Performance of rapid point-of-care and laboratory tests for acute and established HIV infection in San Francisco

Fourth-Generation HIV Testing

A 72-year-old man presented to the emergency department with fevers, night sweats, and rash 3 days after condomless vaginal intercourse. Results of a fourth-generation HIV test were positive and HIV-1-/2 antibody differentiation testing was negative. How would you interpret these results?

2021 European guideline on HIV testing in genito-urinary medicine settings

Testing for HIV is critical for early diagnosis of HIV infection, providing long-term good health for the individual and prevention of onward transmission if antiretroviral treatment is initiated early. The main purpose of the 2021 European Guideline on HIV Testing in Genito-Urinary Settings is to provide advice on testing for HIV infection in individuals aged 16 years and older who present to sexually transmitted infection, genito-urinary or dermato-venereology clinics across Europe. The guideline presents the details of best practice and offers practical guidance to clinicians and laboratories to identify and offer HIV testing to appropriate patient groups.

Altered Antibody Responses in Persons Infected with HIV-1 While Using Preexposure Prophylaxis

Preexposure prophylaxis (PrEP) is an effective HIV prevention tool, although effectiveness is dependent upon adherence. It is important to characterize the impact of PrEP on HIV antibody responses in people who experience breakthrough infections to understand the potential impact on timely diagnosis and treatment. Longitudinal HIV-1-specific antibody responses were evaluated in 42 people who inject drugs (PWID) from the Bangkok Tenofovir Study (BTS) (placebo = 28; PrEP = 14) who acquired HIV while receiving PrEP. HIV-1 antibody levels and avidity to three envelope proteins (gp41, gp160, and gp120) were measured in the plasma using a customized Bio-Plex (Bio-Rad Laboratories, Hercules, CA) assay. A time-to-event analysis was performed for each biomarker to compare the distribution of times at which study subjects exceeded the recent/long-term assay threshold, comparing PrEP and placebo treatment groups. We fit mixed-effects models to identify longitudinal differences in antibody levels and avidity between groups. Overall, longitudinal antibody levels and avidity were notably lower in the PrEP breakthrough group compared to the placebo group. Time-to-event analyses demonstrated a difference in time to antibody reactivity between treatment groups for all Bio-Plex biomarkers. Longitudinal gp120 antibody levels within the PrEP breakthrough group were decreased compared to the placebo group. When accounting for PrEP adherence, both gp120 and gp160 antibody levels were lower in the PrEP breakthrough group compared to the placebo group. We demonstrate hindered envelope antibody maturation in PWID who became infected while receiving PrEP in the BTS, which has significant implications for HIV diagnosis. Delayed maturation of the antibody response to HIV may increase the time to detection for antibody-based tests. Clinical Trial Registration Number, NCT00119106.

HIV false positive screening serology due to sample contamination reduced by a dedicated sample and platform in a high prevalence environment

Automated testing of HIV serology on clinical chemistry analysers has become common. High sample throughput, high HIV prevalence and instrument design could all contribute to sample cross-contamination by microscopic droplet carry-over from seropositive samples to seronegative samples resulting in false positive low-reactive results. Following installation of an automated shared platform at our public health laboratory, we noted an increase in low reactive and false positive results. Subsequently, we investigated HIV serology screening test results for a period of 21 months. Of 485 initially low positive or equivocal samples 411 (85%) tested negative when retested using an independently collected sample. As creatinine is commonly requested with HIV screening, we used it as a proxy for concomitant clinical chemistry testing, indicating that a sample had likely been tested on a shared high-throughput instrument. The contamination risk was stratified between samples passing the clinical chemistry module first versus samples bypassing it. The odds ratio for a false positive HIV serology result was 4.1 (95% CI: 1.69-9.97) when creatinine level was determined first, versus not, on the same sample, suggesting contamination on the chemistry analyser. We subsequently issued a notice to obtain dedicated samples for HIV serology and added a suffix to the specimen identifier which restricted testing to a dedicated instrument. Low positive and false positive rates were determined before and after these interventions. Based on measured rates in low positive samples we estimate that before the intervention, of 44 117 HIV screening serology samples, 753 (1.71%) were false positive, declining to 48 of 7 072 samples (0.68%) post-intervention (p<0.01). Our findings showed that automated high throughput shared diagnostic platforms are at risk of generating false-positive HIV test results, due to sample contamination and that measures are required to address this. Restricting HIV serology samples to a dedicated platform resolved this problem.

Cross-sectional study of sexual behaviour and health of gay and bisexual men in suburban Sydney, New South Wales, Australia: contrasts between sex venue and clinic attendees

Background In Australia, men-who-have-sex-with-men (MSM) have higher rates of sexually transmissible infections (STIs) and HIV compared with heterosexual men. We compared demographics, behaviour and HIV/STI prevalence for MSM attending a sex-on-premises-venue (SOPV) or the local sexual health clinic (SHC) to determine key differences.

METHODS

Men attending a SOPV during onsite HIV/STI screening from November 2015 for 12 months were compared with MSM attending a local SHC for screening. Each group completed a self-administered questionnaire and STI/HIV testing. Data analysis was performed using SPSS.

RESULTS

Compared with SHC participants (n = 108), SOPV participants (n = 84) had a higher median age (47 years [range, 22-88] vs 33 years [range, 19-71]; P < 0.001) and less likely to report previous HIV testing (73% vs 89%; P < 0.01), STI testing (60% vs 90%; P < 0.001) or be vaccinated for hepatitis A (32% vs 65%; P < 0.001) or hepatitis B (35% vs 73%; P < 0.001). SOPV participants were more likely to be married, widowed or have a long-term female partner (39% vs 7%; P < 0.001) and have a higher prevalence of urethral and rectal chlamydia (7% vs 1%; P = 0.02 and 8% vs 2%; P = 0.03, respectively). There was no significant difference between the groups for detection of syphilis (4% vs 9%), gonorrhoea (5% vs 9%) or HIV (1% vs 0%).

