternative approaches for both individual HIV testing and surveillance of various populations.

HIV Self-Testing Increases HIV Testing Frequency in High-Risk Men Who Have Sex With Men: A Randomized Controlled Trial

BACKGROUND

Self-testing may increase HIV testing and decrease the time people with HIV are unaware of their status, but there is concern that absence of counseling may result in increased HIV risk.

SETTING

Seattle, Washington.

METHODS

We randomly assigned 230 high-risk HIV-negative men who have sex with men to have access to oral fluid HIV self-tests at no cost versus testing as usual for 15 months. The primary outcome was self-reported number of HIV tests during follow-up. To evaluate self-testing's impact on sexual behavior, we compared the following between arms: non-HIV-concordant condomless anal intercourse and number of male condomless anal intercourse partners in the last 3 months (measured at 9 and 15 months) and diagnosis with a bacterial sexually transmitted infection (STI: early syphilis, gonorrhea, and chlamydial infection) at the final study visit (15 months). A post hoc analysis compared the number of STI tests reported during follow-up.

RESULTS

Men randomized to self-testing reported significantly more HIV tests during follow-up (mean = 5.3, 95% confidence interval = 4.7 to 6.0) than those randomized to testing as usual (3.6, 3.2 to 4.0; P < 0.0001), representing an average increase of 1.7 tests per participant over 15 months. Men randomized to self-testing reported using an average of 3.9 self-tests. Self-testing was noninferior with respect to all markers of HIV risk. Men in the self-testing arm reported significantly fewer STI tests during follow-up (mean = 2.3, 95% confidence interval = 1.9 to 2.7) than men in the control arm (3.2, 2.8 to 3.6; P = 0.0038).

CONCLUSIONS

Access to free HIV self-testing increased testing frequency among high-risk men who have sex with men and did not impact sexual behavior or STI acquisition.

Treponema pallidum Nucleic Acid Amplification Testing To Augment Syphilis Screening among Men Who Have Sex with Men

Syphilis rates in much of the world are now at their highest levels in almost three decades, and new approaches to controlling syphilis, including diagnostic tests with shorter window periods, are urgently needed. We compared the sensitivity of syphilis serological testing using the rapid plasma reagin (RPR) test with that of the combination of serological testing and an experimental 23S rRNA Treponema pallidum real-time transcription-mediated amplification (TMA) assay performed on rectal and pharyngeal mucosal swabs. T. pallidum PCR assays for the tpp47 gene were performed on all TMA-positive specimens, as well as specimens from 20 randomly selected TMA-negative men. A total of 545 men who have sex with men (MSM) who were seen in a sexually transmitted disease clinic provided 506 pharyngeal specimens and 410 rectal specimens with valid TMA results. Twenty-two men (4%) were diagnosed with syphilis on the basis of positive RPR test results and clinical diagnoses, including 3 men with primary infections, 8 with secondary syphilis, 9 with early latent syphilis, 1 with late latent syphilis, and 1 with an unstaged infection. Two additional men were diagnosed based on positive rectal mucosal TMA assay results alone, and both also tested positive by PCR assay. At least 1 specimen was TMA positive for 12 of 24 men with syphilis (sensitivity, 50% [95% confidence interval [CI], 29 to 71%]). RPR testing and clinical diagnosis were 92% sensitive (95% CI, 73 to 99%) in identifying infected men. Combining mucosal TMA testing and serological testing may increase the sensitivity of syphilis screening in high-risk populations.

Developments in the Diagnostic Techniques of Infectious Diseases: Rural and Urban Prospective

Objectives:

Diagnostics is the first step for the treatment and eradication of infectious microbial diseases. Due to ever evolving pathogens and emerging new diseases, there is an urgent need to identify suitable diagnostic techniques for better management of each disease. The success rate of specific diagnostic technique in any population depends on various factors including type of the microbial pathogen, availability of resources, technical expertise, disease severity and degree of epidemic of disease in the area. One of the important tasks of the policy makers is to identify and implement suitable diagnostic techniques for specific regions based on their specific requirements. In this review we have discussed various techniques available in the literature and their suitability for the target population based on above mentioned criteria.

Methods:

Diagnostic techniques evaluation of well documented representative microbial diseases; Tuberculosis (bacterial), Malaria (parasitic) and HIV (viral) were included in the study. Identification and collection of information and data was performed focusing on the diagnostic techniques used from the scientific publications from Pubmed, Science Access, Scopus, EMBASE and several regional databases. WHO and CDC database for Tuberculosis, Malaria and HIV were also included. These techniques were compared with respect to the financial resource availability, expertise and management, functional capacity, pathogen virulence and degree of epidemic in the population.

Results and Conclusion:

In case of Tuberculosis, ELISA and colorimetric techniques are successful in rural and urban communities with 80% – 90% sensitivity. Genotyping and SNP analysis are useful in drug resistant strains. Parasitic disease Malaria also follows the same trend with diagnostic techniques like RDTs being common in both population with fast results and around 90% sensitivity. STD disease like HIV however shows slight different trends due to urgent need of interference in rural epidemics of the disease. Rapid and sensitive immunotechniques like dipsticks and agglutination with almost 100% sensitivity are used in both rural and urban areas. For the confirmation further tests are done like protein Western and NAAT. Advance techniques could be the option for higher epidemic area, drug resistance and disease research, while rapid techniques would be suitable for low income areas and POC facilities. Therefore, suitability of the diagnostic techniques for better management depends not only on the financial resources and assessment skills of a community but sometimes on the disease itself. We have further discussed the technological improvements for specific settings (rural/urban) based on the past research for better management of diseases, which could be implemented for the understanding of understudied and newly emerging diseases.

