Expanded access to highly active antiretroviral therapy: a potentially powerful strategy to curb the growth of the HIV epidemic

Cost-effectiveness of HIV screening in STD clinics, emergency departments, and inpatient units: a model-based analysis

Background

Identifying and treating persons with human immunodeficiency virus (HIV) infection early in their disease stage is considered an effective means of reducing the impact of the disease. We compared the cost-effectiveness of HIV screening in three settings, sexually transmitted disease (STD) clinics serving men who have sex with men, hospital emergency departments (EDs), settings where patients are likely to be diagnosed early, and inpatient diagnosis based on clinical manifestations.

Methods and Findings

We developed the Progression and Transmission of HIV/AIDS model, a health state transition model that tracks index patients and their infected partners from HIV infection to death. We used program characteristics for each setting to compare the incremental cost per quality-adjusted life year gained from early versus late diagnosis and treatment. We ran the model for 10,000 index patients for each setting, examining alternative scenarios, excluding and including transmission to partners, and assuming HAART was initiated at a CD4 count of either 350 or 500 cells/µL. Screening in STD clinics and EDs was cost-effective compared with diagnosing inpatients, even when including only the benefits to the index patients. Screening patients in STD clinics, who have less-advanced disease, was cost-effective compared with ED screening when treatment with HAART was initiated at a CD4 count of 500 cells/µL. When the benefits of reduced transmission to partners from early diagnosis were included, screening in settings with less-advanced disease stages was cost-saving compared with screening later in the course of infection. The study was limited by a small number of observations on CD4 count at diagnosis and by including transmission only to first generation partners of the index patients.

Conclusions

HIV prevention efforts can be advanced by screening in settings where patients present with less-advanced stages of HIV infection and by initiating treatment with HAART earlier in the course of infection.

'Test-and-treat': the end of the HIV epidemic?

PURPOSE OF REVIEW

The aim is to review recent literature on 'test-and-treat', a prevention strategy that promotes high levels of HIV testing and initiating antiretroviral therapy upon diagnosis, regardless of CD4 cell count. Antiretroviral therapy (ART) has been shown to dramatically reduce viral load which is strongly associated with the risk of transmission, therefore there is the potential to reduce HIV transmissions with ART.

RECENT FINDINGS

Recent papers from observational studies on heterosexual sero-discordant couples found an overall rate of transmission of HIV-1 from ART-treated patients of 0.46 per 100 person-years, confirming the possibility of using ART as a prevention strategy. Several models have been used to predict the effect of this strategy and the potential risks of it. Randomized controlled trials are currently ongoing investigating the effect of ART on reducing infectiousness and the feasibility of this policy.

SUMMARY

More precise estimations of the transmission risk under virally suppressive ART (especially in MSM) and of change in sex risk behaviour at diagnosis and at start of ART are needed. Further, the benefit to individual health of very early ART initiation and the feasibility of this policy need to be evaluated. Achieving very high levels of testing should be a high priority due to the benefits of initiating ART in all those who are in need (CD4 cell count < 350 cells/μl) and potential benefits on incidence due to reductions in risk behaviour in those diagnosed. Use of ART immediately at diagnosis in those with high CD4 cell counts should await results from further studies.

Estimating the impact of expanded access to antiretroviral therapy on maternal, paternal and double orphans in sub-Saharan Africa, 2009-2020

Background

HIV/AIDS has orphaned 11.6 million children in sub-Saharan Africa. Expanded antiretroviral therapy (ART) use may reduce AIDS orphanhood by decreasing adult mortality and population-level HIV transmission.

Methods

We modeled two scenarios to measure the impact of adult ART use on the incidence of orphanhood in 10 sub-Saharan African countries, from 2009 to 2020. Demographic model data inputs were obtained from cohort studies, UNAIDS, UN Population Division, WHO and the US Census Bureau.

Results

Compared to current rates of ART uptake, universal ART access averted 4.37 million more AIDS orphans by year 2020, including 3.15 million maternal, 1.89 million paternal and 0.75 million double orphans. The number of AIDS orphans averted was highest in South Africa (901.71 thousand) and Nigeria (839.01 thousand), and lowest in Zimbabwe (86.96 thousand) and Côte d'Ivoire (109.12 thousand).

Conclusion

Universal ART use may significantly reduce orphanhood in sub-Saharan Africa.

