Order of orifices: sequence of condom use and ejaculation by orifice during anal intercourse among women: implications for HIV transmission

Fundamental aspects of long-acting tenofovir alafenamide delivery from subdermal implants for HIV prophylaxis

Global efforts aimed at preventing human immunodeficiency virus type one (HIV-1) infection in vulnerable populations appear to be stalling, limiting our ability to control the epidemic. Long-acting, controlled drug administration from subdermal implants holds significant potential by reducing the compliance burden associated with frequent dosing. We, and others, are exploring the development of complementary subdermal implant technologies delivering the potent prodrug, tenofovir alafenamide (TAF). The current report addresses knowledge gaps in the preclinical pharmacology of long-acting, subdermal TAF delivery using several mouse models. Systemic drug disposition during TAF implant dosing was explained by a multi-compartment pharmacokinetic (PK) model. Imaging mass spectrometry was employed to characterize the spatial distribution of TAF and its principal five metabolites in local tissues surrounding the implant. Humanized mouse studies determined the effective TAF dose for preventing vaginal and rectal HIV-1 acquisition. Our results represent an important step in the development of a safe and effective TAF implant for HIV-1 prevention.

Promoting safer sex in the context of heterosexual anal intercourse: A scoping review

AIMS AND OBJECTIVES

To locate and summarise existing literature regarding safer sex practices specific to heterosexual anal intercourse and identify promising health promotion strategies.

BACKGROUND

Much of the literature regarding anal intercourse and safer sex is related to men who have sex with men. However, some studies suggest there are more women than men engaging in unprotected receptive anal intercourse. The risks associated with this sexual practice have been well documented, although many healthcare providers fail to ask about anal intercourse while addressing safer sex in the heterosexual population.

DESIGN

The study was based on Arksey and O'Malley's 2005 five-step methodology.

METHODS

A search was conducted of MEDLINE; CINAHL; PsycInfo; Cochrane; and PubMed. Databases were searched from 1990-2020. The 72 studies selected were classified according to their main area of focus. A grey literature search was also included. This scientific submission has been assessed for accuracy and completeness using the PRISMA-ScR guideline criteria (File S1).

RESULTS

The literature in this area is heterogeneous in terms of method and topic. Prevalence and incidence (n = 26) in addition to sexually transmitted infection risks (n = 26) related to heterosexual anal intercourse are well understood. However, there is limited information on condom use (n = 6), factors that influence heterosexual anal intercourse (n = 10) and health promotion strategies for this population and practice (n = 4). Two websites that mentioned heterosexual anal intercourse risk reduction activities were included.

CONCLUSIONS

Although heterosexual anal intercourse appears to be an increasingly common sexual practice, very little is known about health promotion strategies nurses might use for encouraging safer sex in this population.

RELEVANCE TO CLINICAL PRACTICE

Increased awareness of the prevalence and risks of heterosexual anal intercourse could enhance nurses' harm reduction strategies. Screening for sexually transmitted infections may be based on incorrect assumptions about sexual practices or due to stigma linked with anal intercourse. Reducing unprotected heterosexual anal intercourse will reduce sexually transmitted infections and their long-term sequelae.

Psychopathology and HIV diagnosis among older adults in the United States: disparities by age, sex, and race/ethnicity

In 2016, 17% of new HIV infections in the US were among adults aged 50 and older. Differences by age, sex, and race/ethnicity exist among older people living with HIV. Co-morbid mental health and substance use disorders (SUD) are also major challenges for this population. This study examined the association between generalized anxiety disorder (GAD), posttraumatic stress disorder (PTSD), SUD, depression, and HIV diagnosis among adults aged 50 and older, and the disparities by age, sex, and race/ethnicity. Data were obtained from Cerner Corporation's Health Facts® database. Multivariable logistic regression models were used to determine the associations between GAD, PTSD, SUD, and depression, and HIV diagnosis. Results were also stratified by age group, sex, and race/ethnicity. Overall, there were positive associations between SUD, depression, GAD, PTSD and HIV; and differences by age, sex and race/ethnicity existed in these associations. For example, after adjusting for age, race/ethnicity and marital status, men who were diagnosed with GAD were 10 times more likely (adjusted OR: 10.3; 95% CI: 8.75 - 12.1) to have an HIV diagnosis compared to men who were not diagnosed with GAD. Women who were diagnosed with GAD were five times more likely (adjusted OR: 5.01; 95% CI: 3.81 - 6.58) to have an HIV diagnosis compared to women who were not diagnosed with GAD. HIV prevention and intervention programs for older adults should address GAD, PTSD, SUD and depression and consider the age, sex and racial/ethnic disparities in the association between psychopathology and HIV.

