Modelling the impact of antiretroviral therapy on the epidemic of HIV

Long-term outcomes of highly experienced people with HIV undergoing salvage therapy with raltegravir

Raltegravir and other third-line drugs have shown promise in improving outcomes in treatment-experienced patients. However, the efficacy and tolerability of these agents vary. This study assessed real-life virologic success, long-term survival, and adverse events in patients receiving raltegravir or other third-line drugs as salvage regimens. This retrospective cohort study included adults who experienced treatment failure (human immunodeficiency syndrome-1 RNA plasma viral load >1000 copies/mL) and subsequently initiated raltegravir or other third-line drugs (darunavir/ritonavir, maraviroc, or etravirine). Propensity score matching methods were employed to account for differences at the time of switching from failing antiretroviral therapy regimens. The matched subset was analyzed using the Kaplan-Meier method and Generalized Wilcoxon tests to evaluate the probability of achieving virologic suppression (plasma viral load <50 copies/mL). Mortality rates, toxicity, treatment interruption, virologic failure, and loss to follow-up were determined using Poisson regression. One hundred and sixty-eight patients initiating salvage regimens were included, with 123 receiving raltegravir and 45 other third-line drugs. Propensity score matching resulted in a subset of 90 patients, 45 in each group. During the follow-up period, there were no significant differences observed between the groups in terms of virologic suppression (77.8% vs 82.2%, P = .73), mortality rates (4.04 vs 6.18 persons per 100 person-years [p-y]; P = .67), drug toxicity (0.00 vs 2.06 persons per 100 p-y; P = .49), treatment interruption (8.07 vs 0.00 persons per 100 p-y; P = .06), virologic failure (2.02 vs 4.12 persons per 100 p-y; P = .61), and loss of follow-up (6.05 vs 4.12 persons per 100 p-y; P = .70). Our findings indicate comparable survival and virological success rates between raltegravir and other drugs used in salvage regimens. Similar rates of drug toxicity, treatment interruption, virologic failure, and loss of follow-up were also observed. These results suggest that raltegravir may be a viable option for salvage therapy, demonstrating outcomes comparable to other third-line drugs in real life.

Adherence to antiretroviral therapy and associated factors among human immunodeficiency -positive patients accessing treatment at health centers in East Gojjam Zone, Northwest Ethiopia, 2019: Community-based cross-sectional study

Background

To achieve an effective treatment outcome, Antiretroviral Therapy (ART) for people living with the Human immunodeficiency virus (HIV) needs at least a 95% adherence level. The aim was to assess adherence to antiretroviral therapy and its associated factors among patients accessing treatment at Health centers in East Gojjam Zone, Northwest Ethiopia.

Methods

A community-based cross-sectional study was conducted on 770 HIV-positive patients from April 1 to May 10, 2019, in East Gojjam Zone. The study participants were selected by simple random computerized sampling methods. Primary data was collected from the patients through face-to-face interviews and home-to-home visits. Bivariable and multivariable binary logistic regression analyses were done. Independent variables with a P-value of <0.2 in bivariable binary logistic regression analysis were considered for multivariable binary logistic regression analysis. A P-value of <0.05 was used as the cut-off point for the presence of statistical significance.

Results

About 396 (51.8%) of the study participants had good adherence. Being 18-24 years old [Adjusted Odd Ratio (AOR) = 0.43; 95% CI = 0.21-0.86], having a marital status of being widowed (AOR = 0.29; 95% CI = 0.14-0.58), having a disease duration of >10 years (AOR = 0.47; 95% CI = 0.24-0.94), taking a drug regimen of Tenofovir (TDF) + Lamivudine (3 TC) + Nevirapine (NVP) (AOR = 2.94; 95% CI = 1.406.15), not being socially stigmatized (AOR = 0.52; 95% CI = 0.34-0.78), and having not encountered an opportunistic infection (AOR = 3.91; 95% CI = 2.68-5.72) were significant factors.

Conclusions

The level of adherence was low. Opportunistic infection prevention, reduction of social stigma, and other intervention activities should be strengthened to increase the level of adherence.

Thirty years of change in HIV incidence among adults in the Kyamulibwa General Population Cohort in rural southwest Uganda, 1989-2021

OBJECTIVES

To document the changes in HIV incidence over thirty years in Kalungu district, Uganda.

METHODS

Since 1989, residents aged ≥15 years old have been tested for HIV, and data were collected on HIV risk factors annually and later, biennially in the Kyamulibwa open cohort. In the 2019-2021 survey, people living with HIV self-reported on knowledge of their HIV status, antiretroviral therapy (ART) use, and their most recent viral load data were obtained from health facilities. The HIV seroconversion dates were randomly imputed between the last negative and first positive test dates using a uniform distribution.

RESULTS

Among 20,959 residents who were HIV-negative, 669 seroconverted within 176,659 person-years. Data showed a downward trend in age-adjusted HIV incidence over 30 years (P <0.001) even though HIV prevalence steadily increased with ART availability from 2004. Comparing 1990-1992 and 1996-1998, HIV incidence declined by 43% (0.79 to 0.45/100 person-years, P = 0.002). Between 1999 and 2011, the incidence remained stable at 0.49/100 person-years (95% confidence interval: 0.41-0.58) in men but slowly increased in women (average age-adjusted hazard ratio = 1.13 per 3 years, 95% confidence interval: 1.03-1.24; trend P-value = 0.02). After 2011, however, the incidence trends reversed and continued to decline in men and women and in all age groups.

CONCLUSION

Facilitating HIV testing and timely ART initiation, and supporting ART adherence must be emphasized alongside sustainable prevention measures.

Designing a Predictive Model for Antiretroviral Regimen at the Antiretroviral Therapy Center in Chiro Hospital, Ethiopia

