Investing To Meet The Scientific Challenges Of HIV/AIDS

Biomedical prevention: what is the current status?

Biomedical HIV prevention strategies for primary or secondary prevention of HIV transmission can be seen as an adjunct to behavioral prevention approaches. These interventions include vaccination, female controlled vaginal microbicides, male circumcision, treatment of sexually transmitted infections that cause genital ulceration, Pre-Exposure Prophylaxis (PREP) and Post-Exposure Prophylaxis (PEP). This article reviews results from recent randomized controlled trials of novel biomedical prevention approaches and discusses interpretation of the results. The only intervention consistently demonstrating reductions in HIV transmission was adult male circumcision in Sub-Saharan Africa. Results of PREP trials will be available in the next several years.

Effectiveness of UNAIDS targets and HIV vaccination across 127 countries

The HIV pandemic continues to impose enormous morbidity, mortality, and economic burdens across the globe. Simultaneously, innovations in antiretroviral therapy, diagnostic approaches, and vaccine development are providing novel tools for treatment-as-prevention and prophylaxis. We developed a mathematical model to evaluate the added benefit of an HIV vaccine in the context of goals to increase rates of diagnosis, treatment, and viral suppression in 127 countries. Under status quo interventions, we predict a median of 49 million [first and third quartiles 44M, 58M] incident cases globally from 2015 to 2035. Achieving the Joint United Nations Program on HIV/AIDS 95-95-95 target was estimated to avert 25 million [20M, 33M] of these new infections, and an additional 6.3 million [4.8M, 8.7M] reduction was projected with the 2020 introduction of a 50%-efficacy vaccine gradually scaled up to 70% coverage. This added benefit of prevention through vaccination motivates imminent and ongoing clinical trials of viable candidates to realize the goal of HIV control.

The social value of candidate HIV cures: actualism versus possibilism

A sterilising or functional cure for HIV is a serious scientific challenge but presents a viable pathway to the eradication of HIV. Such an event would be extremely valuable in terms of relieving the burden of a terrible disease; however, a coordinated commitment to implement healthcare interventions, particularly in regions that bear the brunt of the HIV epidemic, is lacking. In this paper, we examine two strategies for evaluating candidate HIV cures, based on our beliefs about the likelihood of global implementation. We reject possibilist interpretations of social value that do not account for the likelihood that a plan to cure HIV will be followed through. We argue, instead, for an actualist ranking of options for action, which accounts for the likelihood that a cure will be low cost, scalable and easy to administer worldwide.

Impact of a decade of successful antiretroviral therapy initiated at HIV-1 seroconversion on blood and rectal reservoirs

Persistent reservoirs remain the major obstacles to achieve an HIV-1 cure. Prolonged early antiretroviral therapy (ART) may reduce the extent of reservoirs and allow for virological control after ART discontinuation. We compared HIV-1 reservoirs in a cross-sectional study using polymerase chain reaction-based techniques in blood and tissue of early-treated seroconverters, late-treated patients, ART-naïve seroconverters, and long-term non-progressors (LTNPs) who have spontaneous virological control without treatment. A decade of early ART reduced the total and integrated HIV-1 DNA levels compared with later treatment initiation, but not reaching the low levels found in LTNPs. Total HIV-1 DNA in rectal biopsies did not differ between cohorts. Importantly, lower viral transcription (HIV-1 unspliced RNA) and enhanced immune preservation (CD4/CD8), reminiscent of LTNPs, were found in early compared to late-treated patients. This suggests that early treatment is associated with some immunovirological features of LTNPs that may improve the outcome of future interventions aimed at a functional cure.

DOI:http://dx.doi.org/10.7554/eLife.09115.001

Many people with HIV infections are able to live relatively normal lives thanks to major advances in drug therapies. A cure, however, remains elusive. One reason for this is that the virus can hide in certain types of human cells, where it is protected from the immune system and the effects of “antiretroviral” drugs. This creates reservoirs of virus particles in the body that can quickly multiply and spread if treatment stops.

Some people who become infected with HIV are able to contain the virus without the help of drug treatments. These individuals – known as long-term non-progressors – do not become ill and only have low numbers of HIV particles in reservoirs. People who receive treatment early in the course of an HIV infection also have fewer viruses in reservoirs and are less likely to develop severe illness. Therefore, it might be possible to develop a “functional” cure that may not completely eliminate the virus from the body, but would prevent illness and allow the individuals to eventually stop taking antiretroviral drugs.