Ultra-rapid, sensitive and specific digital diagnosis of HIV with a dual-channel SAW biosensor in a pilot clinical study

Despite widened access to HIV testing, around half of those infected worldwide are unaware of their HIV-positive status and linkage to care remains a major challenge. Current rapid HIV tests are typically analogue risking incorrect interpretation, no facile electronic data capture, poor linkage to care and data loss for public health. Smartphone-connected diagnostic devices have potential to dramatically improve access to testing and patient retention with electronic data capture and wireless connectivity. We report a pilot clinical study of surface acoustic wave biosensors based on low-cost components found in smartphones to diagnose HIV in 133 patient samples. We engineered a small, portable, laboratory prototype and dual-channel biochips, with in-situ reference control coating and miniaturised configuration, requiring only 6 µL plasma. The dual-channel biochips were functionalized by ink-jet printing with capture coatings to detect either anti-p24 or anti-gp41 antibodies, and a reference control. Biochips were tested with 31 plasma samples from patients with HIV, and 102 healthy volunteers. SH-SAW biosensors showed excellent sensitivity, specificity, low sample volumes and rapid time to result, and were benchmarked to commercial rapid HIV tests. Testing for individual biomarkers found sensitivities of 100% (anti-gp41) and 64.5% (anti-p24) (combined sensitivity of 100%) and 100% specificity, within 5 min. All positive results were recorded within 60 s of sample addition with an electronic readout. Next steps will focus on a smartphone-connected device prototype and user-friendly app interface for larger scale evaluation and field studies, towards our ultimate goal of a new generation of affordable, connected point-of-care HIV tests.

No Time to Delay! Fiebig Stages and Referral in Acute HIV infection: Seattle Primary Infection Program Experience

There has been increasing recognition of the importance of diagnosing individuals during the earliest stages of human immunodeficiency virus (HIV) infection. Sera from individuals referred to a primary HIV infection research program were screened using the IgG-sensitive Vironostika HIV-1 Microelisa System, IgG/IgM-sensitive GS HIV-1/HIV-2 Plus O antibody enzyme immunoassay (EIA), or Abbott ARCHITECT HIV antigen (Ag)/antibody (Ab) Combo assay and confirmed by the Bio-Rad Multispot and Western blot. A subset of participants was co-enrolled in a study designed to compare the ability of point-of-care tests to detect early infection. We calculated time within primary infection laboratory stages using actual observed transitions and with an expectation-maximization algorithm. Three hundred and sixty participants contributed data to this analysis. Of 123 persons referred with EIA-negative/RNA-positive test results (Fiebig stage I-II) or for concern for symptoms, 24 (20%) were still in stages I-II, and 99 (80%) were in stages III or later at their screening visit. Participants were estimated to spend a median of 13.5 days in stages I and II, 2.3 days in stage III, and 7.8 days in stage IV. OraQuick performed on oral fluids detected 53% of 17 participants in stage V. The durations of stages we observed are consistent with previous publications. Most persons referred for research no longer had acute infection at their first visit. Programs wishing to identify persons in the very earliest stages of infection need to expedite referrals or develop targeted screening programs.

Selecting an HIV Test: A Narrative Review for Clinicians and Researchers

Given the many options available, selecting an HIV test for a particular clinical or research setting can be daunting. Making an informed decision requires an assessment of the likelihood of acute infection in the test population and an understanding of key aspects of the tests themselves. The ability of individual tests to reliably detect HIV infection depends on the target(s) being detected, when they can be expected to be present after infection, and the concentration of stable target in test specimens, all of which are explained by the virologic and serologic events after infection. The purpose of this article is to review the timeline of HIV infection, nomenclature, and characteristics of different tests; compare point-of-care and laboratory-based tests; discuss the impact of different specimens on test performance; and provide practical advice to help clinicians and researchers new to the field select a test that best suits their needs.

Operationalizing the Measurement of Seroadaptive Behaviors: A Comparison of Reported Sexual Behaviors and Purposely-Adopted Behaviors Among Men who have Sex with Men (MSM) in Seattle

Seroadaptive behaviors are traditionally defined by self-reported sexual behavior history, regardless of whether they reflect purposely-adopted risk-mitigation strategies. Among MSM attending an STD clinic in Seattle, Washington 2013-2015 (N = 3751 visits), we used two seroadaptive behavior measures: (1) sexual behavior history reported via clinical computer-assisted self-interview (CASI) (behavioral definition); (2) purposely-adopted risk-reduction behaviors reported via research CASI (purposely-adopted definition). Pure serosorting (i.e. only HIV-concordant partners) was the most common behavior, reported (behavioral and purposely-adopted definition) by HIV-negative respondents at 43% and 60% of visits, respectively (kappa = 0.24; fair agreement) and by HIV-positive MSM at 30 and 34% (kappa = 0.25; fair agreement). Agreement of the two definitions was highest for consistent condom use [HIV-negative men (kappa = 0.72), HIV-positive men (kappa = 0.57)]. Overall HIV test positivity was 1.4 but 0.9% for pure serosorters. The two methods of operationalizing behaviors result in different estimates, thus the choice of which to employ should depend on the motivation for ascertaining behavioral information.

Evaluation of the performance of a new automated HIV combination assay

BACKGROUND

More and more countries test for HIV infection using combination assays that simultaneously detect p24 antigen and HIV antibodies.

OBJECTIVE

To assess the performance of a new HIV combo assay: LIAISON^® XL murex HIV Ab/Ag HT.

STUDY DESIGN

The assays were examined with a total of 3090 samples that included 769 selected HIV antibody-negative samples, 1849 unselected HIV samples, 15 HIV-1 p24 Ag reference samples, 90 primary HIV-1 infection (PHI) samples, 167 HIV-1 antibody-positive samples (well characterized of groups M and O), 95 HIV-1 antibody-positive samples and 105 HIV-2 antibody-positive samples.

RESULTS

The specificity of the LIAISON^® XL murex HIV Ab/Ag HT was 99.7%. The analytical sensitivity of Ag p24 of the LIAISON^® XL murex HIV Ab/Ag HT was 0.58IU/mL and 9.93pg/mL when using WHO and French national standards, respectively. All screened HIV subtypes was identified by this assay. Also, 90 PHI specimens were detected by this screening assay.

CONCLUSION

The sensitivity and specificity of the LIAISON^® XL murex HIV Ab/Ag HT assay are high. Hence the assay offers automated high-throughput screening with ability to detect primary infection.