CONCLUSION

MSM attending the SOPV had higher anogenital chlamydial prevalence compared with those attending the SHC. They reported higher rates of sex with female partners, which may facilitate STI/HIV transmission to heterosexual populations. Our findings have implications for HIV/STI service provision, contact tracing and local health promotion initiatives.

Go Where the Virus Is: An HIV Micro-epidemic Control Approach to Stop HIV Transmission

Essentially all HIV transmission is from people living with HIV who are not virally suppressed. An HIV micro-epidemic control approach that differentiates treatment support and prevention services for people living with HIV and their network members according to viral burden could optimize the impact of epidemic control efforts.

Use of the Bio-Rad Geenius HIV-1/2 supplemental assay for the testing of oral fluids for the presence of HIV antibody

There is currently an absence of products which are cleared by the FDA to provide supplemental testing for oral fluid for HIV antibody. We created a procedure for the use of the BioRad Geenius HIV-1/2 as a supplemental antibody test for oral fluid specimens. The modified procedure was evaluated for its ability to detect HIV-1 antibody in oral fluid in specimens that were found to be repeatedly reactive for HIV-1 antibody by way of the Avioq HIV-1 enzyme immunoassay (EIA). Evaluated were oral fluid specimens analyzed at a local public health laboratory which were stored frozen and oral fluid specimens collected prospectively. Prospectively collected specimens were from patients whose HIV status was subsequently assessed through blood-based testing. For retrospective specimens found repeatedly EIA reactive, and positive by Western blot, the modified Geenius was found positive in 37/38 instances (97.4 %). Those specimens with a mean EIA signal-to-cutoff (S/CO) greater than 3.00 were found to be positive by Geenius in 34/34 (100 %) of instances. For specimens found repeated reactive by EIA and positive by Western blot with mean S/CO less than or equal to 3.00, the Geenius was positive in 4/5 instances (80 %) of instances. For prospectively collected specimens, the Geenius accurately confirmed infection in 22/24 cases (92 %) while prospective specimens found repeatedly reactive by EIA without supplemental Geenius testing were confirmed positive in 29/37 instances (78 %). A modified usage of the Geenius HIV-1/2 Supplemental Assay antibody test may provide utility in the supplementation of testing of oral fluid for the presence of HIV-1 antibody.

Facilitators and Barriers Associated with Uptake of HIV Self-Testing among Men Who Have Sex with Men in Chongqing, China: A Cross-Sectional Survey

While studies on human immunodeficiency virus self-testing (HIVST) continue to accumulate after the World Health Organization’s recommendation of HIVST as an additional approach to HIV testing services in 2016, few studies have focused on men who have sex with men (MSM) in Chinese cities. A cross-sectional study was conducted to describe the HIVST status of MSM in Chongqing, China. MSM participants were recruited by random sampling, and qualified interviewers collected data, using confidential self-administered questionnaires. Blood specimens were collected for HIV antibody detection. The survey evaluated the uptake and accuracy of HIVST kits and identified factors that may be associated with HIVST. The proportion of HIVST uptake was 15.6%. The sensitivity and specificity of HIVST were 74.2% (95% confidence interval [CI] 66.6%–80.7%) and 99.0% (95% CI 96.9%–99.7%), respectively. The consistency between the HIVST kit and antibody detection results was 90.5% (95% CI 87.5%–93.0%), and the Kappa value was 0.777 (p < 0.001). The positive predictive value of self-testing kits is 80.9% and the negative predictive value is 17.7%. Having been tested ≥2 times in the last year, higher educational levels, and higher scores of basic HIV/AIDS knowledge facilitated higher uptake of HIVST. Self-reported existing barriers for HIVST uptake included older age, marital status, and having resided in Chongqing for more than two years.

Prevalence of sexually transmissible infections and HIV in men attending sex-on-premises venues in Australia: a systematic review and meta-analysis of observational studies

Background In Australia, men who have sex with men (MSM) have high rates sexually transmissible infections (STIs) and sex-on-premises venue (SOPV) patrons are at risk. This paper assesses Neisseria gonorrhoeae (NG), Chlamydia trachomatis (CT), syphilis and HIV prevalence in men tested at Australian SOPVs and describes testing services.

METHODS

EMBASE, Medline, PubMed and international conference proceedings were searched for articles reporting on-site SOPV testing between 1 January 2000 and 31 January 2017. Meta-analysis calculated pooled prevalence estimates of STIs by anatomical site.

RESULTS

Twelve cross-sectional studies were identified. Most (8/12) were local sexual health clinics (SHC) outreach services. Participants' mean age was 41.1 years (95% confidence interval (CI) 37.0-43.3; range 17 to 84 years). Testing included CT and NG (9/12), HIV (8/12) and syphilis (5/12). CT and NG prevalence overall summary estimates were 3.4% (95% CI 1.9-5.2%, I2 = 88.7%, P < 0.01) and 1.3% (95% CI 0.7-2.2%, I2 = 75.5%, P < 0.01) respectively. CT and NG prevalence was highest in the ano-rectum and oro-pharynx respectively. The HIV and syphilis pooled estimates were 2.3% (95% CI 1.6-2.9%, I2 = 93.1%, P < 0.01) and 3.2% (95% CI 1.8-4.6%, I2 = 72.8%, P < 0.01) respectively. Participation rate varied.

CONCLUSION

This review examines HIV and STI testing in Australian SOPVs before HIV pre-exposure prophylaxis (PrEP). Findings indicate a high prevalence of STIs. PrEP use and resultant condomless sex may influence STI prevalence. Further research is required to determine the effect of PrEP on the STI prevalence among SOPV patrons.