Now, Malatinkova, De Spiegelaere et al. studied samples from 84 patients with HIV-1 to find how much effect an early start to treatment has on the amount of the virus in reservoirs. People who started treatment soon after infection had lower levels of HIV-1 in their blood than people who started treatment later (even after 10 years of treatment). However, patients that started treatment early had higher levels of HIV-1 in the blood than the patients who were long-term non-progressors. All the patients had similar levels of HIV-1 in tissue samples taken from the rectum, regardless of when they started treatment.

The experiments suggest that HIV-1 reservoirs form very soon after infection. Malatinkova, De Spiegelaere et al. found that in addition to reducing reservoirs of HIV-1, an early start to drug treatment reduced the ability of the virus to make copies of its genetic code. People who started treatment earlier also had healthier immune cells. Together, the experiments support the benefits of starting drug treatments as soon as possible after a person is infected with HIV-1. It is important to further characterize thoroughly the viral reservoir in patients with limited HIV-1 reservoirs and to look for other immune factors involved in virus control, in the search for a functional cure of HIV.

DOI:http://dx.doi.org/10.7554/eLife.09115.002

Social justice and HIV vaccine research in the age of pre-exposure prophylaxis and treatment as prevention

The advent of pre-exposure prophylaxis (PrEP) and treatment as prevention (TasP) as means of HIV prevention raises issues of justice concerning how most fairly and equitably to apportion resources in support of the burgeoning variety of established HIV treatment and prevention measures and further HIV research, including HIV vaccine research. We apply contemporary approaches to social justice to assess the ethical justification for allocating resources in support of HIV vaccine research given competing priorities to support broad implementation of HIV treatment and prevention measures, including TasP and PrEP. We argue that there is prima facie reason to believe that a safe and effective preventive HIV vaccine would offer a distinct set of ethically significant benefits not provided by current HIV treatment or prevention methods. It is thereby possible to justify continued support for HIV vaccine research despite tension with priorities for treatment, prevention, and other research. We then consider a counter-argument to such a justification based on the uncertainty of successfully developing a safe and effective preventive HIV vaccine. Finally, we discuss how HIV vaccine research might now be ethically designed and conducted given the new preventive options of TasP and PrEP, focusing on the ethically appropriate standard of prevention for HIV vaccine trials.

The impact of Fogarty International Center research training programs on public health policy and program development in Kenya and Uganda

Background

The Fogarty International Center (FIC) has supported research capacity development for over twenty years. While the mission of FIC is supporting and facilitating global health research conducted by U.S. and international investigators, building partnerships between health research institutions in the U.S. and abroad, and training the next generation of scientists to address global health needs, research capacity may impact health policies and programs and therefore have positive impacts on public health. We conducted an exploratory analysis of how FIC research training investments affected public health policy and program development in Kenya and Uganda.

Methods

We explored the long term impacts of all FIC supported research training programs using case studies, in Kenya and Uganda. Semi-structured in-depth interviews were conducted with 53 respondents and 29 focus group discussion participants across the two countries. Qualitative methods were supplemented by structured surveys of trainees and document review, including a review of evidence cited in policy documents.

Results

In the primary focal areas of FIC grants, notably HIV/AIDS, there were numerous examples of work conducted by former FIC trainees that influenced national and global policies. Facilitators for this influence included the strong technical skills and scientific reputations of the trainees, and professional networks spanning research and policy communities. Barriers included the fact that trainees typically had not received training in research communication, relatively few policy makers had received scientific training, and institutional constraints that undermined alignment of research with policy needs.

Conclusions

While FIC has not focused its programs on the goal of policy and program influence, its investments have affected global and national public health policies and practice. These influences have occurred primarily through strengthening research skills of scientists and developing strong in-country networks. Further success of FIC and similar initiatives could be stimulated by investing more in the training of policy-makers, seeking to better align research with policy needs through more grants that are awarded directly to developing country institutions, and grants that better incorporate policy maker perspectives in their design and governance. Addressing structural constraints, for example supporting the development of national research agendas that inform university research, would further support such efforts.

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.

