TYPE Review PUBLISHED 06 December 2022 DOI 10.3389/fimmu.2022.1055042 Women for science and science OPEN ACCESS for women: Gaps, challenges EDITED BY Susan Prockop, Boston Children’s Hospital and and opportunities towards Harvard Medical School, United States REVIEWED BY optimizing pre-exposure Connie Celum, University of Washington, United States prophylaxis for HIV-1 prevention Maud Mavigner, School of Medicine, Emory University, United States Quarraisha Abdool Karim 1,2, Derseree Archary 1,3, *CORRESPONDENCE Françoise Barré-Sinoussi 4, Kristina Broliden 5, Cecilia Cabrera 6, Carolina Herrera Francesca Chiodi 7, Sarah J. Fidler 8, Tanuja N. Gengiah 1, cherrer1@imperial.ac.uk Carolina Herrera 9*, Ayesha B. M. Kharsany 1,3, SPECIALTY SECTION This article was submitted to Lenine J. P. Liebenberg 1,3, Sharana Mahomed 1, Viral Immunology, a section of the journal Elisabeth Menu 10,11, Christiane Moog 12, Gabriella Scarlatti 13, Frontiers in Immunology Nabila Seddiki 10, Aida Sivro 1,3,14 and Mariangela Cavarelli 10 RECEIVED 27 September 2022 on behalf of FEMIN and CAPRISA ACCEPTED 11 November 2022 PUBLISHED 06 December 2022 1 Centre for the AIDS Programme of Research in South Africa (CAPRISA), Doris Duke Medical Research Institute (2Floor), Nelson R Mandela School of Medicine, University of KwaZulu-Natal, CITATION Durban, South Africa, 2 Department of Epidemiology, Mailman School of Public Health, Columbia Karim QA, Archary D, Barré-Sinoussi F, University, New York, NY, United States, 3 Department of Medical Microbiology, School of Broliden K, Cabrera C, Chiodi F, Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa, Fidler SJ, Gengiah TN, Herrera C, 4 Institut Pasteur, Paris, France, 5 Department of Medicine Solna, Division of Infectious Diseases, Kharsany ABM, Liebenberg LJP, Mahomed S, Menu E, Moog C, Karolinska Institutet, Department of Infectious Diseases, Karolinska University Hospital, Center for Scarlatti G, Seddiki N, Sivro A and Molecular Medicine, Stockholm, Sweden, 6 AIDS Research Institute IrsiCaixa, Institut de Recerca en Cavarelli M (2022) Women for science Ciències de la Salut Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat and science for women: Gaps, Autònoma de Barcelona, Barcelona, Spain, 7 Department of Microbiology, Tumor and Cell Biology, challenges and opportunities towards Karolinska Institutet, Stockholm, Sweden, 8 Department of Infectious Disease, Faculty of Medicine, optimizing pre-exposure prophylaxis Imperial College London UK and Imperial College NIHR BRC, London, United Kingdom, for HIV-1 prevention. 9 Department of Infectious Disease, Section of Virology, Faculty of Medicine, Imperial College London, Front. Immunol. 13:1055042. London, United Kingdom, 10Université Paris-Saclay, Inserm, CEA, Center for Immunology of Viral, Auto- doi: 10.3389/fimmu.2022.1055042 immune, Hematological and Bacterial diseases (IMVA-HB/IDMIT), Fontenay-aux-Roses & Le Kremlin- Bicêtre, France, 11MISTIC Group, Department of Virology, Institut Pasteur, Paris, France, 12Laboratoire COPYRIGHT d’ImmunoRhumatologie Moléculaire, Institut national de la santé et de la recherche médicale (INSERM) © 2022 Karim, Archary, Barré-Sinoussi, UMR_S 1109, Institut thématique interdisciplinaire (ITI) de Médecine de Précision de Strasbourg, Broliden, Cabrera, Chiodi, Fidler, Transplantex NG, Faculté de Médecine, Fédération Hospitalo-Universitaire OMICARE, Fédération de Gengiah, Herrera, Kharsany, Liebenberg, Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France, 13Viral Mahomed, Menu, Moog, Scarlatti, Evolution and Transmission Unit, IRCCS Ospedale San Raffaele, Milan, Italy, 14JC Wilt Infectious Disease Seddiki, Sivro and Cavarelli. This is an Research Centre, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, open-access article distributed under Canada the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright Preventing new HIV infections remains a global challenge. Young women owner(s) are credited and that the original publication in this journal is continue to bear a disproportionate burden of infection. Oral pre-exposure cited, in accordance with accepted prophylaxis (PrEP), offers a novel women-initiated prevention technology and academic practice. No use, PrEP trials completed to date underscore the importance of their inclusion distribution or reproduction is permitted which does not comply with early in trials evaluating new HIV PrEP technologies. Data from completed these terms. topical and systemic PrEP trials highlight the role of gender specific physiological and social factors that impact PrEP uptake, adherence and efficacy. Here we review the past and current developments of HIV-1 Frontiers in Immunology 01 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 prevention options for women with special focus on PrEP considering the diverse factors that can impact PrEP efficacy. Furthermore, we highlight the importance of inclusion of female scientists, clinicians, and community advocates in scientific efforts to further improve HIV prevention strategies. KEYWORDS HIV, women, prevention, gender equity, PrEP, mucosal transmission, inflammation, microbiome Introduction Importantly as girls transition from teenagers to adulthood and undergo substantial psychosocial, cognitive, and emotional In 2021, among the estimated 38.4 million people living with changes their vulnerability to HIV is enhanced through HIV-1, 54% were adolescent girls and women (1) and HIV/AIDS multiple complex and diverse structural, social, behavioral, remains the third leading cause of death globally for women aged and biological co-factors (9–11). Typically, young women 15 to 49 years (2). In 2021 girls and women accounted for 49% of have the least amount of power and their HIV risk intersects all new infections globally, a frequency that peaked to 63% in sub- with poverty, race and geospatial location with those in low- Saharan Africa, where six in seven new HIV infections among middle income countries bearing the brunt of HIV infection. adolescents aged 15–19 years were among girls (1). In those Notwithstanding, appropriate information, education, settings, girls and young women aged 15 to 24 years are twice guidance, and support could help young girls transition as likely to be living with HIV compared to their male peers (1). In through this volatile developmental period (9). Risk South Africa, women acquire HIV infection at a younger age, 5 to reduction programs in schools are crucial to promote healthy 7 years before men and are at four times higher risk (3). South behaviors and help develop young people’s identities to Africa is also among the countries with the highest number of enhance self-esteem and rational decision making to towards pregnant women living with HIV (over one-third), contributing to safer adulthood (12). A high proportion of young girls are the highest number of infants born with HIV (4, 5). already sexually active (13), and already have a high prevalence Gender inequalities, including unsafe and non-consenting of HIV infection. Sexual debut is associated with high rates of sex, exacerbate girls’ and women’s physiological vulnerability to unintended pregnancies, sexually transmitted infections HIV together with limited HIV prevention options for women (STIs), increased HIV acquisition rates and often leads to and/or access to health services play an important role in poor school completion rates, and in the longer term poorer contributing to increased HIV risk. Furthermore, domestic health and economic outcomes among young girls (12, 14, 15). violence against women worldwide greatly intensified during Schools and primary care clinics where health services are the COVID-19 pandemic (6). This was accompanied by a sought, provide opportunities to establish what proportion of reduced access to medical care, including HIV treatment and sexual activity is consensual and for increasing co-parenting prevention, as well as sexual and reproductive services. responsibility particularly in teenage pregnancies. Often, young people are denied the information about their Although women comprise nearly half of people living with own sexual and reproductive health and rights, with most HIV, they continue to be largely under-represented in HIV lacking the knowledge required to protect themselves from clinical studies particularly if pregnant or lactating or HIV. This is further compounded by an individuals’ adolescents thereby creating important data gaps and delays in perception of risk. Most persons susceptible to contract HIV safety and efficacy data for those at highest risk of acquiring HIV. do not perceive themselves at high risk. Women may have A systematic literature review conducted in 2016 reported that limited awareness of their partners sexual behaviors, thereby women represented a median of 19.2% participants in underestimating their own HIV risk, or may feel shame or fear antiretroviral treatment/PrEP studies, 38.1% in prophylactic being stigmatized for disclosing their true HIV risk. Self- vaccines studies, and 11.1% in HIV cure strategies studies (16). assessment of risk is challenging when reflecting on intimate This is partially due to the fact that a large proportion of HIV relationships and in settings of intimate partner violence for clinical trials and cure-related research taking place in resource instance, women might feel uncomfortable to discuss or sufficient countries mainly enroll men who have sex with men acknowledge their own risk. The impact of these barriers is (MSM). In these settings enrolling women is difficult not only strongest in high-HIV prevalence settings, predominantly in because MSM represent 80% of the persons living with HIV, but eastern and southern Africa (7, 8). also because of the greater stigma affecting women living with Frontiers in Immunology 02 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 HIV compared to men. In contrast the majority of clinical trial This review has been drafted by female scientists belonging participants in low-middle income countries enroll cis-women. to FEMIN (a network of European female scientists and This under-representation of women included in clinical clinicians with a common interest in mucosal immunology trials generates substantial gaps in our understanding of gender and STIs including HIV-1) and CAPRISA (Centre for the differences in virological, immunological and clinical AIDS Programme of Research in South Africa, a consortium presentation of HIV infection geo-spatially. Importantly, when of five institutions in South Africa and the US). Our common efficacious prevention and treatment products become available, interest is accelerating and expanding evidence-based women- they are used globally despite these gaps in knowledge. In initiated HIV prevention and treatment technologies and to addition, the effect of clinical interventions (safety and amplify the voices of advocates to advance the research agenda efficacy) can differ because of sex/gender. Yet, current towards greater inclusivity in the knowledge generation process guidelines for using antiretroviral treatments do not from conception, to the design and conduct of clinical studies distinguish between men and women, apart from some studies and rapid implementation of efficacious products to address the conducted in pregnant and post-partum women, from whom we needs of all people at HIV risk or living with HIV. have even less information available. Given that women bear a disproportionate higher risk for HIV infection and that their biology differs from those of men, Currently available HIV prevention here we discuss the biological factors affecting the effectiveness of strategies in women pre-exposure prophylaxis (PrEP) in women and the importance of including women in HIV prevention clinical trials. The development of technologies that empower women to Furthermore, we discuss how the outcomes of these studies protect themselves from HIV remains an essential tool in the would greatly benefit from a better understanding of the fight against the HIV epidemic, particularly in high prevalence immunobiological mechanisms of HIV infection and regions such as in sub-Saharan Africa. Since July 2010, when pathogenesis. To conclude, we emphasize the antiretrovirals (ARVs) were first shown by the CAPRISA 004 underrepresentation of female scientists in STEM disciplines trial (17) to prevent sexual transmission of HIV, the HIV and the important role they could play, together with advocates prevention landscape has been transformed, principally and regulatory bodies, in the design and implementation of HIV through oral and topical tenofovir (TFV)-containing PrEP clinical research to advance the field more equitably (Figure 1). (18–23) including the more recent expansion of provider While here we mostly focused on PrEP studies conducted in sub- initiated PrEP options or through early antiretroviral therapy Saharan Africa, this article aims to give voice to women from (ART) initiation in HIV-positive individuals (Treatment as every region of the world and to promote global women’s health. Prevention [TasP]) (24). FIGURE 1 Identification of the gaps to optimize HIV-1 prevention in women. FGT, female genital tract; bNAbs, broad neutralizing antibodies; STI, sexually transmitted infections; ARV, antiretrovirals. Frontiers in Immunology 03 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 PrEP in cis-gender women highlighting that the threshold for drug efficacy is higher in women (17). Efficacy data from completed trials conducted in cis-gender The red algae-derived lectin Q-Griffithsin, when formulated women are summarized in Figure 2. as a vaginal gel, protected Rhesus macaques from a high dose vaginal challenge (32) and was safe in a phase 1, randomized, Topical and oral PrEP placebo-controlled first-in-human trial (33). The results of clinical trials of topical and daily oral PrEP in An in-depth knowledge of the various elements of African women have been inconsistent, most likely due to microbicide acceptability in various cultural contexts is crucial varying adherence and biology (20–23). since acceptability is likely to be a major factor in the actual use While the CAPRISA 004 trial demonstrated partial of PrEP by women, with consequences on adherence and anti- protection with TFV gel used before and after sex in which viral efficacy. This entails investigating acceptability not only in HIV infection was reduced by approximately 39% overall, and terms of product-related issues but also of women’s capacity to by 54% in women with high adherence to the protocol (17), the negotiate the use of PrEP with their partners. Results from a follow on trial FACT001 showed no difference in risk of Phase II study of 1% TFV topical gel as part of the HIV infection between active and placebo groups (25). In a Prevention Trials Network (HPTN) 059 suggested that subgroup analysis consisting of 214 FACTS participants in the microbicides were more acceptable in coitally-associated users TFV-treated group, having high tenofovir drug levels in genital than in daily users (34). However, on demand (event-driven) fluids was significantly associated with a 48% lower risk of HIV and daily PrEP in women have raised significant concerns acquisition. In the VOICE trial none of the evaluated drug about feasibility and acceptability affecting adherence and regimens reduced the rate of HIV acquisition in an intention- whether it can achieve the higher drug level threshold required to-treat analysis however, adherence was suboptimal: only 25%, in women compared to men (35). 