Nowadays, the huge amount of patient's data significantly increases with respect to the time in repositories and data mining is increasingly used as an emerging research area in medical fields for extracting useful and previously unknown insights/patterns from the repository data. These unknown patterns/hidden insights can help in discovering new knowledge hidden in these data repositories. From the observation, different ARV regimens were ordered for different patients. However, combination of these drugs causes different side effects on the patients. It has been observed that there was a lack of predictive studies and designed models available in hospitals specifically ART Centers that accurately determine or classify the patient's ARV regimen to TDF + 3TC + EFV, TDF + 3TC + NVP, AZT + 3TC + ATV/R, AZT + 3TC + LPV/R, TDF + 3TC + LVP/R, TDF + 3TC + ATV/R, 8888, and ABC + 3TC + LPV/R. In order to solve these kinds of problems, we built an accurate classifier system or model using parameters like Patient Age, Patient Encounter Day, Patient Encounter Month, Patient Encounter Year, Patient Weight, Patient CD4 Count Adult, Patient TB Screen, Patient Following WHO Stage, Patient CD4 Percent Child, Patient Regimen Specify, Patient Regimen, and so on. The general objective of this research was predictive modeling for the patient's ARV regimen class through data mining techniques so as to improve them. The study used the CRIPS-DM methodology to find and interpret patterns in repositories. A decision tree (J48 and Random Forest) algorithm was used for classification. Using all tested classifiers, the investigation of the study shows that the total accuracy was more than 60%. On the other hand, among different classifications, class H (ABC + 3TC + LPV/R) has shown the worst prediction. But it was revealed that the J48 classifier relatively produces higher classification accuracy for the D (AZT-3TC-NVP) regimen. Here, classification depended on the selected parameters, which revealed that prediction accuracy value differed among all classifiers and the selected attributes. Finally, the study concluded that data mining can be used as a significant technique to discover patient regimen based on salient affecting factors with 96.1% precision achieved. Ensemble learning resolves the categorizing models of greater anticipating performance with different learning algorithms. This model aligned with sentimental investigation to magnify the appearances of the dataset either from the social media or from primary data collection. The empirical investigation with different parameters shows the detailed improvement of their learning methods.

Development of Triazoles and Triazolium Salts Based on AZT and Their Anti-Viral Activity against HIV-1

We report herein a set of 3'-azido-3'-deoxythymidine (AZT) derivatives based on triazoles and triazolium salts for HIV-1 infection. The compounds were synthesized via click chemistry with Cu(I) and Ru(II) catalysts. Triazolium salts were synthesized by reaction with methyl iodide or methyl triflate in good yields. The antiviral activity of the compounds was tested using two methodologies: In method one the activity was measured on infected cells; in method two a pre-exposure prophylaxis experimental model was employed. For method one the activity of the compounds was moderate, and in general the triazolium salts showed a decreased activity in relation to their triazole precursors. With method two the antiviral activity was higher. All compounds were able to decrease the infection, with two compounds able to clear almost all the infection, while a lower antiviral activity was noted for the triazolium salts. These results suggest that these drugs could play an important role in the development of pre-exposure prophylaxis therapies.

HIV persistence in lymph nodes

PURPOSE OF REVIEW

HIV persists in distinct cellular and anatomical compartments in the body including blood, Central nervous system, and lymphoid tissues (spleen, lymph nodes [LNs], gut-associated lymphoid tissue) by diverse mechanisms despite antiretroviral therapy. Within LNs, human and animal studies have highlighted that a specific CD4 T cell subset - called T follicular helper cells locating in B cell follicles is enriched in cells containing replication-competent HIV as compared to extra-follicular CD4 T cells. Therefore, the objective of the present review is to focus on the potential mechanisms allowing HIV to persist within LN microenvironment.

RECENT FINDINGS

The combination of factors that might be involved in the regulation of HIV persistence within LNs remain to be fully identified but may include - the level of activation, antiretroviral drug concentrations, presence of cytolytic mechanisms and/or regulatory cells, in addition to cell survival and proliferation propensity which would ultimately determine the fate of HIV-infected cells within LN tissue areas.

SUMMARY

HIV persistence in blood and distinct body compartments despite long-standing and potent therapy is one of the major barriers to a cure. Given that the HIV reservoir is established early and is highly complex based on composition, viral diversity, distribution, replication competence, migration dynamics across the human body and possible compartmentalization in specific tissues, combinatorial therapeutic approaches are needed that may synergize to target multiple viral reservoirs to achieve a cure for HIV infection.

Assessing the uncertainty around age-mixing patterns in HIV transmission inferred from phylogenetic trees

Understanding age-mixing patterns in Human Immunodeficiency Virus (HIV) transmission networks can enhance the design and implementation of HIV prevention strategies in sub-Saharan Africa. Due to ethical consideration, it is less likely possible to conduct a benchmark study to assess which sampling strategy, and sub-optimal sampling coverage which can yield best estimates for these patterns. We conducted a simulation study, using phylogenetic trees to infer estimates of age-mixing patterns in HIV transmission, through the computation of proportions of pairings between men and women, who were phylogenetically linked across different age groups (15-24 years, 25-39 years, and 40-49 years); and the means, and standard deviations of their age difference. We investigated also the uncertainty around these estimates as a function of the sampling coverage in four sampling strategies: when missing sequence data were missing completely at random (MCAR), and missing at random (MAR) with at most 30%-50%-70% of women in different age groups being in the sample. The results suggested that age-mixing patterns in HIV transmission can be unveiled from proportions of phylogenetic pairings between men and women across age groups; and the mean, and standard deviation of their age difference. A 55% sampling coverage was sufficient to provide the best values of estimates of age-mixing patterns in HIV transmission with MCAR scenario. But we should be cautious in interpreting proportions of men phylogenetically linked to women because they may be overestimated or underestimated, even at higher sampling coverage. The findings showed that, MCAR was the best sampling strategy. This means, it is advisable not to use sequence data collected in settings where we can find a systematic imbalance of age and gender to investigate age-mixing in HIV transmission. If not possible, ensure to take into consideration the imbalance in interpreting the results.

A high prevalence of potential HIV elite controllers identified over 30 years in Democratic Republic of Congo

Background

In-depth analysis of the HIV pandemic at its epicenter in the Congo basin has been hampered by 40 years of political unrest and lack of functional public health infrastructure. In recent surveillance studies (2017-18), we found that the prevalence of HIV in Kinshasa, Democratic Republic of Congo (11%) far exceeded previous estimates.

Methods

10,457 participants were screened in Kinshasa with rapid tests from 2017-2019. Individuals confirmed as reactive by the Abbott ARCHITECT HIV Ag/Ab Combo assay (n=1968) were measured by the Abbott RealTime HIV-1 viral load assay. Follow up characterization of samples was performed with alternate manufacturer viral load assays, qPCR for additional blood borne viruses, unbiased next generation sequencing, and HIV Western blotting.

Findings

Our data suggested the existence of a significant cohort (n=429) of HIV antibody positive/viral load negative individuals. We systematically eliminated collection site bias, sample integrity, and viral genetic diversity as alternative explanations for undetectable viral loads. Mass spectroscopy unexpectedly detected the presence of 3TC antiviral medication in approximately 60% of those tested (209/354), and negative Western blot results indicated false positive serology in 12% (49/404). From the remaining Western blot positives (n=53) and indeterminates (n=31) with reactive Combo and rapid test results, we estimate 2.7-4.3% of infections in DRC to be potential elite controllers. We also analyzed samples from the DRC collected in 1987 and 2001-03, when antiretroviral drugs were not available, and found similarly elevated trends.