Derivation of non-infectious envelope proteins from virions isolated from plasma negative for HIV antibodies

Natural membrane-bound HIV-1 envelope proteins (mHIVenv) could be used to produce an effective subunit vaccine against HIV infection, akin to effective vaccination against HBV infection using the hepatitis B surface antigen. The quaternary structure of mHIVenv is postulated to elicit broadly neutralizing antibodies protective against HIV-1 transmission. The founder virus transmitted to infected individuals during acute HIV-1 infection is genetically homogeneous and restricted to CCR5-tropic phenotype. Therefore, isolates of plasma-derived HIV-1 (PHIV) from infected blood donors while negative for antibodies to HIV proteins were selected for expansion in primary lymphocytes as an optimized cell substrate (OCS). Virions in the culture supernatants were purified by removing contaminating microvesicles using immunomagnetic beads coated with anti-CD45. Membrane cholesterol was extracted from purified virions with beta-cyclodextrin to permeabilize them and expel p24, RT and viral RNA, and permit protease-free Benzonase to hydrolyze the residual viral/host DNA/RNA without loss of gp120. The resultant mHIVenv, containing gp120 bound to native gp41 in immunoreactive form, was free from infectivity in vitro in co-cultures with OCS and in vivo after inoculating SCID-hu Thy/Liv mice. These data should help development of mHIVenv as a virally safe immunogen and enable preparation of polyclonal hyper-immune globulins for immunoprophylaxis against HIV-1 infection.

Strategies to improve HIV treatment adherence in developed countries: clinical management at the individual level

REMARKABLE ADVANCES IN THE TREATMENT OF HUMAN IMMUNODEFICIENCY VIRUS (HIV) DISEASE HAVE BEEN BLUNTED BY WIDESPREAD SUBOPTIMAL ADHERENCE (IE, NONADHERENCE), WHICH HAS EMERGED AS A MAJOR BARRIER TO ACHIEVING THE PRIMARY GOAL OF ANTIRETROVIRAL (ARV) THERAPY: suppression of HIV viral load. Nonsuppressed HIV viral load is associated with drug resistance, increased morbidity and mortality, and a higher risk of person-to-person HIV transmission. For HIV-infected individuals who are failing HIV treatment due to nonadherence, becoming adherent is a life-saving behavior change. However, overcoming nonadherence is one of the most daunting challenges in the successful management of HIV disease. The purpose of this paper is to provide clinicians with a better understanding of nonadherence to ARV treatment and to review the various factors that have been associated with either adherence or nonadherence. Strategies are presented that may help the nonadherent individual become ready to take HIV medications as prescribed.

Antiretroviral therapy and management of HIV infection

Antiretroviral therapy of HIV infection has changed a uniformly fatal into a potentially chronic disease. There are now 17 drugs in common use for HIV treatment. Patients who can access and adhere to combination therapy should be able to achieve durable, potentially lifelong suppression of HIV replication. Despite the unquestioned success of antiretroviral therapy, limitations persist. Treatment success needs strict lifelong drug adherence. Although the widely used drugs are generally well tolerated, most have some short-term toxic effects and all have the potential for both known and unknown long-term toxic effects. Drug and administration costs limit treatment in resource-poor regions, and are a growing concern even in resource rich settings. Finally, complete or near complete control of viral replication does not fully restore health. Long-term treated patients who are on an otherwise effective regimen often show persistent immune dysfunction and have higher than expected risk for various non-AIDS-related complications, including heart, bone, liver, kidney, and neurocognitive diseases.

Can we treat our way out of HIV?

There is a range of settings in which antiretroviral therapy can decrease the incidence of HIV. Recently, it was revealed that the National Institutes of Health (NIH) and the Centers for Disease Control and Prevention (CDC) plan to study a test and treat strategy to reduce the spread of HIV. A test and treat strategy presents numerous implementation, operational, structural, and policy issues that will require research to be effectively addressed. The timing of the interest in a test and treat strategy and this first foray into exploring its potential implementation come at a critical juncture in the history of HIV/AIDS in the United States, where recent data from the CDC indicate that the prevalence and incidence of HIV are considerably higher than had previously been thought, and the Obama administration is currently developing a National HIV/AIDS Strategy (NHAS) whose three primary goals are reducing HIV incidence, increasing access to care, and reducing HIV-related health disparities. Indeed, the test and treat strategy is possibly unique in its direct relevance to all three main goals of the NHAS. A strategic approach to research will define portfolios and allocate resources based on their ability to move toward accomplishing the three NHAS goals. A National HIV/AIDS Strategy that both informs and is informed by a strong research agenda is a long-awaited and much anticipated development in the battle against HIV/AIDS in the United States.