Increases in HIV Incidence Following Receptive Anal Intercourse Among Women: A Systematic Review and Meta-analysis

Receptive anal intercourse (RAI) carries a greater per-act risk of HIV acquisition than receptive vaginal intercourse (RVI) and may influence HIV epidemics driven by heterosexual sex. This systematic review explores the association between RAI and incident HIV among women, globally. We searched Embase and Medline through September 2018 for longitudinal studies reporting crude (cRR) or adjusted (aRR) relative risks of HIV acquisition by RAI practice among women. Of 27,563 articles identified, 17 eligible studies were included. We pooled independent study estimates using random-effects models. Women reporting RAI were more likely to acquire HIV than women not reporting RAI (pooled cRR = 1.56 95% CI 1.03–2.38, N = 18, I² = 72%; pooled aRR = 2.23, 1.01–4.92, N = 5, I² = 70%). In subgroup analyses the association was lower for women in Africa (pooled cRR = 1.16, N = 13, I² = 21%) than outside Africa (pooled cRR = 4.10, N = 5, I² = 79%) and for high-risk (pooled aRR = 1.69, N = 4, I² = 63%) than general-risk women (pooled aRR = 8.50, N = 1). Interview method slightly influenced cRR estimates (p value = 0.04). In leave-one-out sensitivity analyses pooled estimates were generally robust to removing individual study estimates. Main limitations included poor exposure definition, incomplete adjustment for confounders, particularly condom use, and use of non-confidential interview methods. More and better data are needed to explain differences in risk by world region and risk population. Women require better counselling and greater choice in prevention modalities that are effective during RVI and RAI.

Condom Use, Multiple Rounds of Sex, and Alcohol Use Among South African Women Who Use Alcohol and Other Drugs: An Event-Level Analysis

BACKGROUND

High rates of alcohol and other drug use contribute to the ongoing generalized human immunodeficiency virus epidemic in South Africa. Despite the general link between alcohol use and condomless sex, findings from event-level studies of the relationship between alcohol use and condomless sex during the same encounter have been inconsistent.

METHODS

We conducted event-level analyses of the most recent sexual encounter reported by 636 women who use substances in Pretoria. Data were collected via a questionnaire that included questions about the number of rounds of vaginal and anal sex and condom use during each round. We used multiple logistic regression analyses to model the associations between alcohol use by both partners and having multiple rounds of sex, and alcohol use and condom use during all rounds of sex.

RESULTS

Over 50% of encounters involved multiple rounds of vaginal or anal sex. Encounters that involved multiple rounds of sex were associated with inconsistent condom use. Encounters in which both partners drank alcohol were more likely to involve condomless sex, as compared with encounters in which one or neither partner drank alcohol.

CONCLUSIONS

These findings raise the possibility that prior event-level studies, which do not ask about multiple rounds of sex, may underestimate the prevalence of condomless sex. The association between alcohol use by both partners and condomless sex may partially explain inconsistent associations between alcohol use and condom use in event-level studies that did not assess the number of partners drinking.

Extragenital chlamydia infection among active-duty women in the United States Navy

BACKGROUND

Pharyngeal and anorectal reservoirs of gonorrhea (GC) and chlamydia (CT) are increasingly recognized among heterosexual women. While a number of studies performed at sexually transmitted disease (STD) clinics have found a high prevalence of extragenital GC/CT infection, such screening is typically not offered during routine primary care visits for women. We sought to define the prevalence of and factors associated with extragenital GC/CT among women in the U.S. Navy.