29%, and 30% of women allocated to the daily TFV gel, daily oral Daily oral TDF/FTC has been demonstrated to be tenofovir disoproxil fumarate and emtricitabine (TDF/FTC) and consistently effective in MSM and trans-gender women daily oral TDF groups respectively had detectable drug levels globally (18, 19) and is highly efficacious for HIV prevention (23). While TDF/FTC provides high level of protection from among women if taken with high, but not perfect, adherence. rectal exposure, even with intermittent usage (29), vaginal Similarly to what observed for the VOICE trial, in the FEM- protection appears to require dosing with greater fidelity to PREP trial only 24% of the women allocated to the daily oral achieve and maintain high drug levels needed for protection. PK TDF/FTC group had detectable drug levels, confirming that lack studies have documented significant heterogeneity in active drug of protective effect can partially be explained by suboptimal concentrations between mucosal tissues that may partially adherence (22). In a sub-group analysis of the Partners PrEP explain the disparities in effectiveness between men and Study conducted in women at higher risk for HIV-1 acquisition, women. After a single oral dose of TFV, active drug efficacy point estimates ranging from 64% to 84%. Monthly concentration in the FGT was 100-fold lower compared to the clinic attendance for PrEP refills was > 94% and TFV detection gastrointestinal tissues, and it takes 7–14 days of dosing to reach in plasma was high (> 70%) (36). Interestingly, the Bangkok protective FGT concentrations (30). Although we do not know Tenofovir Study evaluating oral daily use of TDF in male and the effective tissue concentration required to prevent HIV female drug users, reported 79% efficacy in women and was infection, less than 1000 ng/ml of TFV in CVF was associated associated with the highest rates of adherence (66% by with no significant protection in CAPRISA 004 (31), females) (37). FIGURE 2 Effectiveness of PrEP in cis-gender women (17, 20–23, 25–28). *Subgroup analysis of effectiveness by gender, (TDF,Tenofovir disoproxil fumarate; FTC, Emtricitabine; DPV, Dapivirine; CAB LA, Cabotegravir long acting). Frontiers in Immunology 04 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 The DISCOVERY study, evaluating the combination of confidence interval (CI), 1 to 46; p=0.046) than that in the tenofovir alafenamide and emtricitabine (TAF/FTC), did not placebo group (26). In a post-hoc analysis, higher rates of HIV enroll cis-gender women, therefore the drug is not approved for protection were observed among women over the age of 21 years use in this population. Considering the unfavorable results of (56%; 95% CI, 31 to 71; p<0.001) but not among those 21 years of initial clinical studies and the availability of new drugs, cis- age or younger (-27%; 95% CI, -133 to 31; p=0.45), a difference gender women should definitively be included in new clinical that was correlated with reduced adherence (26). In the RING trial of PrEP efficacy. Gilead currently has an ongoing trial trial the incidence of HIV-1 infection was 31% lower in the evaluating the efficacy of oral TAF/FTC in adolescent girls and dapivirine group than in the placebo group (hazard ratio, 0.69; young women as part of their “Women’s HIV Prevention 95% CI, 0.49 to 0.99; p=0.04), however there was no significant Study” (38). difference in efficacy of the dapivirine ring among women older Adherence and persistence are crucial and engaging women than 21 years of age compared to those 21 years of age or younger in PrEP may be particularly challenging, likely due to the for treatment-by-age interaction (27). A secondary analysis from difficulty of taking daily medication. In the HIV Prevention these studies indicated the potential for a substantial reduction in Trials Network (HPTN) 082 trial, PrEP initiation was high and the risk of HIV-1 acquisition – greater than 50%, and potentially half of study participants persisted with PrEP through month 12, as high as 75% to 91% – in women who consistently use the ring resulting in 1% HIV incidence in this cohort (39). Thus, while (48). The WHO formulated a conditional recommendation strategies to support PrEP use and less adherence-dependent supporting the use of dapivirine ring in women and found that formulations are needed, daily oral PrEP should remain an “potential benefits outweigh the harms based on a systematic option for women who can use it. Approval of daily oral PrEP review and meta-analysis of the scientific evidence including data in the form of TDF/FTC (marketed as Truvada®) by regulatory on cost–effectiveness, acceptability, demonstrated feasibility, and authorities in South Africa, the European Union (EU), Canada, the potential to increase equity as an additional prevention Kenya and other countries, following on from the United States choice, noting some variability in effectiveness in younger age (U.S.) Food and Drug Administration (FDA) approval (40, 41) groups and limited data regarding use among pregnant and and the 2015 WHO guidelines that recommend the use of TFV- breastfeeding women” (49). DVR has been formulated also in containing PrEP in both men and women (42), have given the form of an extended-release monthly film (https:// impetus to the search for improved formulations to overcome matrix4prevention.org/products/extended-release-dapivirine- adherence challenges related to daily oral PrEP. However, it also vaginal-film). seems that women are more likely than men to require near- perfect adherence to oral TFV-containing HIV prevention Multi-month injectables therapy and may need to take 5 or 6 out of 7 doses in a week, A long-acting injectable form of cabotegravir (CAB LA), a in order to be protected against HIV (43). On-demand PrEP two monthly injectable has recently been approved by the before and after sex is effective among MSM (44) however, United States Food and Drug Administration (FDA) and EMA findings of small blinded trials suggest low adherence to sex- for its PrEP indication. Tested in cis-gender women for event-driven dosing in African female sex workers and prevention efficacy in the HPTN 084 trial, HIV infection risk serodiscordant couples (45, 46). The results from the HPTN was 88% lower in the cabotegravir group compared to TDF-FTC 067/ADAPT Cape Town trial investigating the feasibility of non- (28). These findings were consistent with results from the HPTN daily PrEP in adult women, supported recommendations for 083 trial, which was conducted in cis-gender men and trans- daily use of PrEP with oral TDF/FTC (47). On-demand oral gender women who have sex with men (50). However, both PrEP is currently not recommended in women due to the lack of these well tolerated phase 3 trials were stopped early due to high efficacy data and concerns about the higher adherence needed levels of efficacy as evidenced by fewer incident HIV infections in for women. participants receiving long-acting cabotegravir every 8 weeks compared with daily oral TDF/FTC for PrEP. Despite these Long-acting topical PrEP successes and the potential for CAB LA to overcome adherence To address the daily adherence challenge, attention has challenges, concerns about cost and access to low- and middle- turned to development of longer acting slow release and/or income countries (LMICs) remains a barrier to use for both provider initiated PrEP options including monthly tablets or treatment and prevention indications (51). ViiV is currently in vaginal rings, 2-6 monthly injections and annual implants. Thus discussions with the Medicines Patent Pool and several generic far proof of concept trials have been completed for the monthly drug manufacturers for low-cost production of their two vaginal ring and a two monthly injectable. In the ASPIRE monthly injectable for LMICs. The recent IAS conference held dapivirine (DVR) vaginal ring trial, where women were in Montreal saw substantial discussions and advocacy efforts to provided with a monthly vaginal ring, the incidence of HIV-1 address the access challenges that was primarily evaluated using infection in the dapivirine group was lower by 27% (95% public sector funding. Frontiers in Immunology 05 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 Trials of 6 monthly injectables, monthly pills and annual concerns (59). For the same reason, women of reproductive age implants are ongoing (https://www.avac.org/). are often excluded from clinical trials of antiretroviral treatments or prevention strategies. This exclusion has generated critical knowledge gaps in optimal dosing during pregnancy, fetal safety PrEP in trans-gender women and maternal outcomes (60). Pharmacokinetics (PK) data specific to pregnancy would inform on the dose required to Fewer studies have investigated PrEP efficacy in trans- protect the women and their offspring, while avoiding their gender women, despite the high rates of HIV infection in this exposure to drug related toxicities or undertreatment (60). In the population. In a sub-group analysis of the iPrEX study, among Partners PrEP study, women who received TDF or TDF/FTC at 296 participants identified as trans-gender there were 11 HIV the time of conception did not differ from those who received a infections in the PrEP group and ten in the placebo group. placebo in terms of pregnancy incidence, birth outcomes, or However, no drug levels were detected in the trans-gender infant weight. A recently completed nonrandomized, phase-IV women at the seroconversion visit (52). prospective study of darunavir and cobicistat PK in pregnant More recently, the combination of TAF/FTC has been women with HIV and their children in the U.S. reported approved as PrEP for both MSM and trans-gender women, significantly lower exposure during pregnancy, which may following the results of the DISCOVER study which showed that increase the risk of virologic failure and perinatal transmission TAF/FTC was non-inferior to TDF/FTC for HIV prevention (61). Daily oral PrEP (TDF/FTC) is now widely used by (IRR 0·47 [95% CI 0·19-1·15] at the time of the primary efficacy adolescents and pregnant and lactating women. A randomized analysis) (53). trial of safety and PK of the dapivirine vaginal ring versus FTC/ The possible interaction between gender-affirming hormone TDF when used during pregnancy is planned (https:// therapy (GAHT) and PrEP drugs, leading to a lower PrEP mtnstopshiv.org/research/studies/mtn-042). These studies are efficacy in trans-gender women is a potential concern that can of utmost importance, considering that the risk of HIV only be addressed by trials that include trans-gender women on acquisition among women increases during pregnancy and the GAHT. Data from PrEP trials completed to date on postpartum period (57). antiretroviral interactions with GAHT have been reassuring. Results from a sub-study in the Phase III DISCOVER trial demonstrated that drug levels in peripheral blood PrEP and hormonal contraception mononuclear cells (PBMC) were comparable between trans- gender women on GAHT and MSM receiving TAF and between Effective contraception and prevention of sexually trans-gender women on GAHT and MSM receiving TDF transmitted infections (STIs), including HIV-1, are global (54). In a recent study with trans-gender women and trans- priorities for women that are ideally addressed through gender men after four weeks of daily TDF/FTC use, PrEP did not comprehensive sexual reproductive health (SRH) service affect estradiol or testosterone levels. Conversely, GAHT did not provision and the development of multi-purpose technologies affect the concentration of PrEP drug levels in the blood, and all that meet HIV, STI and fertility control needs of users. In most trans-women and trans men in the study had drug levels clinical trials of PrEP cis-women participants are required to be expected to provide high protection from HIV (55). In on a reliable form of contraception. Notwithstanding, addition to providing reassurance to individuals taking pregnancies do occur and have enabled some safety data of gender-affirming hormones with daily PrEP, the study opens PrEP use during pregnancy to be generated. In FEM-PrEP, the the possibility of PrEP on demand for trans-individuals taking group of women receiving TDF/FTC experienced more incident hormones who may be exposed to HIV by anal sex. pregnancies than the placebo group, although this difference was Additionally, data from the HPTN 083 trial presented at the not statistically significant when baseline characteristics were AIDS 2022 conference suggested that there is no impact of taken into account (62). An analysis from the Partners PrEP GAHT on CAB LA concentrations (56) study reported that pregnancy incidence among women who used oral contraceptives was comparable to that among those who did not, and this lack of contraceptive effectiveness was PrEP in pregnant women similar for those assigned PrEP and placebo. Injectable or implantable hormonal contraception plus PrEP provides High rates of incident HIV infection have been reported in effective prevention for pregnancy and HIV-1 (63). However, pregnant women in the last trimester and post-partum (57) with women on combined oral contraceptives were also less likely to implications for vertical transmission. Pregnant women are adhere compared to injectable users. While pharmacokinetic among those the most in need of safe HIV prevention interactions between TDF/FTC and hormonal contraceptives treatments however, pregnancy has been an exclusion criterion are not anticipated, pharmacodynamic and/or behavioral for large trials of PrEP (17, 21, 58), mostly because of fetal safety interactions could affect the results of this kind of studies. Frontiers in Immunology 06 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 African adolescent girls and young women (AGYW) starting challenging. Women also face stigma for possession of ART, PrEP have high rates of asymptomatic, curable bacterial STIs particularly because the same drugs are used for both HIV (64, 65) making syndromic STI case management ineffective and treatment and prevention. This associated stigma may lead to necessitating the use of rapid, sensitive and affordable STI testing discontinuation and non-adherence, impacting efficacy. A that is being enabled through point of care diagnostic necessary pre-requisite for PrEP use is a good perception of technologies. The distribution of STIs, as well as HIV risk. Perception of risk particularly in young women incidence and prevalence, is shifted toward younger age transitioning to adulthood is low. groups for females in comparison to males (66). Thus, the urgent need to prioritize and identify groups of AGYW who are most vulnerable to HIV and other STIs. More provider-initiated PrEP technologies PrEP in menopausal women There is a real need to adapt drug formulation and to innovate drug delivery technologies to encourage uptake and Clinical trials evaluating PrEP in women have so far adherence. The PrEP landscape has expanded substantially in primarily targeted younger females however, menopausal the past decade with a focus on slow release long acting agents. women represent another vulnerable population. Menopause Recent promising advances in the field include lenacapavir, a and increasing age do not result in a reduction in sexual activity, long-acting HIV capsid inhibitor that demonstrated viral but can have an impact on how much people perceive suppression in both ART naïve individuals and individuals themselves to be at risk of HIV infection. Both in the U.S. and who had multi-drug resistant virus. This six-monthly in highly endemic regions like South Africa, older adults injectable is currently being assessed in HIV prevention frequently engage in high-risk behaviors like unprotected clinical trials (77–79). The oral islatravir nucleoside reverse sexual activity (67–69). This may be because they are less transcriptase translocation inhibitor, administered monthly concerned about pregnancy protection after menopause and and an islatravir subdermal implant administered annually is underestimate the risk of STIs. Age-related comorbidities, currently being evaluated as PrEP options (80). Of note is that particularly cardiovascular disease, neurocognitive dysfunction, the FDA halted all islatravir studies in December 2021 due to and bone mineral disease are all potentially heightened by HIV unexpected findings of declines in total lymphocyte and CD4+ or its treatment. Of note, women with HIV experience more T-cell count in some study participants, although the vasomotor symptoms than women without HIV around the mechanism and duration of effect of lymphopenia is not clear time of menopause (70, 71), which is associated with reduced yet (81). The lymphocytopenia was transient and normalized adherence to ART and thus, suboptimal clinic attendance (72). once the islatravir was discontinued, however the risk of In addition, several biological risk factors such as vaginal pH, depleted lymphocytes predisposes to increased risk for epithelial function, target cell frequency and innate immunity infections. Under early stage clinical evaluation is also an are altered during menopause (73–75). All those factors may annual TAF implant and an elvitegravir (EVG)/TAF vaginal have an impact on PrEP efficacy. Using ex vivo cervical tissues insert (35, 82, 83). Preclinical proof-of-concept for preventing from premenopausal and postmenopausal women, active vaginal transmission of simian human immunodeficiency virus metabolite concentrations of tenofovir and emtricitabine were (SHIV) in non-human primates has been demonstrated for this lower in postmenopausal explants, indicating that product (35). postmenopausal women need higher doses of tenofovir-based PrEP to achieve protective efficacy (76). These data need to be validated in vivo. Enhancing choice PrEP to meet diverse needs/increasing drug levels at the point of exposure to HIV Challenges to effective prevention strategies in women The use of topical microbicides, in the form of vaginal or rectal inserts, gels or rings, may meet the needs of individuals for Access to health services whom the use of oral or injectable daily PrEP is not acceptable. The development or refinement of such products is a priority in To realize the full impact, PrEP requires access and the field (84) and different formulations, including vaginal films adherence. For women in Africa, access to medical care is not and tablets, are in later-phase preclinical development (https:// always optimal. Women are required to be compliant with daily www.avac.org/infographic/future-arv-based-prevention). oral PrEP and regular visits to the clinic may become Topical inserts may be designed to quickly disintegrate or Frontiers in Immunology 07 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 dissolve within the vagina or rectum to release therapeutic drugs both the FGT and the rectal tract. The interpretation of quickly for event-driven use, or they may provide an conflicting trial results may be affected by differential drug extended/controlled drug release through bioadhesive levels in the vagina and rectum as well as sexual behaviors properties that may prolong retention and pharmacokinetics, across research participants. The risk of contracting HIV during depending on the type of formulation technology used. one receptive anal act without PrEP or condoms use is about 10 Topical microbicides have the advantage, over oral PrEP, to times higher than the risk during one receptive vaginal act release the drug in the anogenital tissues (both the female genital without PrEP or