Interpretation

Viral suppression to undetectable viral loads without therapy occurs infrequently in HIV-1 infected patients around the world. Mining of global data suggests a unique ability to control HIV infection arose early in central Africa and occurs in <1% of founder populations. Identification of this group of elite controllers presents a unique opportunity to study potentially novel genetic mechanisms of viral suppression.

Funding

Abbott Laboratories funded surveillance in DRC and subsequent research efforts. Additional funding was received from a MIZZOU Award from the University of Missouri. Research was supported in part by the Division of Intramural Research, National Institute of Allergy and Infectious Diseases, NIH.

Barriers and Facilitators of Same-Day Antiretroviral Therapy Initiation Among People Newly Diagnosed with HIV in Ethiopia: Qualitative Study Using the Transtheoretical Model of Behavioral Change

Purpose

HIV test and treat approach is currently a strategy used as a part of the prevention and control program in Ethiopia. The strategy adopts initiating antiretroviral therapy (ART) on the same-day as HIV diagnosis or in the next visit. However, there is little evidence on barriers and facilitators of same-day (ART) initiation in Ethiopia. Therefore, this study aimed to investigate barriers and facilitators of same-day (ART) initiation in the northwest Ethiopia.

Patients and Methods

A qualitative study was conducted in East Gojjam Zone in northwest Ethiopia. Purposively selected HIV patients, healthcare workers, and treatment assistants participated in the qualitative study. Data were collected through in-depth interviews and focus group discussions (FGDs). Coding was done via ATLAS.ti software thematically. The interviews and FGDs were conducted in Amharic (local language) and then transcribed verbatim and translated into English. Coding was done via ATLAS.ti software. The thematic analysis approach was employed using the constructs of the transtheoretical behavioral model (TTM) to show stages of change that newly HIV diagnosed experienced in the course of preparation for treatment initiation.

Results

A total of 19 patients, 12 treatment supporters, and 9 healthcare workers participated in the qualitative study. Shocking due to the test result, having no symptoms, mistrust of the test result, and seeking spiritual healing from holy water were the major barriers to start ART in the same-day of diagnosis or within the next visit.

Conclusion

During HIV diagnosis, more barriers were observed in the early stages, while treatment facilitators emerged in the later stages of TTM. The TTM model can be applied to characterize where participants were in the stages of change.

A co-interaction model of HIV and syphilis infection among gay, bisexual and other men who have sex with men

We developed a mathematical model to study the co-interaction of HIV and syphilis infection among gay, bisexual and other men who have sex with men (gbMSM). We qualitatively analysed the model and established necessary conditions under which disease-free and endemic equilibria are asymptotically stable. We gave analytical expressions for the reproduction number, and showed that whenever the reproduction numbers of sub-models and co-interaction model are less than unity, the epidemics die out, while epidemics persist when they are greater than unity. We presented numerical simulations of the full model and showed qualitative changes of the dynamics of the full model to changes in the transmission rates. Our numerical simulations using a set of reasonable parameter values showed that: (a) both diseases die out or co-exist whenever their reproduction number is less than or exceed unity. (b) HIV infection impacts syphilis prevalence negatively and vice versa. (c) one possibility of lowering the co-infection of HIV and syphilis among gbMSM is to increase both testing and treatment rates for syphilis and HIV infection, and decrease the rate at which HIV infected individuals go off treatment.

Magnitude of non-adherence to antiretroviral therapy and associated factors among adult people living with HIV/AIDS in Benishangul-Gumuz Regional State, Ethiopia

Introduction

Following global efforts to increase antiretroviral therapy (ART) access and coverage, Ethiopia has made significant achievement with a 6.3% annual decline in the HIV/AIDS incidence rate between 1990 and 2016. Such success depends not only on access to ART but also on attaining optimum treatment adherence. Emerging studies in Ethiopia has shown the increasing prevalence of poor adherence and lack of the desired viral suppression, but the extent and factors associated with non-adherence to ART are not well known, especially in the current study setup. In this study, we examined the magnitude and factors associated with treatment and non-adherence to ART among people living with HIV in Benishangul-Gumuz Regional State, northwest Ethiopia.

Methods

An institutional facility based cross-sectional descriptive study was carried out among adult people living with HIV/AIDS from mid-December 2016 to February 2017 with only 98.9% response rate. Sociodemographic factors (age, gender, marital status and residential area), economic factors (educational status, income, asset possession, employment status, dietary diversity, nutritional status and food security), and clinical characteristics (CD4 count, duration on ART and history of opportunistic infections) were explanatory variables. ART non-adherence was measured using a visual analogue scale (VAS). We used binary logistic regression and subsequent multivariate logistic regression analysis to determine the factors associated with ART non-adherence.

Result

Overall, 39.7% of the participants were found non-adherent to ART. Strong association was found between non-adherence to ART and young age below 25 years (AOR: 4.30, 95% CI [1.39-3.35]; p = 0.011), urban residential area (AOR: 2.78, CI [1.23-7.09], p = 0.043), lack of employment (AOR: 1.75, 95% CI [1.05-2.91], p = 0.032), food insecurity (AOR: 2.67, 95% CI [7.59-8.97]; p < 0.0001), malnutrition (AOR: 1.55, 95% CI [1.94-2.56]; p = 0.027) and opportunistic infections (AOR: 1.81, 95% CI [1.11-2.97]; p = 0.018).

Conclusion

The prevalence of non-adherence to ART in this study was high. Sociodemographic and economic factors such as young age of below 25 years, urban residential area, lack of employment, food insecurity, malnutrition and opportunistic infections were among the factors associated with non-adherence to ART.

Nurturing the Continuum of HIV Testing, Treatment and Prevention Matrix Cascade in Reducing HIV Transmission

Background

Despite the shift in antiretroviral therapy (ARVs) eligibility cascade from CD4 ≤ 200 to CD4 ≤ 350 to CD4 ≤ 500 mm³, HIV related morbidity and mortality continue to escalate annually, as do HIV infections. The new paradigm of treatment for all HIV positives individual irrespective of CD4 count may significantly reduce HIV and related illnesses. The author assumes that all HIV infected partners should be eligible for HIV treatment and care, irrespective of CD4 count. A second assumption is that high risk HIV negative partners have free access to continuum of HIV pre-exposure prophylaxis (PrEP), post exposure prophylaxis (PEP) and other prevention packages.