METHODS

We recruited servicewomen stationed in San Diego, California, between the ages of 18 and 25 who presented for an annual physical exam between January and September, 2017. Nucleic acid amplification testing was performed on swabs collected at endocervical, oropharyngeal and anorectal sites to assess the presence of GC/CT. An anonymous behavioral questionnaire was also administered to characterize sexual risk. Descriptive statistics were used to compare women with and without a prior history of any sexually transmitted infection (STI) (self-report) along with a current GC/CT diagnosis. This study was approved by the Institutional Review Board of the Uniformed Services University of Health Sciences.

RESULTS

Of the 75 patients who were approached, 60 subjects were enrolled in the study, including white 20 (33.3%), black/African American 18 (31.0%), Hispanic/Latina 13 (21.7%) and Asian/Pacific Islander 9 (15.5%) women. Among all the women, six (10.0%) were diagnosed with CT infection, all via endocervical exam. Of these, five (8.3%) had concurrent anorectal infection, including two cases (3.3%) accompanied by pharyngeal infection. Of the subjects, 15 (25.0%) reported anal intercourse in their most recent sexual encounter, most of which was condomless (13/15, 86.7%). A high number of women who reported sex with a casual male partner (19/45, 42.2%) reported rarely or never using condoms; last, 41.7% consuming at least 3 drinks on a typical drinking day, and one-third of the reported drinking more than once per week.

CONCLUSIONS

We found a high prevalence of anorectal CT infection, although no infections were detected without concurrent endocervical involvement. Nonetheless, the high prevalence of condomless anal intercourse reported by participants argues for further study and ongoing consideration of extragenital screening among high-risk patients. Behavioral interventions are also warranted given the high prevalence of sexual and related risk factors.

Phase I trial of pod-intravaginal rings delivering antiretroviral agents for HIV-1 prevention: Rectal drug exposure from vaginal dosing with tenofovir disoproxil fumarate, emtricitabine, and maraviroc

BACKGROUND

Intravaginal rings (IVRs) can deliver antiretroviral (ARV) agents for HIV pre-exposure prophylaxis (PrEP), theoretically overcoming adherence concerns associated with frequent dosing. However, topical vaginal ARV drug delivery has not simultaneously led to sufficient rectal drug exposure to likely protect from HIV infection as a result of receptive anal intercourse (RAI). Unprotected RAI has a higher risk of infection per sex act and, for women, also can be associated with vaginal exposure during a single sexual encounter, especially in higher-risk subsets of women. The physiologically inflamed, activated, immune-cell dense colorectal mucosa is increasingly appreciated as the sexual compartment with highly significant risk; this risk is increased in the setting of co-infections. Ex vivo studies have shown that colorectal tissue and rectal fluid concentrations correlated with HIV protection. Given these important results, efforts to document colorectal compartment ARV drug concentration from pod-IVR delivery was assessed to determine if vaginal application could provide protective ARV levels in both compartments.

METHODOLOGY/PRINCIPAL FINDINGS

A crossover clinical trial (N = 6) evaluated 7 d of continuous TDF pod-IVR use, a wash-out phase, followed by 7 d with a TDF-FTC pod-IVR. A subsequent clinical trial (N = 6) consisted of 7 d of continuous TDF-FTC-MVC pod-IVR use. Rectal fluids were collected on Day 7 at IVR removal in all three ARV-exposures (two Phase 1 trials) and drug concentrations quantified by LC-MS/MS. Median rectal fluid concentrations of TFV, the hydrolysis product of the prodrug TDF, were between 0.66 ng mg-1 (TDF pod-IVR group) and 1.11 ng mg-1 (TDF-FTC pod-IVR group), but below the analytical lower limit of quantitation in 5/6 samples in the TDF-FTC-MVC pod-IVR group. Unexpectedly, median FTC (TDF-FTC pod-IVR, 20.3 ng mg-1; TDF-FTC-MVC pod-IVR, 0.18 ng mg-1), and MVC rectal fluid concentrations (0.84 ng mg-1) were quantifiable and higher than their respective in vitro EC50 values in most samples. Due to participant burden in these exploratory trials, rectal fluid was used as a surrogate for rectal tissue, where drug concentrations are expected to be higher.

