Biomedical Approaches to HIV Prevention in Women

Preferences for Long-Acting PrEP Products Among Women and Girls: A Quantitative Survey and Discrete Choice Experiment in Eswatini, Kenya, and South Africa

While oral pre-exposure prophylaxis (PrEP) can substantially reduce HIV risk, there are important barriers to uptake and adherence. We explored preferences for long-acting injectable and implantable PrEP among women and girls in Eswatini, Kenya, and South Africa. We conducted an online quantitative survey and discrete choice experiment (DCE) among adolescent girls (15-17), young women (18-29), and adult women (30-49). Participants completed a survey about their demographics and behavior and a DCE with 5 attributes (format, insertion location, number of insertions, dual-protection, and palpability). We recruited 1236 respondents (Eswatini = 420; Kenya = 350; South Africa = 493) in May 2022. Most participants were sexually active (72%), nearly 29% of whom reported recently engaging in transactional sex. 46% had heard of oral PrEP, but of those, only 16% reported having ever used it. Product format and dual-protection were significant predictors of product choice. Relative to a 2-month injection, participants had 1.76 times the odds (95% CI 1.08-2.04) of choosing a 6-month injectable, and 1.70 the odds (95% CI 1.06-1.92) of choosing a 12-month removable implant. Compared to a single-indication product, respondents had 2.46 times the odds (95% CI 1.04-2.68) of preferring a product also protecting against pregnancy, and 2.81 the odds (95% CI 1.04-3.05) of choosing a product that also protected against STIs. Adolescent girls and women in these countries showed strong preferences for longer-acting PrEP product formats, as well as those offering dual-protection. Introduction of long-acting options could improve PrEP uptake and reduce HIV burdens in east and southern African settings.

Sexually transmitted infections and female reproductive health

Women are disproportionately affected by sexually transmitted infections (STIs) throughout life. In addition to their high prevalence in women, STIs have debilitating effects on female reproductive health due to female urogenital anatomy, socio-cultural and economic factors. In this Review, we discuss the prevalence and impact of non-HIV bacterial, viral and parasitic STIs on the reproductive and sexual health of cisgender women worldwide. We analyse factors affecting STI prevalence among transgender women and women in low-income settings, and describe the specific challenges and barriers to improved sexual health faced by these population groups. We also synthesize the latest advances in diagnosis, treatment and prevention of STIs.

Women are more affected by sexually transmitted infections than men. This Review examines the impact of non-HIV STIs on women’s health, and discusses recent advances and current challenges in the treatment and prevention of STIs.

Contribution of Sex Differences to HIV Immunology, Pathogenesis, and Cure Approaches

Approximately 38 million people were living with human immunodeficiency virus (HIV) in 2020 and 53% of those infected were female. A variety of virological and immunological sex-associated differences (sexual dimorphism) in HIV infection have been recognized in males versus females. Social, behavioral, and societal influences play an important role in how the HIV pandemic has affected men and women differently. However, biological factors including anatomical, physiologic, hormonal, and genetic differences in sex chromosomes can each contribute to the distinct characteristics of HIV infection observed in males versus females. One striking example of this is the tendency for women to have lower HIV plasma viral loads than their male counterparts early in infection, though both progress to AIDS at similar rates. Sex differences in acquisition of HIV, innate and adaptive anti-HIV immune responses, efficacy/suitability of specific antiretroviral drugs, and viral pathogenesis have all been identified. Sex differences also have the potential to affect viral persistence, latency, and cure approaches. In this brief review, we summarize the major biological male/female sex differences in HIV infection and their importance to viral acquisition, pathogenesis, treatment, and cure efforts.

Impact of Dapivirine and Placebo Vaginal Rings on the Microbiota of Adolescent, Lactating, and Postmenopausal Females

BACKGROUND

A 25 mg dapivirine vaginal ring has been demonstrated to reduce risk of HIV acquisition in nonpregnant adult women. In this secondary analysis of studies conducted in US adolescent, lactating, and postmenopausal females, vaginal microbiota was assessed prior to and after ring use, and between dapivirine and placebo ring users.