Methods

A literature review search was used to extract evidence-based ARVs-HIV treatment and prevention interventions among HIV positives and high risk partners respectively. Only articles published in English and indexed in journal nuclei were used for the study. The information was used to nurture understanding of HIV treatment and prevention approaches as well as HIV incidence multiplier effect among HIV serodiscordant partners. The imputed HIV incident reference was assumed at 1.2 per 100 person-years (2). This was based on the imputation that retention in care, adherence and other predetermined factors are functions of an effective health care delivery system.

Result

The model showed a reduced HIV transmission from 1.2 per 100 person-years to 1.032 per 100 person-years in 6 months. The average threshold period of HIV suppressed partners on ARVs to an undetectable level. The combined multiplier protective-effect probability of transmitting HIV from HIV positive partners on ARVs-suppressed viremic load to HIV negative partners on PrEP/PEP-prevention was detected at 86%

Conclusion

The model showed a significant reduction in HIV incidence. Placing serodiscordant sexual partners in HIV treatment and prevention plays a significant role in reducing and controlling HIV infection. Therefore, the policy of enrolling all HIV positives irrespective of CD4 count on ARVs and high risk partners on prevention if adopted and sustained may underpin reduction and control of HIV genotype and HIV related morbidity, mortality and opportunistic infections.

Residual T cell activation and skewed CD8+ T cell memory differentiation despite antiretroviral therapy-induced HIV suppression

HIV infection results in excessive T cell activation and dysfunction which may persist even during effective antiretroviral therapy (ART). The dynamics of immune 'deactivation' and extent to which T cell memory subsets normalize after ART are unclear. We longitudinally assessed the influence of 1 year of ART on the phenotype of T cells in HIV-infected African women, relative to matched HIV-uninfected women, using activation (CD38, HLA-DR) and differentiation markers (CD27, CD45RO). ART induced a substantial reduction in T cell activation, but remained higher than HIV-uninfected controls. ART largely normalized the distribution of CD4+ T cell memory subsets, while the distribution of CD8+ T cell memory subsets remained significantly skewed compared to HIV-uninfected individuals. Thus, there was a considerable but only partial reversal of T cell defects upon ART. Understanding T cell impairment may provide important insights into mechanisms of HIV pathogenesis in the era of ART.

Impact of antiretroviral and tuberculosis therapies on CD4+ and CD8+ HIV/M. tuberculosis-specific T-cell in co-infected subjects

BACKGROUND

Human Immunodeficiency Virus (HIV) infection is a risk factor for tuberculosis (TB). Antiretroviral therapy (ART) changed HIV clinical management but it is still unclear how pre-existing HIV/Mycobacterium tuberculosis (Mtb)-specific CD4⁺ and CD8⁺ T-cells are restored.

AIM

to evaluate the impact of ART and TB therapies on the functional and phenotypic profile of Mtb-specific antigen-response of CD4⁺ and CD8⁺ T-cells in prospectively enrolled HIV-TB co-infected patients.

METHODS

ART-naïve HIV-infected patients, with or without active TB or latent TB infection (LTBI), were enrolled before and after starting ART and TB therapies. Peripheral blood mononuclear cells (PBMC) were stimulated overnight with Mtb and HIV antigens (GAG). Cytokine expression and phenotype profile were evaluated by flow cytometry. Cytomegalovirus (CMV) and staphylococcal enterotoxin B (SEB) were also used.

RESULTS

The median of absolute number of CD4⁺ T-cells increased after ART and TB therapies in all groups analyzed, while the median of absolute number of CD8⁺ T-cells decreases in HIV and HIV-LTBI groups. Treatments significantly increased the frequency of Mtb-specific CD4⁺ T-cells in the HIV-LTBI (p = 0.015) with a rise of the central memory compartment. The magnitude of the CD4⁺ T-cell response to HIV-GAG significantly increased in active TB (p = 0.03), whereas the magnitude of CMV-specific CD4⁺ T-cell response decreased in all the groups. Similarly, the treatments increased the number of Mtb-specific CD8⁺ responders in both HIV-LTBI and HIV-TB groups, whereas the phenotype distribution was dependent on the antigens used and on the stage of infection/disease.

CONCLUSIONS

After therapies the median of absolute number and the proportion of CD4⁺ T-cells increased in all groups whereas the median of absolute count and proportion of CD8⁺ T-cells decreased in the HIV and HIV-LTBI subjects. Interestingly, an increased frequency of CD4⁺ T-cell response to RD1 proteins in HIV-LTBI subjects was found. These results contribute to a better understanding of the effect of ART and TB therapies on the modulation of Mtb-specific CD4⁺ and CD8⁺ T-cells subsets.

Socio-demographic factors predicting HIV test seeking behaviour among MSM in 6 EU cities

Background

HIV testing is generally accepted as being the lynchpin of a prevention strategy to tackle the HIV epidemic among MSM. However, few studies have analysed in detail the factors that influence HIV test seeking behaviour.

Methods

The objective of this article is to analyse the relationship between HIV test seeking behaviour and individual, social and demographic factors in a sample of MSM recruited though a multi-centre bio-behavioural cross-sectional study. A multi-level analysis was conducted to identify factors associated with HIV test seeking behaviour.

Results

A total of 2400 men were included in the sample. Age, self-reported sexual orientation, residence, household composition, educational status and perceived homonegativity all seem to impact on test seeking behaviour.

Conclusions

The results suggest the need for more targeted testing promotion strategies among MSM that take structural and environmental factors into consideration, as part of a comprehensive public health strategy to address the HIV epidemic.

Current approaches to assess HIV-1 persistence

PURPOSE OF REVIEW

The persistence of HIV within long-lived HIV-infected CD4 T cells is the primary obstacle towards HIV eradication and numerous strategies are currently being evaluated to target and kill HIV-infected cells to ultimately find a cure. HIV reservoirs are classically quantified by standard methods such as integrated HIV DNA (Alu PCR) and/or quantitative viral outgrowth assay; however, recent technical advances may offer new opportunities to comprehensively assess the impact of clinical interventions.

RECENT FINDINGS

Digital droplet PCR, tat/rev-induced limiting dilution analysis, enhanced quantitative viral outgrowth assay, and whole genome sequencing technologies offer increased precision and/or higher sensitivity to quantify and characterize HIV reservoirs in antiretroviral therapy-treated HIV-infected patients.

SUMMARY

The objective of this review is to highlight the characteristics and limits of recent technical advances that may help to monitor the impact of clinical interventions in antiretroviral therapy-treated patients.