Improved matrix pooling

Pooled testing is useful to identify positive specimens for large-scale screening. Matrix pooling is one of the commonly used algorithms. In this work, we investigate the properties of matrix pooling and reveal that the efficiency of matrix pooling is related with the magnitude of overlapping among groups. Based on this property, we develop a new design to further improve the efficiency while taking into account of testing error. The efficiency, pooling sensitivity and specificity of this algorithm are explicitly derived and verified through plasmode simulation of detecting acute human immunodeficiency virus among patients who were suspected to have malaria in rural Ugandan. We show that the new design outperforms matrix pooling in efficiency while retain the pooling sensitivity and specificity.

A comparison of effectiveness between oral rapid testing and routine serum-based testing for HIV in an outpatient dental clinic in Yuxi Prefecture, China: a case-control study

OBJECTIVE

To compare the outcomes of routine provider-initiated HIV testing and counselling (PITC) and oral rapid HIV testing for dental clinic outpatients in a hospital.

DESIGN

We employed a case-control study design and recruited dental outpatients into routine serum-based and oral rapid testing groups. We compared the acceptance, completion and result notification rate between groups.

SETTING

A dental outpatient clinic in the Yuxi People's Hospital, Yunnan.

PARTICIPANTS

A total of 758 and 816 dental outpatients were enrolled for routine and oral rapid testing, respectively.

RESULTS

The percentage of participants willing to receive routine HIV testing was 28.1% (95% CI 24.9% to 31.3%) and 96.1% (95% CI 94.8% to 97.4%, χ2=186.4, p<0.001) for the rapid testing. Among accepted participants, the percentage of participants who received HIV testing was 26.8% (95% CI 20.9% to 32.7%) in the routine testing group and 100.0% in the oral rapid HIV testing group (χ2=77.5, p<0.001). About 93.0% of routine testers returned for the test results on the next day, whereas all rapid testers received their test results on the same day (χ2=34.6, p<0.001). These correspond to an overall completion rate of 7.0% (95% CI 5.2% to 8.8%) and 96.1% (95% CI 94.8% to 97.4%, p<0.001), respectively. Among the 545 patients who declined routine serum-based HIV testing, the main reasons included, an unnecessary hassle (254/545, 46.6%), having been previously tested (124/545, 22.8%) and self-perceived low risk of HIV infection (103/545, 18.9%). In contrast, only 32 individuals declined oral rapid testing, and having received a previous test was the primary reason. Three patients in the rapid testing group were later confirmed HIV-positive, yielding an HIV prevalence of 0.38%.

CONCLUSION

Oral rapid HIV testing is a feasible and efficient approach in a clinical setting.

Changes in Condomless Sex and Serosorting Among Men Who Have Sex With Men After HIV Diagnosis

BACKGROUND

Among men who have sex with men (MSM) diagnosed with HIV, high-risk sexual behaviors may decline in the year after diagnosis. The sustainability of these changes is unknown.

METHODS

We created a retrospective cohort (Seroconversion Cohort) of MSM attending an STD clinic in Seattle, Washington who tested HIV positive between 2001 and 2013 and had a negative HIV test <2 years before diagnosis. We randomly selected 1000 HIV-negative controls (men who always tested HIV negative) who were frequency-matched to the Seroconversion Cohort based on HIV diagnosis year. 12-month sexual behavior data were collected at each clinic visit. We examined condomless anal intercourse (CAI) with HIV-negative, HIV-positive, and HIV unknown-status partners before diagnosis and up to 4 years thereafter.

RESULTS

Of the 26,144 clinic visits where MSM tested for HIV, there were 655 (2.5%) new HIV diagnoses. Of these, 186 (28%) men had previously tested HIV negative and were included in the Seroconversion Cohort. The proportion (of the 186) reporting CAI with HIV-negative partners declined from 73% at diagnosis to 12% after diagnosis (P < 0.001), whereas CAI with HIV-positive partners increased (11%-67%; P < 0.001). The proportion who serosorted (ie, CAI only with HIV-concordant partners) did not change before or after diagnosis (34%-40%; P = 0.65). These 3 behaviors remained stable for up to 4 years after diagnosis. Among HIV-negative controls, serosorting and CAI with HIV-positive and HIV-negative partners was constant.

CONCLUSIONS

MSM substantially modify their sexual behavior after HIV diagnosis. These changes are sustained for several years and may reduce HIV transmission to HIV-uninfected men.

Performance evaluation of the point-of-care INSTI™ HIV-1/2 antibody test in early and established HIV infections

BACKGROUND

The flow-through INSTI™ HIV-1/HIV-2 Rapid Antibody (INSTI) test is a 60s FDA-approved test for HIV-1 and HIV-2 antibody testing using whole blood and plasma.

OBJECTIVE

We evaluated the performance of INSTI using plasma and simulated whole blood specimens.

STUDY DESIGN

INSTI's performance in plasma specimens from commercial seroconversion panels was assessed by estimating the relative sensitivity using a 50% cumulative frequency analysis and by comparing its performance with other FDA-approved rapid tests (RTs). INSTI was further evaluated using 320 HIV-1 plasma specimens collected during a cross-sectional study and with 107 HIV-1 and 24 HIV-2 simulated whole blood specimens. Sensitivity and specificity were calculated using 615 known HIV-1 group M/O and 80 HIV-2 (Western blot (WB)-positive), and 497 HIV-negative plasma specimens, respectively.

RESULTS

In HIV-1 seroconversion panels, INSTI became reactive 9days before a positive WB. When compared to FDA-approved antibody-based lateral flow RTs, INSTI detected significantly more early infections. Among HIV-1-infected cross-sectional plasma samples, INSTI detected 23 (27%) of 85 Architect-positive/Multispot-negative or indeterminate specimens. For plasma specimens, the sensitivity was 99.84% for HIV-1 and 100% for HIV-2, and the specificity was 99.80%. Using simulated whole blood from seroconverters, INSTI performed similarly to plasma.

CONCLUSIONS

INSTI performed significantly better than antibody-based lateral flow RTs during early stages of seroconversion. Sensitivity and specificity were within the manufacturer's reported ranges. Considering the observed test performance and the almost immediate results, INSTI is an accurate option to detect HIV-1/HIV-2 antibodies in point-of-care settings where lab testing is not feasible.