METHODS

Vaginal fluid swabs were collected before and after product use for the evaluation of microbiota using Nugent's criteria, quantitative culture, and qPCR.

RESULTS

Vaginal ring use did not impact bacterial vaginosis prevalence among the three populations and was associated with minimal shifts in microbiota. Adolescents in both arms demonstrated an increased prevalence of Lactobacillus crispatus and a decrease in quantity of Megasphaera lornae. Postmenopausal active and placebo ring users demonstrated an increased prevalence of lactobacilli and non-albicans yeast while dapivirine ring users demonstrated an increased prevalence of Candida albicans, and increased quantity of Group B Streptococcus (GBS) and non-albicans yeasts. Prevotella species were increased in lactating women while P. timonensis increased in prevalence and concentration among adolescent and postmenopausal women and P. bivia increased in prevalence among adolescent dapivirine ring users.

CONCLUSIONS

Dapivirine vaginal ring use was associated with minimal changes in the vaginal microbiota that are likely not clinically significant.

Acceptability of a Tenofovir Disoproxil Fumarate Intravaginal Ring for HIV Pre-Exposure Prophylaxis Among Sexually Active Women

INTRODUCTION

Vaginal ring delivery of antiretroviral drugs may provide protection against acquisition of HIV-1 when used as Pre-Exposure prophylaxis. As part of a randomized placebo-controlled safety trial of a tenofovir disoproxil fumarate (TDF) intravaginal ring (IVR), we assessed product acceptability through surveys of women after continuous ring use.

METHODS

Sexually active, HIV-negative women were enrolled to investigate the safety and pharmacokinetics of 3 months of continuous TDF IVR use. The study was designed to include 40 US participants randomly assigned (3:1) to a TDF or placebo IVR. Twelve were randomized to TDF and 5 to the placebo group before the study was electively discontinued because of the development of vaginal ulcerations in 8 women in the TDF group. Acceptability data were gathered via self-administered, computer-based questionnaires.

RESULTS

The average age of the 17 participants was 31 years (range, 18-42 years). Sixteen participants (94%) completed all questions at 2 study visits. When asked about ring likeability after 1 month of ring use, 12 (75%) of 16 reported overall liking the ring, including 6 (75%) of 8 who developed ulcerations. In addition, 10 (83%) of 12 who had their menses during the first month of ring use were not bothered by the ring, and 11 (69%) of 16 stated that the ring was not bothersome with use during sex.

CONCLUSIONS

Despite unanticipated ulcers, TDF and placebo IVRs were acceptable to some women, even when used with menses and during sex, which is promising for continued development of IVRs for HIV prevention.

Integrating Economic Evaluation and Implementation Science to Advance the Global HIV Response

BACKGROUND

Numerous cost-effectiveness analyses have indicated good value for money from a wide array of interventions for treatment and prevention of HIV/AIDS. There is limited evidence, however, regarding how cost-effectiveness information contributes to better decision-making around investment and action in the global HIV response.

METHODS

We review challenges for economic evaluation relevant to the global HIV response and consider how the practice of cost-effectiveness analysis could integrate approaches and insights from implementation science to enhance the impact and efficiency of HIV investments.

RESULTS

In light of signals that cost-effectiveness analyses may be vulnerable to systematic bias toward overly optimistic conclusions, we emphasize two priorities for advancing the field of economic evaluation in HIV/AIDS and more broadly in global health: (1) systematic reevaluation of the cost-effectiveness literature with reference to ex-post empirical evidence on costs and effects in real-world programs and (2) development and adoption of good-practice guidelines for incorporating implementation and delivery aspects into economic evaluations. Toward the latter aim, we propose an integrative approach that focuses on comparative evaluation of strategies, which specify both technologies/interventions as well as the delivery platforms, complementary interventions, and actions needed to increase coverage, quality, and uptake of those technologies/interventions. Specific recommendations draw on several existing implementation science models that provide systematic frameworks for understanding implementation barriers and enablers, designing and choosing specific implementation and policy actions, and evaluating outcomes.

DISCUSSION

These preliminary steps aimed at bridging the divide between economic evaluation and implementation science can help to advance the practice of economic evaluation toward a science of comparative strategy evaluation.