CONCLUSIONS/SIGNIFICANCE

The concentrations of FTC and MVC in rectal fluids obtained in two exploratory clinical trials of IVRs delivering ARV combinations exceeded levels associated with in vitro efficacy in HIV inhibition. Unexpectedly, MVC appeared to depress the distribution of TFV and FTC into the rectal lumen. Here we show that vaginal delivery of ARV combinations may provide adherence and coitally independent dual-compartment protection from HIV infection during both vaginal and receptive anal intercourse.

Transcutaneously refillable nanofluidic implant achieves sustained level of tenofovir diphosphate for HIV pre-exposure prophylaxis

Pre-exposure prophylaxis (PrEP) with antiretroviral (ARV) drugs are effective at preventing human immunodeficiency virus (HIV) transmission. However, implementation of PrEP presents significant challenges due to poor user adherence, low accessibility to ARVs and multiple routes of HIV exposure. To address these challenges, we developed the nanochannel delivery implant (NDI), a subcutaneously implantable device for sustained and constant delivery of tenofovir alafenamide (TAF) and emtricitabine (FTC) for HIV PrEP. Unlike existing drug delivery platforms with finite depots, the NDI incorporates ports allowing for transcutaneous refilling upon drug exhaustion. NDI-mediated drug delivery in rhesus macaques resulted in sustained release of both TAF and FTC for 83 days, as indicated by concentrations of TAF, FTC and their respectively metabolites in plasma, PBMCs, rectal mononuclear cells and tissues associated with HIV transmission. Notably, clinically relevant preventative levels of tenofovir diphosphate were achieved as early as 3 days after NDI implantation. We also demonstrated the feasibility of transcutaneous drug refilling to extend the duration of PrEP drug delivery in NHPs. Overall, the NDI represents an innovative strategy for long-term HIV PrEP administration in both developed and developing countries.

Incursions from the epicentre: Southern theory, social science, and the global HIV research domain

Research about HIV constitutes a global domain of academic knowledge. The patterns that structure this domain reflect inequalities in the production and dissemination of knowledge, as well as broader inequalities in geopolitics. Conventional metrics for assessing the value and impact of academic research reveal that "Northern" research remains dominant, while "Southern" research remains peripheral. Southern theory provides a framework for greater critical engagement with knowledge produced by researchers within the global South. With a focus on HIV social science, we show that investigators working in and from Africa have produced and disseminated knowledge fundamental to the global domain of HIV research, and argue that their epistemological contribution may be understood within the framework of Southern theory. Through repurposing a bibliometrical measure of citation count, we constitute a new archive of highly cited social science research. With a focus on South Africa, we situate this archive within changing historical contexts, connecting research findings to developments in medicine, health sciences and politics. We focus on two key themes in the evolution of HIV knowledge: (1) the significance of context and locality - the "setting" of HIV research; and (2) sex, race and risk - changing ideas about the social determinants of HIV transmission.

The Strategies of Heterosexuals from Large Metropolitan Areas for Assessing the Risks of Exposure to HIV or Other Sexually Transmitted Infections from Partners Met Online