Cigarette smoking is associated with high HIV viral load among adults presenting for antiretroviral therapy in Vietnam

High HIV viral load (VL >100,000 cp/ml) is associated with increased HIV transmission risk, faster progression to AIDS, and reduced response to some antiretroviral regimens. To better understand factors associated with high VL, we examined characteristics of patients presenting for treatment in Hanoi, Vietnam. We examined baseline data from the Viral Load Monitoring in Vietnam Study, a randomized controlled trial of routine VL monitoring in a population starting antiretroviral therapy (ART) at a clinic in Hanoi. Patients with prior treatment failure or ART resistance were excluded. Characteristics examined included demographics, clinical and laboratory data, and substance use. Logistic regression was used to calculate crude and adjusted odds ratios (aOR) and 95% confidence intervals (95% CI). Out of 636 patients, 62.7% were male, 72.9% were ≥30 years old, and 28.3% had a history of drug injection. Median CD4 was 132 cells/mm3, and 34.9% were clinical stage IV. Active cigarette smoking was reported by 36.3% with 14.0% smoking >10 cigarettes per day. Alcohol consumption was reported by 20.1% with 6.1% having ≥5 drinks per event. Overall 53.0% had a VL >100,000 cp/ml. Male gender, low body weight, low CD4 count, prior TB, and cigarette smoking were associated with high VL. Those who smoked 1–10 cigarettes per day were more likely to have high VL (aOR = 1.99, 95% CI = 1.15–3.45), while the smaller number of patients who smoked >10 cigarettes per day had a non-significant trend toward higher VL (aOR = 1.41, 95% CI = 0.75–2.66). Alcohol consumption was not significantly associated with high VL. Tobacco use is increasingly recognized as a contributor to premature morbidity and mortality among HIV-infected patients. In our study, cigarette smoking in the last 30 days was associated with a 1.5 to 2-fold higher odds of having an HIV VL >100,000 cp/ml among patients presenting for ART. These findings provide further evidence of the negative effects of tobacco use among HIV-infected patients.

The impact of antiretroviral therapy on population-level virulence evolution of HIV-1

In HIV-infected patients, an individual's set point viral load (SPVL) strongly predicts disease progression. Some think that SPVL is evolving, indicating that the virulence of the virus may be changing, but the data are not consistent. In addition, the widespread use of antiretroviral therapy (ART) has the potential to drive virulence evolution. We develop a simple deterministic model designed to answer the following questions: what are the expected patterns of virulence change in the initial decades of an epidemic? Could administration of ART drive changes in virulence evolution and, what is the potential size and direction of this effect? We find that even without ART we would not expect monotonic changes in average virulence. Transient decreases in virulence following the peak of an epidemic are not necessarily indicative of eventual evolution to avirulence. In the short term, we would expect widespread ART to cause limited downward pressure on virulence. In the long term, the direction of the effect is determined by a threshold condition, which we define. We conclude that, given the surpassing benefits of ART to the individual and in reducing onward transmission, virulence evolution considerations need have little bearing on how we treat.

Prospects for Foamy Viral Vector Anti-HIV Gene Therapy

Stem cell gene therapy approaches for Human Immunodeficiency Virus (HIV) infection have been explored in clinical trials and several anti-HIV genes delivered by retroviral vectors were shown to block HIV replication. However, gammaretroviral and lentiviral based retroviral vectors have limitations for delivery of anti-HIV genes into hematopoietic stem cells (HSC). Foamy virus vectors have several advantages including efficient delivery of transgenes into HSC in large animal models, and a potentially safer integration profile. This review focuses on novel anti-HIV transgenes and the potential of foamy virus vectors for HSC gene therapy of HIV.

Factors associated with initiation of antiretroviral therapy among HIV-positive people who use injection drugs in a Canadian setting

OBJECTIVE

To identify behavioral, social, and structural factors associated with time from HIV seroconversion to antiretroviral therapy (ART) initiation among people who use injection drugs (PWID).

DESIGN

Two complementary prospective cohorts of PWID linked to comprehensive ART dispensation records in a setting of universal no-cost HIV/AIDS treatment and care.

METHODS

Multivariable extended Cox models of time to ART initiation among baseline HIV-seronegative PWID who seroconverted after recruitment adjusted with a time-updated measure of clinical eligibility for ART.

RESULTS

We included 133 individuals of whom 98 (74%) initiated ART during follow-up at a rate of 12.4 per 100 person-years. In a multivariable model adjusted for ART eligibility, methadone maintenance therapy [adjusted hazard ratio (AHR) = 2.37, 95% confidence interval (95% CI): 1.56-3.60] and a more recent calendar year of observation (AHR = 1.06, 95% CI: 1.00-1.12) were associated with more rapid ART initiation, whereas informal income generation (AHR = 0.51, 95% CI: 0.32-0.79) and incarceration (AHR = 0.52, 95% CI: 0.28-0.97) were negatively associated with ART initiation.

CONCLUSION

In this sample of community-recruited HIV-positive PWID with well defined dates of HIV seroconversion, we found that two measures related to the criminalization of illicit drug use each independently delayed ART initiation regardless of clinical eligibility. Engagement in methadone promoted ART initiation. Programs to scale-up HIV treatment among PWID should consider decreased criminalization of PWID and increased access to opioid substitution therapy to optimize the impact of ART on HIV/AIDS-associated morbidity, mortality, and HIV transmission.

Programmatic Implications of Acute and Early HIV Infection

Human immunodeficiency virus (HIV) infection includes acute, early, chronic, and late stages. Acute HIV infection lasts approximately 3 weeks and early HIV infection, which includes acute HIV infection, lasts approximately 7 weeks. Many testing and blood screening algorithms detect HIV antibodies about 3 weeks after HIV infection. Incidence estimates are based on results of modeling, cohort studies, surveillance, and/or assays. Viral load is the key modifiable risk factor for HIV transmission and peaks during acute and early HIV infection. Empirical evidence characterizing the impact of acute and early HIV infection on the spread of the HIV epidemic are limited. Time trends of HIV prevalence collected from concentrated and generalized epidemics suggest that acute and early HIV infection may have a limited role in population HIV transmission. Collectively, these data suggest that acute and early HIV infection is relatively short and does not currently require fundamentally different programmatic approaches to manage the HIV/AIDS epidemic in most settings. Research and surveillance will inform which epidemic contexts and phases may require tailored strategies for these stages of HIV infection.