Drug treatment as HIV prevention: expanding treatment options

Research conducted during the first 20 years of the AIDS epidemic provided a solid foundation of data supporting methadone treatment as HIV prevention. Drug users in methadone treatment were consistently found to reduce the frequency of drug use, risk behaviors, and infections. These data have been consistent over time and across cultural settings and have been used to promote the expansion of drug treatment as a prevention intervention. More recently, data have emerged suggesting the prevention potential of medication-assisted treatments other than methadone (buprenorphine/naloxone and naltrexone). Still, with a few notable exceptions, global drug treatment coverage for opiate injectors remains remarkably low and only a few treatment interventions for stimulant use have shown efficacy in reducing HIV risk. Importantly, more recent data provide support for the role of drug treatment programs in improving access and adherence to antiretroviral treatment and that injection drug users in substance abuse treatment are more likely to achieve sustained viral suppression. While important challenges remain in maximizing its impact, the scientific literature provides strong evidence of the efficacy of drug treatment as an HIV prevention strategy.

Regional and temporal trends in migration among people living with HIV/AIDS in British Columbia, 1993-2005

OBJECTIVES

To examine regional and temporal trends in migration among patients receiving HIV treatment in British Columbia (BC).

METHODS

Patients initiating antiretroviral therapy in BC between January 1993 and November 2004 were followed until November 2005. Migration was calculated as the cumulative number of times a patient's residential address changed during their course of treatment. Analyses were performed at the provincial and at the regional health authority (HA) and local health area levels. Demographic methods were used to estimate the in- and out-migration rates, indices of dissimilarity and concentration across regions over time.

RESULTS

A total of 3,588 participants were followed during the study period. Individuals who migrated most often migrated to the Vancouver Coastal HA (from the Interior: 30%, Fraser: 41%, Vancouver Island: 28%, and Northern: 19%), specifically the city of Vancouver, which has been treating the most patients with HIV since the early stages of the epidemic. We also showed that this movement intensified as more contemporary HAART regimens became available (p-value for trend < 0.01).

DISCUSSION

Our results demonstrate that migration among people with HIV in BC is not homogeneous, with areas around large urban centres having the highest influx of patients. It is thus important that health authorities in BC work in partnership to monitor and evaluate accessibility of HIV-related health care services to ensure universal access for all patients. Furthermore, enhanced HIV care and support services need to be developed, on a province-wide basis, and funding allocation needs to be adjusted to reflect patient migration in BC.

Antiretroviral therapy use among HIV-infected men who have sex with men attending a sexually transmitted diseases clinic

We examined antiretroviral therapy (ART) use among 501 previously diagnosed HIV-infected men who have sex with men who sought care at a sexually transmitted disease clinic in King County, WA, during 2004-2008. Overall, 42% of men were not taking ART, 71% of whom had CD4 counts >350 cells per microliter. Of those who reported unprotected anal intercourse with a partner of nonconcordant HIV status in the prior year, 48% were not taking ART (78% with CD4 counts >350 cells/μL). Sexually transmitted disease clinics may be an important venue in which to identify persons who are not taking ART. Treating these persons could help diminish HIV transmission.

HIV-related risky practices among Brazilian young men, 2007

Behavioral surveillance surveys have been carried among military conscripts, in Brazil, since 1996. This paper presents the results of the 2007 survey and compares actual findings with those obtained in previous studies carried out in the period 1999-2002. The conscripts were selected with a two stage sampling stratified by geographical region. The study included a self-reported questionnaire and blood collection for HIV and syphilis testing. Data from 35,432 conscripts aged 17-20 years old were analyzed. The findings show a reduction in regular condom use, with fixed and casual partners, mainly among those with poor educational level. The proportion of conscripts that have sex with other men was maintained (3.2%), but the index of risky sexual behavioral showed worsening results in this group. Also, the HIV prevalence rate increased from 9 to 11.3 per 10,000 in 2007, though the increase was not statistically significant. In conclusion, the evidences found in this paper indicate the need of reformulate policy among young adults.

Drug treatment as HIV prevention: a research update

Drug use continues to be a major factor fueling the global epidemic of HIV infection. This article reviews the current literature on the ability of drug treatment programs to reduce HIV transmission among injection and noninjection drug users. Most data come from research on the treatment of opiate dependence and provide strong evidence on the effectiveness of medication-assisted treatment for reducing the frequency of drug use, risk behaviors, and HIV infections. This has been a consistent finding since the epidemic began among diverse populations and cultural settings. Use of medications other than methadone (such as buprenorphine/naloxone and naltrexone) has increased in recent years with promising data on their effectiveness as HIV prevention and as new treatment options for communities heavily affected by opiate use and HIV infection. However, few treatment interventions for stimulant abuse and dependence have shown efficacy in reducing HIV risk. The cumulative literature provides strong support of drug treatment programs for improving access and adherence to antiretroviral treatment. Drug users in substance abuse treatment are significantly more likely to achieve sustained viral suppression, making viral transmission less likely. Although there are challenges to implementing drug treatment programs for maximum impact, the scientific literature leaves no doubt about the effectiveness of drug treatment as an HIV prevention strategy.