Heterosexuals' use of the Internet for meeting romantic or sexual partners is rapidly increasing, raising concerns about the Internet's potential to facilitate encounters that place individuals at risk for acquiring HIV or other sexually transmitted infections (STIs). For example, online sharing of personal information and self-revelations can foster virtual intimacy, promoting a false sense of familiarity that might accelerate progression to unprotected sex. Therefore, it is critical to understand how those who meet sexual partners online attempt to assess the possible risk of acquiring HIV or STIs posed by having unprotected sex with a new partner and decide whether to use a condom. To investigate this issue, in-depth interviews were conducted with a diverse sample of heterosexual male and female participants from large metropolitan cities who had had unprotected vaginal or anal sex with at least two partners met online in the past 3 months. With few exceptions, participants relied on faulty strategies and heuristics to estimate these risks; yet, most engaged in unprotected sex at their first meeting or very soon afterward. While some seemed to try to make a genuine effort to arrive at a reliable assessment of the HIV risk posed, most appeared to be looking for a way to justify their desire and intention to have unprotected sex. The findings suggest the need for more HIV and sexual health education targeted at heterosexuals, especially for those who go online to meet partners.

Prevalence and Correlates of Heterosexual Anal Intercourse Among Men and Women, 20 U.S. Cities

Heterosexual anal intercourse (HAI) is not an uncommon behavior and it confers a higher risk of HIV transmission than vaginal intercourse. We examined data from heterosexuals recruited in 20 US cities for the 2013 National HIV Behavioral Surveillance system. We assessed correlates of reporting HAI in the previous year. Then, among people reporting HAI in the past year, we assessed what event-level factors are associated with having HAI at last sex. Thirty percent of women and 35 % of men reported HAI in the past year. Among people who had HAI in the past year, those who had HAI at last sex were more likely to have a partner who was HIV-positive or of unknown status or to have exchanged money or drugs for sex at last sex. Information that highlights the risk of HIV transmission associated with HAI would complement existing HIV prevention messages focused on heterosexuals in the U.S.

Contextual Factors Surrounding Anal Intercourse in Women: Implications for Sexually Transmitted Infection/HIV Prevention

BACKGROUND

Our objectives were to describe women's reasons for engaging in anal intercourse (AI), contextual factors surrounding AI, and how these vary by current rectal sexually transmitted infection (STI) status, and to assess women's knowledge and concerns about rectal infections.

METHODS

Between January 2011 and June 2013, we conducted semistructured, qualitative interviews among 40 women attending public sexually transmitted disease clinics in Los Angeles County, California. Women were eligible if they were at least 18 years of age, reported AI in the past 90 days, and were tested for rectal Chlamydia trachomatis and Neisseria gonorrhoeae. Interviews, which were guided by the theory of gender and power, were transcribed and coded to explore contextual factors surrounding AI.

RESULTS

On average, participants reported having 3 AI partners in their lifetime and most (n = 30) reported being in a serious relationship with a main/regular sex partner at the time of the interview. Motivations for engaging in AI and feelings about AI varied by rectal STI status. Women with a rectal STI more prominently conveyed the idea that AI was intended to please their sexual partner, whereas those who did not have a rectal STI reported AI more as a way to increase intimacy and personal sexual gratification. Almost all women (regardless of rectal STI status) reported limited to no knowledge about the risk of rectal STIs.

CONCLUSIONS

Among women, risk of acquiring rectal STIs may vary by reason for engaging in unprotected AI as well as other contextual factors. Providers should consider addressing these contextual factors to reduce risk.

Animal and human mucosal tissue models to study HIV biomedical interventions: can we predict success?

Introduction

Preclinical testing plays an integral role in the development of HIV prevention modalities. Several models are used including humanized mice, non-human primates and human mucosal tissue cultures.

Discussion

Pharmaceutical development traditionally uses preclinical models to evaluate product safety. The HIV prevention field has extended this paradigm to include models of efficacy, encompassing humanized mice, non-human primates (typically Asian macaques) and human mucosal tissue (such as cervical and colorectal). As our understanding of the biology of HIV transmission improves and includes the influence of human behaviour/biology and co-pathogens, these models have evolved as well to address more complex questions. These three models have demonstrated the effectiveness of systemic (oral) and topical use of antiretroviral drugs. Importantly, pharmacokinetic/pharmacodynamic relationships are being developed and linked to information gathered from human clinical trials. The models are incorporating co-pathogens (bacterial and viral) and the effects of coitus (mucosal fluids) on drug distribution and efficacy. Humanized mice are being tailored in their immune reconstitution to better represent humans. Importantly, human mucosal tissue cultures are now being used in early clinical trials to provide information on product efficacy to more accurately characterize efficacious products to advance to larger clinical trials. While all of these models have made advancements in product development, each has limitations and the data need to be interpreted by keeping these limitations in mind.