Cross-Subtype Detection of HIV-1 Capsid p24 Antigen Using a Sensitive Europium Nanoparticle Assay

Accurate and early detection of diverse HIV-1 subtypes using currently available p24 antigen assays have been a major challenge. We report the development of a sensitive time resolved fluorescence (TRF) europium nanoparticle immuno assay for cross subtype detection of p24 antigen using broadly cross-reactive antibodies. Several antibodies were tested for optimal reactivity with antigens of diverse HIV-1 subtypes and circulating recombinant forms. We tested HIV strains using this assay for sensitivity and quantification ability at the pico-gram per millilter level. We identified two broadly cross-reactive HIV-1 p24 antibodies C65690M and ANT-152, which detected all strains of HIV tested. These two antibodies also yielded a better signal to cutoff ratio for the same amount of antigen tested in comparison to a commercial assay. Using an appropriate combination of C65690M and ANT-152 p24 antibodies capable of detecting all HIV types and highly sensitive TRF-based europium nano particle assay platform, we developed a sensitive p24 antigen assay that can detect HIV infection of all HIV subtypes and may be useful in early detection.

Analysis of False-Negative Human Immunodeficiency Virus Rapid Tests Performed on Oral Fluid in 3 International Clinical Research Studies

Background.

The OraQuick Advance Rapid HIV-1/2 Test is a point-of-care test capable of detecting human immunodeficiency virus (HIV)-specific antibodies in blood and oral fluid. To understand test performance and factors contributing to false-negative results in longitudinal studies, we examined results of participants enrolled in the Botswana TDF/FTC Oral HIV Prophylaxis Trial, the Bangkok Tenofovir Study, and the Bangkok MSM Cohort Study, 3 separate clinical studies of high-risk, HIV-negative persons conducted in Botswana and Thailand.

Methods.

In a retrospective observational analysis, we compared oral fluid OraQuick (OFOQ) results among participants becoming HIV infected to results obtained retrospectively using enzyme immunoassay and nucleic acid amplification tests on stored specimens. We categorized negative OFOQ results as true-negative or false-negative relative to nucleic acid amplification test and/or enzyme immunoassay, and determined the delay in OFOQ conversion relative to the estimated time of infection. We used log-binomial regression and generalized estimating equations to examine the association between false-negative results and participant, clinical, and testing-site factors.

Results.

Two-hundred thirty-three false-negative OFOQ results occurred in 80 of 287 seroconverting individuals. Estimated OFOQ conversion delay ranged from 14.5 to 547.5 (median, 98.5) days. Delayed OFOQ conversion was associated with clinical site and test operator (P < .05), preexposure prophylaxis (P = .01), low plasma viral load (P < .02), and time to kit expiration (P < .01). Participant age, sex, and HIV subtype were not associated with false-negative results. Long OFOQ conversion delay time was associated with antiretroviral exposure and low plasma viral load.

Conclusions.

Failure of OFOQ to detect HIV-1 infection was frequent and multifactorial in origin. In longitudinal trials, negative oral fluid results should be confirmed via testing of blood samples.

Perceptions of HIV Self-Testing Among Men Who Have Sex With Men in the United States: A Qualitative Analysis

HIV testing is the gateway into both prevention and treatment services. It is important to understand how men who have sex with men (MSM) perceive HIV self-tests. We conducted focus groups and individual interviews to collect feedback on two HIV self-tests, and on a dried blood spot (DBS) specimen collection kit. Perceptions and attitudes around HIV self-testing (HIVST), and willingness to distribute HIV self-tests to others were assessed. MSM reported HIVST to be complementary to facility-based testing, and liked this approach because it offers privacy and convenience, does not require counseling, and could lead to linkage to care. However, they also had concerns around the accuracy of HIV self-tests, their cost, and receiving a positive test result without immediate access to follow-up services. Despite these issues, they perceived HIVST as a positive addition to their HIV prevention toolbox.

Platinum Nanocatalyst Amplification: Redefining the Gold Standard for Lateral Flow Immunoassays with Ultrabroad Dynamic Range

Paper-based lateral flow immunoassays (LFIAs) are one of the most widely used point-of-care (PoC) devices; however, their application in early disease diagnostics is often limited due to insufficient sensitivity for the requisite sample sizes and the short time frames of PoC testing. To address this, we developed a serum-stable, nanoparticle catalyst-labeled LFIA with a sensitivity surpassing that of both current commercial and published sensitivities for paper-based detection of p24, one of the earliest and most conserved biomarkers of HIV. We report the synthesis and characterization of porous platinum core-shell nanocatalysts (PtNCs), which show high catalytic activity when exposed to complex human blood serum samples. We explored the application of antibody-functionalized PtNCs with strategically and orthogonally modified nanobodies with high affinity and specificity toward p24 and established the key larger nanoparticle size regimes needed for efficient amplification and performance in LFIA. Harnessing the catalytic amplification of PtNCs enabled naked-eye detection of p24 spiked into sera in the low femtomolar range (ca. 0.8 pg·mL^-1) and the detection of acute-phase HIV in clinical human plasma samples in under 20 min. This provides a versatile absorbance-based and rapid LFIA with sensitivity capable of significantly reducing the HIV acute phase detection window. This diagnostic may be readily adapted for detection of other biomolecules as an ultrasensitive screening tool for infectious and noncommunicable diseases and can be capitalized upon in PoC settings for early disease detection.

Antibody detection by agglutination-PCR (ADAP) enables early diagnosis of HIV infection by oral fluid analysis

Oral fluid (OF) is a highly effective substrate for population-based HIV screening efforts, as it is noninfectious and significantly easier to collect than blood. However, anti-HIV antibodies are found at far lower concentrations in OF compared with blood, leading to poor sensitivity and a longer period of time from infection to detection threshold. Thus, despite its inherent advantages in sample collection, OF is not widely used for population screening. Here we report the development of an HIV OF assay based on Antibody Detection by Agglutination-PCR (ADAP) technology. This assay is 1,000-10,000 times more analytically sensitive than clinical enzyme-linked immunoassays (EIAs), displaying both 100% clinical sensitivity and 100% specificity for detecting HIV antibodies within OF samples. We show that the enhanced analytical sensitivity enables this assay to correctly identify HIV-infected individuals otherwise missed by current OF assays. We envision that the attributes of this improved HIV OF assay can increase testing rates of at-risk individuals while enabling diagnosis and treatment at an earlier time point.