Postexposure prophylaxis, preexposure prophylaxis or universal test and treat: the strategic use of antiretroviral drugs to prevent HIV acquisition and transmission

This review considers the use of antiretroviral drugs specifically to prevent HIV transmission. Antiretroviral therapy (ART) can be implemented for the protection of uninfected individuals both before (preexposure prophylaxis) and after (postexposure prophylaxis) exposure to HIV infection. Preexposure prophylaxis may be used coitally dependently when individuals are intermittently exposed or by continuous daily dosing for those constantly exposed; postexposure prophylaxis is used in 28-day courses. Alternatively, ART can be used strategically to reduce the viral load and consequent infectiousness of an HIV-infected individual, thereby limiting the risk of onward viral transmission. A policy of universal HIV testing to enhance the identification of all HIV-positive individuals followed by immediate treatment of all HIV-positive individuals, irrespective of their CD4 cell counts (universal test and treat), has been postulated as a potential tool capable of reducing HIV incidence at a population level. This concept represents a paradigm shift in the use of ART, targeting infectious individuals for prevention rather than protecting uninfected exposed populations. This strategy could have the advantage of preventing transmission and reducing HIV incidence at a population level, as well as delivering universal access to therapy for all people living with HIV and AIDS, potentially eliminating mother-to-child HIV transmission and limiting concomitant diseases such as tuberculosis. This review critically examines the scientific basis of ART for HIV prevention, summarizing the risks and opportunities of the potential expansion of ART for prevention. Specifically, we consider the evidences for and against targeting HIV-uninfected individuals compared with enhanced HIV testing and treatment of HIV-infected individuals in terms of impact on viral transmission.

An overview of the relative risks of different sexual behaviours on HIV transmission

PURPOSE OF REVIEW

Sexual intercourse represents the majority of HIV transmission and is preventable. Overall, the risk of HIV transmission following a single sexual exposure is low especially in comparison with other sexually transmitted infections (STIs), with estimates of the average probability of male-to-female HIV transmission only 0.0005-0.0026 per coital act. The risk of acquiring HIV from a single contact varies enormously and is dependant upon the infectiousness of the HIV-positive individual and the susceptibility to HIV of their sexual partner.

RECENT FINDINGS

Of concern, unprotected sex among men who have sex with men (MSM) has increased in recent years and HIV incidence in both MSM and heterosexuals remains a considerable public health concern. Sexual practices and health optimism about HIV have changed, which have significantly impacted HIV risk behaviour.

SUMMARY

In this review article we summarize the current evidence regarding the observed relative risks of HIV transmission for each different types of sex act, relationship type and the strategies that have been tested to interrupt transmission.

Rethinking prevention of HIV type 1 infection

Research on the prevention of human immunodeficiency virus (HIV)-1 infection is at a critical juncture. Major methodological challenges to performing prevention trials have emerged, and one after another promising biomedical interventions have failed to reduce the incidence of HIV-1 infection. Nevertheless, there is growing optimism that progress can be achieved in the near term. Mathematical modeling indicates that 2 new strategies, "test and treat" and preexposure prophylaxis, could have a major impact on the incidence of HIV-1 infection. Will our hopes be justified? We review the potential strengths and limitations of these antiretroviral "treatment as prevention" strategies and outline other new options for reducing the incidence of HIV-1 infection in the near term. By maximizing the potential of existing interventions, developing other effective strategies, and combining them in an optimal manner, we have the opportunity to bring the HIV-1 epidemic under control.

Association of highly active antiretroviral therapy coverage, population viral load, and yearly new HIV diagnoses in British Columbia, Canada: a population-based study

BACKGROUND

Results of cohort studies and mathematical models have suggested that increased coverage with highly active antiretroviral therapy (HAART) could reduce HIV transmission. We aimed to estimate the association between plasma HIV-1 viral load, HAART coverage, and number of new cases of HIV in the population of a Canadian province.

METHODS

We undertook a population-based study of HAART coverage and HIV transmission in British Columbia, Canada. Data for number of HIV tests done and new HIV diagnoses were obtained from the British Columbia Centre for Disease Control. Data for viral load, CD4 cell count, and HAART use were extracted from the British Columbia Centre for Excellence in HIV/AIDS population-based registries. We modelled trends of new HIV-positive tests and number of individuals on HAART using generalised additive models. Poisson log-linear regression models were used to estimate the association between new HIV diagnoses and viral load, year, and number of individuals on HAART.

FINDINGS

Between 1996 and 2009, the number of individuals actively receiving HAART increased from 837 to 5413 (547% increase; p=0.002), and the number of new HIV diagnoses fell from 702 to 338 per year (52% decrease; p=0.001). The overall correlation between number of individuals on HAART and number of individuals newly testing positive for HIV per year was -0.89 (p<0.0001). For every 100 additional individuals on HAART, the number of new HIV cases decreased by a factor of 0.97 (95% CI 0.96-0.98), and per 1 log(10) decrease in viral load, the number of new HIV cases decreased by a factor of 0.86 (0.75-0.98).

