Promising prevention approaches: tenofovir gel and prophylactic use of antiretroviral medications

Hydroxychloroquine Controversies: Clinical Trials, Epistemology, and the Democratization of Science

The claim that anti-malaria drugs, chloroquine and hydroxychloroquine, can cure COVID-19 became a focus of fierce political battles that pitted promoters of these pharmaceuticals, Presidents Bolsonaro and Trump among them, against "medical elites." At the center of these battles are different meanings of effectiveness in medicine, the complex role of randomized clinical trials (RCTs) in proving such effectiveness, the task of medical experts and the state in regulating pharmaceuticals, patients' activism, and the collective production of medical knowledge. This article follows the trajectory of chloroquine and hydroxychloroquine as anti-COVID-19 drugs, focusing on the reception of views of their main scientific promoter, the French infectious disease specialist, Didier Raoult. The surprising career of these drugs, our text proposes, is fundamentally a political event, not in the narrow sense of engaging specific political fractions, but in the much broader sense of the politics of public participation in science.

Using eHealth to Reach Black and Hispanic Men Who Have Sex With Men Regarding Treatment as Prevention and Preexposure Prophylaxis: Protocol for a Small Randomized Controlled Trial

BACKGROUND

Black and Hispanic men who have sex with men in the United States continue to be disproportionately affected by HIV and AIDS. Uptake of and knowledge about biobehavioral HIV prevention approaches, such as treatment as prevention and preexposure prophylaxis, are especially low in these populations. eHealth campaigns and social media messaging about treatment as prevention and preexposure prophylaxis may help to fill this gap in knowledge and lead to increased uptake of such strategies; however, no evidence exists of the effects of these targeted forms of communication on treatment as prevention and preexposure prophylaxis uptake in these populations.

OBJECTIVE

We describe the protocol for a 3-part study aiming to develop and evaluate an eHealth intervention with information about treatment as prevention and preexposure prophylaxis for HIV-positive and HIV-negative black and Hispanic men who have sex with men.

METHODS

Phases 1 and 2 will involve focus groups and cognitive interviews with members of the target populations, which we will use to create a culturally tailored, interactive website and applicable social media messaging for these men. Phase 3 will be a small randomized controlled trial of the eHealth intervention, in which participants will receive guided social media messages plus the newly developed website (active arm) or the website alone (control arm), with assessments at baseline and 6 months.

RESULTS

Participant recruitment began in August 2017 and will end in August 2020.

CONCLUSIONS

Public health interventions are greatly needed to increase knowledge about and uptake of biobehavioral HIV prevention strategies such as treatment as prevention and preexposure prophylaxis among black and Hispanic men who have sex with men. eHealth communication campaigns offer a strategy for engaging these populations in health communication about biobehavioral HIV prevention.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03404531; https://www.clinicaltrials.gov/ct2/show/NCT03404531 (Archived by WebCite at http://www.webcitation.org/70myofp0R).

REGISTERED REPORT IDENTIFIER

RR1-10.2196/11047.

Prospects for a Globally Effective HIV-1 Vaccine

A globally effective vaccine strategy must cope with the broad genetic diversity of HIV and contend with multiple transmission modalities. Understanding correlates of protection and the role of diversity in limiting protective vaccines with those correlates is key. RV144 was the first HIV-1 vaccine trial to demonstrate efficacy against HIV-1 infection. A correlates analysis comparing vaccine-induced immune responses in vaccinated-infected and vaccinated-uninfected volunteers suggested that IgG specific for the V1V2 region of gp120 was associated with reduced risk of HIV-1 infection and that plasma Env IgA was directly correlated with infection risk. RV144 and recent non-human primate (NHP) challenge studies suggest that Env is essential and perhaps sufficient to induce protective antibody responses against mucosally acquired HIV-1. Whether RV144 immune correlates can apply to different HIV vaccines, to populations with different modes and intensity of transmission, or to divergent HIV-1 subtypes remains unknown. Newer prime-boost mosaic and conserved sequence immunization strategies aiming at inducing immune responses of greater breadth and depth as well as the development of immunogens inducing broadly neutralizing antibodies should be actively pursued. Efficacy trials are now planned in heterosexual populations in southern Africa and men who have sex with men in Thailand. Although NHP challenge studies may guide vaccine development, human efficacy trials remain key to answer the critical questions leading to the development of a global HIV-1 vaccine for licensure.