Detection of HIV RNA in dried blood spots and oral fluids

: We evaluated detection of HIV-1 RNA from dried blood spots (DBS) and oral fluid specimens. Between February 2010 and August 2014, HIV-1 was newly diagnosed in eight (2.6%) study participants who had median blood HIV-1 RNA of 61 500 copies/ml (interquartile range 7500-146 000). RNA was detected in seven (87.5%) DBS and three (37.5%) oral fluid swabs but was not detected in either specimen from one participant. DBS may be a reasonable specimen collection method to detect acute infection.

Comparative evaluation of three FDA-approved HIV Ag/Ab combination tests using a genetically diverse HIV panel and diagnostic specimens

BACKGROUND

HIV Ag/Ab combination assays are recommended by CDC for routine screening and several HIV Ag/Ab combination tests are now FDA-approved. Maintaining high specificity and consistent sensitivity across diverse HIV strains is critical for these assays to accurately detect HIV infection and expedite delivery of patient results.

OBJECTIVES

To evaluate performance of three FDA-approved HIV tests: ARCHITECT HIV Combo (Abbott), ADVIA Centaur HIV Combo (Siemens) and BioPlex HIV Ag-Ab (Bio-Rad).

STUDY DESIGN

Sensitivity and specificity were evaluated using an extensive panel of 28 HIV infected human specimens and 17 cultured virus isolates representing multiple genotypes, 6 seroconversion panels, 4 human samples with acute infection, WHO p24 standard and 4020 clinical specimens.

RESULTS

The p24 limit of detection (LOD) for the WHO standard was 0.19IU/ml, 0.70IU/ml, and 1.77IU/ml in BioPlex, ARCHITECT, and Centaur respectively. The distribution of LODs across 15 HIV-1 isolates was substantially narrower in ARCHITECT (5-33pg/ml) than in BioPlex (11-198pg/ml) and Centaur (6-384pg/ml). All assays detected antibodies to the majority of HIV-1 and HIV-2 variants. However, reduced sensitivity was observed for Centaur in detection of antibodies to HIV-1 group M (CRF02_AG), O and N variants. BioPlex and ARCHITECT showed better seroconversion sensitivity than Centaur, detecting one bleed (3-7 days) earlier in 4 (BioPlex) and 3 (ARCHITECT) of 6 seroconversion panels. ARCHITECT demonstrated the highest specificity (99.90-100%) compared to BioPlex (99.80%) and Centaur (99.42%).

CONCLUSIONS

The overall performance of ARCHITECT and BioPlex was superior to Centaur, especially for detection of acute HIV infection.

Performance of serological and molecular tests within acute HIV infection

BACKGROUND

Early diagnosis of acute HIV infection can be challenging and is critical in regards to early therapeutic decision making.

OBJECTIVES

To evaluate the performance of different HIV tests in detecting early infections.

STUDY DESIGN

A total of 83 leftover specimens of 61 study participants who seroconverted were used in this sub-study. 35 HIV RNA positive but still seronegative specimens (acute infections) were used for analysis of the sensitivity of the different assays in detecting early infections and 42 HIV RNA and antibody negative specimens were used for specificity analysis.

RESULTS

Four (11%) specimens out of 35 acute infections were reactive with the Enzygnost^® Anti-HIV 1/2 Plus and 12/35 (34%) with the Vironostika^® HIV Ag/Ab. 16 (46%) specimens were confirmed as acute by the INNOTEST^® HIV antigen mAb Antigen test. Only three (9%), 10 (29%) and 9 (27%) specimens were reactive with the Determine HIV-1/2 Ag/Ab Combo, SD Bioline HIV Ag/Ab Combo test and the HIV Combo test, respectively. The specificity of the different tests were 100%, 95%, 100%, 93%, 100% and 93% for Enzygnost^® Anti-HIV 1/2 Plus, Vironostika^® HIV Ag/Ab, INNO-Test HIV antigen mAb, Determine HIV-1/2 Ag/Ab Combo, SD Bioline HIV Ag/Ab Combo test and HIV Combo test respectively.

CONCLUSION

RNA test, 4th generation ELISA and Single Ag test are the most sensitive tests for detection of an acute infection. As an alternative, the HIV Combo test is generally slightly more sensitive compared to its previous version, but the SD Bioline HIV Ag/Ab Combo tests has the best performance compared to the other simple rapid tests (SRTs) but none of them are precise in detecting Ag in the determination of acute infections.

Current diagnostic methods for HIV

Detection of HIV infection is essential for diagnosis and monitoring of the infection. There are different types of diagnostic tools available that are based on detection of HIV-specific antibodies, viral antigen or nucleic acid. Sensitivities and specificities of assays utilized for HIV detection have improved. Newer HIV testing technologies such as third-generation enzyme immunoassay which detect HIV-specific IgG and IgM antibodies, fourth-generation enzyme immunoassay which detect both anti-HIV antibodies and HIV p24 antigen and nucleic acid based tests for HIV RNA have significantly decreased the window period. This review provides an overview of current technologies for the detection and monitoring of HIV infection and recent advances in the field of HIV diagnosis.

Fluorescent silver nanoparticle based highly sensitive immunoassay for early detection of HIV infection

Fluorescent silver nanoparticles have been employed in an immunoassay to detect HIV p24 antigen with high sensitivity in the linear range of 10–1000 pg mL⁻¹.