INTERPRETATION

We have shown a strong population-level association between increasing HAART coverage, decreased viral load, and decreased number of new HIV diagnoses per year. Our results support the proposed secondary benefit of HAART used within existing medical guidelines to reduce HIV transmission.

FUNDING

Ministry of Health Services and Ministry of Healthy Living and Sport, Province of British Columbia; US National Institute on Drug Abuse; US National Institutes of Health; Canadian Institutes of Health Research.

Expanding access to HAART: a cost-effective approach for treating and preventing HIV

OBJECTIVE

HIV continues to present a substantial global health burden. Given the high direct medical costs associated with the disease, prevention of new transmission is an important element in limiting economic burden. In addition to providing therapeutic benefit, treatment with HAART has potential to prevent transmission of HIV. The objective in this study was to perform an economic evaluation of the incremental net benefit associated with an intervention to expand treatment with HAART in British Columbia, Canada.

DESIGN

A mathematical model describing transmission of HIV, integrated with a microsimulation model describing the clinical and economic course of HIV.

METHODS

The primary outcome was the incremental net benefit of expanding treatment with HAART from 50 to 75% of clinically eligible individuals in British Columbia, assuming a willingness-to-pay threshold of US$ 50,000 per quality-adjusted life year. Direct medical costs included were antiretroviral and nonantiretroviral medications, hospitalizations, physician visits, and laboratory tests. The mathematical and microsimulation models were based on patient characteristics observed in British Columbia. Longitudinal data described health services utilization, clinical progression, and survival for all individuals receiving treatment for HIV in British Columbia.

RESULTS

Over 30 years, the HAART expansion scenario was associated with a net benefit of US$ 900 million (95% confidence interval US$ 493 million to 1.45 billion).

CONCLUSION

Increasing the HAART treatment rate from 50 to 75% of clinically eligible individuals in British Columbia appears to be a cost-effective strategy based on this model. These cost-effectiveness results are consistent with public health objectives: all individuals who are eligible for an established life-saving treatment should receive it.

Addressing research priorities for prevention of HIV infection in the United States

More than half a million Americans became newly infected with human immunodeficiency virus (HIV) in the first decade of the new millennium. The domestic epidemic has had the heaviest impact on men who have sex with men and persons from racial and ethnic minority populations, particularly black persons. For example, black men who have sex with men represent <1% of the US population but 25% of new HIV infections, according to Centers for Disease Control and Prevention estimates published in 2008. Although black and Hispanic women constitute 24% of all US women, they accounted for 82% of HIV infections among women in 2005, according to data from 33 states with confidential name-based reporting. There is a nearly 23-fold higher rate of AIDS diagnoses among black women (45.5 diagnoses per 100,000 women) and a nearly 6-fold higher rate among Hispanic women (11.2 diagnoses per 100,000 women), compared with the rate among white women (2.0 diagnoses per 100,000 women). Investigators from the HIV Prevention Trials Network, a National Institutes of Health-sponsored collaborative clinical trials group, have crafted a domestic research agenda with community input. Two new domestic studies are in progress (2009), and a community-based clinical trial feasibility effort is in development (2010 start date). These studies focus on outreach, testing, and treatment of infected persons as a backbone for prevention of HIV infection. Reaching persons not receiving health messages and services with novel approaches to both prevention and treatment is an essential priority for control of HIV infection in the United States; our research is designed to guide the best approaches and assess the impact of bridging treatment and prevention.

Modelling sexual transmission of HIV: testing the assumptions, validating the predictions

PURPOSE OF REVIEW

To discuss the role of mathematical models of sexual transmission of HIV: the methods used and their impact.

RECENT FINDINGS

We use mathematical modelling of 'universal test and treat' as a case study to illustrate wider issues relevant to all modelling of sexual HIV transmission.

SUMMARY

Mathematical models are used extensively in HIV epidemiology to deduce the logical conclusions arising from one or more sets of assumptions. Simple models lead to broad qualitative understanding, whereas complex models can encode more realistic assumptions and, thus, be used for predictive or operational purposes. An overreliance on model analysis in which assumptions are untested and input parameters cannot be estimated should be avoided. Simple models providing bold assertions have provided compelling arguments in recent public health policy, but may not adequately reflect the uncertainty inherent in the analysis.