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.

Towards an ultra-rapid smartphone- connected test for infectious diseases

The development is reported of an ultra-rapid, point-of-care diagnostic device which harnesses surface acoustic wave (SAW) biochips, to detect HIV in a finger prick of blood within 10 seconds (sample-in-result-out). The disposable quartz biochip, based on microelectronic components found in every consumer smartphone, is extremely fast because no complex labelling, amplification or wash steps are needed. A pocket-sized control box reads out the SAW signal and displays results electronically. High analytical sensitivity and specificity are found with model and real patient blood samples. The findings presented here open up the potential of consumer electronics to cut lengthy test waiting times, giving patients on the spot access to potentially life-saving treatment and supporting more timely public health interventions to prevent disease transmission.

Human Immunodeficiency Virus

In this chapter we will discuss the diagnosis and monitoring of individuals with HIV infection. The application and interpretation of these tests does not change dramatically when used in the immunocompromised host. The principal approach to the diagnosis of HIV infection involves serologic testing, although nucleic acid amplification tests play an important role in the diagnosis of acute HIV infection. The algorithm for diagnosis of HIV continues to evolve with newer assays that are able to detect infection within an earlier timeframe after HIV transmission. Viral load testing for HIV-1 is the cornerstone for monitoring patients on antiretroviral therapy. Genotypic and phenotypic resistance tests are employed when antiretroviral resistance is suspected and results help guide therapy. The tropism assay must be performed to determine the efficacy of CCR5 chemokine receptor antagonists. Next-generation sequencing methods are an innovative approach to assessing archived antiretroviral resistance in patients with virologic suppression. The success of antiretroviral therapy with improved long-term outcomes has made transplantation in HIV-infected patients a reality.

Saliva and viral infections

Over the last 10 years there have been only a handful of publications dealing with the oral virome, which is in contrast to the oral microbiome, an area that has seen considerable interest. Here, we survey viral infections in general and then focus on those viruses that are found in and/or are transmitted via the oral cavity; norovirus, rabies, human papillomavirus, Epstein‐Barr virus, herpes simplex viruses, hepatitis C virus, and HIV. Increasingly, viral infections have been diagnosed using an oral sample (e.g. saliva mucosal transudate or an oral swab) instead of blood or urine. The results of two studies using a rapid and semi‐quantitative lateral flow assay format demonstrating the correlation of HIV anti‐IgG/sIgA detection with saliva and serum samples are presented. When immediate detection of infection is important, point‐of‐care devices that obtain a non‐invasive sample from the oral cavity can be used to provide a first line diagnosis to assist in determining appropriate counselling and therapeutic path for an increasing number of diseases.

Human immunodeficiency virus: Diagnostic approach

First descriptions of acquired immunodeficiency syndrome appeared in 1981. Four years later the causative agent was cultured which lead to development and production of tests that helped healthcare providers to identify persons living with HIV. Currently, diagnosis of HIV is performed with fourth generation immunoassays (those that detect p24 antigen together with IgM and IgG antibodies to HIV-1 and -2) which if positive need to be followed by an assay that can differentiate between HIV-1 and HIV-2 viruses. The Western blot is no longer used to confirm HIV infections per CDC guidelines. In case there is a positive fourth generation assay but negative differentiation assay, nucleic acid testing for HIV-1 should be performed. This algorithm allows for detection of acute infections. Alternatively, the World Health Organization has algorithms that use rapid testing for diagnosis of HIV infections. This review will describe the evolution of tests and diagnostic algorithms from the 1980s to the current state. Special situations regarding diagnosis will also be discussed.

Infection in Organ Transplantation

The prevention, diagnosis, and management of infectious disease in transplantation are major contributors to improved outcomes in organ transplantation. The risk of serious infections in organ recipients is determined by interactions between the patient's epidemiological exposures and net state of immune suppression. In organ recipients, there is a significant incidence of drug toxicity and a propensity for drug interactions with immunosuppressive agents used to maintain graft function. Thus, every effort must be made to establish specific microbiologic diagnoses to optimize therapy. A timeline can be created to develop a differential diagnosis of infection in transplantation based on common patterns of infectious exposures, immunosuppressive management, and antimicrobial prophylaxis. Application of quantitative molecular microbial assays and advanced antimicrobial therapies have advanced care. Pathogen-specific immunity, genetic polymorphisms in immune responses, and dynamic interactions between the microbiome and the risk of infection are beginning to be explored. The role of infection in the stimulation of alloimmune responses awaits further definition. Major hurdles include the shifting worldwide epidemiology of infections, increasing antimicrobial resistance, suboptimal assays for the microbiologic screening of organ donors, and virus-associated malignancies. Transplant infectious disease remains a key to the clinical and scientific investigation of organ transplantation.

The performance of the Alere HIV combo point-of-care test on stored serum samples; useful for detection of early HIV-1 infections?

INTRODUCTION

The Alere HIV-1/2 Antigen/Antibody Combo point-of-care test is a commercially available 4th-generation rapid test for the diagnosis of HIV infection, including acute infection. We evaluated the sensitivity of this test in samples from patients with acute, recent or chronic HIV-1 infection.

METHODS

A validation of the test was performed using 89 HIV-positive serum samples collected in 2008-2016, that were stored at -20°C. Twenty-three samples were only p24-positive (acute infection); 49 samples were antibody-positive and p24-positive (recent infection); 17 samples were only antibody-positive (chronic infection). HIV infection was confirmed by standard-of-care assays and PCR. Samples came from patients attending an outpatient clinic for STDs at the Public Health Department and from patients within the Erasmus Medical Center, Rotterdam, the Netherlands.