condoms (97, 100, 101). Q-Griffithsin was tract (FGT) and rectal tissues)and fluids, potentially providing also assessed as a rectal microbicide, as part of the PREVENT protection at the site of virus transmission. Indeed, TFV levels in program and the in vivo effect on mucosal cell populations was the cervico-vaginal fluids (CVF) and in genital tissues are more evaluated in Rhesus macaques. The study indicated that despite than 100-fold higher after vaginal gel insertion than after oral multiple application of Griffithsin, the frequencies of rectal E- tablet ingestion (30, 31, 85–87). Protection may require both cadherin+ cells remain stable, whereas a minor increase in the systemic and mucosal concentrations in a combination that frequencies of rectal mucosal CD4+ cells was observed (102). A differs between oral and topical dosing, and the use of phase 1 clinical trial of Q-Griffithsin against rectal HIV preclinical models could be very informative in that sense. The transmission is ongoing in adult men and women and will R-PrEP trial, comparing the PK of raltegravir and lamivudine in inform on the safety and pharmacokinetics of this microbicide genital tissue against ex vivo tissue infection with HIV-1, (https://clinicaltrials.gov/ct2/show/NCT04032717). The efficacy demonstrated that after 7 days of raltegravir dosed with or of TAF/EVG inserts as topical on-demand rectal PrEP was without lamivudine twice a day, protective levels were reached demonstrated in non-human primates (103). The Microbicide at different times in the FGT and the rectum, and that different Trail Network (MTN) 039 is an ongoing phase 1 open label PK and PD profiles were observed after dosing cessation (88). In safety and PK study of single dose rectal administration of a spite of the high efficacy of CAB LA, pharmacodynamics (PD) TAF/EVG insert (https://www.mtnstopshiv.org/research/ data indicated low drug levels in the genital tract, suggesting that studies/mtn-039). reaching sufficient drug concentration in the regional lymphoid tissue might be more important than topical genital levels (89). Moreover, drug distribution in different mucosal cells needs Biological factors influencing HIV to be considered. In vitro studies using human tissues from the transmission and the efficacy of upper and lower FGT suggested that concentrations of active TFV were 100 times higher in epithelial cells than in CD4+ T prevention strategies in women: cells (90), and imaging methods in animal vaginal tissues were what do we know and where are used to confirm the preferential TFV concentration in the the gaps? epithelium (91). Additional studies showed that after first TFV treatment, endometrial, endocervical and ectocervical polarized While adherence is a key factor to guarantee efficacy of PrEP epithelial cells secreted TFV that partially protected CD4+ T trials, it is becoming increasingly evident that several biological cells in vitro for at least 3 days (92). Importantly, luminal factors can modify microbicide efficacy in women. Those factors epithelial secretions were not protective, but TFV release was should be considered when planning both PrEP interventions specific towards the basolateral epithelial compartment. This and when analyzing safety and efficacy of treatments. suggests that when TFV concentrations are below ideal levels, factors that increase target cell presence on the mucosal surface, such as inflammation or damage, would overcome the TFV Genital inflammation protective effects. This concept is supported by CAPRISA 004 clinical data describing ideal conditions for increased It is well known that genital inflammation plays a significant intracellular metabolite competition and reduced drug efficacy role in the susceptibility to HIV infection (104). The risk of in the context of inflammation and immune cell activation (93). contracting HIV has been linked to epithelial disruption, Rectal HIV transmission to women is an under-studied area elevated levels of pro-inflammatory cytokines and chemokines in HIV research, although a largely overlooked fraction of men in genital secretions and the activation or recruitment of HIV to female transmission is due to anal intercourse (94–97). It is target cells (105–111). Genetic factors, vaginal microbial recognized that women engage in receptive anal intercourse and diversity, intravaginal practices, sexually transmitted infections, often due to violence (98). While it is possible for products semen exposure, endocrine sex hormones, and hormonal applied vaginally to reach the rectum, as shown in non-human contraceptives are some of the factors linked to genital primate (NHP) models (99), it is unknown if these levels offer inflammation (111–114). However, the type of inflammatory protection against anal HIV acquisition. In addition, both PK signals that are more relevant to HIV infectivity/fitness and/or and PD of drugs differs by gender and needs to be defined in susceptibility are not known and need to be investigated. Frontiers in Immunology 08 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 Genital inflammation has been clearly implicated in risk acquisition increased markedly with increased dysbiosis, diminished protection by topical TFV. McKinnon et al. and remarkably, none of the women whose microbiota was showed TFV to be 57% protective against HIV in women dominated by Lactobacillus crispatus acquired HIV-1 without vaginal inflammation but only 3% protective if genital throughout the one year of the study (125). inflammation was present. Among women who used the gel PrEP products that will work effectively in an environment consistently, TFV protection was 75% in women without of vaginal dysbiosis are needed. Furthermore, an understanding inflammation compared to -10% in those with inflammation of the similarities and differences in the vaginal microbiome of (115). An additional significant factor that may modify cis-gender and the neovaginal microbiome of trans-women protection following topical application is the potential ability would inform the development of appropriate targeted of TFV to delay wound healing, as shown in vitro (116). strategies (126). Indeed, it has been shown that the genital According to the results of the Progect Gel phase I clinical microbiome influences the effectiveness of TFV gel and trial, rectal administration of 1% TFV gel caused considerable dapivirine, with higher protection in women whose vaginal changes in the proteome of epidermal cells, including microbiomes is dominated by Lactobacilli than in women with extracellular matrix, tissue remodeling, epidermal growth, tight vaginal dysbiosis (125, 127). Although the methods used were junctions, and cellular stress pathways (117). Additionally, the sometimes insufficient to distinguish Lactobacillus communities development of vaginal ulcers forced the termination of a recent dominated by beneficial species such as Lactobacillus crispatus clinical trial investigating the safety of a tenofovir disoproxil versus less beneficial species such as Lactobacillus iners, they fumarate ring in healthy women (118). raised concerns that TFV-based microbicides could be While inflammation has been independently associated with undermined by microorganisms like G. vaginalis or Prevotella HIV risk and CD4+CCR5+ T cell target concentrations, a direct species, which could effectively reduce the level of drug available cellular mechanism for the relationship between HIV and locally. Also, in women using TFV vaginal gel or vaginal film, inflammation has not been established and a cellular lower levels of TFV and the active metabolite, tenofovir- biomarker of HIV risk remains unconfirmed. The ability of diphosphate (TFV-DP), were found in the genital tissues of endometrial stromal fibroblasts to facilitate HIV acquisition by those with higher concentrations of G. vaginalis, Atopobium trans-infection (119) is exacerbated in conditions of genital vaginae, or a diagnosis of bacterial vaginosis (128). It is possible inflammation however, the threshold level of infection that declines in drug levels might be countered by increasing the required to undermine the efficacy of PrEP, especially in amount of drug supplied or by using continuous release drug women with inflammation, is unknown. delivery platforms, like a vaginal ring. In support of the latter hypothesis, a study demonstrated no changes in the level of tenofovir-diphosphate in women wearing TFV vaginal rings Genital microbiome stratified by Lactobacillus dominating versus dysbiotic vaginal community states (129). Results from in vitro studies aiming at The microbiome that is considered a key regulator of genital understanding the mechanisms through which the vaginal inflammation and vaginal dysbiosis, has been linked to HIV risk microbiota might alter the drug concentrations in genital (108, 110, 120). This poses a serious public health concern given tissues, lead to the hypothesis that G. vaginalis, which is often that bacterial vaginosis is widespread in areas with a high present in greater quantities among women with non- prevalence of HIV. Several studies have shown that a vaginal Lactobacillus dominant microbiota, metabolizes TFV to environment dominated by some Lactobacillus species promotes adenine or secretes adenine which is consumed by A. vaginae, vaginal acidity, anti-microbial defense, and an anti- creating bacterial synergy between these species in the vaginal inflammatory tissue environment, and has been consistently ecosystem (125, 127). TFV metabolism can occur quite quickly. associated with healthy pregnancy outcomes, lack of abnormal In the presence of high concentrations of G. vaginalis TFV-DP vaginal symptoms and reduced risk for acquiring HIV and other levels were reduced within two hours in cervical tissue and in STIs (121–123). Vaginal dysbiosis results in an increased one week in CVF and plasma (125, 128). It has been also number of activated CCR5+ CD4+ T cells in the vaginal reported that dapivirine binds irreversibly to bacteria in vitro mucosa, and higher production of pro-inflammatory cytokines (127), thus impacting the availability of the drug to diffuse into in the cervical secretions (110, 124). Women having the highest the genital tract tissues. Retrospective study of the Partners PrEP concentrations of Lactobacillus crispatus had a decreased HIV study, however, did not uncover any appreciable variations in acquisition risk relative to those dominated by Gardnerella effectiveness (130). There are still unanswered questions vaginalis and other anaerobes (125). However, women having regarding the biological mechanisms of the potential a vaginal microbiome dominated by Lactobacillus iners had interaction between vaginal dysbiosis and PrEP effectiveness in similar incidence of HIV compared to women having preventing HIV acquisition, as well as whether this relationship dysbiotic microbiota. The FRESH Cohort study, enrolling 200 differs depending on the formulations (i.e. TFV-, dapivirine-, South African women aged 18-23 years old, showed that HIV-1 etc) and delivery methods of PrEP (such as oral, topical). Frontiers in Immunology 09 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 A regular collection of vaginal swabs and mucosal biopsies tract, mainly linked to a high inflammatory environment (161– may allow to better examine the relationship between PrEP 164). Evidence suggests that for HIV positive individuals, effectiveness and changes of the microbial community. Since persistent high risk behaviors increase susceptibility to STIs, there are increasing indications that vaginal bacteria can modify and advancing HIV infection may increase the frequency of STIs topical TFV efficacy (125, 131), additional studies determining if treatment failures (161, 162). Conversely, asymptomatic or a particular bacterial species or the diversity of bacterial symptomatic STIs strongly predict susceptibility to HIV, communities as a whole are linked to decreased efficacy of augment HIV shedding at genital mucosal sites and increase new PrEP candidates are warranted. A rapid and precise infectiousness from HIV positive individuals. Potential biologic diagnosis of vaginal dysbiosis and local inflammation, mechanisms that facilitate and activate HIV replication include although challenging and not everywhere possible, will be alterations in the genital tract microbiome, localized critical in improving the efficacy of HIV prevention efforts in inflammation, recruitment of CD4+ T-cells, monocytes, women and to improve public health policy (132). Furthermore, Langerhans’ cells, and increased levels of interleukin-10 (165, the effect of other non-bacterial components of the microbiome 166). Recent studies have delineated the role and biologic such as viruses and fungi on the efficacy of PrEP need to be mechanisms of STIs with disturbances in the vaginal investigated. Several efforts are underway to evaluate vaginal microbiome, inducing mucosal inflammation, yielding unique inserts to restore the vaginal microbiome in women with cytokine profiles that evoke an influx of HIV receptor cells in dysbiosis (133). genital mucosal epithelium that has been found to be associated with almost a three-fold increase in HIV viral shedding potentially enhancing sexual transmission of HIV (166). Thus, Semen treatment of STIs remains a public health priority to potentially reduce STIs related HIV acquisition and transmission. In the Semen in addition to being a carrier of HIV is also an important population-based survey undertaken in rural and peri-urban modulator of genital inflammation and immune activation at both KwaZulu-Natal, the province with the highest HIV prevalence in the FGT (134–136) and the rectal mucosa (137, 138). The South Africa, just over half of participants in the study area had production of pro-inflammatory and chemotactic cytokines is HSV-2 infection and just under one-quarter had at least one increased in the female genital mucosa in the presence of semen curable STIs of syphilis, N. gonorrhoeae, C. trachomatis, T. (139–145). Several of these cytokines are linked to leukocyte vaginalis and/or M. genitalium (167). Estimates of curable recruitment (141, 144–146) and decreased mucosal barrier STIs were higher in the younger age groups, particularly in integrity (147, 148), both of which play a significant role in HIV’s younger females, which is the same group among whom a peak ability to enter and access target cells at the mucosal sites. The in HIV incidence occurs (168). This study also found an impact of the level of inflammation in the semen on the female association of HIV positive status and curable STIs (167). genital tract and rectal mucosa needs further investigations. In Whilst ART benefits HIV positive individuals by achieving addition, studies indicated that semen exposure and sexual HIV viral suppression to prevent onward transmission, ART intercourse may promote a shift in the microbial environments of itself has no impact on STIs (169) and STIs often remain the FGT, inducing bacterial vaginosis, that may facilitate HIV untreated contributing to transient or intermittent HIV viral infection in women (134, 149–151). On the other hand, semen shedding in genital secretions (162, 170), thus the sustained has been shown to be able to prevent viral entrance into the genital potential elevated risk of onward HIV transmission. These mucosa, because of the presence of several inhibitory factors like findings highlight the importance of enhanced STIs cationic polypeptides and reactive oxygen species with anti-HIV surveillance and investment in targeted STI control programs activity (152, 153). Importantly, semen exposure and sexual for younger populations. STIs also impact efficacy of PrEP by intercourse may also affect efficacy of topical PrEP (154–156) by damaging the vaginal epithelium or through other redistributing cervicovaginal fluid and topically applied immunological mechanisms that need to be further microbicides (157, 158). After coitus, tenofovir gel concentrations investigated. In CAPRISA 004 women with high cytokine were noticeably lower in CVL, cervical tissues, and vaginal tissues levels, as is typical of STIs, experienced a reduction in the (155), and in in vitro studies a significant reduction in the antiviral efficacy of TFV gel (17). On the other hand, TFV gel in activity of PRO2000 gel was observed post-coitus (156). CAPRISA 004 was 51% protective against HSV-2 acquisition (17) and Andrei et al. demonstrated that the concentration achieved intravaginally with a 1% TFV topical gel has direct Sexually transmitted infections anti-herpetic activity (171). The Partners PrEP study additionally demonstrated that daily oral TDF-based PrEP STIs and HIV share a complex, synergistic bidirectional significantly reduced the risk for HSV-2 acquisition among relationship (159, 160) and are associated with an increased risk heterosexual men and women (172). It was also shown that of HIV acquisition and transmission at both the FGT and rectal PrEP differentially altered the activation of circulating versus Frontiers in Immunology 10 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 mucosal immune cells in HSV-2 seropositive women (173). Sex differences in immune responses Griffithsin, which is currently under evaluation at the University of Pittsburgh as rectal microbicide against HIV Sex differences have been implicated in outcome from rectal transmission, is a highly potent viral entry inhibitor with vaccines and infections in adults and children (193, 194). In broad activity against HSV-2, HCV, and HPV (32, 174). The