How HIV treatment could result in effective prevention

As the number of HIV infections continues to surpass treatment capacity, new HIV prevention strategies are imperative. Beyond individual clinical benefits, by rendering an individual less infectious, expanding access to highly active antiretroviral therapy (HAART) could also have a larger public health impact of curbing new HIV infections. Recent guidelines have moved towards initiating HAART at higher CD4 cell counts, thus increasing the number of individuals in need of treatment. A new treatment strategy is wanting that can simultaneously curb the epidemic and provide necessary treatment to those most in need. A recent debate has centered on whether an expansion of free and universal treatment, regardless of CD4 cell count, could be a means of HIV prevention. In light of the growing access to HAART in resource-limited settings and increasing evidence suggesting the clinical and prevention benefits of initiating treatment at higher CD4 cell counts, it is conceivable that, in the future, HAART will be an integral part of both individual-level clinical treatment programs as well as public health-based HIV prevention interventions.

Decreases in community viral load are accompanied by reductions in new HIV infections in San Francisco

Background

At the individual level, higher HIV viral load predicts sexual transmission risk. We evaluated San Francisco's community viral load (CVL) as a population level marker of HIV transmission risk. We hypothesized that the decrease in CVL in San Francisco from 2004–2008, corresponding with increased rates of HIV testing, antiretroviral therapy (ART) coverage and effectiveness, and population-level virologic suppression, would be associated with a reduction in new HIV infections.

Methodology/Principal Findings

We used San Francisco's HIV/AIDS surveillance system to examine the trends in CVL. Mean CVL was calculated as the mean of the most recent viral load of all reported HIV-positive individuals in a particular community. Total CVL was defined as the sum of the most recent viral loads of all HIV-positive individuals in a particular community. We used Poisson models with robust standard errors to assess the relationships between the mean and total CVL and the primary outcome: annual numbers of newly diagnosed HIV cases. Both mean and total CVL decreased from 2004–2008 and were accompanied by decreases in new HIV diagnoses from 798 (2004) to 434 (2008). The mean (p = 0.003) and total CVL (p = 0.002) were significantly associated with new HIV cases from 2004–2008.

Conclusions/Significance

Reductions in CVL are associated with decreased HIV infections. Results suggest that wide-scale ART could reduce HIV transmission at the population level. Because CVL is temporally upstream of new HIV infections, jurisdictions should consider adding CVL to routine HIV surveillance to track the epidemic, allocate resources, and to evaluate the effectiveness of HIV prevention and treatment efforts.

Expanding HAART treatment to all currently eligible individuals under the 2008 IAS-USA Guidelines in British Columbia, Canada

Background

In 2008, the IAS-USA published the revised guidelines for the use of HAART in adults substantially increasing the number of individuals eligible for HAART. The epidemic in British Columbia (BC) is mainly among men who have sex with men and those with injection drug use. Here, we explored the potential impact of different HAART coverage scenarios, based on the new guidelines, on the HIV-related incidence, morbidity and mortality in BC, Canada.

Methodology

We built a mathematical transmission model to investigate different HAART coverage scenarios (50%, 60%, 75% and 100%) of those medically eligible to receive HAART under the 2008 IAS guidelines. All new scenarios were compared to the current coverage in BC under the 2006 IAS guidelines (i.e. baseline scenario). In BC, it is estimated that 25–30% of individuals are unaware of their status. Costs were drug-related and reported in Canadian dollars. HIV-related morbidity and mortality were estimated based on the disability-adjusted life years (DALY) methodology.

Principal Findings

Currently, there are 4379 individuals on HAART under the IAS 2006 guidelines and 6781 individuals who qualify for treatment based on the new guidelines. Within 5 years, increasing HAART coverage decreased yearly new infections by at least 44.8%. In the 50% scenario, in 5 years, DALY decreased by 53% corresponding to 4155 averted DALYs, and in 25 years it decreased by 66% corresponding to 5837 averted DALYs. The effect was even stronger if the 75% scenario was chosen instead. Compared to the 100% expansion scenario, we observed an excess in annual direct treatment expenditures at the end of 5 years of approximately 1 million dollars in the 75% scenario, and of approximately 2 million dollars in the 50% scenario.

Conclusions/Significance

The individual and public health benefits of these new guidelines are immense. The results show that by increasing the number of individuals on HAART save lives, it is cost averting, and it positively impacts society by decreasing the number of new HIV infections. Thus, public health community should consider incremental gains when considering guidelines and policy.

Treatment to prevent transmission of HIV-1

Antiretroviral therapy (ART) has the potential to prevent human immunodeficiency virus (HIV) transmission by reducing the concentration of HIV in blood and genital secretions. Indeed, mathematical models with favorable assumptions suggest the potential of ART to stop the spread of HIV infection. Empirical results from ecological and population-based studies and from several short-term observational studies involving HIV status-discordant heterosexual couples suggest that ART reduces the rate of HIV transmission. A multinational, randomized, controlled trial (National Institutes of Health HPTN052) examining the reliability and durability of ART as prevention of transmission in HIV status-discordant couples is under way. The latter and other studies also consider sexual risk-taking behavior and transmission of HIV-resistant variants when ART is used as prevention. Early HIV detection and treatment (ie, test and treat) are being considered as an important prevention strategy. In this article, we review the data supporting the use of ART to prevent HIV transmission and critically examine the public health implications of this strategy.