Prospects for a globally effective HIV-1 vaccine

A globally effective vaccine strategy must cope with the broad genetic diversity of HIV and contend with multiple transmission modalities. Understanding correlates of protection and the role of diversity in limiting protective vaccines with those correlates is key. RV144 was the first HIV-1 vaccine trial to demonstrate efficacy against HIV-1 infection. A correlates analysis compared vaccine-induced immune responses in vaccinated-infected and vaccinated-uninfected volunteers suggested that IgG specific for the V1V2 region of gp120 was associated with reduced risk of HIV-1 infection and that plasma Env IgA was directly correlated with infection risk. RV144 and recent NHP challenge studies suggest that Env is essential and perhaps sufficient to induce protective antibody responses against mucosally acquired HIV-1. Whether RV144 immune correlates can apply to different HIV vaccines, to populations with different modes and intensity of transmission, or to divergent HIV-1 subtypes remains unknown. Newer prime-boost mosaic and conserved sequence immunization strategies aiming at inducing immune responses of greater breadth and depth as well as the development of immunogens inducing broadly neutralizing antibodies should be actively pursued. Efficacy trials are now planned in heterosexual populations in southern Africa and MSM in Thailand. Although NHP challenge studies may guide vaccine development, human efficacy trials remain key to answer the critical questions leading to the development of a global HIV-1 vaccine for licensure.

New prospects for a preventive HIV-1 vaccine

The immune correlates of risk analysis and recent non-human primate (NHP) challenge studies have generated hypotheses that suggest HIV-1 envelope may be essential and, perhaps, sufficient to induce protective antibody responses against HIV-1 acquisition at the mucosal entry. New prime-boost mosaic and conserved-sequence, together with replicating vector immunisation strategies aiming at inducing immune responses or greater breadth, as well as the development of immunogens inducing broadly neutralising antibodies and mucosal responses, should be actively pursued and tested in humans. Whether the immune correlates of risk identified in RV144 can be extended to other vaccines, other populations, or different modes and intensity of transmission, and against increasing HIV-1 genetic diversity, remains to be demonstrated. Although NHP challenge studies may guide vaccine development, human efficacy trials remain key for answering the critical questions leading to the development of a global HIV-1 vaccine for licensure.

HIV-1 vaccines: challenges and new perspectives

The development of a safe and effective preventive HIV-1 vaccine remains a public health priority. Despite scientific difficulties and disappointing results, HIV-1 vaccine clinical development has, for the first time, established proof-of-concept efficacy against HIV-1 acquisition and identified vaccine-associated immune correlates of risk. The correlate of risk analysis showed that IgG antibodies against the gp120 V2 loop correlated with decreased risk of HIV infection, while Env-specific IgA directly correlated with increased risk. The development of vaccine strategies such as improved envelope proteins formulated with potent adjuvants and DNA and vectors expressing mosaics, or conserved sequences, capable of eliciting greater breadth and depth of potentially relevant immune responses including neutralizing and non-neutralizing antibodies, CD4+ and CD8+ cell-mediated immune responses, mucosal immune responses, and immunological memory, is now proceeding quickly. Additional human efficacy trials combined with other prevention modalities along with sustained funding and international collaboration remain key to bring an HIV-1 vaccine to licensure.

Antiretroviral treatment of HIV-1 prevents transmission of HIV-1: where do we go from here?

Antiretroviral drugs that inhibit viral replication were expected to reduce transmission of HIV by lowering the concentration of HIV in the genital tract. In 11 of 13 observational studies, antiretroviral therapy (ART) provided to an HIV-infected index case led to greatly reduced transmission of HIV to a sexual partner. In the HPTN 052 randomised controlled trial, ART used in combination with condoms and counselling reduced HIV transmission by 96·4%. Evidence is growing that wider, earlier initiation of ART could reduce population-level incidence of HIV. However, the full benefits of this strategy will probably need universal access to very early ART and excellent adherence to treatment. Challenges to this approach are substantial. First, not all HIV-infected individuals can be located, especially people with acute and early infection who are most contagious. Second, the ability of ART to prevent HIV transmission in men who have sex with men (MSM) and people who use intravenous drugs has not been shown. Indeed, the stable or increased incidence of HIV in MSM in some communities where widespread use of ART has been established emphasises the concern that not enough is known about treatment as prevention for this crucial population. Third, although US guidelines call for immediate use of ART, such guidelines have not been embraced worldwide. Some experts do not believe that immediate or early ART is justified by present evidence, or that health-care infrastructure for this approach is sufficient. These concerns are very difficult to resolve. Ongoing community-based prospective trials of early ART are likely to help to establish the population-level benefit of ART, and-if successful-to galvanise treatment as prevention.

An HIV Vaccine for South-East Asia-Opportunities and Challenges

Recent advances in HIV vaccine development along with a better understanding of the immune correlates of risk have emerged from the RV144 efficacy trial conducted in Thailand. Epidemiological data suggest that CRF01_AE is still predominant in South-East Asia and is spreading in China with a growing number of circulating recombinant forms due to increasing human contact, particularly in large urban centers, tourist locations and in sites of common infrastructure. A vaccine countering CRF01_AE is a priority for the region. An Asia HIV vaccine against expanding B/E or BCE recombinant forms should be actively pursued. A major challenge that remains is the conduct of efficacy trials in heterosexual populations in this region. Men who have sex with men represent the main target population for future efficacy trials in Asia. Coupling HIV vaccines with other prevention modalities in efficacy trials might also be envisaged. These new avenues will only be made possible through the conduct of large-scale efficacy trials, interdisciplinary teams, international collaborations, and strong political and community commitments.