Restoration of CD4+ Responses to Copathogens in HIV-Infected Individuals on Antiretroviral Therapy Is Dependent on T Cell Memory Phenotype

Antiretroviral therapy (ART) induces rapid suppression of viral replication and a progressive replenishment of CD4(+) T cells in HIV-infected individuals. However, the effect of ART on restoring pre-existing memory CD4(+) T cells specific for common copathogens is still unclear. To better understand the dynamics of Ag-specific CD4(+) T cells during ART, we assessed the frequency, functional capacity, and memory profile of CD4(+) T cells specific for Mycobacterium tuberculosis and CMV in 15 HIV-infected individuals before and 1 y after ART initiation. After ART initiation, the frequency of M. tuberculosis-specific CD4(+) T cells showed little change, whereas CMV-specific CD4(+) T cells were significantly lower (p = 0.003). There was no difference in the polyfunctional or memory profile of Ag-specific CD4(+) T cells before and after ART. The replenishment of Ag-specific CD4(+) T cells correlated with the memory differentiation profile of these cells prior to ART. Pathogen-specific CD4(+) T cells exhibiting a late differentiated profile (CD45RO(+)CD27(-)) had a lower capacity to replenish (p = 0.019; r = -0.5) compared with cells with an early differentiated profile (CD45RO(+)CD27(+); p = 0.04; r = 0.45). In conclusion, restoration of copathogen-specific memory CD4(+) T cells during treated HIV infection is related to their memory phenotype, in which early differentiated cells (such as most M. tuberculosis-specific cells) have a higher replenishment capacity compared with late differentiated cells (such as most CMV-specific cells). These data identify an important, hitherto unrecognized, factor that may limit restoration of copathogen immunity in HIV-infected individuals on ART.

Human Immunodeficiency Virus Type 1 Cellular Entry and Exit in the T Lymphocytic and Monocytic Compartments: Mechanisms and Target Opportunities During Viral Disease

During the course of human immunodeficiency virus type 1 infection, a number of cell types throughout the body are infected, with the majority of cells representing CD4+ T cells and cells of the monocyte-macrophage lineage. Both types of cells express, to varying levels, the primary receptor molecule, CD4, as well as one or both of the coreceptors, CXCR4 and CCR5. Viral tropism is determined by both the coreceptor utilized for entry and the cell type infected. Although a single virus may have the capacity to infect both a CD4+ T cell and a cell of the monocyte-macrophage lineage, the mechanisms involved in both the entry of the virus into the cell and the viral egress from the cell during budding and viral release differ depending on the cell type. These host-virus interactions and processes can result in the differential targeting of different cell types by selected viral quasispecies and the overall amount of infectious virus released into the extracellular environment or by direct cell-to-cell spread of viral infectivity. This review covers the major steps of virus entry and egress with emphasis on the parts of the replication process that lead to differences in how the virus enters, replicates, and buds from different cellular compartments, such as CD4+ T cells and cells of the monocyte-macrophage lineage.

The Impact of Implementing a Test, Treat and Retain HIV Prevention Strategy in Atlanta among Black Men Who Have Sex with Men with a History of Incarceration: A Mathematical Model

Background

Annually, 10 million adults transition through prisons or jails in the United States (US) and the prevalence of HIV among entrants is three times higher than that for the country as a whole. We assessed the potential impact of increasing HIV Testing/Treatment/Retention (HIV-TTR) in the community and within the criminal justice system (CJS) facilities, coupled with sexual risk behavior change, focusing on black men-who-have-sex-with-men, 15–54 years, in Atlanta, USA.

Methods

We modeled the effect of a HIV-TTR strategy on the estimated cumulative number of new (acquired) infections and mortality, and on the HIV prevalence at the end of ten years. We additionally assessed the effect of increasing condom use in all settings.

Results

In the Status Quo scenario, at the end of 10 years, the cumulative number of new infections in the community, jail and prison was, respectively, 9246, 77 and 154 cases; HIV prevalence was 10815, 69 and 152 cases, respectively; and the cumulative number of deaths was 2585, 18 and 34 cases, respectively. By increasing HIV-TTR coverage, the cumulative number of new infections could decrease by 15% in the community, 19% in jail, and 8% in prison; HIV prevalence could decrease by 8%, 9% and 7%, respectively; mortality could decrease by 20%, 39% and 18%, respectively. Based on the model results, we have shown that limited use and access to condoms have contributed to the HIV incidence and prevalence in all settings.

Conclusions

Aggressive implementation of a CJS-focused HIV-TTR strategy has the potential to interrupt HIV transmission and reduce mortality, with benefit to the community at large. To maximize the impact of these interventions, retention in treatment, including during the period after jail and prison release, and increased condom use was vital for decreasing the burden of the HIV epidemic in all settings.

Modeling scenarios for the end of AIDS

At the end of 2012, 3 decades after the human immunodeficiency virus (HIV) was first identified, neither a cure nor a fully preventive vaccine was available. Despite multiple efforts, the epidemic remains an exceptional public health challenge. At the end of 2012, it was estimated that, globally, 35 million people were living with HIV, 2.3 million had become newly infected, and 1.6 million had died from AIDS-related causes. Despite substantial prevention efforts and increases in the number of individuals on highly active antiretroviral therapy (HAART), the epidemic burden continues to be high. Here, we provide a brief overview of the epidemiology of HIV transmission, the work that has been done to date regarding HIV modeling in different settings around the world, and how to finance the response to the HIV epidemic. In addition, we suggest discussion topics on how to move forward with the prevention agenda and highlight the role of treatment as prevention (TasP) in curbing the epidemic.

Different dimensions of HIV-related stigma may have opposite effects on hiv testing: evidence among young men and women in South Africa

Although HIV-related stigma in general is known to deter HIV-testing, the extent to which different dimensions of stigma independently influence testing behaviour is poorly understood. We used data on young black men (n = 553) and women (n = 674) from the 2009 Cape Area Panel Study to examine the independent effects of stigmatising attitudes, perceived stigma and observed enacted stigma on HIV-testing. Multivariate logistic regression models showed that stigma had a strong relationship with HIV-testing among women, but not men. Women who held stigmatising attitudes were more likely to have been tested (OR 3, p < 0.01), while perceived stigma (OR 0.61, p < 0.1) and observed enacted stigma (OR 0.42, p < 0.01) reduced the odds significantly of women having had an HIV test. Our findings highlight that different dimensions of stigma may have opposite effects on HIV testing, and point towards the need for interventions that limit the impact of enacted and perceived stigma on HIV-testing among women.

How acceptable are antiretrovirals for the prevention of sexually transmitted HIV?: A review of research on the acceptability of oral pre-exposure prophylaxis and treatment as prevention

Recent research has demonstrated how antiretrovirals (ARVs) could be effective in the prevention of sexually transmitted HIV. We review research on the acceptability of oral pre-exposure prophylaxis (PrEP) and treatment as prevention (TasP) for HIV prevention amongst potential users. We consider with whom, where and in what context this research has been conducted, how acceptability has been approached, and what research gaps remain. Findings from 33 studies show a lack of TasP research, PrEP studies which have focused largely on men who have sex with men (MSM) in a US context, and varied measures of acceptability. In order to identify when, where and for whom PrEP and TasP would be most appropriate and effective, research is needed in five areas: acceptability of TasP to people living with HIV; motivation for PrEP use and adherence; current perceptions and management of risk; the impact of broader social and structural factors; and consistent definition and operationalisation of acceptability which moves beyond adherence.