Conclusions

Development and refinement of each of these models has been an iterative process and linkages to data generated among each of them and from human clinical trials are needed to determine their reliability. Preclinical testing has evolved from simply identifying products that demonstrate efficacy prior to clinical trials to defining essential pharmacokinetic/pharmacodynamic relationships under a variety of conditions and has the potential to improve product selection prior to the initiation of large-scale human clinical trials. The goal is to provide researchers with ample information to make conversant decisions that guide optimized and efficient product development.

The rational design and development of a dual chamber vaginal/rectal microbicide gel formulation for HIV prevention

The DuoGel™ was developed for safe and effective dual chamber administration of antiretroviral drugs to reduce the high incidence of HIV transmission during receptive vaginal and anal intercourse. The DuoGel™s containing IQP-0528, a non-nucleoside reverse transcriptase inhibitor (NNRTI), were formulated from GRAS excipients approved for vaginal and rectal administration. The DuoGel™s were evaluated based upon quantitative physicochemical and biological evaluations defined by a Target Product Profile (TPP) acceptable for vaginal and rectal application. From the two primary TPP characteristics defined to accommodate safe rectal administration three DuoGel™ formulations (IQB3000, IQB3001, and IQB3002) were developed at pH 6.00 and osmolality ⩽400mmol/kg. The DuoGel™s displayed no in vitro cellular or bacterial toxicity and no loss in viability in ectocervical and colorectal tissue. IQB3000 was removed from consideration due to reduced NNRTI delivery (∼65% reduction) and IQB3001 was removed due to increase spread resulting in leakage. IQB3002 containing IQP-0528 was defined as our lead DuoGel™ formulation, possessing potent activity against HIV-1 (EC50=10nM). Over 12month stability evaluations, IQB3002 maintained formulation stability. This study has identified a lead DuoGel™ formulation that will safely deliver IQP-0528 to prevent sexual HIV-1 transmission in the vagina and rectum.

Safety and efficacy of tenofovir/IQP-0528 combination gels - a dual compartment microbicide for HIV-1 prevention

Tenofovir (TFV) is a nucleotide reverse transcriptase inhibitor and IQP-0528 is a non-nucleoside reverse transcriptase inhibitor that also blocks virus entry. TFV and IQP-0528 alone have shown antiviral activity as microbicide gels. Because combination therapy will likely be more potent than mono-therapy, these drugs have been chosen to make a combination microbicide gel containing 2.5% TFV/1% IQP-0528. Safety and efficacy testing was done to evaluate five prototype combination gels. The gels retained TZM-bl cell and ectocervical and colorectal tissue viability. Further, the epithelium of the ectocervical and colorectal tissue remained intact after a 24h exposure. The ED(50) calculated from the formulations for IQP-0528 was ~32nM and for TFV was ~59nM and their inhibitory activity was not affected by semen. The ED(50) of TFV in the combination gels was ~100-fold lower than when calculated for the drug substance alone reflecting the activity of the more potent IQP-0528. When ectocervical and colorectal tissue were treated with the combination gels, HIV-1 p24 release was reduced by ≥1log(10) and ≥2log(10), respectively. Immunohistochemistry for the ectocervical tissues treated with combination gels showed no HIV-1 infected cells at study end. With the increased realization of receptive anal intercourse among heterosexual couples often in conjunction with vaginal intercourse, having a safe and effective microbicide for both mucosal sites is critical. The safety and efficacy profiles of the gels were similar for ectocervical and colorectal tissues suggesting these gels have the potential for dual compartment use.