Combination prevention: new hope for stopping the epidemic

HIV research has identified approaches that can be combined to be more effective in transmission reduction than any 1 modality alone: delayed adolescent sexual debut, mutual monogamy or sexual partner reduction, correct and consistent condom use, pre-exposure prophylaxis with oral antiretroviral drugs or vaginal microbicides, voluntary medical male circumcision, antiretroviral therapy (ART) for prevention (including prevention of mother to child HIV transmission [PMTCT]), treatment of sexually transmitted infections, use of clean needles for all injections, blood screening prior to donation, a future HIV prime/boost vaccine, and the female condom. The extent to which evidence-based modalities can be combined to prevent substantial HIV transmission is largely unknown, but combination approaches that are truly implementable in field conditions are likely to be far more effective than single interventions alone. Analogous to PMTCT, "treatment as prevention" for adult-to-adult transmission reduction includes expanded HIV testing, linkage to care, antiretroviral coverage, retention in care, adherence to therapy, and management of key co-morbidities such as depression and substance use. With successful viral suppression, persons with HIV are far less infectious to others, as we see in the fields of sexually transmitted infection control and mycobacterial disease control (tuberculosis and leprosy). Combination approaches are complex, may involve high program costs, and require substantial global commitments. We present a rationale for such investments and cite an ongoing research agenda that seeks to determine how feasible and cost-effective a combination prevention approach would be in a variety of epidemic contexts, notably that in a sub-Saharan Africa.

Considerations regarding antiretroviral chemoprophylaxis in MSM

PURPOSE OF REVIEW

HIV infection among MSM remains a significant issue. Data relevant to MSM populations from animal models, pharmacokinetic studies and clinical trials are summarized and challenges and potential consequences of use of preexposure prophylaxis (PrEP) by MSM are discussed.

RECENT FINDINGS

Rectal simian-human immunodeficiency virus transmission in macaque models can be prevented by intermittent PrEP dosing. The Preexposure Prophylaxis Initiative (iPrEx) study found that daily oral emtricitabine-tenofovir disoproxyl fumarate (TDF/FTC) decreased HIV infection by 44% among 2499 high-risk MSM. Men with detectable levels of TDF or FTC in plasma and peripheral blood mononuclear cells experienced more than 90% protective effect, emphasizing the importance of adherence. In iPrEX and other studies, PrEP was generally safe and well tolerated. However, it appears that TDF use is associated with a small but significant decrease in mean bone mineral density. No risk compensation has been demonstrated, but this remains an area of potential concern when PrEP is used outside the setting of a placebo-controlled trial. Numerous PrEP trials in MSM are currently underway.

SUMMARY

Oral FTC/TDF is effective in preventing HIV infection among MSM. Optimal PrEP agents and dosing regimens now need to be identified. Understanding the patterns of and impediments to PrEP use among MSM is vital and these should be monitored in ongoing demonstration projects and open-label studies.

Controlling the HIV/AIDS epidemic: current status and global challenges

This review provides an overview of the current status of the global HIV pandemic and strategies to bring it under control. It updates numerous preventive approaches including behavioral interventions, male circumcision (MC), pre- and post-exposure prophylaxis (PREP and PEP), vaccines, and microbicides. The manuscript summarizes current anti-retroviral treatment options, their impact in the western world, and difficulties faced by emerging and resource-limited nations in providing and maintaining appropriate treatment regimens. Current clinical and pre-clinical approaches toward a cure for HIV are described, including new drug compounds that target viral reservoirs and gene therapy approaches aimed at altering susceptibility to HIV infection. Recent progress in vaccine development is summarized, including novel approaches and new discoveries.

Towards combination HIV prevention for injection drug users: addressing addictophobia, apathy and inattention

PURPOSE OF REVIEW

Recent breakthroughs in HIV-prevention science led us to evaluate the current state of combination HIV prevention for injection drug users (IDUs). We review the recent literature focusing on possible reasons why coverage of prevention interventions for HIV, hepatitis C virus (HCV) and tuberculosis among IDUs remains dismal. We make recommendations for future HIV research and policy.

RECENT FINDINGS

IDUs disproportionately under-utilize voluntary HIV counseling and testing (VCT), primary care and antiretroviral therapy (ART), especially in countries that have the largest burden of HIV among IDUs. IDUs present later in the course of HIV infection and experience greater morbidity and mortality. Why are IDUs under-represented in HIV-prevention research, access to treatment for both HIV and addiction, and access to HIV combination prevention? Possible explanations include addictophobia, apathy, and inattention, which we describe in the context of recent literature and events.

SUMMARY

This commentary discusses the current state of HIV-prevention interventions for IDUs including VCT, needle and syringe program (NSP), opioid substitution therapy (OST), ART and pre-exposure chemoprophylaxis (PrEP), and discusses ways to work towards true combination HIV prevention for IDU populations. Communities need to overcome tacit assumptions that IDUs can navigate through systems that are maintained as separate silos, and begin to take a rights-based approach to HIV prevention to ensure that IDUs have equitable access to life-saving prevention and treatments.