Challenges and potential barriers to the uptake of antiretroviral-based prevention in Asia and the Pacific region

Evidence has emerged over the past few years on the effectiveness of antiretroviral-based prevention technologies to prevent (i) HIV transmission while decreasing morbidity and mortality in HIV-infected persons, and (ii) HIV acquisition in HIV-uninfected individuals through pre-exposure prophylaxis (PrEP). Only few of the planned studies on treatment as prevention (TasP) are conducted in Asia. TasP might be more feasible and effective in concentrated rather than in generalised epidemics, as resources for HIV testing and antiretroviral treatment could focus on confined and much smaller populations than in the generalised epidemics observed in sub-Saharan Africa. Several countries such as Cambodia, China, Thailand and Vietnam, are now paving the way to success. Similar challenges arise for both TasP and PrEP. However, the operational issues for PrEP are amplified by the need for frequent retesting and ensuring adherence. This paper describes challenges for the implementation of antiretroviral-based prevention and makes the case that TasP and PrEP implementation research in Asia is much needed to provide insights into the feasibility of these interventions in populations where firm evidence of ‘real world’ effectiveness is still lacking.

HIV treatment as prevention: the key to an AIDS-free generation

The presence of elevated HIV viral load within blood and genital secretions is a critical driver of transmission events. Long-term suppression of viral load to undetectable levels through the use of antiretroviral therapy is now standard practice for clinical management of HIV. Antiretroviral therapy therefore can play a key role as a means to curb HIV transmission. Results of a randomized clinical trial, in conjunction with several observational studies, have now confirmed that antiretroviral therapy markedly decreases HIV transmission risk. Mathematical models and population-based ecologic studies suggest that further expansion of antiretroviral coverage within current guidelines can play a major role in controlling the spread of HIV. Expansion of so-called "Treatment as Prevention" initiatives relies upon maximal uptake of the HIV continuum-of-care cascade to allow for successful identification of those not yet known to be HIV-infected, engagement of patients in appropriate care, and subsequently achieving sustained virologic suppression in patients with the use of antiretroviral therapy. Since 2010, the Joint United Nations AIDS (UNAIDS) program has called for the inclusion of antiretroviral treatment as a key pillar in the global strategy to control the spread of HIV infection. This has now been invigorated by the release of the World Health Organization's 2013 Consolidated Antiretroviral Therapy Guidelines, recommending treatment to be offered to all HIV-infected individuals with CD4 cell counts below 500/mm³, and, regardless of CD4 cell count, to serodiscordant couples, TB and HBV co-infected individuals, pregnant women, and children below the age of 5 years.

Combinatorial RNA-based gene therapy for the treatment of HIV/AIDS

INTRODUCTION

HIV/AIDS continues to be a worldwide health problem and viral eradication has been an elusive goal. HIV+ patients are currently treated with combination antiretroviral therapy (cART) which is not curative. For many patients, cART is inaccessible, intolerable or unaffordable. Therefore, a new class of therapeutics for HIV is required to overcome these limitations. Cell and gene therapy for HIV has been proposed as a way to provide a functional cure for HIV in the form of a virus/infection resistant immune system.

AREAS COVERED

In this review, the authors describe the standard therapy for HIV/AIDS, its limitations, current areas of investigation and the potential of hematopoietic stem cells modified with anti-HIV RNAs as a means to affect a functional cure for HIV.

EXPERT OPINION

Cell and gene therapy for HIV/AIDS is a promising alternative to antiviral drug therapy and may provide a functional cure. In order to show clinical benefit, multiple mechanisms of inhibition of HIV entry and lifecycle are likely to be required. Among the most promising antiviral strategies is the use of transgenic RNA molecules that provide protection from HIV infection. When these molecules are delivered as gene-modified hematopoietic stem and progenitor cells, long-term repopulation of the patient's immune system with gene-modified progeny has been observed.

Clinical uncertainties, health service challenges, and ethical complexities of HIV "test-and-treat": a systematic review

Despite the HIV "test-and-treat" strategy's promise, questions about its clinical rationale, operational feasibility, and ethical appropriateness have led to vigorous debate in the global HIV community. We performed a systematic review of the literature published between January 2009 and May 2012 using PubMed, SCOPUS, Global Health, Web of Science, BIOSIS, Cochrane CENTRAL, EBSCO Africa-Wide Information, and EBSCO CINAHL Plus databases to summarize clinical uncertainties, health service challenges, and ethical complexities that may affect the test-and-treat strategy's success. A thoughtful approach to research and implementation to address clinical and health service questions and meaningful community engagement regarding ethical complexities may bring us closer to safe, feasible, and effective test-and-treat implementation.

Considerations regarding antiretroviral chemoprophylaxis and heterosexuals in generalized epidemic settings

PURPOSE OF REVIEW

To discuss the factors pertinent to the use of pre-exposure prophylaxis (PrEP) by at-risk heterosexuals in countries with generalized HIV epidemics.

RECENT FINDINGS

PrEP will have the greatest prevention effect if targeted to those at highest risk, but identifying and engaging such persons is challenging. Serodiscordant couples account for a high proportion of new infections and are an appropriate target for PrEP, but the proportion of people in such relationships is small and outside partnerships are common. Differences in adherence coupled to pharmacology of the drugs may account for differences in efficacy seen in the trials. Mathematical modeling indicates that the benefits of PrEP in highly endemic settings outweigh the risk of induced viral resistance. Behavioral risk compensation was not observed in the trials, but current open-label studies will better determine if disinhibition will be an important problem.

CONCLUSIONS

PrEP is a potentially useful HIV-prevention strategy for generalized heterosexual epidemics. Optimal implementation will require learning more about ways to improve acceptability and adherence and how best to deliver PrEP within the context of limited resource availability.