COVID-19 pandemic we have been able to clearly observe sex CONRAD’s topical insert combining TAF with elvitegravir differences in the immune response to the virus, and how these (EVG), an integrase inhibitor, provides a wide pre- and post- translate into clinical outcomes (195). Differences in the coital window of prophylaxis against both HIV and HSV (35). acquisition of HIV and in disease pathogenesis between men How STIs treatments might impact PrEP efficacy is an and women have long been also reported in epidemiological open question. studies (196, 197). The X chromosome encodes the most immune-related genes of any chromosome (198) and significant sex differences in Sex hormones innate and adaptive immune responses have been described (199). The important genes reported to locate on the X Hormonal changes during the menstrual cycle induce several chromosome that play a role in immunity include CD40L, modifications of the immune system and of the microbiota CXCR3 and Foxp3. These genes are crucial for B cell composition within the FGT, affecting the susceptibility to HIV maturation and antibody response regulation, tissue effector T and other STIs. The immune protection is dampened during the cell recruitment and immune tolerance (200–202). Toll like secretory phase of the cycle to optimize conditions for fertilization receptor 7 (TLR7) is the most described gene-driven and pregnancy, and the progesterone-high phase of the menstrual production of interferon (IFN-I) by plasmacytoid dendritic cycle is indeed a risk factor for HIV acquisition (175). Furthermore, cells (pDCs) (203, 204). Seminal studies from infected during menses, the local vaginal inflammation increases and the macaques with simian immunodeficiency virus (SIV) point to vaginal microbiota is disturbed (176). pDCs as the critical IFN-I producers in this process (205, 206), The impact of women’s exogenous and endogenous hormones and human studies univocally demonstrated that compared to (including the hormone replacement therapy (HRT) in trans- men, pDCs from women produce more IFN-a/b in response to gender women) on the efficacy of PrEP and their risk of TLR7 ligands, resulting in higher induction of interferon- contracting HIV deserves further investigations. Through a stimulated genes (ISGs) (207–210). number of biological mechanisms, including changes in gene There is also an increased risk of in utero infection among expression, progesterone-induced epithelium thinning, females. Sex-specific innate immune selection of HIV in utero is microbiome alterations, increased HIV target cells in the FGT, associated with increased female susceptibility to infection (211). hormonal contraceptives such as medroxyprogesterone acetate In Hepatitis C virus (HCV) infection, female infants are twice as (DMPA), which is widely used in sub-Saharan Africa, may susceptible to mother-to-child transmission (212, 213). In enhance susceptibility to HIV (177–183) and impact FGT congenital cytomegalovirus (CMV), females have 3-fold more immune responses in women. According to a post-hoc analysis of neurological disease (214). All these studies highlighting the the Partners PrEP study, DMPA users still received protective need for a gender-diverse inclusion in immunological research benefit from oral TDF/FTC or TDF alone however, there was an (204). The inclusion of sex differences in the analysis of observed 10% increase in HIV incidence in women using hormonal immunological and clinical data will lead to a better contraception compared to those who didn’t used DMPA (184). understanding of the immunobiology of HIV disease. Although the ECHO trial did not find a substantial difference in A better understanding of the immunobiological HIV risk among women using DPMA as a contraceptive (185), this mechanisms of HIV infection, co-infections and pathogenesis, study had several limitations and more research is required to better at the level of both the FGT and the rectal tract, could provide understand the effects of hormonal contraceptives and of the direction toward developing strategies for prevention in women. menstrual cycle on antiretroviral activity in the vaginal tract as well as possible pharmacological interactions between hormonal contraceptives and PrEP (186–188). Identification of the immunological There is emerging evidence that gender and sex hormones can play a role in the interplay between the microbiome and mechanisms to be investigated gastrointestinal diseases (189, 190). Since the gut microbiome is to inform prevention involved in the excretion and circulation process of estrogen and treatment development androgen, the concept of “microgenderome” indicating the interaction between sex hormone and the gut microbiota has In contrast to studies in MSM populations to understand been recently suggested and represents an emerging research pathogenesis of HIV infection and studies of vertical topic (191, 192). transmission that inform ed t arg et ed and e ffec tiv e Frontiers in Immunology 11 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 interventions, pathogenesis studies in women globally have been epithelium and microbial translocation (229). Whether other more limited and patchy. immune cells contribute to the loss of the EB during HIV Considerable effort by the research community has advanced infection, has been less explored. Recently, a role for intestinal our understanding of the early events of HIV genital CX3CR1+ mononuclear phagocytes and NKG2a/c+CD8+ T has transmission and of the initial interactions between the virus been proposed in the protection of the gut barrier function to and the mucosal immunity. However, several knowledge gaps avoid intestinal inflammation during SIV infection (230, 231). stem predominantly from challenges related to the practicality of While those cells are implicated in the EB protection also in the appropriate, standardized and timely mucosal sampling in large FGT is unknown. Bacterial metabolites such as D-lactic acid, are studies and clinical trials. This limits the understanding of the differentially produced from various Lactobacillus species (232). effects of HIV treatment in women, and our ability to address For instance, Lactobacillus spp. that specifically produce D-lactic gender differences in HIV treatment and prevention outcomes. acid were associated with long-term protection In order to fill those gaps, we need a better understanding of the against Chlamydia trachomatis infection, consistent with mechanisms of HIV entry at the genital mucosa and of the reduced protection associated with Lactobacillus iners, which factors that limit this. Here, we aim to highlight, without does not produce this isoform (233). The direct effect of prioritization, the immunological factors that need to be protection was noted when FGT cells were first primed in studied to address this paucity of knowledge, with the vitro with D-lactic acid in contrast to adding the D-lactic acid translational belief that understanding these biological to Chlamydia trachomatis first, which conferred no effect on the mechanisms is key for product development. bacteria. These data demonstrate that the bacterial metabolites An important factor to consider in early mucosal HIV act on the cells directly rather than on the microbiota. However, transmission, and that has been mostly overlooked, is the further studies are needed to unravel how those mechanisms source of transmitted virus, whether it comes from cell-free contribute to break-down of the EB and establishment of genital virions or infected cells. Both cell-free virions and HIV-infected and generalized inflammation and potentially affect the efficacy cells (T lymphocytes and macrophages) have been identified in of prevention strategies. Furthermore, the specific role of the the female genital secretions and semen from HIV-infected men microbiota/immune cells interaction in the regulation of those and have been shown in vitro and in vivo in animal models to processes needs to be further explored. Therapeutic interact with epithelial tissue and transmit infection (137, 143, interventions aiming to promote barrier integrity and to 215, 216). However, HIV transmission by cell-associated HIV reduce microbial translocation-induced inflammation are seems to be more efficient than by cell-free virions in male, essential to improve the prognoses of infected individuals. female and anorectal mucosa (217–220). Yet, most research is Another priority for the research community is done using cell-free virus inoculum and we still do not know the identification of HIV target cells in the mucosa and of the what is the relative contribution of cell-free virions and infected mechanism(s) contributing to their recruitment. Whether the cells to viral entry. Different modes of transmission may also inflammation that drives HIV acquisition risk is due to an have implications in terms of the types of immune mechanisms increased frequency of CD4+ cells at the mucosa, remains an playing a role in protection, with an impact on the efficacy of unanswered question. The presence of susceptible target cells, preventive treatments. such as CD4+ T cells and in particular memory CD4+ T cells The genital and rectal mucosal epithelia represent one of the expressing high levels of CCR5, is a critical determinant in the first barriers during sexual intercourse. It is well known that establishment of HIV infection at mucosa (234, 235). during HIV infection, the gastrointestinal epithelial barrier (EB) Nevertheless, during the early phases of viral transmission, not is severely compromised, leading to translocation of microbial all CD4+ T cell subsets are equally infected. In the SIV infection product into the systemic circulation, with consequent immune model, the Th17 were the primary targets during both vaginal activation and inflammation establishment (221). Microbial and rectal transmission, together with immature DCs in the translocation is considered a leading cause of inflammation in latter case (225, 236). In support of this, HIV infection in female treated and untreated HIV infection. Mechanisms contributing sex workers from Kenya resulted in significant depletion of to EB loss have not been fully elucidated, although a number of mucosal Th17 CD4+ T cells compared to uninfected samples processes have been identified. Epithelial cells tight junction (235). However, preferential infection of Th17 cells in humans downregulation by HIV proteins and by inflammatory cytokines has not been definitively demonstrated. In addition, antigen was observed using primary cells isolated from the human FGT presenting cells (APCs), including DCs, LCs and macrophages, and CD4+ T cell depletion in the gut of NHPs during acute are strategically located to be initial target of the virus and to infection was vastly documented (222–224). This included the transfer infection to T lymphocytes (219, 237–239). We are just loss of Th17 and Th22 cells, cells that are thought to function as starting to have a more precise idea of the different APC subsets innate regulators of mucosal integrity (225–228). In SIV present in the genital mucosa and the specific role each of those infection, immunological disorders, such as Th17 depletion, subsets play in both HIV infection and anti-viral immune happened later than changes to the structural proteins of the responses (230, 240–242). The distribution of immune cells as Frontiers in Immunology 12 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 well as their ability to respond to a stimulus differs according to PrEP from a trans-competent practitioner was reported as the female genital tract compartment and are distinct from crucial for PrEP adoption and adherence (257). systemic immune cells (243). The susceptibility of HIV target Even though the majority of PrEP trials are being cells may vary depending on their localization at the mucosa and undertaken in cis-women in Africa, this is no guarantee for by their activation status. When compared to the endocervix or access or affordability. Inequities in access to HIV prevention vagina, the ectocervix and the transformation zone have a larger and treatment for women remain a global challenge. Efforts concentration of intraepithelial CD4+ T cells and macrophages, should be put in increasing awareness among vulnerable women indicating that this is likely where HIV transmission most of the existence of PrEP as a viable preventive measure. In frequently occurs (244). In addition, the CD4+ T cells from addition, health care professionals, researchers and community ectocervix appeared to be more sensitive to HIV infection representatives should be involved in initiatives aiming to compared to those from the endocervix and endometrium, promote equality of access to care and implement PrEP probably because of their Th17 profile and high expression of availability for women across the globe; these initiatives should CCR5 (245). include a close dialogue with pharma companies involved in the Collection of mucosal samples is often complicated by both design and production of PrEP drugs aimed at speed-up the technical and ethical reasons (246, 247) however, it is necessary development of HIV preventive measures tailored for women to fill in the key knowledge gaps with respects to mucosal genital tract. Additional efforts are needed to make PrEP a immunology. In addition, it would be relevant to collect paired successful prevention tool not only for men but also for vaginal and rectal tissues from women, as to directly compare women of all ages. the two mucosal sites. Closing the gender gap: Let’s give Additional approaches to women access to a range of safe HIV prevention and efficacious PrEP including Intersections between HIV and other sexually transmitted multi-purpose technologies (MPTs) infections represent another potential avenue for HIV prevention interventions. For example, human papillomavirus Women represent an important population to consider in (HPV) vaccination could decrease genital inflammation and the evolution of PrEP and unlike other HIV prevention HIV risk considering the established relationship between strategies, a range of efficacious PrEP options create the HPV infection, genital cytokines and increased HIV risk (258, opportunity to empower women to take control of their own 259). Similarly, considering the universal sub-optimal nature of health without requiring negotiation or consent from their syndromic management of STIs, opportunities exist to design partner. Yet, women are not always seen as a “key target” for appropriate point-of-care strategies to treat current infections HIV prevention and in many countries are not even considered and limit the development of a genital immune and microbial as a group at risk of HIV infection (248). As a consequence, PrEP environment susceptible to HIV infection (260, 261). An services focused mostly on key populations, such as MSM and, to important fact to consider is a possible increase in STIs a lesser extent, trans-gender women (248–251), and the overall prevalence following the distribution of long-acting ARVs or utilization of PrEP by women remains low. In 2018 only 7% of future HIV vaccines. Some evidence for this exists in MSM woman were prescribed PrEP in the US (252) and the European populations following oral PrEP (262), and, more recently, the Centre for Disease Prevention and Control in 2019 estimated resurgence of syphilis during the global COVID pandemic (263). that less than 10% of PrEP users in Europe were women Although the latter may in part be due to limitations to service (including trans-gender women) (253). Recent European delivery, additional efforts to avoid complacency and reductions survey studies evidenced that, while women’s access to PrEP in condom use or other risk-reducing efforts may need to be remains limited (248), those who perceive themselves to be at considered to prevent STIs on administration of interventions high HIV risk are interested in using PrEP (254). Similar results like HIV vaccination or long-acting ARV. It remains essential were reported in two US survey studies within cis-women for research to focus on developing multipurpose interventions attending a family planning clinic or presenting for HIV/STD that women can use to prevent a range of viral and bacterial testing. Over 70-80% of participants reported not knowing PrEP STIs, including HIV, and manage fertility simultaneously. was an option for them and over two-thirds declared they would Given the limitations of available biomedical options for probably or definitely like to take it (255, 256). According to a HIV-1 prevention in women, there is a critical need for new qualitative study that assessed PrEP acceptability among 30 technologies. The use of broadly neutralizing antibodies trans-gender women in San Francisco, knowledge of PrEP was (bNAbs) to HIV may represent an alternate strategy to low, interest was relatively high and the opportunity to acquire overcome challenges seen with other available PrEP strategies. Frontiers in Immunology 13 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 Compared with ART, PrEP mediated by bNAb can neutralize differences between the sexes in HIV infection and to design sex- the free virus before the infection and act earlier than antivirals, specific strategies to HIV treatment. Acknowledging these with a reduced side effects profile expected and less concerns for differences when planning and administering care can help the development of resistance when used in double or triple address disparities. It takes dedication from