RESULTS

The overall sensitivity of the test for diagnosing HIV infection based on detection of p24 antigen and/or antibodies was 92% (95% CI 86% to 98%) (82/89). In acute sera with only p24 antigen positivity, the sensitivity of the test decreased to 65% (95% CI 46% to 85%) (15/23). When both antibody and antigen testing were positive, the p24 sensitivity was only 24% (95% CI 12% to 36%) (12/49), but in these sera the final test result was positive in all sera (49/49) due to the positive antibody component.

CONCLUSIONS

In a laboratory setting, this test has an overall sensitivity of 92% to detect any stage of HIV-1 infection using sera specimens. It performs relatively well in detecting early HIV and may be beneficial as an initial screening in patients with a recent exposure to HIV. Additional testing in a laboratory setting remains mandatory as a proportion of acute HIV-1 infections are missed with this test.

Rapid Human Immunodeficiency Virus Testing and Risk Prevention in Residents of Battered Women's Shelters

BACKGROUND

Human immunodeficiency virus (HIV) infection and intimate partner violence (IPV) are interconnected public health problems. However, few HIV prevention interventions address the unique needs of IPV survivors in shelter and none of the Centers for Disease Control and Prevention's best-evidence risk reduction interventions adequately explore the complex relationship between IPV and HIV risk. Although battered women's shelters provide a safe and supportive environment for women in crisis, most do not offer HIV risk reduction services or sexual safety planning.

METHODS

This study evaluated the feasibility, acceptability, and initial efficacy of rapid HIV testing and brief risk prevention intervention developed for residents of battered women's shelters. The Safe Alternatives For Empowered sex for intimate partner violence intervention (SAFE-IPV) was evaluated in an open trial (N = 98). Participants were assessed with a series of standardized interviews and self-reports at screening and 3 months after leaving the shelter.

RESULTS

Few eligible participants declined SAFE-IPV and participants who received SAFE-IPV reported high levels of satisfaction. No participants in the open trial tested positive for HIV. However, participants reported significantly fewer unprotected vaginal and anal sexual occasions and increased intentions to engage in risk preventative behaviors 3 months after leaving shelter compared with the 3 months before shelter. Additionally, participants reported significant improvements on HIV risk factors addressed in SAFE-IPV at the 3-month follow-up (i.e., reduced emotional, physical, and sexual harm by abuser, posttraumatic stress symptoms, hazardous alcohol use, and drug use).

DISCUSSION

These results extend prior research on HIV prevention with women with IPV, demonstrating the acceptability, feasibility, and initial efficacy of SAFE-IPV within battered women's shelter settings.

Multi-centre field evaluation of the performance of the Trinity Biotech Uni-Gold HIV 1/2 rapid test as a first-line screening assay for gay and bisexual men compared with 4th generation laboratory immunoassays

BACKGROUND

The Trinity Biotech Uni-Gold HIV test (Uni-Gold) is often used as a supplementary rapid test in testing algorithms.

OBJECTIVE

To evaluate the operational performance of the Uni-Gold as a first-line screening test among gay and bisexual men (GBM) in a setting where 4th generation HIV laboratory assays are routinely used.

STUDY DESIGN

We compared the performance of Uni-Gold with conventional HIV serology conducted in parallel among GBM attending 22 testing sites. Sensitivity was calculated separately for acute and established infection, defined using 4th generation screening Ag/Ab immunoassay (EIA) and Western blot results. Previous HIV testing history and results of supplementary 3rd generation HIV Ab EIA, and p24 antigen EIA were used to further characterise cases of acute infection.

RESULTS

Of 10,793 specimens tested with Uni-Gold and conventional serology, 94 (0.90%, 95%CI:0.70-1.07) were confirmed as HIV-positive by conventional serology, and 37 (39.4%) were classified as acute infection. Uni-Gold sensitivity was 81.9% overall (77/94, 95%CI:72.6-89.1); 56.8% for acute infection (21/37, 95%CI:39.5-72.9) and 98.2% for established infection (56/57, 95%CI:90.6-100.0). Of 17 false non-reactive Uni-Gold results, 16 were acute infections, and of these seven were p24 antigen reactive but antibody negative. Uni-Gold specificity was 99.9% (10,692/10,699, 95%CI:99.9-100.0), PPV was 91.7% (95%CI:83.6-96.6) and NPV was 99.8% (95%CI:99.7-99.9), respectively.

CONCLUSIONS

In this population, Uni-Gold had good specificity and sensitivity was high for established infections when compared to 4th generation laboratory assays, however sensitivity was lower in acute infections. Where rapid tests are used in populations with a high proportion of acute infections, additional testing strategies are needed to detect acute infections.

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.

Evaluation of SMARTube to Detect HIV Infection Before Seroconversion Using Standard Methods

The acute phase of HIV infection carries substantial risk of transmission; identification of acute-phase infections may offer opportunities to reduce that risk. SMARTube incubation of blood specimens is designed to stimulate in vivo-primed HIV-specific lymphocytes to produce HIV antibodies in vitro. The resulting supernatant (S-plasma) can be tested to identify acute infections with commercially available HIV assays. We assessed the performance of the SMARTube to identify acute HIV infections in studies at three developing country sites. We conducted HIV incidence studies in Ho Chi Minh City, Vietnam, and Bloemfontein and Rustenburg, South Africa. We estimated HIV incidence in cross-sectional samples and measured prospective incidence in uninfected women followed for up to 12 months. We incorporated SMARTube into the HIV testing algorithm at cross-sectional screening and monthly follow-up visits. We tested 1,384 persons in Vietnam, 1,145 women in Bloemfontein, and 538 persons in Rustenburg. Cross-sectional samples from 11 participants that tested positive with SMARTube after an initial unincubated negative test result (11 of 2,472; 0.4% of all specimens) were considered "potential acute" infections. Matching samples from 3 of the 11 (27.3%) were confirmed by polymerase chain reaction (PCR) testing. In follow-up of 355, 401, and 223 uninfected women in Vietnam, Bloemfontein, and Rustenburg, respectively, 11 seroconversions occurred in Bloemfontein and Rustenburg. In four of these incident infections (36.4%), SMARTube testing had resulted in earlier detection of HIV infection than the eventual seroconversion visits. In our field studies, pretreatment with SMARTube allowed the identification of acute HIV-1 infection in some new infections, but with a positive predictive value of 27%. Larger studies are needed to evaluate SMARTube as an alternative to technically challenging and costly enzyme immunoassay and PCR testing to detect acute HIV infection.