Combinatorial anti-HIV gene therapy: using a multipronged approach to reach beyond HAART

The 'Berlin Patient', who maintains suppressed levels of HIV viremia in the absence of antiretroviral therapy, continues to be a standard bearer in HIV eradication research. However, the unique circumstances surrounding his functional cure are not applicable to most HIV(+) patients. To achieve a functional or sterilizing cure in a greater number of infected individuals worldwide, combinatorial treatments, targeting multiple stages of the viral life cycle, will be essential. Several anti-HIV gene therapy approaches have been explored recently, including disruption of the C-C chemokine receptor 5 (CCR5) and CXC chemokine receptor 4 (CXCR4) coreceptor loci in CD4(+) T cells and CD34(+) hematopoietic stem cells. However, less is known about the efficacy of these strategies in patients and more relevant HIV model systems such as non-human primates (NHPs). Combinatorial approaches, including genetic disruption of integrated provirus, functional enhancement of endogenous restriction factors and/or the use of pharmacological adjuvants, could amplify the anti-HIV effects of CCR5/CXCR4 gene disruption. Importantly, delivering gene disruption molecules to genetic sites of interest will likely require optimization on a cell type-by-cell type basis. In this review, we highlight the most promising gene therapy approaches to combat HIV infection, methods to deliver these therapies to hematopoietic cells and emphasize the need to target viral replication pre- and post-entry to mount a suitably robust defense against spreading infection.

The world must build on three decades of scientific advances to enable a new generation to live free of HIV/AIDS

The extraordinary scientific advances made in the past three decades to understand, treat, and prevent HIV infection have contributed to the hope that a world free of AIDS is achievable. The growing armamentarium of scientifically proven interventions-including the use of antiretroviral medications to treat and prevent HIV infection, voluntary medical male circumcision, education and counseling about HIV risk and behavior change, condom use, drug and alcohol treatment, and needle exchange programs for injection drug users-offers an unprecedented opportunity to make major gains in the fight against HIV/AIDS. Combining and implementing these interventions as effectively as possible has the potential to dramatically change the trajectory of the HIV/AIDS pandemic. Substantive challenges remain, especially obtaining sufficient funding for HIV-related interventions and developing the operational capacity to deliver them cost-effectively to all in need. If these challenges can be met, the world will have a clear path toward an "AIDS-free generation" in which new HIV infections, as well as illness and death due to AIDS, are increasingly rare.

Biology as population dynamics: heuristics for transmission risk

Population-type models, accounting for phenomena such as population lifetimes, mixing patterns, recruitment patterns, genetic evolution and environmental conditions, can be usefully applied to the biology of HIV infection and viral replication. A simple dynamic model can explore the effect of a vaccine-like stimulus on the mortality and infectiousness, which formally looks like fertility, of invading virions; the mortality of freshly infected cells; and the availability of target cells, all of which impact on the probability of infection. Variations on this model could capture the importance of the timing and duration of different key events in viral transmission, and hence be applied to questions of mucosal immunology. The dynamical insights and assumptions of such models are compatible with the continuum of between- and within-individual risks in sexual violence and may be helpful in making sense of the sparse data available on the association between HIV transmission and sexual violence.

Treatment as prevention: translating efficacy trial results to population effectiveness

PURPOSE OF REVIEW

The understanding that antiretroviral treatment prevents HIV transmission through suppression of viral load provides significant new opportunities in HIV prevention. However, knowledge of efficacy is only a first step to having an impact on the spread of HIV at a population level, the ultimate goal of all primary prevention modalities. This review explores what we know about treatment as prevention and how it could be used as a tool, as part of a combination approach, in the global response to HIV.

RECENT FINDINGS

Efficacy data show that treatment as prevention works at high levels in trial conditions in stable serodiscordant couples; a finding that can reasonably be generalized to other populations at risk of transmitting the virus. Modelling shows that treatment as prevention should have an impact, but the extent of this depends primarily upon whether optimistic or pessimistic assumptions are made about the programmatic use of antiretrovirals (ARVs).

SUMMARY

We describe research questions that need to be addressed in developing optimal programmatic public health treatment strategies including how best to target and implement the use of treatment as prevention, how to balance the needs of treatment for the individual patients' clinical benefit against population level benefits, and how to create programmes that are able to link people to and retain them in care.

Preventing HIV transmission through antiretroviral treatment-mediated virologic suppression: aspects of an emerging scientific agenda

PURPOSE OF REVIEW

This review describes important aspects of the research agenda that have emerged as a result of the recent findings of the HIV transmission study in sero-discordant couples conducted by the National Institute of Allergy and Infectious Disease (NIAID)-supported HIV Prevention Trials Network (HPTN) and referred to as HPTN 052.

RECENT FINDINGS

The HPTN 052 study provided strong evidence that antiretroviral treatment (ART), given to HIV-infected partners with the purpose of achieving and maintaining full virologic suppression, could prevent linked HIV transmission in sero-discordant couples. These findings have implications in all future combination prevention strategies.

SUMMARY

The HPTN 052 study demonstrated that sustained virus suppression, below detectable levels, can prevent HIV transmission in sero-discordant couples. As a result of this study, we have now identified ART as a key component for all combination prevention strategies. Additionally, this study demonstrates that HIV testing is the single door of entry for individualized HIV treatment and prevention. The challenge now is to create a robust, seamless linkage and retention system so that the vision of HIV treatment as prevention can be realized. Such a system will maximize both the treatment and the prevention benefits of ART. The research agenda outlined here describes the need to extend this finding to areas of implementation science, such as the development of simpler, easier to use point-of-care assays for virus load, and improved, better tolerated, more durable combinations and formulations of antiretroviral drugs.

HIV treatment as prevention: debate and commentary--will early infection compromise treatment-as-prevention strategies?

Universal HIV testing and immediate antiretroviral therapy for infected individuals has been proposed as a way of reducing the transmission of HIV and thereby bringing the HIV epidemic under control. It is unclear whether transmission during early HIV infection--before individuals are likely to have been diagnosed with HIV and started on antiretroviral therapy--will compromise the effectiveness of treatment as prevention. This article presents two opposing viewpoints by Powers, Miller, and Cohen, and Williams and Dye, followed by a commentary by Fraser.

Treatment as prevention: preparing the way

Potent antiretroviral therapy (ART) reduces mortality and morbidity in people living with HIV by reducing viral load and allowing their immune systems to recover. The reduction in viral load soon after starting ART has led to the hypothesis that early and widespread ART could prevent onward transmission and therefore eliminate the HIV epidemic in the long term. While several authors have argued that it is feasible to use HIV treatment as prevention (TasP), provided treatment is started sufficiently early, others have reasonably drawn attention to the many operational difficulties that will need to be overcome if the strategy is to succeed in reducing HIV transmission. Furthermore, international public health policy must be based on more than theoretical studies, no matter how appealing. Community randomized controlled trials provide the gold standard for testing the extent to which early treatment reduces incidence, but much still needs to be understood and the immediate need is for operational studies to explore the practical feasibility of this approach. Here, we examine some of the issues to be addressed, the obstacles to be overcome, and strategies that may be necessary if TasP is to be effective. Studies of this kind will provide valuable information for the design of large-scale trials, as well as essential information that will be needed if early treatment is to be incorporated into public health policy.