Evaluation of a Computer-Based Recruitment System for Enrolling Men Who Have Sex With Men Into an Observational HIV Behavioral Risk Study

Enrolling large numbers of high-risk men who have sex with men (MSM) into human immunodeficiency virus (HIV) prevention studies is necessary for research with an HIV outcome, but the resources required for in-person recruitment can be prohibitive. New methods with which to efficiently recruit large samples of MSM are needed. At a sexually transmitted disease clinic in Seattle, Washington, in 2013-2014, we used an existing clinical computer-assisted self-interview that collects patients' medical and sexual history data to recruit, screen, and enroll MSM into an HIV behavioral risk study and compared enrollees with men who declined to enroll. After completing the clinical computer-assisted self-interview, men aged ≥18 years who reported having had sex with men in the prior year were presented with an electronic study description and consent statement. We enrolled men at 2,661 (54%) of 4,944 visits, including 1,748 unique individuals. Enrolled men were younger (mean age = 34 years vs. 37 years; P < 0.001) and reported more male sex partners (11 vs. 8; P < 0.001) and more methamphetamine use (15% vs. 8%; P < 0.001) than men who declined to enroll, but the HIV test positivity of the two groups was similar (1.9% vs. 2.0%; P = 0.80). Adapting an existing computerized clinic intake system, we recruited a large sample of MSM who may be an ideal population for an HIV prevention study.

Sensitivity of HIV rapid tests compared with fourth-generation enzyme immunoassays or HIV RNA tests

OBJECTIVE

Determine the sensitivity of HIV rapid tests compared with fourth-generation enzyme immunoassays (EIA) or nucleic acid amplification tests (NAAT) in clinical settings.

DESIGN

Systematic review and meta-analysis.

METHODS

Medline, PubMed, Embase, Cochrane Controlled Trials Register, Cochrane reviews and Cumulative Index to Nursing and Allied Health Literature were searched until 14 July 2015 for studies of adults comparing point-of-care HIV rapid tests to fourth-generation HIV EIA antibody/p24 antigen or HIV NAAT.

RESULTS

From 953 titles, 18 studies were included, involving 110 122 HIV rapid test results. Compared with EIA, the estimated sensitivity (random effects) of HIV rapid tests was 94.5% [95% confidence interval (CI): 87.4-97.7]. Compared with NAAT, the sensitivity of HIV rapid tests was 93.7% (95% CI: 88.7-96.5). The sensitivity of HIV rapid tests in high-income countries was 85.7% (95% CI: 81.9-88.9) and in low-income countries was 97.7% (95% CI: 95.2-98.9) compared with either EIA or NAAT (P < 0.01 for difference between settings). Proportions of antibody negative acute infections were 13.6 (95% CI: 10.1-18.0) and 4.7% (95% CI: 2.8-7.7) in studies from high-income and low-income countries, respectively (P < 0.01).

CONCLUSION

In clinical settings, HIV rapid tests were less sensitive in high-income countries compared with low-income countries, missing about one in seven infections, possibly because of the larger proportion of acute infections in targeted populations. This suggests that in high-income countries, HIV rapid tests should be used in combination with fourth-generation EIA or NAAT tests, except in special circumstances. Prospective Registration of Systematic Reviews registration number CRD42015020154.Supplementary video link: http://links.lww.com/QAD/A924.

Trends in Serosorting and the Association With HIV/STI Risk Over Time Among Men Who Have Sex With Men

BACKGROUND

Serosorting among men who have sex with men (MSM) is common, but recent data to describe trends in serosorting are limited. How serosorting affects population-level trends in HIV and other sexually transmitted infection (STI) risk is largely unknown.

METHODS

We collected data as part of routine care from MSM attending a sexually transmitted disease clinic (2002-2013) and a community-based HIV/sexually transmitted disease testing center (2004-2013) in Seattle, WA. MSM were asked about condom use with HIV-positive, HIV-negative, and unknown-status partners in the prior 12 months. We classified behaviors into 4 mutually exclusive categories: no anal intercourse (AI); consistent condom use (always used condoms for AI); serosorting [condom-less anal intercourse (CAI) only with HIV-concordant partners]; and nonconcordant CAI (CAI with HIV-discordant/unknown-status partners; NCCAI).

RESULTS

Behavioral data were complete for 49,912 clinic visits. Serosorting increased significantly among both HIV-positive and HIV-negative men over the study period. This increase in serosorting was concurrent with a decrease in NCCAI among HIV-negative MSM, but a decrease in consistent condom use among HIV-positive MSM. Adjusting for time since last negative HIV test, the risk of testing HIV positive during the study period decreased among MSM who reported NCCAI (7.1%-2.8%; P= 0.02), serosorting (2.4%-1.3%; P = 0.17), and no CAI (1.5%-0.7%; P = 0.01). Serosorting was associated with a 47% lower risk of testing HIV positive compared with NCCAI (adjusted prevalence ratio = 0.53; 95% confidence interval: 0.45 to 0.62).

CONCLUSIONS

Between 2002 and 2013, serosorting increased and NCCAI decreased among Seattle MSM. These changes paralleled a decline in HIV test positivity among MSM.

Incidence of HIV Infection and Sexually Transmitted Infections and Related Risk Factors Among Very Young Men Who Have Sex With Men

INTRODUCTION

The HIV epidemic continues to disproportionately affect men who have sex with men (MSM) in the United States, with over a third of new infections in MSM occurring in younger men. Very few studies have reported on HIV and sexually transmitted infection (STI) incidence and related risks among younger MSM, particularly among minors under 18 years of age.

METHODS

Data analyzed herein are from a longitudinal study of HIV risk among 450 very young MSM in Chicago aged 16 to 20, recruited via respondent-driven sampling and followed-up for 2 years, with annual HIV and STI testing. We report estimated cumulative HIV and STI incidence over the 24-month follow-up using Kaplan-Meier methods and evaluated associations with incident infections using Cox proportional hazards regression.

RESULTS

The final analytic sample was primarily non-white (83%); median age was 19; 25% of the sample was under age 18. Twenty-six new HIV infections were detected over 632 person-years of follow-up. HIV incidence was 4.11/100 person-years [95% confidence interval (CI): 2.80 to 6.04] and STI incidence was 6.22/100 person-years (95% CI: 4.54 to 8.51). Cumulative HIV incidence over 24 months of follow-up was 7.32% (95% CI: 5.05 to 10.57), with higher incidence among racial/ethnic minorities. In multivariate analyses, non-white race and recent sexual partner concurrency were associated with both HIV and STI infection; HIV testing history and sex with an HIV-positive partner were associated with increased risk of HIV infection.