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.

Ten Years of Screening and Testing for Acute HIV Infection in North Carolina

OBJECTIVE

To describe demographic and behavioral characteristics of persons with acute HIV infection (AHI) over time.

METHODS

We conducted a retrospective assessment of AHI identified through the Screening and Tracing Active Transmission (STAT) program from 2003 to 2012 in North Carolina (NC). AHI was identified using pooled nucleic acid amplification for antibody negative samples and individual HIV-1 RNA for antibody indeterminate samples. The STAT program provides rapid notification and evaluation. We compared STAT-collected demographic and risk characteristics with all persons requesting tests and all non-AHI diagnoses from the NC State Laboratory of Public Health.

RESULTS

The STAT Program identified 236 AHI cases representing 3.4% (95% confidence interval: 3.0% to 3.9%) of all HIV diagnoses. AHI cases were similar to those diagnosed during established HIV. On pretest risk-assessments, AHI cases were predominately black (69.1%), male (80.1%), young (46.8% < 25 years), and men who have sex with men (MSM) (51.7%). Per postdiagnosis interviews, the median age decreased from 35 (interquartile range 25-42) to 27 (interquartile range 22-37) years, and the proportion <25 years increased from 23.8% to 45.2% (trend P = 0.04) between 2003 and 2012. AHI men were more likely to report MSM risk post-diagnosis than on pretest risk-assessments (64%-82.9%; P < 0.0001). Post-diagnosis report of MSM risk in men with AHI increased from 71.4% to 96.2%.

CONCLUSIONS

In NC, 3.4% of individuals diagnosed with HIV infection have AHI. AHI screening provides a real-time source of incidence trends, improves the diagnostic yield of HIV testing, and offers an opportunity to limit onward transmission.

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.

Assessment of Oral Fluid HIV Test Performance in an HIV Pre-Exposure Prophylaxis Trial in Bangkok, Thailand

Background

Rapid easy-to-use HIV tests offer opportunities to increase HIV testing among populations at risk of infection. We used the OraQuick Rapid HIV-1/2 antibody test (OraQuick) in the Bangkok Tenofovir Study, an HIV pre-exposure prophylaxis trial among people who inject drugs.

Methods

The Bangkok Tenofovir Study was a randomized, double-blind, placebo-controlled trial. We tested participants’ oral fluid for HIV using OraQuick monthly and blood using a nucleic-acid amplification test (NAAT) every 3 months. We used Kaplan-Meier methods to estimate the duration from a positive HIV NAAT until the mid-point between the last non-reactive and first reactive oral fluid test and proportional hazards to examine factors associated with the time until the test was reactive.

Results

We screened 3678 people for HIV using OraQuick. Among 447 with reactive results, 436 (97.5%) were confirmed HIV-infected, 10 (2.2%) HIV-uninfected, and one (0.2%) had indeterminate results. Two participants with non-reactive OraQuick results were, in fact, HIV-infected at screening yielding 99.5% sensitivity, 99.7% specificity, a 97.8% positive predictive value, and a 99.9% negative predictive value. Participants receiving tenofovir took longer to develop a reactive OraQuick (191.8 days) than participants receiving placebo (16.8 days) (p = 0.02) and participants infected with HIV CRF01_AE developed a reactive OraQuick earlier than participants infected with other subtypes (p = 0.04).

Discussion

The oral fluid HIV test performed well at screening, suggesting it can be used when rapid results and non-invasive tools are preferred. However, participants receiving tenofovir took longer to develop a reactive oral fluid test result than those receiving placebo. Thus, among people using pre-exposure prophylaxis, a blood-based HIV test may be an appropriate choice.

Trial Registration

ClinicalTrials.gov NCT00119106.

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.

Costs per Diagnosis of Acute HIV Infection in Community-based Screening Strategies: A Comparative Analysis of Four Screening Algorithms

BACKGROUND

In nonhealthcare settings, widespread screening for acute human immunodeficiency virus (HIV) infection (AHI) is limited by cost and decision algorithms to better prioritize use of resources. Comparative cost analyses for available strategies are lacking.

METHODS

To determine cost-effectiveness of community-based testing strategies, we evaluated annual costs of 3 algorithms that detect AHI based on HIV nucleic acid amplification testing (EarlyTest algorithm) or on HIV p24 antigen (Ag) detection via Architect (Architect algorithm) or Determine (Determine algorithm) as well as 1 algorithm that relies on HIV antibody testing alone (Antibody algorithm). The cost model used data on men who have sex with men (MSM) undergoing community-based AHI screening in San Diego, California. Incremental cost-effectiveness ratios (ICERs) per diagnosis of AHI were calculated for programs with HIV prevalence rates between 0.1% and 2.9%.

RESULTS

Among MSM in San Diego, EarlyTest was cost-savings (ie, ICERs per AHI diagnosis less than $13.000) when compared with the 3 other algorithms. Cost analyses relative to regional HIV prevalence showed that EarlyTest was cost-effective (ie, ICERs less than $69.547) for similar populations of MSM with an HIV prevalence rate >0.4%; Architect was the second best alternative for HIV prevalence rates >0.6%.