basic, clinical, and combinations. bNAbs have been engineered with the LS (lysine- social scientists, as well as education of women about the goals serine) mutations to have a longer half-life in vivo (264). These and importance of clinical research. Without it, putting a stop to modifications translate to less frequent administration the HIV epidemic will not be possible. compared to current PrEP strategies that require daily or Including women in research is not just a matter of enrolling intermittent administration. bNAbs can provide protection for women in clinical trials, but also of involving female scientists a longer period and circumvents the adherence required for daily and potential users in the conceptualization, design and pill-taking or vaginal applications. The administration of bNAbs implementation of these studies. Gender inequalities in would also be unrelated to sexual intercourse and the delivery science, technology, engineering, and mathematics (STEM) method could minimize stigma. However, there are limitations have been well documented (266–269). There is quite a lot of in the use of bNAbs due to a problem of costs and evidence that women in science need to have support networks administration. In addition, given the global diversity of HIV- to enhance their visibility, efficacy and bring unique skills to the 1, combination of bNAbs or multiple-specific antibodies will scientific field. Efforts should be made to provide equal probably be needed to generate the essential breadth for opportunities and encourage the participation of female efficient protection. scientists in the establishment of clinical cohorts and leading of clinical studies. Sustainable development and the contribution that women make to science and technology are inextricably Conclusions and future directions linked; neither can exist apart. Women and men have different biology, different sex organs, different hormones, different susceptibility to infections and Author contributions different cultural influences, all of which can lead to difference in health and in the response to medical treatments. There is MC wrote the initial draft. All authors revised the growing recognition that proper evaluation of important manuscript and approved the submitted version. biological factors, such as sex and gender, is necessary to ensure the quality and generalizability of biomedical research. However, cis- and trans-gender women have historically been Conflict of interest underrepresented in clinical trials, including but not limited to those evaluating HIV prevention strategies, although we The authors declare that the research was conducted in the acknowledge that over the past few decades, there has been a absence of any commercial or financial relationships that could steady rise in their presence, partly as a result of laws, policies, be construed as a potential conflict of interest. regulations and guidance (265). The underrepresentation of women in HIV clinical research has generated important knowledge gaps applying to both cis- Publisher’s note and trans-women worldwide, from US to Europe to Sub- Saharan Africa. In order to fill these gaps, we should ensure All claims expressed in this article are solely those of the that HIV research addresses specific sex and gender differences authors and do not necessarily represent those of their affiliated and supports the full participation and meaningful involvement organizations, or those of the publisher, the editors and the of women across their life-course. Women participation in reviewers. Any product that may be evaluated in this article, or clinical trials and independent analysis of data for men and claim that may be made by its manufacturer, is not guaranteed women are crucial to gain more knowledge about the biological or endorsed by the publisher. References 1. UNAIDS. FACTSHEET 2022 (2022). UNAIDS. Available at: https://www. 3. KarimSSA,BaxterC.HIVIncidenceratesinadolescentgirlsandyoungwomeninsub- unaids.org/en/resources/fact-sheet (Accessed August 30, 2022). Saharan Africa. Lancet Glob Heal (2019) 7:e1470–1. doi: 10.1016/S2214-109X(19)30404-8 2. UNAIDS. In danger: UNAIDS global AIDS update 2022. Geneva: Joint United 4. WHO. Start free stay free AIDS free - 2020 report (2020). Available at: https:// Nations Programme on HIV/AIDS (2022). Available at: https://www.unaids.org/ www.unaids.org/sites/default/files/media_asset/start-free-stay-free-aids-free-2020- en/resources/documents/2022/in-danger-global-aids-update. progress-report_en.pdf#page=80 (Accessed September 13, 2022). Frontiers in Immunology 14 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 5. Naicker N, Yende-Zuma N, Kharsany ABM, Shozi H, Nkosi D, Naidoo A, 26. Baeten JM, Palanee-Phillips T, Brown ER, Schwartz K, Soto-Torres LE, et al. Pregnancy rates and outcomes in a longitudinal HIV cohort in the context of Govender V, et al. Use of a vaginal ring containing dapivirine for HIV-1 prevention evolving antiretroviral treatment provision in south Africa. BMC Pregnancy in women. N Engl J Med (2016) 375:2121–32. doi: 10.1056/NEJMOA1506110/ Childbirth (2022) 22:1–11. doi: 10.1186/S12884-022-04829-2/FIGURES/3 SUPPL_FILE/NEJMOA1506110_DISCLOSURES.PDF 6. UN Women. The shadow epidemic: violence against women during COVID- 27. Nel A, van Niekerk N, Kapiga S, Bekker L-G, Gama C, Gill K, et al. Safety 19 (2022). Available at: https://www.unwomen.org/en/news/in-focus/in-focus- and efficacy of a dapivirine vaginal ring for HIV prevention in women. N Engl J gender-equality-in-covid-19-response/violence-against-women-during-covid-19. Med (2016) 375:2133–43. doi: 10.1056/NEJMOA1602046 7. Govere SM, Galagan S, Tlou B, Mashamba-Thompson T, Bassett IV, Drain 28. Delany-Moretlwe S, Hughes JP, Bock P, Ouma SG, Hunidzarira P, Kalonji PK. Effect of perceived HIV risk on initiation of antiretroviral therapy during the D, et al. Cabotegravir for the prevention of HIV-1 in women: Results from HPTN universal test and treat era in south Africa. BMC Infect Dis (2021) 21:7. 084, a phase 3, randomised clinical trial. Lancet (London England) (2022) doi: 10.1186/S12879-021-06689-1 399:1779–89. doi: 10.1016/S0140-6736(22)00538-4 8. Muravha T, Hoffmann CJ, Botha C, Maruma W, Charalambous S, Chetty- 29. US Food and Drug Administration. FDA Approves second drug to prevent Makkan CM. Exploring perceptions of low risk behaviour and drivers to test for HIV infection as part of ongoing efforts to end the HIV epidemic. (2019). Available HIV among south African youth. PloS One (2021) 16:e0245542. doi: 10.1371/ at: https://www.fda.gov/news-events/press-announcements/fda-approves-second- JOURNAL.PONE.0245542 drug-prevent-hiv-infection-part-ongoing-efforts-end-hiv-epidemic. 9. Sanders RA. Adolescent psychosocial, social, and cognitive development. 30. Patterson KB, Prince HA, Kraft E, Jenkins AJ, Shaheen NJ, Rooney JF, et al. Pediatr Rev (2013) 34:354–9. doi: 10.1542/PIR.34-8-354 Penetration of tenofovir and emtricitabine in mucosal tissues: Implications for 10. Blakemore SJ, Mills KL. Is adolescence a sensitive period for sociocultural prevention of HIV-1 transmission. Sci Transl Med (2011) 3:112re4. doi: 10.1126/ processing? Annu Rev Psychol (2014) 65:187–207. doi: 10.1146/ANNUREV- SCITRANSLMED.3003174 PSYCH-010213-115202 31. Karim SSA, Kashuba AD, Werner L, Karim QA. Drug concentrations after 11. Patton GC, Sawyer SM, Santelli JS, Ross DA, Afifi R, Allen NB, et al. Our topical and oral antiretroviral pre-exposure prophylaxis: Implications for HIV future: A lancet commission on adolescent health and wellbeing. Lancet (London prevention in women. Lancet (London England) (2011) 378:279–81. doi: 10.1016/ England) (2016) 387:2423–78. doi: 10.1016/S0140-6736(16)00579-1 S0140-6736(11)60878-7 12. United Nations Childrens Fund. Preventing HIV from early adolescence to 32. Derby N, Lal M, Aravantinou M, Kizima L, Barnable P, Rodriguez A, et al. young adulthood OPPORTUNITY in CRISIS (2011). Available at: www.greencom. Griffithsin carrageenan fast dissolving inserts prevent SHIV HSV-2 and HPV ca (Accessed September 21, 2022). infections in vivo. Nat Commun (2018) 9:1–9. doi: 10.1038/s41467-018-06349-0 13. Kharsany ABM, Buthelezi TJ, Frohlich JA, Yende-Zuma N, Samsunder N, 33. Teleshova N, Keller MJ, Romero JAF, Friedland BA, Creasy GW, Plagianos Mahlase G, et al. HIV Infection in high school students in rural south Africa: Role MG, et al. Results of a phase 1, randomized, placebo-controlled first-in-human trial of transmissions among students. AIDS Res Hum Retroviruses (2014) 30:956. of griffithsin formulated in a carrageenan vaginal gel. PloS One (2022) 17:e0261775. doi: 10.1089/AID.2014.0110 doi: 10.1371/JOURNAL.PONE.0261775 14. Pettifor AE, Rees HV, Kleinschmidt I, Steffenson AE, MacPhail C, Hlongwa- 34. Mehendale S, Deshpande S, Kohli R, Tsui S, Tolley E. Acceptability of Madikizela L, et al. Young people’s sexual health in south Africa: HIV prevalence coitally-associated versus daily use of 1% tenofovir vaginal gel among women in and sexual behaviors from a nationally representative household survey. AIDS pune, India. Int Health (2012) 4:63–9. doi: 10.1016/J.INHE.2011.11.003/2/4-1-63- (2005) 19:1525–34. doi: 10.1097/01.AIDS.0000183129.16830.06 TBL003.GIF 15. Pettifor AE, van der Straten A, Dunbar MS, Shiboski SC, Padian NS. Early 35. Peet MM, Agrahari V, Anderson SM, Hanif H, Singh ON, Thurman AR, age of first sex: A risk factor for HIV infection among women in Zimbabwe. AIDS et al. Topical inserts: A versatile delivery form for HIV prevention. Pharmaceutics (2004) 18:1435–42. doi: 10.1097/01.AIDS.0000131338.61042.B8 (2019) 11:374–90. doi: 10.3390/PHARMACEUTICS11080374 16. Curno MJ, Rossi S, Hodges-Mameletzis I, Johnston R, Price MA, Heidari S. 36. Murnane PM, Celum C, Mugo N, Campbell JD, Donnell D, Bukusi E, et al. A systematic review of the inclusion (or exclusion) of women in HIV research: Efficacy of pre-exposure prophylaxis for HIV-1 prevention among high risk From clinical studies of antiretrovirals and vaccines to cure strategies. J Acquir heterosexuals: subgroup analyses from the partners PrEP study. AIDS (2013) Immune Defic Syndr (2016) 71:181–8. doi: 10.1097/QAI.0000000000000842 27:2155–60. doi: 10.1097/QAD.0B013E3283629037 17. Abdool Karim Q, Abdool Karim SS, Frohlich JA, Grobler AC, Baxter C, 37. Choopanya K, Martin M, Suntharasamai P, Sangkum U, Mock PA, Mansoor LE, et al. Effectiveness and safety of tenofovir gel, an antiretroviral Leethochawalit M, et al. Antiretroviral prophylaxis for HIV infection in injecting microbicide, for the prevention of HIV infection in women. Science (2010) drug users in Bangkok, Thailand (the Bangkok tenofovir study): A randomised, 329:1168–74. doi: 10.1126/SCIENCE.1193748 double-blind, placebo-controlled phase 3 trial. Lancet (2013) 381:2083–90. doi: 10.1016/S0140-6736(13)61127-7 18. Grant RM, Lama JR, Anderson PL, McMahan V, Liu AY, Vargas L, et al. Preexposure chemoprophylaxis for HIV prevention in men who have sex with 38. Gilead. Gilead (2020). Available at: https://www.gilead.com/news-and-press/ men. N Engl J Med (2010) 363:2587. doi: 10.1056/NEJMOA1011205 company-statements/gilead-announces-new-arm-of-hiv-womens-prevention-study. 19. McCormack S, Dunn DT, Desai M, Dolling DI, Gafos M, Gilson R, et al. 39. Celum C, Hosek S, Tsholwana M, Kassim S, Mukaka S, Dye BJ, et al. PrEP Pre-exposure prophylaxis to prevent the acquisition of HIV-1 infection (PROUD): uptake, persistence, adherence, and effect of retrospective drug level feedback on Effectiveness results from the pilot phase of a pragmatic open-label randomised PrEP adherence among young women in southern Africa: Results from HPTN 082, trial. Lancet (London England) (2016) 387:53–60. doi: 10.1016/S0140-6736(15) a randomized controlled trial. PloS Med (2021) 18:e1003670. doi: 10.1371/ 00056-2 JOURNAL.PMED.1003670 20. Thigpen MC, Kebaabetswe PM, Paxton LA, Smith DK, Rose CE, Segolodi 40. U.S. Food and Drug Administration. FDA Approves first drug for reducing TM, et al. Antiretroviral preexposure prophylaxis for heterosexual HIV the risk of sexually acquired HIV infection | HIV.gov (2012). Available at: https:// transmission in Botswana a BS TRACT. N Engl J Med (2012) 367:423–57. www.hiv.gov/blog/fda-approves-first-drug-for-reducing-the-risk-of-sexually- doi: 10.1056/NEJMoa1110711 acquired-hiv-infection (Accessed September 27, 2022). 21. Baeten JM, Donnell D, Ndase P, Mugo NR, Campbell JD, Wangisi J, et al. 41. Fonner VA, Dalglish SL, Kennedy CE, Baggaley R, O’Reilly KR, Koechlin Antiretroviral prophylaxis for HIV prevention in heterosexual men and women. N FM, et al. Effectiveness and safety of oral HIV preexposure prophylaxis for all Engl J Med (2012) 367:399–410. doi: 10.1056/NEJMOA1108524/SUPPL_FILE/ populations. AIDS (2016) 30:1973–83. doi: 10.1097/QAD.0000000000001145 NEJMOA1108524_DISCLOSURES.PDF 42. World Health Organization. GUIDELINE ON WHEN TO START 22. Van Damme L, Corneli A, Ahmed K, Agot K, Lombaard J, Kapiga S, et al. ANTIRETROVIRAL THERAPY AND ON PRE-EXPOSURE PROPHYLAXIS FOR Preexposure prophylaxis for HIV infection among African women. N Engl J Med HIV GUIDELINES. Geneva: World Health Organization (2015). (2012) 367:411–22. doi: 10.1056/NEJMOA1202614 43. Donnell D, Baeten JM, Bumpus NN, Brantley J, Bangsberg DR, Haberer JE, 23. Marrazzo JM, Ramjee G, Richardson BA, Gomez K, Mgodi N, Nair G, et al. et al. HIV Protective efficacy and correlates of tenofovir blood concentrations in a Tenofovir-based preexposure prophylaxis for HIV infection among African clinical trial of PrEP for HIV prevention. J Acquir Immune Defic Syndr (2014) women. N Engl J Med (2015) 372:509–18. doi: 10.1056/NEJMOA1402269 66:340. doi: 10.1097/QAI.0000000000000172 24. Cohen MS, Chen YQ, McCauley M, Gamble T, Hosseinipour MC, 44. Molina J-M, Capitant C, Spire B, Pialoux G, Cotte L, Charreau I, et al. On- Kumarasamy N, et al. Prevention of HIV-1 infection with early antiretroviral demand preexposure prophylaxis in men at high risk for HIV-1 infection. N Engl J therapy. N Engl J Med (2011) 365:493–505. doi: 10.1056/NEJMOA1105243/ Med (2015) 373:2237–46. doi: 10.1056/NEJMOA1506273/SUPPL_FILE/ SUPPL_FILE/NEJMOA1105243_DISCLOSURES.PDF NEJMOA1506273_DISCLOSURES.PDF 25. Delany-Moretlwe S, Lombard C, Baron D, Bekker LG, Nkala B, Ahmed K, 45. Mutua G, Sanders E, Mugo P, Anzala O, Haberer JE, Bangsberg D, et al. et al. Tenofovir 1% vaginal gel for prevention of HIV-1 infection in women in south Safety and adherence to intermittent pre-exposure prophylaxis (PrEP) for HIV-1 in Africa (FACTS-001): A phase 3, randomised, double-blind, placebo-controlled African men who have sex with men and female sex workers. PloS One (2012) 7: trial. Lancet Infect Dis (2018) 18:1241–50. doi: 10.1016/S1473-3099(18)30428-6 e33103. doi: 10.1371/JOURNAL.PONE.0033103 Frontiers in Immunology 15 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 46. Kibengo FM, Ruzagira E, Katende D, Bwanika AN, Bahemuka U, Haberer 64. Celum CL, Delany-Moretlwe S, Baeten JM, Straten A, Hosek S, Bukusi EA, JE, et al. Safety, adherence and acceptability of intermittent tenofovir/emtricitabine et al. HIV Pre-exposure prophylaxis for adolescent girls and young women in as HIV pre-exposure prophylaxis (PrEP) among HIV-uninfected Ugandan Africa: From efficacy trials to delivery. J Int AIDS Soc (2019) 22(Suppl 4):e25298. volunteers living in HIV-serodiscordant relationships: A randomized, clinical doi: 10.1002/JIA2.25298 trial. PloS One (2013) 8:e74314. doi: 10.1371/JOURNAL.PONE.0074314 65. Comins CA, Rucinski KB, Baral S, Abebe SA, Mulu A, Schwartz SR. 47. Bekker LG, Roux S, Sebastien E, Yola N, Amico KR, Hughes JP, et al. Daily Vulnerability profiles and prevalence of HIV and other sexually transmitted and non-daily pre-exposure prophylaxis in African women (HPTN 067/ADAPT infections among adolescent girls and young women in Ethiopia: A latent class cape town trial): a randomised, open-label, phase 2 trial. Lancet HIV (2018) 5:e68– analysis. PloS One (2020) 15:e0232598. doi: 10.1371/JOURNAL.PONE.0232598 78. doi: 10.1016/S2352-3018(17)30156-X 66. Murewanhema G, Musuka G, Moyo P, Moyo E, Dzinamarira T. HIV And 48. Brown ER, Hendrix CW, van der Straten A, Kiweewa FM, Mgodi NM, adolescent girls and young women in sub-Saharan Africa: A call for expedited Palanee-Philips T, et al. Greater dapivirine release from the dapivirine vaginal ring action to reduce new infections. IJID Reg (2022) 5:30–2. doi: 10.1016/ is correlated with lower risk of HIV-1 acquisition: A secondary analysis from a J.IJREGI.2022.08.009 randomized, placebo-controlled trial. J Int AIDS Soc (2020) 23:e25634. 67. Taylor TN, Weedon J, Golub ET, Karpiak SE, Gandhi M, Cohen MH, et al. doi: 10.1002/JIA2.25634 Longitudinal trends in sexual behaviors with advancing age and menopause among 49. WHO. WHO recommends the dapivirine vaginal ring as a new choice for women with and without HIV-1 infection. AIDS Behav (2015) 19:931. doi: 10.1007/ HIV prevention for women at substantial risk of HIV infection (2021). Available at: S10461-014-0901-1 https://www.who.int/news/item/26-01-2021-who-recommends-the-dapivirine- 68. Massad LS, Evans CT, Wilson TE, Golub ET, Goparaju L, Howard A, et al. vaginal-ring-as-a-new-choice-for-hiv-prevention-for-women-at-substantial-risk- Impact of menopause on condom use by HIV-seropositive and comparison of-hiv-infection (Accessed September 27, 2022). seronegative women. J Acquir Immune Defic Syndr (2008) 47:401–2. 