DISCUSSION

High rates of incident HIV infection and STIs among very young MSM and the relationship between incidence and race/ethnicity, concurrency and partner characteristics indicate potential focal points of future intervention and the need for continued vigilance.

Evaluation of a Rapid Point of Care Test for Detecting Acute and Established HIV Infection, and Examining the Role of Study Quality on Diagnostic Accuracy: A Bayesian Meta-Analysis

Introduction

Fourth generation (Ag/Ab combination) point of care HIV tests like the FDA-approved Determine HIV1/2 Ag/Ab Combo test offer the promise of timely detection of acute HIV infection, relevant in the context of HIV control. However, a synthesis of their performance has not yet been done. In this meta-analysis we not only assessed device performance but also evaluated the role of study quality on diagnostic accuracy.

Methods

Two independent reviewers searched seven databases, including conferences and bibliographies, and independently extracted data from 17 studies. Study quality was assessed with QUADAS-2. Data on sensitivity and specificity (overall, antigen, and antibody) were pooled using a Bayesian hierarchical random effects meta-analysis model. Subgroups were analyzed by blood samples (serum/plasma vs. whole blood) and study designs (case-control vs. cross-sectional).

Results

The overall specificity of the Determine Combo test was 99.1%, 95% credible interval (CrI) [97.3–99.8]. The overall pooled sensitivity for the device was at 88.5%, 95% [80.1–93.4]. When the components of the test were analyzed separately, the pooled specificities were 99.7%, 95% CrI [96.8–100] and 99.6%, 95% CrI [99.0–99.8], for the antigen and antibody components, respectively. Pooled sensitivity of the antibody component was 97.3%, 95% CrI [60.7–99.9], and pooled sensitivity for the antigen component was found to be 12.3%, 95% (CrI) [1.1–44.2]. No significant differences were found between subgroups by blood sample or study design. However, it was noted that many studies restricted their study sample to p24 antigen or RNA positive specimens, which may have led to underestimation of overall test performance. Detection bias, selection (spectrum) bias, incorporation bias, and verification bias impaired study quality.

Conclusions

Although the specificity of all test components was high, antigenic sensitivity will merit from an improvement. Besides the accuracy of the device itself, study quality, also impacts the performance of the test. These factors must be kept in mind in future evaluations of an improved device, relevant for global scale up and implementation.

HIV testing updates and challenges: when regulatory caution and public health imperatives collide

Numerous improvements in HIV testing technology led recently to the first revision of recommendations for diagnostic laboratory testing in the USA in 25 years. Developments in HIV testing continue to produce tests that identify HIV infection earlier with faster turnaround times for test results. These play an important role in identifying HIV infection during the highly infectious acute phase, which has implication for both patient management and public health interventions to control the spread of HIV. Access to these developments, however, is often delayed by the regulatory apparatus for approval and oversight of HIV testing in the USA. This article summarizes recent developments in HIV diagnostic testing technology, outlines their implications for clinical management and public health, describes current systems of regulatory oversight for HIV testing in the USA, and proposes alternatives that could expedite access to improved tests as they become available.

Performance of Determine Combo and other point-of-care HIV tests among Seattle MSM

BACKGROUND AND OBJECTIVE

The rapid test study was a real-time comparison of point-of-care (POC) HIV tests to determine their abilities to detect early HIV infection.

STUDY DESIGN

Men and transgender persons reporting sex with men in the prior year were recruited at the Public Health-Seattle & King County STD Clinic, Gay City Health Project, and University of Washington Primary Infection Clinic. Study tests included the OraQuick ADVANCE Rapid HIV-1/2 Antibody Test performed on oral fluids and tests performed on fingerstick whole blood specimens including OraQuick, Uni-Gold Recombigen HIV test, Determine HIV-1/2 Ag/Ab Combo, and INSTI HIV-1 Rapid Antibody Test. Specimens from subjects with negative results were sent for EIA and nucleic acid amplification testing. McNemar's exact tests compared the numbers of HIV-infected subjects detected.

RESULTS

Between February 2010 and August 2014, there were 3438 study visits. Twenty-four subjects had discordant POC results with at least one reactive and one non-reactive test, including one subject with a reactive Determine p24 antigen. OraQuick performed on oral fluids identified fewer persons compared to all fingerstick tests. OraQuick performed on fingerstick whole blood detected fewer persons compared to the Determine Combo antibody component (p=.008) and Combo overall (p=.004), and there was a trend when compared to INSTI (p=.06). The Determine Combo specificity was 98.99%.

CONCLUSIONS

As reported by others, Determine Combo underperforms compared to laboratory-based testing, but it did detect one acute infection. If these results are validated, the specificity of Determine Combo may limit its usefulness in populations with lower HIV incidence.

Using a Multitest Algorithm to Improve the Positive Predictive Value of Rapid HIV Testing and Linkage to HIV Care in Nonclinical HIV Test Sites

BACKGROUND

Use of a rapid HIV testing algorithm (RTA) in which all tests are conducted within one client appointment could eliminate off-site confirmatory testing and reduce the number of persons not receiving confirmed results.

METHODS

An RTA was implemented in 9 sites in Los Angeles and San Francisco; results of testing at these sites were compared with 23 sites conducting rapid HIV testing with off-site confirmation. RTA clients with reactive results on more than 1 rapid test were considered HIV+ and immediately referred for HIV care. The positive predictive values (PPVs) of a single rapid HIV test and the RTA were calculated compared with laboratory-based confirmatory testing. A Poisson risk regression model was used to assess the effect of RTA on the proportion of HIV+ persons linked to HIV care within 90 days of a reactive rapid test.

RESULTS

The PPV of the RTA was 100% compared with 86.4% for a single rapid test. The time between testing and receipt of RTA results was on average 8 days shorter than laboratory-based confirmatory testing. For risk groups other than men who had sex with men, the RTA increased the probability of being in care within 90 days compared with standard testing practice.

CONCLUSIONS

The RTA increased the PPV of rapid testing to 100%, giving providers, clients, and HIV counselors timely information about a client's HIV-positive serostatus. Use of RTA could reduce loss to follow-up between testing positive and confirmation and increase the proportion of HIV-infected persons receiving HIV care.