27 years of the HIV epidemic amongst men having sex with men in the Netherlands: an in depth mathematical model-based analysis

BACKGROUND

There has been increasing concern about a resurgent epidemic of HIV-1 amongst men having sex with men in the Netherlands, which has parallels with similar epidemics now occurring in many other countries.

METHODS

A transmission model applicable to HIV-1 epidemics, including the use of antiretroviral therapy, is presented in a set of ordinary differential equations. The model is fitted by maximum likelihood to national HIV-1 and AIDS diagnosis data from 1980 to 2006, estimating parameters on average changes in unsafe sex and time to diagnosis. Robustness is studied with a detailed univariate sensitivity analysis, and a range of hypothetical scenarios are explored for the past and next decade.

RESULTS

With a reproduction number around the epidemic threshold one, the HIV-1 epidemic amongst men having sex with men in the Netherlands is still not under control. Scenario analysis showed that in the absence of antiretroviral therapy limiting infectiousness in treated patients, the epidemic could have been more than double its current size. Ninety percent of new HIV transmissions are estimated to take place before diagnosis of the index case. Decreasing time from infection to diagnosis, which was 2.5 years on average in 2006, can prevent many future infections.

CONCLUSIONS

Sexual risk behaviour amongst men having sex with men who are not aware of their infection is the most likely factor driving this epidemic.

Late-disease stage at presentation to an HIV clinic in the era of free antiretroviral therapy in Sub-Saharan Africa

BACKGROUND

Access to free antiretroviral therapy in sub-Saharan Africa has been steadily increasing, and the success of large-scale antiretroviral therapy programs depends on early initiation of HIV care. However, little is known about the stage at which those infected with HIV present for treatment in sub-Saharan Africa.

METHODS

We conducted a cross-sectional analysis of initial visits to the Immune Suppression Syndrome Clinic of the Mbarara University Teaching Hospital, including patients who had their initial visit between February 2007 and February 2008 (N = 2311).

RESULTS

The median age of the patients was 33 years (range 16-81 years), and 64% were female. More than one third (40%) were categorized as late presenters, that is, World Health Organization disease stage 3 or 4. Male gender, age 46-60 years (vs. younger), lower education level, being unemployed, living in a household with others, being unmarried, and lack of spousal HIV status disclosure were independently associated with late presentation, whereas being pregnant, having young children, and consuming alcohol in the prior year were associated with early presentation.

CONCLUSIONS

Targeted public health interventions to facilitate earlier entry into HIV care are needed, as well as additional study to determine whether late presentation is due to delays in testing vs. delays in accessing care.

XVII International AIDS Conference: From Evidence to Action - Clinical and biomedical prevention science

The question of whether to initiate ART at higher CD4+ cell counts than currently recommended by World Health Organization (WHO) treatment guidelines received much attention at the XVII International AIDS Conference (AIDS 2008). If studies presented at the conference ultimately lead to a revision of WHO treatment guidance, the estimated number of people who will need ART globally will increase substantially. Task-shifting is emerging as an important strategy for dealing with the acute shortage of health care workers in many high-burden countries, and several studies presented at AIDS 2008 demonstrated the impressive health system efficiencies garnered by using nurses or other health care providers to deliver HIV care and treatment. Other key presentations and discussion at the conference focused on the optimal time to start TB treatment in HIV-infected patients, the growing risk of resistance in high-burden countries, including its impact on future treatment options, and several large cohort trials testing optimal drug regimens in resource-limited settings.Biomedical prevention research continues to confirm the long-term, protective benefits of circumcision. Several studies involving HIV serodiscordant heterosexual couples have produced data suggesting a strong protective effect of ART for HIV-negative partners. Disappointing results from recent vaccine and non-ARV based microbicides trials are nevertheless providing important data to this field, and the expanding number of pre-exposure prophylaxis (PrEP) trials and ARV-based microbicides appear to provide the best hope for a new, efficacious biomedical prevention intervention.

Health-related beliefs and decisions about accessing HIV medical care among HIV-infected persons who are not receiving care

In the United States, the publically supported national HIV medical care system is designed to provide HIV medical care to those who would otherwise not receive such care. Nevertheless, many HIV-infected persons are not receiving medical care. Limited information is available from HIV-infected persons not currently in care about the reasons they are not receiving care. From November 2006 to February 2007, we conducted five focus groups at community-based organizations and health departments in five U.S. cities to elicit qualitative information about barriers to entering HIV care. The 37 participants were mostly male (n = 29), over the age of 30 (n = 34), and all but one had not received HIV medical care in the previous 6 months. The focus group discussions revealed health belief-related barriers that have often been overlooked by studies of access to care. Three key themes emerged: avoidance and disbelief of HIV serostatus, conceptions of illness and appropriate health care, and negative experiences with, and distrust of, health care. Our findings point to the potentially important influence of these health-related beliefs on individual decisions about whether to access HIV medical care. We also discuss the implications of these beliefs for provider-patient communication, and suggest that providers frame their communications with patients such that they are attentive to the issues identified by our respondents, to better engage patients as partners in the treatment process.