CONCLUSIONS

Identification of AHI by the dual EarlyTest screening algorithm is likely to be cost-effective not only among at-risk MSM in San Diego but also among similar populations of MSM with HIV prevalence rates >0.4%.

HIV infection

More than 75 million people worldwide have been infected with human immunodeficiency virus (HIV), and there are now approximately 37 million individuals living with the infection. Untreated HIV replication causes progressive CD4(+) T cell loss and a wide range of immunological abnormalities, leading to an increased risk of infectious and oncological complications. HIV infection also contributes to cardiovascular disease, bone disease, renal and hepatic dysfunction and several other common morbidities. Antiretroviral drugs are highly effective at inhibiting HIV replication, and for individuals who can access and adhere to these drugs, combination antiretroviral therapy leads to durable (and probably lifelong) suppression of viral replication. Viral suppression enables immune recovery and the near elimination of the risk for developing acquired immune deficiency syndrome (AIDS). Despite effective treatment, HIV-infected individuals have a higher than expected risk of heart, bone, liver, kidney and neurological disease. When used optimally by an infected (or by an uninfected) person, antiretroviral drugs can virtually eliminate the risk of HIV transmission. Despite major advances in prevention sciences, HIV transmission remains common in many vulnerable populations, including men who have sex with men, injection drug users and sex workers. Owing to a lack of widespread HIV testing and the costs and toxicities associated with antiretroviral drugs, the majority of the infected population is not on effective antiretroviral therapy. To reverse the pandemic, improved prevention, treatment and implementation approaches are necessary.

How can we better identify early HIV infections?

PURPOSE OF REVIEW

Detection of early HIV infections (EHIs), including acute HIV infection (AHI), is important for individual health, prevention of HIV transmission, and measurement of HIV incidence. We describe markers of EHI, diagnostic strategies for detecting these markers, and ways to incorporate these strategies into diagnostic and HIV incidence algorithms.

RECENT FINDINGS

For individual diagnosis in the USA and Europe, laboratory-based diagnostic algorithms increasingly incorporate fourth-generation HIV antigen tests, allowing for earlier detection. In some sub-Saharan African settings, symptom-based screening is being explored to identify subsets of persons at high risk for AHI. Point-of-care diagnostics designed for AHI detection are in the pipeline and, if validated, represent an opportunity for real-time AHI diagnosis. At the population level, multiassay algorithms are promising new strategies for estimating HIV incidence on the basis of several assays applied to cross-sectional samples. These algorithms can be developed to optimize performance, in addition to cost and logistical considerations.

SUMMARY

There are important recent advances in detection of EHIs at the individual and population levels. Applying optimal combinations of tests in diagnostic and HIV incidence algorithms is urgently needed to support the multiple goals derived from enhanced detection and discrimination of EHIs.

Re-Testing and Seroconversion Among HIV Testing and Counseling Clients in Lesotho

HIV testing and counseling (HTC) is an essential component of comprehensive HIV programs. Retrospective HTC program data from 2006 to 2010 were examined to determine patterns of re-testing and seroconversion in Lesotho. Among 104,662 initially negative clients, 6,777 (6.5%) were re-testers. Predictors of re-testing included being male, age ≥ 25 years, divorced/separated, having more than a high school education, being tested as a couple, testing in the year 2006, testing in the capital city, and awareness of partner's recent testing behavior. Among re-testers who seroconverted (N = 259), predictors included being female and having less than a high school education. There is a critical need for more effectively targeting HIV retesting messages to align with WHO (2010) guidelines and identify persons at highest risk for HIV, to increase timely diagnoses and link persons to appropriate HIV prevention, care, and treatment services.

Ongoing HIV Transmission and the HIV Care Continuum in North Carolina

OBJECTIVE

HIV transmission is influenced by status awareness and receipt of care and treatment. We analyzed these attributes of named partners of persons with acute HIV infection (index AHI cases) to characterize the transmission landscape in North Carolina (NC).

DESIGN

Secondary analysis of programmatic data.

METHODS

We used data from the NC Screening and Tracing of Active Transmission Program (2002-2013) to determine HIV status (uninfected, AHI, or chronic HIV infection [CHI]), diagnosis status (new or previously-diagnosed), and care and treatment status (not in care, in care and not on treatment, in care and on treatment) of index AHI cases' named partners. We developed an algorithm identifying the most likely transmission source among known HIV-infected partners to estimate the proportion of transmissions arising from contact with persons at different HIV continuum stages. We conducted a complementary analysis among a subset of index AHI cases and partners with phylogenetically-linked viruses.

RESULTS

Overall, 358 index AHI cases named 932 partners, of which 218 were found to be HIV-infected (162 (74.3%) previously-diagnosed, 11 (5.0%) new AHI, 45 (20.6%) new CHI). Most transmission events appeared attributable to previously-diagnosed partners (77.4%, 95% confidence interval 69.4-85.3%). Among these previously-diagnosed partners, 23.2% (14.0-32.3%) were reported as in care and on treatment near the index AHI case diagnosis date. In the subset study of 33 phylogenetically-linked cases and partners, 60.6% of partners were previously diagnosed (43.9-77.3%).

CONCLUSIONS

A substantial proportion of HIV transmission in this setting appears attributable to contact with previously-diagnosed partners, reinforcing the need for improved engagement in care after diagnosis.

Impact of nucleic acid testing relative to antigen/antibody combination immunoassay on the detection of acute HIV infection

OBJECTIVE

To assess the addition of HIV nucleic acid testing (NAT) to fourth-generation (4thG) HIV antigen/antibody combination immunoassay in improving detection of acute HIV infection (AHI).

METHODS

Participants attending a major voluntary counseling and testing site in Thailand were screened for AHI using 4thG HIV antigen/antibody immunoassay and sequential less sensitive HIV antibody immunoassay. Samples nonreactive by 4thG antigen/antibody immunoassay were further screened using pooled NAT to identify additional AHI. HIV infection status was verified following enrollment into an AHI study with follow-up visits and additional diagnostic tests.