50. Landovitz RJ, Li S, Grinsztejn B, Dawood H, Liu AY, Magnus M, et al. Safety, doi: 10.1097/QAI.0B013E31815E7466 tolerability, and pharmacokinetics of long-acting injectable cabotegravir in low-risk 69. Rosenberg MS, Gó mez-Olivé FX, Rohr JK, Houle BC, Kabudula CW, HIV-uninfected individuals: HPTN 077, a phase 2a randomized controlled trial. Wagner RG, et al. Sexual behaviors and HIV status: A population-based study PloS Med (2018) 15:e1002690. doi: 10.1371/JOURNAL.PMED.1002690 among older adults in rural south Africa. J Acquir Immune Defic Syndr (2017) 74: 51. Phillips AN, Bansi-Matharu L, Cambiano V, Ehrenkranz P, Serenata C, e9. doi: 10.1097/QAI.0000000000001173 Venter F, et al. The potential role of long-acting injectable cabotegravir-rilpivirine 70. Looby SE. Symptoms of menopause or symptoms of HIV? untangling the in the treatment of HIV in sub-Saharan Africa: A modelling analysis. Lancet Glob knot. Menopause (2018) 25:728–30. doi: 10.1097/GME.0000000000001129 Heal (2021) 9:e620–7. doi: 10.1016/S2214-109X(21)00025-5 71. Looby SE, Psaros C, Raggio G, Rivard C, Smeaton L, Shifren J, et al. 52. Deutsch MB, Glidden DV, Sevelius J, Keatley J, McMahan V, Guanira J, Association between HIV-status and psychological symptoms in perimenopausal et al. HIV Pre-exposure prophylaxis in transgender women: a subgroup analysis of women. Menopause (2018) 25:648. doi: 10.1097/GME.0000000000001058 the iPrEx trial. Lancet HIV (2015) 2:e512–9. doi: 10.1016/S2352-3018(15)00206-4 72. Solomon D, Sabin CA, Burns F, Gilson R, Allan S, de Ruiter A, et al. The 53. Mayer KH, Molina JM, Thompson MA, Anderson PL, Mounzer KC, De association between severe menopausal symptoms and engagement with HIV care Wet JJ, et al. Emtricitabine and tenofovir alafenamide vs emtricitabine and and treatment in women living with HIV. AIDS Care (2021) 33:101–8. tenofovir disoproxil fumarate for HIV pre-exposure prophylaxis (DISCOVER): doi: 10.1080/09540121.2020.1748559 Primary results from a randomised, double-blind, multicentre, active-controlled, phase 3, non-inferiority trial. Lancet (London England) (2020) 396:239–54. 73. Meditz AL, Moreau KL, MaWhinney S, Gozansky WS, Melander K, Kohrt doi: 10.1016/S0140-6736(20)31065-5 WM, et al. CCR5 expression is elevated on endocervical CD4+ T cells in healthy postmenopausal women. J Acquir Immune Defic Syndr (2012) 59:221–8. 54. Cespedes MS, Das M, Yager J, Prins M, Krznaric I, de JJ, et al. Gender doi: 10.1097/QAI.0B013E31823FD215 affirming hormones do not affect the exposure and efficacy of F/TDF or F/TAF for HIV preexposure prophylaxis: A subgroup analysis from the DISCOVER trial. 74. Farage MA, Maibach HI. Morphology and physiological changes of genital Transgender Health. (2022). doi: 10.1089/TRGH.2022.0048 skin and mucosa. Curr Probl Dermatol (2011) 40:9–19. doi: 10.1159/000321042 55. Grant RM, Pellegrini M, Defechereux PA, Anderson PL, Yu M, Glidden DV, 75. Chappell CA, Isaacs CE, Xu W, Meyn LA, Uranker K, Dezzutti CS, et al. The et al. Sex hormone therapy and tenofovir diphosphate concentration in dried blood effect of menopause on the innate anti-viral activity of cervicovaginal lavage. Am J spots: Primary results of the interactions between antiretrovirals and transgender Obstet Gynecol (2015) 213:204.e1. doi: 10.1016/J.AJOG.2015.03.045 hormones study. Clin Infect Dis (2021) 73:e2117–23. doi: 10.1093/CID/CIAA1160 76. Nicol MR, Brewers LM, Kashuba ADM, Sykes C. The role of menopause in 56. Grinsztejn B. Transgender women (TGW) in HPTN 083: An evaluation of tenofovir diphosphate and emtricitabine triphosphate concentrations in cervical safety, efficacy, and gender affirming hormonal therapy (GAHT) interactions with tissue. AIDS (2018) 32:11. doi: 10.1097/QAD.0000000000001678 long-acting cabotegravir (CAB-LA) . Available at: https://programme.aids2022.org/ 77. Molina J, Segal-Maurer S, Stellbrink H, Castagna A, Al. E. Efficacy and safety Abstract/Abstract/?abstractid=12707. of long-acting subcutaneous lenacapavir in phase 2/3 in heavily treatment- 57. Thomson KA, Hughes J, Baeten JM, John-Stewart G, Celum C, Cohen CR, experienced people with HIV: Week 26 results (Capella study). J Int AIDS Soc et al. Increased risk of HIV acquisition among women throughout pregnancy and (2021) 24(S4):75–6. doi: 10.1002/jia2.25755 during the postpartum period: A prospective per-Coital-Act analysis among 78. Gupta S, Berhe M, Crofoot G, Sims J, Benson P, Ramgopal M, et al. Long- women with HIV-infected partners. J Infect Dis (2018) 218:16–25. doi: 10.1093/ acting subcutaneous lenacapavir dosed every six months as part of a combination INFDIS/JIY113 regimen in treatment-naive people with HIV: Interim 16-week results of a 58. Guffey MB, Richardson B, Husnik M, Makanani B, Chilongozi D, Yu E, et al. randomized, open-label, phase 2 induction-maintenance study (CALIBRATE). J HPTN 035 phase II/IIb randomised safety and effectiveness study of the vaginal Int AIDS Soc (2021) 24(S4):13–4. doi: 10.1002/jia2.25755 microbicides BufferGel and 0.5% PRO 2000 for the prevention of sexually 79. Dvory-Sobol H, Shaik N, Callebaut C, Rhee MS. Lenacapavir: A first-in-class transmitted infections in women. Sex Transm Infect (2014) 90:363–9. HIV-1 capsid inhibitor. Curr Opin HIV AIDS (2022) 17:15–21. doi: 10.1097/ doi: 10.1136/SEXTRANS-2014-051537 COH.0000000000000713 59. Committee on Ethics. ACOG committee opinion no. 646: Ethical 80. Matthews RP, Patel M, Barrett SE, Haspeslagh L, Reynders T, Zhang S, et al. considerations for including women as research participants. Obstet Gynecol Safety and pharmacokinetics of islatravir subdermal implant for HIV-1 pre- (2015) 126:e100–7. doi: 10.1097/AOG.0000000000001150 exposure prophylaxis: a randomized, placebo-controlled phase 1 trial. Nat Med 60. Lyerly AD, Beigi R, Bekker LG, Chi BH, Cohn SE, Diallo DD, et al. Ending (2021) 27:1712–7. doi: 10.1038/S41591-021-01479-3 the evidence gap for pregnancy, HIV and co-infections: Ethics guidance from the 81. Barreiro P, Soriano V. News from CROI 2022 – caveats using antiretrovirals PHASES project. J Int AIDS Soc (2021) 24:e25846. doi: 10.1002/JIA2.25846 as HIV prophylaxis. AIDS Rev (2022) 24:98–9. doi: 10.24875/ 61. Momper JD, Wang J, Stek A, Shapiro DE, Scott GB, Paul ME, et al. AIDSREV.M22000049 Pharmacokinetics of darunavir and cobicistat in pregnant and postpartum 82. Gunawardana M, Remedios-Chan M, Sanchez D, Webster S, Castonguay women with HIV. AIDS (2021) 35:1191–9. doi: 10.1097/QAD.0000000000002857 AE, Webster P, et al. Fundamental aspects of long-acting tenofovir alafenamide 62. Callahan R, Nanda K, Kapiga S, Malahleha M, Mandala J, Ogada T, et al. delivery from subdermal implants for HIV prophylaxis. Sci Rep (2022) 12:121–25. Pregnancy and contraceptive use among women participating in the FEM-PrEP trial. J doi: 10.1038/s41598-022-11020-2 Acquir Immune Defic Syndr (2015) 68:196–203. doi: 10.1097/QAI.0000000000000413 83. Flexner C. The future of long-acting agents for preexposure prophylaxis. 63. Murnane PM, Heffron R, Ronald A, Bukusi EA, Donnell D, Mugo NR, et al. Curr Opin HIV AIDS (2022) 17:192–8. doi: 10.1097/COH.0000000000000735 Pre-exposure prophylaxis for HIV-1 prevention does not diminish the pregnancy 84. Palanee-Phillips T, Baeten JM. Topical delivery of long-acting antiretrovirals prevention effectiveness of hormonal contraception. AIDS (2014) 28:1825. to prevent HIV acquisition. Curr Opin HIV AIDS (2020) 15:42–8. doi: 10.1097/ doi: 10.1097/QAD.0000000000000290 COH.0000000000000598 Frontiers in Immunology 16 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 85. Hendrix CW, Chen BA, Guddera V, Hoesley C, Justman J, Nakabiito C, infections and the genital microbiome. J Reprod Immunol (2021) 145:103291–7. et al. MTN-001: Randomized pharmacokinetic cross-over study comparing doi: 10.1016/J.JRI.2021.103291 tenofovir vaginal gel and oral tablets in vaginal tissue and other compartments. 105. Masson L, Passmore JAS, Liebenberg LJ, Werner L, Baxter C, Arnold KB, PloS One (2013) 8:e55013. doi: 10.1371/JOURNAL.PONE.0055013 et al. Genital inflammation and the risk of HIV acquisition in women. Clin Infect 86. Schwartz JL, Rountree W, Kashuba ADM, Brache V, Creinin MD, Dis (2015) 61:260–9. doi: 10.1093/CID/CIV298 Poindexter A, et al. A multi-compartment, single and multiple dose 106. Passmore JAS, Jaspan HB. Vaginal microbes, inflammation, and HIV risk pharmacokinetic study of the vaginal candidate microbicide 1% tenofovir gel. in African women. Lancet Infect Dis (2018) 18:483–4. doi: 10.1016/S1473-3099(18) PloS One (2011) 6:e25974. doi: 10.1371/JOURNAL.PONE.0025974 30061-6 87. Louissaint NA, Cao YJ, Skipper PL, Liberman RG, Tannenbaum SR, 107. Dabee S, Barnabas SL, Lennard KS, Jaumdally SZ, Gamieldien H, Balle C, Nimmagadda S, et al. Single dose pharmacokinetics of oral tenofovir in plasma, et al. Defining characteristics of genital health in south African adolescent girls and peripheral blood mononuclear cells, colonic tissue, and vaginal tissue. AIDS Res young women at high risk for HIV infection. PloS One (2019) 14:e0213975. Hum Retroviruses (2013) 29:1443. doi: 10.1089/AID.2013.0044 doi: 10.1371/JOURNAL.PONE.0213975 88. Herrera C, Lwanga J, Lee M, Mantori S, Amara A, Else L, et al. 108. Gosmann C, Anahtar MN, Handley SA, Farcasanu M, Abu-Ali G, Bowman Pharmacokinetic/pharmacodynamic investigation of raltegravir with or without BA, et al. Lactobacillus-deficient cervicovaginal bacterial communities are lamivudine in the context of HIV-1 pre-exposure prophylaxis (PrEP). J Antimicrob associated with increased HIV acquisition in young south African women. Chemother (2021) 76:2129–36. doi: 10.1093/JAC/DKAB136 Immunity (2017) 46:29–37. doi: 10.1016/J.IMMUNI.2016.12.013 89. Sadik Shaik J, Weld ED, Edick S, Fuchs E, Riddler S, Marzinke MA, et al. 109. Arnold KB, Burgener A, Birse K, Romas L, Dunphy LJ, Shahabi K, et al. Multicompartmental pharmacokinetic evaluation of long-acting cabotegravir in Increased levels of inflammatory cytokines in the female reproductive tract are healthy adults for HIV preexposure prophylaxis. Br J Clin Pharmacol (2021) associated with altered expression of proteases, mucosal barrier proteins, and an 88:1667–8. doi: 10.1111/bcp.14980 influx of HIV-susceptible target cells. Mucosal Immunol (2016) 9:194–205. 90. Shen Z, Fahey JV, Bodwell JE, Rodriguez-Garcia M, Kashuba ADM, Wira doi: 10.1038/MI.2015.51 CR. Sex hormones regulate tenofovir-diphosphate in female reproductive tract cells 110. Anahtar MN, Byrne EH, Doherty KE, Bowman BA, Yamamoto HS, in culture. PloS One (2014) 9:e100863. doi: 10.1371/JOURNAL.PONE.0100863 Soumillon M, et al. Cervicovaginal bacteria are a major modulator of host 91. Chuchuen O, Maher JR, Henderson MH, Desoto M, Rohan LC, Wax A, inflammatory responses in the female genital tract. Immunity (2015) 42:965–76. et al. Label-free analysis of tenofovir delivery to vaginal tissue using co-registered doi: 10.1016/J.IMMUNI.2015.04.019 confocal raman spectroscopy and optical coherence tomography. PloS One (2017) 111. Lennard K, Dabee S, Barnabas SL, Havyarimana E, Blakney A, Jaumdally 12:e0185633. doi: 10.1371/JOURNAL.PONE.0185633 SZ, et al. Microbial composition predicts genital tract inflammation and persistent 92. Shen Z, Rodriguez-Garcia M, Patel MV, Bodwell J, Wira CR. Epithelial cells bacterial vaginosis in south African adolescent females. Infect Immun (2017) 86: and fibroblasts from the human female reproductive tract accumulate and release e00410-17. doi: 10.1128/IAI.00410-17 TFV and TAF to sustain inhibition of HIV infection of CD4+ T cells. Sci Rep (2019) 112. Alcaide ML, Rodriguez VJ, Brown MR, Pallikkuth S, Arheart K, Martinez 9:1864–77. doi: 10.1038/S41598-018-38205-Y O, et al. High levels of inflammatory cytokines in the reproductive tract of women 93. Liebenberg LJP, Passmore J-AS, Osman F, Jewanraj J, Mtshali A, Gerardo with BV and engaging in intravaginal douching: A cross-sectional study of Garcia-Lerma J, et al. Genital immune cell activation and tenofovir gel efficacy: A participants in the women interagency HIV study. AIDS Res Hum Retroviruses case-control study. Clin Infect Dis (2022) 75:1088–91. doi: 10.1093/CID/CIAC115 (2017) 33:309. doi: 10.1089/AID.2016.0187 94. Gross M, Holte SE, Marmor M, Mwatha A, Koblin BA, Mayer KH. Anal sex 113. Wessels JM, Felker AM, Dupont HA, Kaushic C. The relationship between among HIV-seronegative women at high risk of HIV exposure. the HIVNET sex hormones, the vaginal microbiome and immunity in HIV-1 susceptibility in vaccine preparedness study 2 protocol team. J Acquir Immune Defic Syndr (2000) women. Dis Model Mech (2018) 11:dmm035147. doi: 10.1242/DMM.035147 24:393–8. doi: 10.1097/00126334-200008010-00015 114. Bradley F, Birse K, Hasselrot K, Noël-Romas L, Introini A, Wefer H, et al. 95. Exner TM, Correale J, Carballo-Dié guez A, Salomon L, Morrow KM, The vaginal microbiome amplifies sex hormone-associated cyclic changes in Dolezal C, et al. Women’s anal sex practices: Implications for formulation and cervicovaginal inflammation and epithelial barrier disruption. Am J Reprod promotion of a rectal microbicide. AIDS Educ Prev (2008) 20:148–59. doi: 10.1521/ Immunol (2018) 80:e12863. doi: 10.1111/AJI.12863 AEAP.2008.20.2.148 115. McKinnon LR, Liebenberg LJ, Yende-Zuma N, Archary D, Ngcapu S, Sivro 96. McGowan I, Taylor DJ. Heterosexual anal intercourse has the potential to A, et al. Genital inflammation undermines the effectiveness of tenofovir gel in cause a significant loss of power in vaginal microbicide effectiveness studies. Sex preventing HIV acquisition in women. Nat Med (2018) 24:491–6. doi: 10.1038/ Transm Dis (2010) 37:361–4. doi: 10.1097/OLQ.0B013E3181CD70C2 NM.4506 97. Baggaley RF, White RG, Boily MC. HIV Transmission risk through anal 116. Rodriguez-Garcia M, Patel MV, Shen Z, Bodwell J, Rossoll RM, Wira CR. intercourse: systematic review, meta-analysis and implications for HIV prevention. Tenofovir inhibits wound healing of epithelial cells and fibroblasts from the upper Int J Epidemiol (2010) 39:1048–63. doi: 10.1093/IJE/DYQ057 and lower human female reproductive tract. Sci Rep (2017) 2017 71:7. doi: 10.1038/ 98. Stannah J, Silhol R, Elmes J, Owen B, Shacklett BL, Anton P, et al. Increases srep45725 in HIV incidence following receptive anal intercourse among women: A systematic 117. Romas L, Birse K, Mayer KH, Abou M, Westmacott G, Giguere R, et al. review and meta-analysis. AIDS Behav (2020) 24:667–81. doi: 10.1007/S10461-019- Rectal 1% tenofovir gel use associates with altered epidermal protein expression. 02651-0/TABLES/2 AIDS Res Hum Retroviruses (2016) 32:1005. doi: 10.1089/AID.2015.0381 99. Nuttall J, Kashuba A, Wang R, White N, Allen P, Roberts J, et al. 118. Keller MJ, Wood L, Billingsley JM, Ray LL, Goymer J, Sinclair S, et al. Pharmacokinetics of tenofovir following intravaginal and intrarectal Tenofovir disoproxil fumarate intravaginal ring for HIV pre-exposure prophylaxis administration of tenofovir gel to rhesus macaques. Antimicrob Agents in sexually active women: a phase 1, single-blind, randomised, controlled trial. Chemother (2012) 56:103–9. doi: 10.1128/AAC.00597-11 Lancet HIV (2019) 6:e498–508. doi: 10.1016/S2352-3018(19)30145-6 100. Boily MC, Baggaley RF, Wang L, Masse B, White RG, Hayes RJ, et al. 119. Neidleman JA, Chen JC, Kohgadai N, Müller JA, Laustsen A, Heterosexual risk of HIV-1 infection per sexual act: Systematic review and meta- Thavachelvam K, et al. Mucosal stromal fibroblasts markedly enhance HIV analysis of observational studies. Lancet Infect Dis (2009) 9:118–29. doi: 10.1016/ infection of CD4+ T cells. PloS Pathog (2017) 13:e1006163. doi: 10.1371/ S1473-3099(09)70021-0 JOURNAL.PPAT.1006163 101. Baggaley RF, Owen BN, Silhol R, Elmes J, Anton P, McGowan I, et al. Does 120. McClelland RS, Lingappa JR, Srinivasan S, Kinuthia J, John-Stewart GC, per-act HIV-1 transmission risk through anal sex vary by gender? an updated Jaoko W, et al. Evaluation of the association between the concentrations of key systematic review and meta-analysis. Am J Reprod Immunol (2018) 80:e13039. vaginal bacteria and the increased risk of HIV acquisition in African women from doi: 10.1111/AJI.13039 five cohorts: A nested case-control study. Lancet Infect Dis (2018) 18:554–64. 102. Günaydın G, Edfeldt G, Garber DA, Asghar M, Noёl-Romas L, Burgener doi: 10.1016/S1473-3099(18)30058-6 A, et al. Impact of q-griffithsin anti-HIV microbicide gel in non-human primates: 121. McKinnon LR, Achilles SL, Bradshaw CS, Burgener A, Crucitti T, Fredricks In situ analyses of epithelial and immune cell markers in rectal mucosa. Sci Rep DN, et al. The evolving facets of bacterial vaginosis: Implications for HIV transmission. (2019) 9:18120–31. doi: 10.1038/S41598-019-54493-4 AIDS Res Hum Retroviruses (2019) 35:219–28. doi: 10.1089/AID.2018.0304 103. Makarova N, Singletary T, Peet MM, Mitchell J, Holder A, Dinh C, et al. 122. Tachedjian G, O’Hanlon DE, Ravel J. The implausible “in vivo” role of Pharmacokinetics and efficacy of topical inserts containing tenofovir alafenamide hydrogen peroxide as an antimicrobial factor produced by vaginal microbiota. fumarate and elvitegravir administered rectally in macaques. eBioMedicine (2022) Microbiome (2018) 6:1–5. doi: 10.1186/S40168-018-0418-3/TABLES/1 86:104338. doi: 10.1016/J.EBIOM.2022.104338 123. Tyssen D, Wang Y-Y, Hayward JA, Agius PA, DeLong K, Aldunate M, 104. Mtshali A, Ngcapu S, Mindel A, Garrett N, Liebenberg L. HIV et al. Anti-HIV-1 activity of lactic acid in human cervicovaginal fluid. mSphere Susceptibility in women: The roles of genital inflammation, sexually transmitted (2018) 3:e00055-18. doi: 10.1128/MSPHERE.00055-18 Frontiers in Immunology 17 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 124. Passmore JAS, Jaspan HB, Masson L. Genital inflammation, immune 144. Sharkey DJ, Tremellen KP, Jasper MJ, Gemzell-Danielsson K, Robertson activation and risk of sexual HIV acquisition. Curr Opin HIV AIDS (2016) SA. Seminal fluid induces leukocyte recruitment and cytokine and chemokine 11:156–62. doi: 10.1097/COH.0000000000000232 mRNA expression in the human cervix after coitus. J Immunol (2012) 188:2445–54. 