Field accuracy of fourth-generation rapid diagnostic tests for acute HIV-1: a systematic review

INTRODUCTION

Fourth-generation HIV-1 rapid diagnostic tests (RDTs) detect HIV-1 p24 antigen to screen for acute HIV-1. However, diagnostic accuracy during clinical use may be suboptimal.

METHODS

Clinical sensitivity and specificity of fourth-generation RDTs for acute HIV-1 were collated from field evaluation studies in adults identified by a systematic literature search.

RESULTS

Four studies with 17 381 participants from Australia, Swaziland, the United Kingdom and Malawi were identified. All reported 0% sensitivity of the HIV-1 p24 component for acute HIV-1 diagnosis; 26 acute infections were missed. Specificity ranged from 98.3 to 99.9%.

CONCLUSION

Fourth-generation RDTs are currently unsuitable for the detection of acute HIV-1.

"Just Because It's Out There, People Aren't Going to Use It." HIV Self-Testing Among Young, Black MSM, and Transgender Women

HIV disproportionately affects young black MSM and transgender women in the US. Increasing HIV testing rates among these populations is a critical public health goal. Although HIV self-tests are commercially available, there is a need to better understand access to and uptake of HIV self-testing among this population. Here, we report results of a qualitative study of 30 young black MSM and transgender women residing in the New York City area to understand facilitators of and barriers to a range of HIV testing approaches, including self-testing. Mean age was 23.7 years (SD = 3.4). Over half (54%) had some college or an associate's degree, yet 37% had an annual personal income of less than $10,000 per year. Most (64%) participants had tested in the past 6 months; venues included community health/free clinics, medical offices, mobile testing units, hospitals, emergency departments, and research sites. Just one participant reported ever using a commercially available HIV self-test. Facilitators of self-testing included convenience, control, and privacy, particularly as compared to venue-based testing. Barriers to self-testing included the cost of the test, anxiety regarding accessing the test, concerns around correct test operation, and lack of support if a test result is positive. Participants indicated that instruction in correct test operation and social support in the event of a positive test result may increase the likelihood that they would use the self-test. Alongside developing new approaches to HIV prevention, developing ways to increase HIV self-testing is a public health priority for young, black MSM, and transgender women.

The evaluation of accuracy of serial rapid HIV test algorithm in the diagnosis of HIV antibodies among pregnant women in south east Nigeria

Background

Accurate HIV testing in pregnancy is critical to the prevention of mother to child transmission of HIV infection and linkages to other preventive strategies.

Aims and objectives

This study determined the sensitivity, specificity negative and positive predictive value of serial rapid testing of HIV among pregnant women in Nnewi, south east Nigeria.

Methodology

This was a comparative descriptive study conducted over a 4-month period. Serial rapid testing algorithm was compared with conventional ELISA testing after obtaining informed consents from the pregnant women. All positive and discordant results were confirmed with western blot HIV test. Participants also completed a questionnaire. Data analysis was done using SPSS version 20.

Result

A total of 166 pregnant women participated in this study. The mean age of the participants was 29 ± 4.3 years. The HIV prevalence was highest in the 25–29 years category. This was also the modal age category. Majority of the women were multiparous. The prevalence of HIV infection was 12 %. The sensitivity, specificity, negative and positive predictive value of serial rapid HIV testing was 95, 100, 99.3 and 100 % respectively.

Conclusion

The sensitivity of the serial rapid test algorithm was high but still lower than the WHO recommended 99 % and above. The 100 % specificity and positive predictive value makes it a good diagnostic test strategy. There is need for regular review of HIV test kits and policy.

Rapid, Fully Automated Digital Immunoassay for p24 Protein with the Sensitivity of Nucleic Acid Amplification for Detecting Acute HIV Infection

BACKGROUND

Nucleic acid testing (NAT) has become the standard for high sensitivity in detecting low levels of virus. However, adoption of NAT can be cost prohibitive in low-resource settings where access to extreme sensitivity could be clinically advantageous for early detection of infection. We report development and preliminary validation of a simple, low-cost, fully automated digital p24 antigen immunoassay with the sensitivity of quantitative NAT viral load (NAT-VL) methods for detection of acute HIV infection.

METHODS

We developed an investigational 69-min immunoassay for p24 capsid protein for use on a novel digital analyzer on the basis of single-molecule-array technology. We evaluated the assay for sensitivity by dilution of standardized preparations of p24, cultured HIV, and preseroconversion samples. We characterized analytical performance and concordance with 2 NAT-VL methods and 2 contemporary p24 Ag/Ab combination immunoassays with dilutions of viral isolates and samples from the earliest stages of HIV infection.

RESULTS

Analytical sensitivity was 0.0025 ng/L p24, equivalent to 60 HIV RNA copies/mL. The limit of quantification was 0.0076 ng/L, and imprecision across 10 runs was <10% for samples as low as 0.09 ng/L. Clinical specificity was 95.1%. Sensitivity concordance vs NAT-VL on dilutions of preseroconversion samples and Group M viral isolates was 100%.

CONCLUSIONS

The digital immunoassay exhibited >4000-fold greater sensitivity than contemporary immunoassays for p24 and sensitivity equivalent to that of NAT methods for early detection of HIV. The data indicate that NAT-level sensitivity for acute HIV infection is possible with a simple, low-cost digital immunoassay.

Clinical Applications of Quantitative Real-Time PCR in Virology

Since the invention of the polymerase chain reaction (PCR) and discovery of Taq polymerase, PCR has become a staple in both research and clinical molecular laboratories. As clinical and diagnostic needs have evolved over the last few decades, demanding greater levels of sensitivity and accuracy, so too has PCR performance. Through optimisation, the present-day uses of real-time PCR and quantitative real-time PCR are enumerable. The technique, combined with adoption of automated processes and reduced sample volume requirements, makes it an ideal method in a broad range of clinical applications, especially in virology. Complementing serologic testing by detecting infections within the pre-seroconversion window period and infections with immunovariant viruses, real-time PCR provides a highly valuable tool for screening, diagnosing, or monitoring diseases, as well as evaluating medical and therapeutic decision points that allows for more timely predictions of therapeutic failures than traditional methods and, lastly, assessing cure rates following targeted therapies. All of these serve vital roles in the continuum of care to enhance patient management. Beyond this, quantitative real-time PCR facilitates advancements in the quality of diagnostics by driving consensus management guidelines following standardisation to improve patient outcomes, pushing for disease eradication with assays offering progressively lower limits of detection, and rapidly meeting medical needs in cases of emerging epidemic crises involving new pathogens that may result in significant health threats.