RESULTS

Among 74 334 clients screened for HIV infection, HIV prevalence was 10.9% and the overall incidence of AHI (N = 112) was 2.2 per 100 person-years. The inclusion of pooled NAT in the testing algorithm increased the number of acutely infected patients detected, from 81 to 112 (38%), relative to 4thG HIV antigen/antibody immunoassay. Follow-up testing within 5 days of screening marginally improved the 4thG immunoassay detection rate (26%). The median CD4 T-cell count at the enrollment visit was 353 cells/μl and HIV plasma viral load was 598 289 copies/ml.

CONCLUSION

The incorporation of pooled NAT into the HIV testing algorithm in high-risk populations may be beneficial in the long term. The addition of pooled NAT testing resulted in an increase in screening costs of 22% to identify AHI: from $8.33 per screened patient to $10.16. Risk factors of the testing population should be considered prior to NAT implementation given the additional testing complexity and costs.

Usage and acceptability of HIV self-testing in men who have sex with men in Hong Kong

Whilst studies on over-the-counter HIV tests continue to accumulate after FDA's approval of OraQuick Advance in 2012, few have focused on men who have sex with men (MSM) in Asian cities. An internet survey was conducted on 1,122 MSM in Hong Kong, revealing a low usage (6.1 %) and acceptability rate (43.8 %) on self-testing despite its availability in the market. Hierarchical logistic regression models showed that having received relevant information and users' attitudes on self-testing were the determinants of usage and acceptability. These factors had greater effects than sexual behaviors and social-networking on MSM's decision on self-testing. Majority of ever self-testers only repeated the self-test after a non-negative result, and overall only 26.6 % went for a formal test subsequent to the self-test. Concerns regarding the tests' accuracy were expressed by respondents. In conclusion, appropriate and accessible information and evidence-based guidance are needed to incorporate self-testing into HIV prevention strategies targeting MSM.

Quantification of plasma HIV RNA using chemically engineered peptide nucleic acids

The remarkable stability of peptide nucleic acids (PNAs) toward enzymatic degradation makes this class of molecules ideal to develop as part of a diagnostic device. Here we report the development of chemically-engineered PNAs for the quantitative detection of HIV RNA at clinically relevant levels that are competitive with current PCR-based assays. Using a sandwich hybridization approach, chemical groups were systematically introduced into a surface PNA probe and a reporter PNA probe to achieve quantitative detection for HIV RNA as low as 20 copies per milliliter of plasma. For the surface PNA probe, four cyclopentane groups were incorporated to promote stronger binding to the target HIV RNA compared to PNA without the cyclopentanes. For the reporter PNA probe, 25 biotin groups were attached to promote strong signal amplification after binding to the target HIV RNA. These general approaches to engineer PNA probes may be used to detect other RNA target sequences.

Acceptability of using electronic vending machines to deliver oral rapid HIV self-testing kits: a qualitative study

Introduction

Rates of unrecognized HIV infection are significantly higher among Latino and Black men who have sex with men (MSM). Policy makers have proposed that HIV self-testing kits and new methods for delivering self-testing could improve testing uptake among minority MSM. This study sought to conduct qualitative assessments with MSM of color to determine the acceptability of using electronic vending machines to dispense HIV self-testing kits.

Materials and Methods

African American and Latino MSM were recruited using a participant pool from an existing HIV prevention trial on Facebook. If participants expressed interest in using a vending machine to receive an HIV self-testing kit, they were emailed a 4-digit personal identification number (PIN) code to retrieve the test from the machine. We followed up with those who had tested to assess their willingness to participate in an interview about their experience.

Results

Twelve kits were dispensed and 8 interviews were conducted. In general, participants expressed that the vending machine was an acceptable HIV test delivery method due to its novelty and convenience.

Discussion

Acceptability of this delivery model for HIV testing kits was closely associated with three main factors: credibility, confidentiality, and convenience. Future research is needed to address issues, such as user-induced errors and costs, before scaling up the dispensing method.

Multi-centre evaluation of the Determine HIV Combo assay when used for point of care testing in a high risk clinic-based population

Background

Determine HIV Combo (DHC) is the first point of care assay designed to increase sensitivity in early infection by detecting both HIV antibody and antigen. We conducted a large multi-centre evaluation of DHC performance in Sydney sexual health clinics.

Methods

We compared DHC performance (overall, by test component and in early infection) with conventional laboratory HIV serology (fourth generation screening immunoassay, supplementary HIV antibody, p24 antigen and Western blot tests) when testing gay and bisexual men attending four clinic sites. Early infection was defined as either acute or recent HIV infection acquired within the last six months.

Results

Of 3,190 evaluation specimens, 39 were confirmed as HIV-positive (12 with early infection) and 3,133 were HIV-negative by reference testing. DHC sensitivity was 87.2% overall and 94.4% and 0% for the antibody and antigen components, respectively. Sensitivity in early infection was 66.7% (all DHC antibody reactive) and the DHC antigen component detected none of nine HIV p24 antigen positive specimens. Median HIV RNA was higher in false negative than true positive cases (238,025 vs. 37,591 copies/ml; p = 0.022). Specificity overall was 99.4% with the antigen component contributing to 33% of false positives.

Conclusions

The DHC antibody component detected two thirds of those with early infection, while the DHC antigen component did not enhance performance during point of care HIV testing in a high risk clinic-based population.

Toward an endgame: finding and engaging people unaware of their HIV-1 infection in treatment and prevention

Epidemic modeling suggests that a major scale-up in HIV treatment could have a dramatic impact on HIV incidence. This has led both researchers and policymakers to set a goal of an "AIDS-Free Generation." One of the greatest obstacles to achieving this objective is the number of people with undiagnosed HIV infection. Despite recent innovations, new research strategies are needed to identify, engage, and successfully treat people who are unaware of their infection.