125. Klatt NR, Cheu R, Birse K, Zevin AS, Perner M, Noël-Romas L, et al. doi: 10.4049/jimmunol.1102736 Vaginal bacteria modify HIV tenofovir microbicide efficacy in African women. 145. Sharkey D, Macpherson A, Tremellen K, Robertson S. Seminal plasma Science (2017) 356:938–45. doi: 10.1126/SCIENCE.AAI9383 differentially regulates inflammatory cytokine gene expression in human cervical 126. Birse KD, Kratzer K, Zuend CF, Mutch S, Noël-Romas L, Lamont A, et al. and vaginal epithelial cells. Mol Hum Reprod (2007) 13:491–501. doi: 10.1093/ The neovaginal microbiome of transgender women post-gender reassignment MOLEHR/GAM028 surgery. Microbiome (2020) 8:1–13. doi: 10.1186/S40168-020-00804-1/FIGURES/3 146. Venn A, Watson LF, Hemminki E, Healy D, Bruinsma FJ. Mortality in a 127. Taneva E, Sinclair S, Mesquita PM, Weinrick B, Cameron SA, Cheshenko cohort of IVF patients. Hum Reprod (2001) 16:2691–6. doi: 10.1093/humrep N, et al. Vaginal microbiome modulates topical antiretroviral drug 147. Bruewer M, Utech M, Ivanov AI, Hopkins AM, Parkos CA, Nusrat A. pharmacokinetics. JCI Insight (2018) 3:e99545. doi: 10.1172/JCI.INSIGHT.99545 Interferon-gamma induces internalization of epithelial tight junction proteins via a 128. Bunge KE, Dezzutti CS, Hendrix CW, Marzinke MA, Spiegel HML, macropinocytosis-like process. FASEB J (2005) 19:923–33. doi: 10.1096/FJ.04- Moncla BJ, et al. FAME-04: A phase 1 trial to assess the safety, acceptability, 3260COM pharmacokinetics and pharmacodynamics of film and gel formulations of 148. Al-Sadi RM, Ma TY. IL-1b causes an increase in intestinal epithelial tight tenofovir. J Int AIDS Soc (2018) 21:e25156. doi: 10.1002/JIA2.25156 junction permeability. J Immunol (2007) 178:4641. doi: 10.4049/ 129. Thurman AR, Schwartz JL, Ravel J, Gajer P, Marzinke MA, Yousefieh N, JIMMUNOL.178.7.4641 et al. Vaginal microbiota and mucosal pharmacokinetics of tenofovir in healthy 149. Gallo MF, Warner L, King CC, Sobel JD, Klein RS, Cu-Uvin S, et al. women using tenofovir and tenofovir/levonorgestrel vaginal rings. PloS One (2019) Association between semen exposure and incident bacterial vaginosis. Infect Dis 14:e0217229. doi: 10.1371/JOURNAL.PONE.0217229 Obstet Gynecol (2011) 2011:842652–61. doi: 10.1155/2011/842652 130. Heffron R, McClelland RS, Celum C, Cohen CR, Mugo N, Bukusi E, et al. 150. Verstraelen H, Verhelst R, Vaneechoutte M, Temmerman M. The Efficacy of oral pre-exposure prophylaxis (PrEP) for HIV among women with epidemiology of bacterial vaginosis in relation to sexual behaviour. BMC Infect abnormal vaginal microbiota: A post-hoc analysis of the randomised, placebo- Dis (2010) 10:172–6. doi: 10.1186/1471-2334-10-81 controlled partners PrEP study. Lancet HIV (2017) 4: e449–56. doi: 10.1016/S2352- 151. Turner AN, Reese PC, Snead MC, Fields K, Ervin M, Kourtis AP, et al. 3018(17)30110-8 Recent biomarker-confirmed unprotected vaginal sex, but not self-reported 131. Cheu RK, Gustin AT, Lee C, Schifanella L, Miller CJ, Ha A, et al. Impact of unprotected sex, is associated with recurrent bacterial vaginosis. Sex Transm Dis vaginal microbiome communities on HIV antiretroviral-based pre-exposure (2016) 43:172–6. doi: 10.1097/OLQ.0000000000000414 prophylaxis (PrEP) drug metabolism. PloS Pathog (2020) 16:e1009024. 152. Martellini JA, Cole AL, Venkataraman N, Quinn GA, Svoboda P, doi: 10.1371/JOURNAL.PPAT.1009024 Gangrade BK, et al. Cationic polypeptides contribute to the anti-HIV-1 activity 132. Gustin A, Cromarty R, Schifanella L, Klatt NR. Microbial mismanagement: of human seminal plasma. FASEB J (2009) 23:3609–18. doi: 10.1096/FJ.09-131961 how inadequate treatments for vaginal dysbiosis drive the HIV epidemic in women. 153. Politch JA, Tucker L, Bowman FP, Anderson DJ. Concentrations and Semin Immunol (2021) 51:101482. doi: 10.1016/J.SMIM.2021.101482 significance of cytokines and other immunologic factors in semen of healthy fertile 133. Lagenaur LA, Hemmerling A, Chiu C, Miller S, Lee PP, Cohen CR, et al. men. Hum Reprod (2007) 22:2928–35. doi: 10.1093/humrep/dem281 Connecting the dots: Translating the vaginal microbiome into a drug. J Infect Dis 154. Zirafi O, Kim KA, Roan NR, Kluge SF, Müller JA, Jiang S, et al. Semen (2021) 223:S296. doi: 10.1093/INFDIS/JIAA676 enhances HIV infectivity and impairs the antiviral efficacy of microbicides. Sci 134. Jewanraj J, Ngcapu S, Osman F, Mtshali A, Singh R, Mansoor LE, et al. The Transl Med (2014) 6:262ra157. doi: 10.1126/SCITRANSLMED.3009634/ impact of semen exposure on the immune and microbial environments of the SUPPL_FILE/6-262RA157_SM.PDF female genital tract. Front Reprod Heal (2020) 0:566559. doi: 10.3389/ 155. Herold BC, Chen BA, Salata RA, Marzinke MA, Kelly CW, Dezzutti CS, FRPH.2020.566559 et al. Impact of sex on the pharmacokinetics and pharmacodynamics of 1% 135. Cavarelli M, Le Grand R. The importance of semen leukocytes in HIV-1 tenofovir gel. Clin Infect Dis Off Publ Infect Dis Soc Am (2016) 62:375. transmission and the development of prevention strategies. Hum Vaccin doi: 10.1093/CID/CIV913 Immunother (2020) 16:2018–32. doi: 10.1080/21645515.2020.1765622 156. Keller MJ, Mesquita PMM, Torres NM, Cho S, Shust G, Madan RP, et al. 136. Jewanraj J, Ngcapu S, Liebenberg LJP. Semen: A modulator of female Postcoital bioavailability and antiviral activity of 0.5% PRO 2000 gel: Implications genital tract inflammation and a vector for HIV-1 transmission. Am J Reprod for future microbicide clinical trials. PloS One (2010) 5:e8781. doi: 10.1371/ Immunol (2021) 86:e13478. doi: 10.1111/AJI.13478 JOURNAL.PONE.0008781 137. Suphaphiphat K, Bernard-Stoecklin S, Gommet C, Delache B, Dereuddre- 157. Barnhart KT, Pretorius ES, Timbers K, Shera D, Shabbout M, Malamud D. Bosquet N, Kent SJ, et al. Innate and adaptive anti-SIV responses in macaque In vivo distribution of a vaginal gel: MRI evaluation of the effects of gel volume, semen: Implications for infectivity and risk of transmission. Front Immunol (2020) time and simulated intercourse. Contraception (2004) 70:498–505. doi: 10.1016/ 11:850. doi: 10.3389/fimmu.2020.00850 J.CONTRACEPTION.2004.06.013 138. Cavarelli M, Hua S, Hantour N, Tricot S, Tchitchek N, Gommet C, et al. 158. Barnhart K, Kulp JL, Rosen M, Shera DM. A randomized trial to determine Leukocytospermia induces intraepithelial recruitment of dendritic cells and the distribution of four topical gel formulations in the human vagina. increases SIV replication in colorectal tissue explants. Commun Biol (2021) Contraception (2009) 79:297–303. doi: 10.1016/J.CONTRACEPTION.2008.11.001 4:861–73. doi: 10.1038/S42003-021-02383-9 159. Wasserheit JN. Epidemiological synergy. interrelationships between 139. Berlier W, Cremel M, Hamzeh H, Lé vy R, Lucht F, Bourlet T, et al. Seminal human immunodeficiency virus infection and other sexually transmitted diseases plasma promotes the attraction of langerhans cells via the secretion of CCL20 by . Sex Transm Dis (1992) 19:61–77. vaginal epithelial cells: Involvement in the sexual transmission of HIV. Hum 160. Røttingen J, Cameron D, Garnett G. A systematic review of the Reprod (2006) 21:1135–42. doi: 10.1093/humrep/dei496 epidemiologie interactions between classic sexually transmitted diseases and 140. Joseph T, Zalenskaya IA, Sawyer LC, Chandra N, Doncel GF. Seminal HIV: How much really is known? Sex Transm Dis (2001) 28:579–97. plasma induces prostaglandin-endoperoxide synthase (PTGS) 2 expression in doi: 10.1097/00007435-200110000-00005 immortalized human vaginal cells: involvement of semen prostaglandin E2 in 161. Galvin SR, Cohen MS. The role of sexually transmitted diseases in HIV PTG S2 upre gu lation. Biol Reprod ( 201 3) 88:1–1 0. d o i: 1 0.1095 / transmission. Nat Rev Microbiol (2004) 2:33–42. doi: 10.1038/nrmicro794 BIOLREPROD.112.101956 162. Cohen MS, Council OD, Chen JS. Sexually transmitted infections and HIV 141. Chen JC, Brittni JA, Erikson DW, Piltonen TT, Barragan F, Chu S, et al. in the era of antiretroviral treatment and prevention: The biologic basis for Seminal plasma induces global transcriptomic changes associated with cell epidemiologic synergy. J Int AIDS Soc (2019) 22:e25355. doi: 10.1002/JIA2.25355 migration, proliferation and viability in endometrial epithelial cells and stromal fibroblasts - PubMed. Hum Reprod (2014) 29:1255–70. doi: 10.1093/humrep/ 163. Jin F, Prestage GP, Prestage GP, Imrie J, Kippax SC, Donovan B, et al. Anal deu047 sexually transmitted infections and risk of HIV infection in homosexual men article. JAIDS J Acquir Immune Defic Syndr (2009) 53:144–9. doi: 10.1097/QAI.0b013e3181b48f33 142. Rametse CL, Adefuye AO, Olivier AJ, Curry L, Gamieldien H, Burgers WA, et al. Inflammatory cytokine profiles of semen influence cytokine responses of 164. Barbee LA, Khosropour CM, Dombrowksi JC, Golden MR. New HIV cervicovaginal epithelial cells. Front Immunol (2018) 9:2721. doi: 10.3389/ diagnosis independently associated with rectal gonorrhea and chlamydia in men fimmu.2018.02721 who have sex with men. Sex Transm Dis (2017) 44:385. doi: 10.1097/ OLQ.0000000000000614 143. Introini A, Boström S, Bradley F, Gibbs A, Glaessgen A, Tjernlund A, et al. Seminal plasma induces inflammation and enhances HIV-1 replication in human 165. Abdool Karim SS, Baxter C, Passmore JAS, McKinnon LR, Williams BL. cervical tissue explants. PloS Pathog (2017) 13:e1006402. doi: 10.1371/ The genital tract and rectal microbiomes: Their role in HIV susceptibility and journal.ppat.1006402 prevention in women. J Int AIDS Soc (2019) 22:e25300. doi: 10.1002/JIA2.25300 Frontiers in Immunology 18 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 166. Mwatelah R, McKinnon LR, Baxter C, Abdool Karim Q, Abdool Karim SS. 185. Ahmed K, Baeten JM, Beksinska M, Bekker LG, Bukusi EA, Donnell D, Mechanisms of sexually transmitted infection-induced inflammation in women: e t a l . H I V I n c i d e n c e am o n g w o m e n u s i n g i nt r a m u s c u l a r d e p o t implications for HIV risk. J Int AIDS Soc (2019) 22:e25346. doi: 10.1002/ medroxyprogesterone acetate, a copper intrauterine device, or a levonorgestrel JIA2.25346 implant for contraception: a randomised, multicentre, open-label trial. Lancet 167. Kharsany ABM, McKinnon LR, Lewis L, Cawood C, Khanyile D, Maseko (2019) 394:303–13. doi: 10.1016/S0140-6736(19)31288-7 DV, et al. Population prevalence of sexually transmitted infections in a high HIV 186. El-Ibiary SY, Cocohoba JM. Effects of HIV antiretrovirals on the burden district in KwaZulu-natal, south Africa: Implications for HIV epidemic pharmacokinetics of hormonal contraceptives. Eur J Contracept Reprod Health control. Int J Infect Dis (2020) 98:130–7. doi: 10.1016/J.IJID.2020.06.046 Care (2008) 13:123–32. doi: 10.1080/13625180701829952 168. Kharsany ABM, Cawood C, Lewis L, Yende-Zuma N, Khanyile D, Puren A, 187. Kearney BP, Mathias A. Lack of effect of tenofovir disoproxil fumarate on et al. Trends in HIV prevention, treatment, and incidence in a hyperendemic area pharmacokinetics of hormonal contraceptives. Pharmacotherapy (2009) 29:924–9. of KwaZulu-natal, south Africa. JAMA Netw Open (2019) 2:e1914378. doi: 10.1001/ doi: 10.1592/PHCO.29.8.924 JAMANETWORKOPEN.2019.14378 188. Stuart GS, Moses A, Corbett A, Phiri G, Kumwenda W, Mkandawire N, 169. Champredon D, Bellan SE, Delva W, Hunt S, Shi CF, Smieja M, et al. The et al. Combined oral contraceptives and antiretroviral PK/PD in Malawian women: effect of sexually transmitted co-infections on HIV viral load amongst individuals Pharmacokinetics and pharmacodynamics of a combined oral contraceptive and a on antiretroviral therapy: A systematic review and meta-analysis. BMC Infect Dis generic combined formulation antiretroviral in Malawi. J Acquir Immune Defic (2015) 15:1–11. doi: 10.1186/S12879-015-0961-5/FIGURES/4 Syndr (2011) 58:e40–3. doi: 10.1097/QAI.0B013E31822B8BF8 170. Chun HM, Carpenter RJ, Macalino GE, Crum-Cianflone NF. The role of 189. Yoon K, Kim N. Roles of sex hormones and gender in the gut microbiota. J sexually transmitted infections in HIV-1 progression: A comprehensive review of Neurogastroenterol Motil (2021) 27:314–25. doi: 10.5056/JNM20208 the literature. J Sex Transm Dis (2013) 2013:1–15. doi: 10.1155/2013/176459 190. He S, Li H, Yu Z, Zhang F, Liang S, Liu H, et al. The gut microbiome and 171. Andrei G, Lisco A, Vanpouille C, Introini A, Balestra E, Van Den Oord J, sex hormone-related diseases. Front Microbiol (2021) 12:711137/BIBTEX. et al. A microbicide effective against HIV, inhibits herpes simplex virus-2 doi: 10.3389/FMICB.2021.711137/BIBTEX replication. Cell Host Microbe (2011) 10:379. doi: 10.1016/J.CHOM.2011.08.015 191. Mulak A, Taché Y, Larauche M. Sex hormones in the modulation of 172. Celum C, Morrow RA, Donnell D, Hong T, Hendrix CW, Thomas KK, irritable bowel syndrome. World J Gastroenterol (2014) 20:2433–48. doi: 10.3748/ et al. Daily oral tenofovir and emtricitabine-tenofovir preexposure prophylaxis WJG.V20.I10.2433 reduces herpes simplex virus type 2 acquisition among heterosexual HIV-1- 192. Kwa M, Plottel CS, Blaser MJ, Adams S. The intestinal microbiome and uninfected men and women: a subgroup analysis of a randomized trial. Ann estrogen receptor–positive female breast cancer. JNCI J Natl Cancer Inst (2016) Intern Med (2014) 161:11–9. doi: 10.7326/M13-2471 108:djw029. doi: 10.1093/JNCI/DJW029 173. Richert-Spuhler LE, Pattacini L, Plews M, Irungu E, Muwonge TR, 193. Klein SL, Flanagan KL. Sex differences in immune responses. Nat Rev Katabira E, et al. Pre-exposure prophylaxis differentially alters circulating and Immunol (2016) 16:626–38. doi: 10.1038/NRI.2016.90 mucosal immune cell activation in HSV-2 seropositive women. AIDS (2019) 33:2125. doi: 10.1097/QAD.0000000000002323 194. Flanagan KL, Fink AL, Plebanski M, Klein SL. Sex and gender differences in the outcomes of vaccination over the life course. Annu Rev Cell Dev Biol (2017) 174. Nixon B, Stefanidou M, Mesquita PMM, Fakioglu E, Segarra T, Rohan L, 33:577–99. doi: 10.1146/ANNUREV-CELLBIO-100616-060718 et al. Griffithsin protects mice from genital herpes by preventing cell-to-Cell spread. J Virol (2013) 87:6257. doi: 10.1128/JVI.00012-13 195. Takahashi T, Ellingson MK, Wong P, Israelow B, Lucas C, Klein J, et al. Sex differences in immune responses that underlie COVID-19 disease outcomes. Nat 175. Wira CR, Rodriguez-Garcia M, Patel MV. The role of sex hormones in (2020) 588:315–20. doi: 10.1038/s41586-020-2700-3 immune protection of the female reproductive tract. Nat Rev Immunol (2015) 15:217–30. doi: 10.1038/NRI3819 196. Scully EP. Sex differences in HIV infection: Mystique versus machismo. Pathog Immun (2018) 3:82–113. doi: 10.20411/PAI.V3I1.238 176. Adapen C, Ré ot L, Nunez N, Cannou C, Marlin R, Lemaı̂tre J, et al. Local innate markers and vaginal microbiota composition are influenced by hormonal 197. Addo MM, Altfeld M. Sex-based differences in HIV type 1 pathogenesis. J cycle phases. Front Immunol (2022) 13:841723/BIBTEX. doi: 10.3389/ Infect Dis (2014) 209:S86. doi: 10.1093/INFDIS/JIU175 FIMMU.2022.841723/BIBTEX 198. Bianchi I, Lleo A, Gershwin ME, Invernizzi P. The X chromosome and 177. Heffron R, Donnell D, Rees H, Celum C, Mugo N, Were E, et al. Use of immune associated genes. J Autoimmun (2012) 38:J187–92. doi: 10.1016/ hormonal contraceptives and risk of HIV-1 transmission: a prospective cohort J.JAUT.2011.11.012 study. Lancet Infect Dis (2012) 12:19–26. doi: 10.1016/S1473-3099(11) 199. Ziegler SM, Altfeld M. Human immunodeficiency virus 1 and type I 70247-X interferons-where sex makes a difference. Front Immunol (2017) 8:1224. 178. Hel Z, Stringer E, Mestecky J. Sex steroid hormones, hormonal doi: 10.3389/FIMMU.2017.01224 contraception, and the immunobiology of human immunodeficiency virus-1 200. Dimitrijević M, Arsenović -Ranin N, Kosec D, Bufan B, Nacka-Aleksić M, infection. Endocr Rev (2010) 31:79–97. doi: 10.1210/ER.2009-0018 Pilipović I, et al. Sex differences in tfh cell help to b cells contribute to sexual 179. Ferreira VH, Dizzell S, Nazli A, Kafka JK, Mueller K, Nguyen PV, et al. dimorphism in severity of rat collagen-induced arthritis. Sci Rep (2020) 2020 Medroxyprogesterone acetate regulates HIV-1 uptake and transcytosis but not 101:10. doi: 10.1038/s41598-020-58127-y replication in primary genital epithelial cells, resulting in enhanced T-cell infection. 