Potential impact of early antiretroviral therapy on transmission

PURPOSE OF REVIEW

In this review, we will discuss the potential of early highly active antiretroviral therapy (HAART) to reduce the sexual transmission of HIV on an individual and population level. We will focus on the biological plausibility and behavioural factors associated with HAART use and interventions that might influence such a strategy.

RECENT FINDINGS

Empiric and phylogenetic studies support the view that recent HIV infection is a highly infectious disease stage. Evidence increasingly demonstrates that individuals on fully suppressive HAART are significantly less likely to transmit HIV to sexual partners and some even suggest that such individuals cannot transmit HIV. Changes in risk behaviour are associated with the availability of HAART but behavioural studies offer contradictory observations regarding the direction and magnitude of these changes. This in turn makes the intricate assumptions and therefore outcomes of many complex mathematical modelling studies less secure. Furthermore, there is evidence that it is those individuals with undiagnosed HIV infection who contribute significantly to onward sexual transmission.

SUMMARY

At an individual level, HAART will reduce viral load and, therefore, infectiousness, although whether to zero or not remains controversial. At a population level, if recent infection and undiagnosed infections continue to drive onward transmission, earlier treatment will only alter the pandemic if accompanied by an improvement in diagnosing the undiagnosed and recognizing recent infection.

Should HIV therapy be started at a CD4 cell count above 350 cells/microl in asymptomatic HIV-1-infected patients?

PURPOSE OF REVIEW

The aim is to review the available data that contribute to the debate on the optimal time to initiate highly active antiretroviral therapy (HAART) in HIV-infected individuals with a CD4 cell count more than 350 cells/microl.

RECENT FINDINGS

Although few randomized data exist that can contribute to this debate, a number of findings from observational studies generally support earlier initiation of HAART. In particular, the findings that death rates remain higher in HIV-infected individuals than in uninfected individuals, even when successfully treated, and that both AIDS and several serious non-AIDS events are more common in those with a lower CD4 cell count (even when this count is above 350 cells/microl), suggest that earlier initiation of HAART may prevent much of the excess morbidity and mortality that remains in this patient group.

SUMMARY

Currently, the data would generally support initiation of HAART in patients with CD4 cell counts more than 350 cells/microl. However, given the strong potential for confounding in observational studies and the lack of adjustment for lead-time bias in many analyses, it is not possible to rule out possible long-term detrimental effects of earlier use of HAART until the results from fully powered randomized trials that directly address this issue become available.

Mortality is influenced by locality in a major HIV/AIDS epidemic

OBJECTIVES

The aim of the study was to compare the risks of death among HIV-infected patients on highly active antiretroviral therapy (HAART) in two proximate, yet distinct neighbourhoods: a neighbourhood with a high concentration of gay men, and a neighbourhood with a high concentration of injecting drug users.

METHODS

We compared the clinical and socioeconomic characteristics of HIV-infected patients from the two neighbourhoods entering the British Columbia Centre for Excellence in HIV/AIDS Drug Treatment Program from 1 September 1997 to 30 November 2005, using contingency table statistics. Cox survival models and Kaplan-Meier methods were used to estimate the cumulative mortality rates.

RESULTS

We found significant differences between patients from the two neighbourhoods for all socioeconomic variables. Patients in the neighbourhood with a high concentration of injecting drug users were more likely to be female, have a history of injecting drug use, have a less HIV-experienced physician and be less adherent. Patients in the neighbourhood with a high concentration of gay men were more likely to have AIDS. Mortality was significantly higher for patients in the neighbourhood with a high concentration of injecting drug users [hazard ratio (HR) 3.01; 95% confidence interval (CI) 1.73, 5.24].

CONCLUSIONS

A threefold increase was observed in the risk of death among HIV-infected individuals on HAART in the neighbourhood with a high concentration of injecting drug users relative to the neighbourhood with a high concentration of gay men. The implications of this study should be assessed in similar HIV/AIDS epicentres.