The cost of implementing rapid HIV testing in sexually transmitted disease clinics in the United States

INTRODUCTION

Rapid HIV testing in high-risk populations can increase the number of persons who learn their HIV status and avoid spending clinic resources to locate persons identified as HIV infected.

METHODS

We determined the cost to sexually transmitted disease (STD) clinics of point-of-care rapid HIV testing using data from 7 public clinics that participated in a randomized trial of rapid testing with and without brief patient-centered risk reduction counseling in 2010. Costs included counselor and trainer time, supplies, and clinic overhead. We applied national labor rates and test costs. We calculated median clinic start-up costs and mean cost per patient tested, and projected incremental annual costs of implementing universal rapid HIV testing compared with current testing practices.

RESULTS

Criteria for offering rapid HIV testing and methods for delivering nonrapid test results varied among clinics before the trial. Rapid HIV testing cost an average of US $22/patient without brief risk reduction counseling and US $46/patient with counseling in these 7 clinics. Median start-up costs per clinic were US $1100 and US $16,100 without and with counseling, respectively. Estimated incremental annual costs per clinic of implementing universal rapid HIV testing varied by whether or not brief counseling is conducted and by current clinic testing practices, ranging from a savings of US $19,500 to a cost of US $40,700 without counseling and a cost of US $98,000 to US $153,900 with counseling.

CONCLUSIONS

Universal rapid HIV testing in STD clinics with same-day results can be implemented at relatively low cost to STD clinics, if brief risk reduction counseling is not offered.

Targeting the use of pooled HIV RNA screening to reduce cost in health department STD clinics: New York City, 2009-2011

OBJECTIVE

Staff at public New York City sexually transmitted disease (STD) clinics screen patients for acute HIV infection (AHI) using pooled nucleic acid amplification tests. AHI screening is expensive but important for populations at high risk of acquiring HIV. We analyzed if targeting AHI screening in STD clinics could reduce program costs while maintaining AHI case detection.

METHODS

From January 2009 through May 2010, we screened all patients with negative rapid HIV tests for AHI. Using risk information on cases detected during this universal screening period, we developed criteria for targeted AHI screening and compared case yields and testing costs during 12 months of universal screening (June 2009 through May 2010) vs. 12 months of targeted screening (June 2010 through May 2011).

RESULTS

During the defined period of universal screening, we identified 40 AHI cases, and during targeted screening, we identified 35 AHI cases. Because of targeting efforts, the number needed to test to find one AHI case dropped from 1,631 to 254. With targeted screening, it cost an average of $4,535 per case detected and 39.3 cases were detected per 10,000 specimens; using universal screening, $29,088 was spent per case detected and 6.1 cases were detected per 10,000 specimens processed.

CONCLUSION

Targeted screening identified similar numbers of AHI cases as when screening all clinic patients seeking HIV testing, but at one-seventh the cost.

HIV self-testing among online MSM in China: implications for expanding HIV testing among key populations

HIV self-testing offers an alternative to facility-based testing that could expand HIV testing among men who have sex with men (MSM). We organized an online survey of MSM in China to better understand the frequency and correlates of HIV self-testing. A total of 1342 individuals completed the survey. About 20.3% of MSM reported previous HIV self-testing. Self-testing was correlated with being married, having 6 or greater male anal sex partners in the past 3 months, and having HIV tested within 12 months in the multivariable analysis. Our study suggests that HIV self-testing may be able to reach subgroups of high-risk MSM and enable more frequent HIV testing.

[Microbiological diagnosis of human immunodeficiency virus infection]

This document attempts to update the main tasks and roles of the Clinical Microbiology laboratory in HIV diagnosis and monitoring. The document is divided into three parts. The first deals with HIV diagnosis and how serological testing has changed in the last few years, aiming to improve diagnosis and to minimize missed opportunities for diagnosis. Technological improvements for HIV Viral Load are shown in the second part of the document, which also includes a detailed description of the clinical significance of low-level and very low-level viremia. Finally, the third part of the document deals with resistance to antiretroviral drugs, incorporating clinical indications for integrase and tropism testing, as well as the latest knowledge on minority variants.

Evaluating New Definitions of Acute and Early HIV Infection from HIV Surveillance Data

BACKGROUND

The U.S. HIV staging system is being revised to more comprehensively track early and acute HIV infection (AHI). We evaluated our ability to identify known cases of AHI using King County (KC) HIV surveillance data.

METHODOLOGY

AHI cases were men who have sex with men (MSM) with negative antibody and positive pooled nucleic acid amplification (NAAT) tests identified through KC testing sites. We used KC surveillance data to calculate inter-test intervals (ITI, time from last negative to first positive test) and the serologic algorithm for recent HIV seroconversion (STARHS). For surveillance data, AHI was defined as an ITI of ≤ 30 days and early infection as an ITI ≤ 180 days or STARHS recent result. Dates of last negative HIV tests were obtained from lab reports in the HIV surveillance system or data collected for HIV Incidence Surveillance.

RESULTS

Between 2005 and 2011, 47 MSM with AHI were identified by pooled NAAT. Of the 47 cases, 36% had ITI < 1 day, 60% had an ITI < 30 days, and 70% (95% CI=55-82%) had an ITI ≤ 6 months and would have been identified as early HIV infection. Of the 47, 38% had STARHS testing and 94% were STARHS recent.

CONCLUSION

MSM with known AHI were not identified by proposed definitions of AHI and early infection. These known AHI cases were frequently missed by HIV surveillance because concurrent negative antibody tests were not reported. Successful implementation of the revisions to the HIV staging system will require more comprehensive reporting.