201. Tukiainen T, Villani AC, Yen A, Rivas MA, Marshall JL, Satija R, et al. J Infect Dis (2015) 211:1745–56. doi: 10.1093/INFDIS/JIU832 Landscape of X chromosome inactivation across human tissues. Nat (2017) 180. Wessels JM, Lajoie J, Hay Cooper MIJ, Omollo K, Felker AM, Vitali D, 550:244–8. doi: 10.1038/nature24265 et al. Medroxyprogesterone acetate alters the vaginal microbiota and 202. Thevarajan I, Nguyen THO, Koutsakos M, Druce J, Caly L, van de Sandt microenvironment in women and increases susceptibility to HIV-1 in CE, et al. Breadth of concomitant immune responses prior to patient recovery: A humanized mice. Dis Model Mech (2019) 12:dmm039669. doi: 10.1242/ case report of non-severe COVID-19. Nat Med (2020) 26:453–5. doi: 10.1038/ DMM.039669 s41591-020-0819-2 181. Edfeldt G, Lajoie J, Röhl M, Oyugi J, Åhlberg A, Khalilzadeh-Binicy B, et al. 203. Gué ry JC. Sex differences in primary HIV infection: Revisiting the role of Regular use of depot medroxyprogesterone acetate causes thinning of the TLR7-driven type 1 IFN production by plasmacytoid dendritic cells in women. superficial lining and apical distribution of human immunodeficiency virus Front Immunol (2021) 12:729233. doi: 10.3389/FIMMU.2021.729233 target cells in the human ectocervix. J Infect Dis (2022) 225:1151–61. doi: 10.1093/INFDIS/JIAA514 204. Peckham H, Webb K, Rosser EC, Butler G, Ciurtin C. Gender-diverse inclusion in immunological research: Benefits to science and health. Front Med 182. Huijbregts RPH, Helton ES, Michel KG, Sabbaj S, Richter HE, Goepfert (2022) 9:909789/BIBTEX. doi: 10.3389/FMED.2022.909789/BIBTEX PA, et al. Hormonal contraception and HIV-1 infection: Medroxyprogesterone acetate suppresses innate and adaptive immune mechanisms. Endocrinology (2013) 205. Malleret B, Mané glier B, Karlsson I, Lebon P, Nascimbeni M, Perié L, et al. 154:1282–95. doi: 10.1210/EN.2012-1850 Primary infection with simian immunodeficiency virus: plasmacytoid dendritic cell homing to lymph nodes, type I interferon, and immune suppression. Blood (2008) 183. Ray RM, Maritz MF, Avenant C, Tomasicchio M, Dlamini S, van der Spuy 112:4598–608. doi: 10.1182/BLOOD-2008-06-162651 Z, et al. The contraceptive medroxyprogesterone acetate, unlike norethisterone, directly increases R5 HIV-1 infection in human cervical explant tissue at 206. Bruel T, Dupuy S, Dé moulins T, Rogez-Kreuz C, Dutrieux J, Corneau A, physiologically relevant concentrations. Sci Rep (2019) 9:4334–51. doi: 10.1038/ et al. Plasmacytoid dendritic cell dynamics tune interferon-Alfa production in SIV- S41598-019-40756-7 infected cynomolgus macaques. PloS Pathog (2014) 10:e1003915. doi: 10.1371/ JOURNAL.PPAT.1003915 184. Heffron R, Mugo N, Were E, Kiarie J, Bukusi EA, Mujugira A, et al. Preexposure prophylaxis is efficacious for HIV-1 prevention among women using 207. Berghöfer B, Frommer T, Haley G, Fink L, Bein G, Hackstein H. TLR7 depot medroxyprogesterone acetate for contraception. AIDS (2014) 28:2771–6. ligands induce higher IFN-alpha production in females. J Immunol (2006) doi: 10.1097/QAD.0000000000000493 177:2088–96. doi: 10.4049/JIMMUNOL.177.4.2088 Frontiers in Immunology 19 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 208. Chang JJ, Woods M, Lindsay RJ, Doyle EH, Griesbeck M, Chan ES, et al. mucosal damage in SIV infection. Mucosal Immunol (2012) 5:646–57. doi: 10.1038/ Higher expression of several interferon-stimulated genes in HIV-1-infected females MI.2012.38 after adjusting for the level of viral replication. J Infect Dis (2013) 208:830–8. 229. Hensley-McBain T, Berard AR, Manuzak JA, Miller CJ, Zevin AS, Polacino doi: 10.1093/INFDIS/JIT262 P, et al. Intestinal damage precedes mucosal immune dysfunction in SIV infection. 209. Meier A, Chang JJ, Chan ES, Pollard RB, Sidhu HK, Kulkarni S, et al. Sex Mucosal Immunol (2018) 11:1429–40. doi: 10.1038/s41385-018-0032-5 differences in the toll-like receptor-mediated response of plasmacytoid dendritic 230. Cavarelli M, Foglieni C, Hantour N, Schorn T, Ferrazzano A, Dispinseri S, cells to HIV-1. Nat Med (2009) 15:955–9. doi: 10.1038/NM.2004 et al. Identification of CX3CR1 + mononuclear phagocyte subsets involved in HIV- 210. Seillet C, Laffont S, Tré mollières F, Rouquié N, Ribot C, Arnal JF, et al. The 1 and SIV colorectal transmission. iScience (2022) 25:104346. doi: 10.1016/ TLR-mediated response of plasmacytoid dendritic cells is positively regulated by J.ISCI.2022.104346 estradiol in vivo through cell-intrinsic estrogen receptor a signaling. Blood (2012) 231. Huot N, Rascle P, Tchitchek N, Wimmer B, Passaes C, Contreras V, et al. 119:454–64. doi: 10.1182/BLOOD-2011-08-371831 Role of NKG2a/c+CD8+ T cells in pathogenic versus non-pathogenic SIV 211. Adland E, Millar J, Bengu N, Muenchhoff M, Fillis R, Sprenger K, et al. Sex- infections. iScience (2021) 24:102314–32. doi: 10.1016/j.isci.2021.102314 specific innate immune selection of HIV-1 in utero is associated with increased 232. Witkin SS, Mendes-Soares H, Linhares IM, Jayaram A, Ledger WJ, Forney LJ. female susceptibility to infection. Nat Commun (2020) 11:1–9. doi: 10.1038/ Influence of vaginal bacteria and d- and l-lactic acid isomers on vaginal extracellular s41467-020-15632-y matrix metalloproteinase inducer: implications for protection against upper genital tract 212. Amoroso A, Asensi-Botet F, Pereda A, Balossini V, Bona G, Zaffaroni M, infections. MBio (2013) 4:e00460-13. doi: 10.1128/MBIO.00460-13 et al. A significant sex–but not elective cesarean section–effect on mother-to-child 233. Edwards VL, Smith SB, McComb EJ, Tamarelle J, Ma B, Humphrys MS, transmission of hepatitis c virus infection. J Infect Dis (2005) 192:1872–9. et al. The cervicovaginal microbiota-host interaction modulates chlamydia doi: 10.1086/497695 trachomatis infection. MBio (2019) 10:e01548-19. doi: 10.1128/MBIO.01548-19 213. Mast EE, Hwang LY, Seto DSY, Nolte FS, Nainan OV, Wurtzel H, et al. 234. Gupta P, Collins KB, Ratner D, Watkins S, Naus GJ, Landers DV, et al. Risk factors for perinatal transmission of hepatitis c virus (HCV) and the natural Memory CD4(+) T cells are the earliest detectable human immunodeficiency virus history of HCV infection acquired in infancy. J Infect Dis (2005) 192:1880–9. type 1 (HIV-1)-infected cells in the female genital mucosal tissue during HIV-1 doi: 10.1086/497701 transmission in an organ culture system. J Virol (2002) 76:9868–76. doi: 10.1128/ 214. Watt AP, Loughlin L, Coyle PV. Congenital CMV disease–a female bias in JVI.76.19.9868-9876.2002 northern Ireland? J Clin Virol (2016) 77:99–100. doi: 10.1016/J.JCV.2016.02.012 235. McKinnon LR, Nyanga B, Chege D, Izulla P, Kimani M, Huibner S, et al. 215. Bernard-Stoecklin S, Gommet C, Cavarelli M, Le Grand R. Nonhuman Characterization of a human cervical CD4+ T cell subset coexpressing multiple primate models for cell-associated simian immunodeficiency virus transmission: markers of HIV susceptibility. J Immunol (2011) 187:6032–42. doi: 10.4049/ The need to better understand the complexity of HIV mucosal transmission. J JIMMUNOL.1101836 Infect Dis (2014) 210(Suppl 3):S660–6. doi: 10.1093/infdis/jiu536 236. Maric D, Grimm WA, Greco N, McRaven MD, Fought AJ, Veazey RS, et al. 216. Barreto-de-Souza V, Arakelyan A, Margolis L, Vanpouille C. HIV-1 Th17 T cells and immature dendritic cells are the preferential initial targets after vaginal transmission: Cell-free or cell-associated virus? Am J Reprod Immunol rectal challenge with a simian immunodeficiency virus-based replication-defective (2014) 71:589. doi: 10.1111/AJI.12240 dual-reporter vector. J Virol (2021) 95:e0070721. doi: 10.1128/JVI.00707-21/ 217. Kolodkin-Gal D, Hulot SL, Korioth-Schmitz B, Gombos RB, Zheng Y, FORMAT/EPUB Owuor J, et al. Efficiency of cell-free and cell-associated virus in mucosal 237. Cavarelli M, Foglieni C, Rescigno M, Scarlatti G. R5 HIV-1 envelope transmission of human immunodeficiency virus type 1 and simian attracts dendritic cells to cross the human intestinal epithelium and sample luminal immunodeficiency virus. J Virol (2013) 87:13589–97. doi: 10.1128/jvi.03108-12 virions via engagement of the CCR5. EMBO Mol Med (2013) 5:776–94. 218. Ganor Y, Zhou Z, Tudor D, Schmitt A, Vacher-Lavenu MC, Gibault L, doi: 10.1002/emmm.201202232 et al. Within 1 h, HIV-1 uses viral synapses to enter efficiently the inner, but not 238. Shen R, Smythies LE, Clements RH, Novak L, Smith PD. Dendritic cells outer, foreskin mucosa and engages langerhans-T cell conjugates. Mucosal transmit HIV-1 through human small intestinal mucosa. J Leukoc Biol (2010) Immunol (2010) 3:506–22. doi: 10.1038/MI.2010.32 87:663–70. doi: 10.1189/jlb.0909605 219. Zhou Z, Barry de Longchamps N, Schmitt A, Zerbib M, Vacher-Lavenu 239. Hladik F, Sakchalathorn P, Ballweber L, Lentz G, Fialkow M, Eschenbach MC, Bomsel M, et al. HIV-1 efficient entry in inner foreskin is mediated by elevated D, et al. Initial events in establishing vaginal entry and infection by human CCL5/RANTES that recruits T cells and fuels conjugate formation with langerhans immunodeficiency virus type-1. Immunity (2007) 26:257–70. doi: 10.1016/ cells. PloS Pathog (2011) 7:e1002100. doi: 10.1371/JOURNAL.PPAT.1002100 j.immuni.2007.01.007 220. Bracq L, Xie M, Benichou S, Bouchet J. Mechanisms for cell-to-Cell 240. Rhodes JW, Botting RA, Bertram KM, Vine EE, Rana H, Baharlou H, et al. transmission of HIV-1. Front Immunol (2018) 9:260. doi: 10.3389/ Human anogenital monocyte-derived dendritic cells and langerin+cDC2 are major FIMMU.2018.00260 HIV target cells. Nat Commun (2021) 12:1–15. doi: 10.1038/s41467-021-22375-x 221. Marchetti G, Tincati C, Silvestri G. Microbial translocation in the 241. Bertram KM, Botting RA, Baharlou H, Rhodes JW, Rana H, Graham JD, pathogenesis of HIV infection and AIDS. Clin Microbiol Rev (2013) 26:2–18. et al. Identification of HIV transmitting CD11c+ human epidermal dendritic cells. doi: 10.1128/CMR.00050-12 Nat Commun (2019) 10:1–15. doi: 10.1038/s41467-019-10697-w 222. Nazli A, Chan O, Dobson-Belaire WN, Ouellet M, Tremblay MJ, Gray- 242. Rodriguez-Garcia M, Shen Z, Barr FD, Boesch AW, Ackerman ME, Owen SD, et al. Exposure to HIV-1 directly impairs mucosal epithelial barrier Kappes JC, et al. Dendritic cells from the human female reproductive tract integrity allowing microbial translocation. PloS Pathog (2010) 6:e1000852. rapidly capture and respond to HIV. Mucosal Immunol (2016) 10:531–44. doi: 10.1371/journal.ppat.1000852 doi: 10.1038/mi.2016.72 223. Estes JD, Harris LD, Klatt NR, Tabb B, Pittaluga S, Paiardini M, et al. 243. Benjelloun F, Quillay H, Cannou C, Marlin R, Madec Y, Fernandez H, et al. Damaged intestinal epithelial integrity linked to microbial translocation in Activation of toll-like receptors differentially modulates inflammation in the pathogenic simian immunodeficiency virus infections. PloS Pathog (2010) 6: human reproductive tract: Preliminary findings. Front Immunol (2020) 11:1655. e1001052. doi: 10.1371/journal.ppat.1001052 doi: 10.3389/FIMMU.2020.01655 224. Veazey RS, DeMaria MA, Chalifoux LV, Shvetz DE, Pauley DR, Knight 244. Pudney J, Quayle AJ, Anderson DJ. Immunological microenvironments in HL, et al. Gastrointestinal tract as a major site of CD4+ T cell depletion and viral the human vagina and cervix: Mediators of cellular immunity are concentrated in replication in SIV infection. Science (1998) 280:427–31. doi: 10.1126/ the cervical transformation zone. Biol Reprod (2005) 73:1253–63. doi: 10.1095/ science.280.5362.427 BIOLREPROD.105.043133 225. Stieh DJ, Matias E, Xu H, Fought AJ, Blanchard JL, Marx PA, et al. Th17 245. Rodriguez-Garcia M, Barr FD, Crist SG, Fahey JV, Wira CR. Phenotype cells are preferentially infected very early after vaginal transmission of SIV in and susceptibility to HIV infection of CD4+ Th17 cells in the human female macaques. Cell Host Microbe (2016) 19:529–40. doi: 10.1016/j.chom.2016.03.005 reproductive tract. Mucosal Immunol (2014) 7:1375–85. doi: 10.1038/MI.2014.26 226. Ryan ES, Micci L, Fromentin R, Paganini S, McGary CS, Easley K, et al. 246. Hasselrot K, Cheruiyot J, Kimani J, Ball TB, Kaul R, Hirbod T. Feasibility Loss of function of intestinal IL-17 and IL-22 producing cells contributes to and safety of cervical biopsy sampling for mucosal immune studies in female sex inflammation and viral persistence in SIV-infected rhesus macaques. PloS Pathog workers from Nairobi, Kenya. PloS One (2012) 7:e47570. doi: 10.1371/ (2016) 12:e1005412. doi: 10.1371/journal.ppat.1005412 JOURNAL.PONE.0047570 227. Xu H, Wang X, Veazey RS. Th17 cells coordinate with Th22 cells in 247. Lajoie J, Boily-Larouche G, Doering K, Cheruiyot J, Oyugi J, Broliden K, maintaining homeostasis of intestinal tissues and both are depleted in SIV-infected et al. Improving adherence to post-cervical biopsy sexual abstinence in Kenyan macaques. J AIDS Clin Res (2014) 5:302–10. doi: 10.4172/2155-6113.1000302 female sex workers. Am J Reprod Immunol (2016) 76:82–93. doi: 10.1111/AJI.12520 228. Klatt NR, Estes JD, Sun X, Ortiz AM, Barber JS, Harris LD, et al. Loss of 248. Moseholm E, Gilleece Y, Collins B, Kowalska JD, Vasylyev M, Pé rez Elı́a mucosal CD103+ DCs and IL-17+ and IL-22+ lymphocytes is associated with MJ, et al. Achievements and gaps to provide pre-exposure prophylaxis (PrEP) for Frontiers in Immunology 20 frontiersin.org Karim et al. 10.3389/fimmu.2022.1055042 women across the European region – results from a European survey study. J Virus 259. Looker KJ, Rönn MM, Brock PM, Brisson M, Drolet M, Mayaud P, et al. Erad (2021) 7:100026. doi: 10.1016/J.JVE.2020.100026 Evidence of synergistic relationships between HIV and human papillomavirus 249. Hodges-Mameletzis I, Dalal S, Msimanga-Radebe B, Rodolph M, Baggaley (HPV): Systematic reviews and meta-analyses of longitudinal studies of HPV R. Going global: The adoption of the world health organization’s enabling acquisition and clearance by HIV status, and of HIV acquisition by HPV status. J recommendation on oral pre-exposure prophylaxis for HIV. Sex Health (2018) Int AIDS Soc (2018) 21:e25110. doi: 10.1002/JIA2.25110 15:489–500. doi: 10.1071/SH18125 260. Garrett N, Mtshali A, Osman F, Masson L, Mckinnon LR, Singh R, et al. 250. Hodges-Mameletzis I, Fonner VA, Dalal S, Mugo N, Msimanga-Radebe B, Impact of point-of-care testing and treatment of sexually transmitted infections Baggaley R. Pre-exposure prophylaxis for HIV prevention in women: Current and bacterial vaginosis on genital tract inflammatory cytokines in a cohort of young status and future directions. Drugs (2019) 79:1263–76. doi: 10.1007/S40265-019- south African women. Sex Transm Infect (2021) 97:555–65. doi: 10.1136/ 01143-8 SEXTRANS-2020-054740 251. European Centre for Disease Prevention and Control (ECDC). Pre- 261. Mtshali A, San JE, Osman F, Garrett N, Balle C, Giandhari J, et al. exposure prophylaxis for HIV prevention in Europe and central Asia (2019). Temporal changes in vaginal microbiota and genital tract cytokines among south Available at: https://www.ecdc.europa.eu/en/publications-data/ecdc-evidence- African women treated for bacterial vaginosis. Front Immunol (2021) 12:730986. brief-pre-exposure-prophylaxis-hiv-prevention-europe-and-central (Accessed doi: 10.3389/FIMMU.2021.730986 September 2, 2022). 262. Pampati S, Emrick K, Siegler AJ, Jones J. Changes in sexual behavior, PrEP 252. Center for disease control and prevention. PrEP coverage | women | gender | adherence, and access to sexual health services because of the COVID-19 pandemic HIV by group | HIV/AIDS | CDC (2022). Available at: https://www.cdc.gov/hiv/ among a cohort of PrEP-using MSM in the south. J Acquir Immune Defic Syndr group/gender/women/prep-coverage.html (Accessed September 2, 2022). (2021) 87:639–43. doi: 10.1097/QAI.0000000000002640 253. Hayes R, Schmidt AJ, Pharris A, Azad Y, Brown AE, Weatherburn P, et al. 263. Pagaoa M, Grey J, Torrone E, Kreisel K, Stenger M, Weinstock H. Trends Estimating the “PrEP gap”: how implementation and access to PrEP differ between in nationally notifiable sexually transmitted disease case reports during the US countries in Europe and central Asia in 2019. Euro Surveill (2019) 24:1900598–604. COVID-19 pandemic, January to December 2020. Sex Transm Dis (2021) 48:798– doi: 10.2807/1560-7917.ES.2019.24.41.1900598 804. doi: 10.1097/OLQ.0000000000001506 254. Delabre RM, Bernier A, Sá nchez F, Vilotitch A, Chanos S, Cosmaro ML, 264. Ko SY, Pegu A, Rudicell RS, Yang ZY, Joyce MG, Chen X, et al. Enhanced et al. “Yes, i’m interested in taking PrEP!”: PrEP interest among women neonatal fc receptor function improves protection against primate SHIV infection. respondents to the European community-based survey “Flash! PrEP in europe.” Nature (2014) 514:642–5. doi: 10.1038/NATURE13612 PloS One (2021) 16:e0246037. doi: 10.1371/JOURNAL.PONE.0246037 265. Studies I of M (US) C on E and LIR to the I of W in C, Mastroianni AC, 255. Johnson AK, Fletcher FE, Ott E, Wishart M, Friedman EE, Terlikowski J, Faden R, Federman D. NIH Revitalization act of 1993 public law 103-43 (1994). et al. Awareness and intent to use pre-exposure prophylaxis (PrEP) among African Available at: https://www.ncbi.nlm.nih.gov/books/NBK236531/ (Accessed American women in a family planning clinic. J racial Ethn Heal disparities (2020) September 13, 2022). 7:550–4. doi: 10.1007/S40615-019-00683-9 266. Murphy MC, Mejia AF, Mejia J, Yan X, Cheryan S, Dasgupta N, et al. Open 256. Raifman JR, Schwartz SR, Sosnowy CD, Montgomery MC, Almonte A, science, communal culture, and women’s participation in the movement to Bazzi AR, et al. Brief report: Pre-exposure prophylaxis awareness and use among improve science. Proc Natl Acad Sci USA (2020) 117:24154–64. doi: 10.1073/ cisgender women at a sexually transmitted disease clinic. J Acquir Immune Defic PNAS.1921320117/-/DCSUPPLEMENTAL Syndr (2019) 80:36–9. doi: 10.1097/QAI.0000000000001879 267. Casad BJ, Franks JE, Garasky CE, Kittleman MM, Roesler AC, Hall DY, 257. Sevelius JM, Keatley JA, Calma N, Arnold E. “I am not a man”: Trans- et al. Gender inequality in academia: Problems and solutions for women faculty in specific barriers and facilitators to PrEP acceptability among transgender women. STEM. J Neurosci Res (2021) 99:13–23. doi: 10.1002/JNR.24631 Glob Public Health (2016) 11:1060–75. doi: 10.1080/17441692.2016.1154085 268. Ross MB, Glennon BM, Murciano-Goroff R, Berkes EG, Weinberg BA, 258. Liebenberg LJP, McKinnon LR, Yende-Zuma N, Garrett N, Baxter C, Lane JI. Women are credited less in science than men. Nature (2022) 608:135. Kharsany ABM, et al. HPV infection and the genital cytokine milieu in women at doi: 10.1038/S41586-022-04966-W high risk of HIV acquisition. Nat Commun (2019) 10:1–12. doi: 10.1038/s41467- 269. Okeke FN. Science and technology development in Africa needs women. 019-13089-2 Nat Hum Behav (2020) 4:1218. doi: 10.1038/S41562-020-00960-2 Frontiers in Immunology 21 frontiersin.org