Migration adversely affects antiretroviral adherence in a population-based cohort of HIV/AIDS patients

Migration among persons with HIV/AIDS is common; however, it is not clear how migration relates to antiretroviral adherence, a key determinant of treatment efficacy. Therefore, our objective was to determine the scale of regional migration and its association with adherence patterns over time among HIV-infected individuals in British Columbia (BC), Canada. Participants initiated HAART in August 1996-November 2004, and were followed until November 2005. Adherence was defined as the number of days worth of antiretrovirals dispensed divided by the number of days of follow-up (expressed as a percentage), and considered a binary time-dependent outcome: 'non-adherence' (less than 95%) versus 'adherence' (95% or more). Migration was calculated as the cumulative number of times a patient's residential address changed during the course of treatment, and treated as a time-dependent variable. Non-linear mixed-effects models were used to estimate the association between migration and adherence over time. All analyses were adjusted for relevant fixed and time-dependent variables. A total of 2421 participants were followed during the study period. Descriptive analysis demonstrated high stability in adherence over time, with more than 55% of patients moving at least once during the course of their treatment. We observed that those individuals migrating at least 3 times were 1.79 times more likely to be in the 'non-adherence' group than individuals who did not migrate. Our results demonstrate that migration in BC is not homogeneous across subpopulations. These results suggest that proactive strategies are needed to ensure that antiretroviral therapy remains available on a continued basis to highly migrant populations.

Universal voluntary HIV testing with immediate antiretroviral therapy as a strategy for elimination of HIV transmission: a mathematical model

BACKGROUND

Roughly 3 million people worldwide were receiving antiretroviral therapy (ART) at the end of 2007, but an estimated 6.7 million were still in need of treatment and a further 2.7 million became infected with HIV in 2007. Prevention efforts might reduce HIV incidence but are unlikely to eliminate this disease. We investigated a theoretical strategy of universal voluntary HIV testing and immediate treatment with ART, and examined the conditions under which the HIV epidemic could be driven towards elimination.

METHODS

We used mathematical models to explore the effect on the case reproduction number (stochastic model) and long-term dynamics of the HIV epidemic (deterministic transmission model) of testing all people in our test-case community (aged 15 years and older) for HIV every year and starting people on ART immediately after they are diagnosed HIV positive. We used data from South Africa as the test case for a generalised epidemic, and assumed that all HIV transmission was heterosexual.

FINDINGS

The studied strategy could greatly accelerate the transition from the present endemic phase, in which most adults living with HIV are not receiving ART, to an elimination phase, in which most are on ART, within 5 years. It could reduce HIV incidence and mortality to less than one case per 1000 people per year by 2016, or within 10 years of full implementation of the strategy, and reduce the prevalence of HIV to less than 1% within 50 years. We estimate that in 2032, the yearly cost of the present strategy and the theoretical strategy would both be US$1.7 billion; however, after this time, the cost of the present strategy would continue to increase whereas that of the theoretical strategy would decrease.

INTERPRETATION

Universal voluntary HIV testing and immediate ART, combined with present prevention approaches, could have a major effect on severe generalised HIV/AIDS epidemics. This approach merits further mathematical modelling, research, and broad consultation.

HIV prevention: What have we learned from community experiences in concentrated epidemics?

Drawing on lessons learned from community experiences in concentrated epidemics, this paper explores three imperatives in the effort to reduce the sexual transmission of HIV: combat prevention fatigue, diversify HIV testing and combat stigma and discrimination. The paper argues for a non-judgmental harm reduction approach to the prevention of sexual transmission of HIV that takes into account the interpretation of risk by diverse individuals and communities in the era of antiretroviral therapy. This approach requires greater attention to increasing access to opportunities to know one's serostatus, especially among key populations at greater risk. Novel approaches to diversifying HIV testing approaches at community level are needed. Finally, the paper makes a plea for bold measures to combat stigma and discrimination, which continues to represent a formidable barrier for access to services for affected populations and may contribute to HIV-related risk behaviours. A "triple therapy" approach to address stigma and discrimination is discussed, which includes greater acceptance of people living with HIV and AIDS (PLWHA), improving relevant laws and policies, and involving prevention users- working with people rather than for people-.Note: this paper corresponds to the plenary talk of Bruno Spire at the XVIIth World AIDS Conference, August 8th, Mexico city: http://www.kaisernetwork.org/health_cast/player.cfm?id=4383.

Prevention of the sexual transmission of HIV-1: preparing for success

There are four opportunities for HIV prevention: before exposure, at the moment of exposure, immediately after exposure, and as secondary prevention focused on infected subjects. Until recently, most resources have been directed toward behavioral strategies aimed at preventing exposure entirely. Recognizing that these strategies are not enough to contain the epidemic, investigators are turning their attention to post-exposure prevention opportunities. There is increasing focus on the use of ART–either systemic or topical (microbicides)–to prevent infection at the moment of exposure. Likewise, there is growing evidence that ART treatment of infected people could serve as prevention as well. A number of ongoing clinical trials will shed some light on the potential of these approaches. Above all, prevention of HIV requires decision-makers to focus resources on strategies that are most effective. Finally, treatment of HIV and prevention of HIV must be considered and deployed together.