The future of PrEP: novel long-acting HIV prevention agents for adolescent women

Adolescent girls and young women in Africa are at high risk of HIV and should be considered a key population for HIV prevention initiatives. Oral Tenofovir/Emtricitabine as pre-exposure prophylaxis (PrEP) has been shown to be effective on an individual and population level among key populations in Europe, Australia, and the US. However, studies in sub-Saharan Africa in a generalised epidemic have been less promising with adherence to daily tablets identified as a major problem. Long-acting PrEP drugs are being developed as a response to this problem. The first of these long-acting agents, injectable Cabotegravir given every two months has shown superiority to oral PreP and has been approved by the US Food and Drug Administration (FDA). Another long-acting PrEP drug in development is Lenacapavir which is an investigational, first-in-class long-acting HIV-1 capsid inhibitor that can be given as a six-monthly injection. These long-acting drugs could be a highly effective public health HIV prevention intervention. If made readily available to a vulnerable population of adolescent young women who are at high risk of HIV they could play an important role in protecting this key population against HIV and potentially reduce the population level risk of HIV.

SARS-CoV-2 seroprevalence and implications for population immunity: Evidence from two Health and Demographic Surveillance System sites in Kenya, February-December 2022

BACKGROUND

We sought to estimate SARS-CoV-2 antibody seroprevalence within representative samples of the Kenyan population during the third year of the COVID-19 pandemic and the second year of COVID-19 vaccine use.

METHODS

We conducted cross-sectional serosurveys among randomly selected, age-stratified samples of Health and Demographic Surveillance System (HDSS) residents in Kilifi and Nairobi. Anti-spike (anti-S) immunoglobulin G (IgG) serostatus was measured using a validated in-house ELISA and antibody concentrations estimated with reference to the WHO International Standard for anti-SARS-CoV-2 immunoglobulin.

RESULTS

HDSS residents were sampled in February-June 2022 (Kilifi HDSS N = 852; Nairobi Urban HDSS N = 851) and in August-December 2022 (N = 850 for both sites). Population-weighted coverage for ≥1 doses of COVID-19 vaccine were 11.1% (9.1-13.2%) among Kilifi HDSS residents by November 2022 and 34.2% (30.7-37.6%) among Nairobi Urban HDSS residents by December 2022. Population-weighted anti-S IgG seroprevalence among Kilifi HDSS residents increased from 69.1% (65.8-72.3%) by May 2022 to 77.4% (74.4-80.2%) by November 2022. Within the Nairobi Urban HDSS, seroprevalence by June 2022 was 88.5% (86.1-90.6%), comparable with seroprevalence by December 2022 (92.2%; 90.2-93.9%). For both surveys, seroprevalence was significantly lower among Kilifi HDSS residents than among Nairobi Urban HDSS residents, as were antibody concentrations (p < 0.001).

CONCLUSION

More than 70% of Kilifi residents and 90% of Nairobi residents were seropositive for anti-S IgG by the end of 2022. There is a potential immunity gap in rural Kenya; implementation of interventions to improve COVID-19 vaccine uptake among sub-groups at increased risk of severe COVID-19 in rural settings is recommended.

URCHOICE: Preferences for Pre-Exposure Prophylaxis (PrEP) Options for HIV Prevention Among Kenyan men who have sex with men and Transgender Women in Nairobi, Kisumu and the Coast

HIV prevention method preferences were evaluated among Kenyan men who have sex with men (MSM) and transgender women (TW) from three sites: Kisumu, Nairobi and the Coast. Information sessions detailing the attributes, duration of protection, route of administration and probable visibility were attended by 464 HIV negative participants, of whom 423 (median age: 24 years) agreed to be interviewed. Across pairwise comparisons daily PrEP was by far the least preferred (1%); quarterly injections (26%) and monthly pills (23%) were most preferred, followed by yearly implant (19%) and condoms (12%). When participants were "forced" to choose their most preferred PrEP option, only 10 (2.4%) chose the daily pill; more (37.1%) chose the quarterly injection than the monthly pill (34.8%) and the yearly implant (25.8%). TW preferred the yearly implant over the quarterly injection. To achieve the rates of PrEP uptake and adherence necessary for protecting large proportions of vulnerable MSM and TW, a variety of long-acting products should be developed and made accessible to appeal to a diversity of preferences.

Low-Dose Acetylsalicylic Acid Reduces T Cell Immune Activation: Potential Implications for HIV Prevention

Introduction

Acetylsalicylic acid (ASA) is a well-known and safe anti-inflammatory. At low-dose, it is prescribed to prevent secondary cardiovascular events in those with pre-existing conditions and to prevent preeclampsia. Little is known about how low-dose ASA affects the immune response. In this study, we followed women to assess how ASA use modifies T cells immune phenotypes in the blood and at the genital tract.

Methods

HIV uninfected women from Kenya were enrolled in this study and followed for one month to assess baseline responses including systemic/mucosal baseline immune activation. Participants then received 81mg of ASA daily for 6 weeks to assess changes to T cell immune activation (systemic and mucosal) relative to baseline levels.

Results

The concentration of ASA measured in the blood was 58% higher than the level measured at the female genital tract. In the blood, the level of ASA was inversely correlated with the following: the proportion of Th17 expressing HLA-DR (p=0.04), the proportion of effector CD4⁺ T cells expressing CCR5 (p=0.03) and the proportion of CD8⁺Tc17 expressing CCR5 (p=0.04). At the genital tract, ASA use correlated with a decreased of activated CD4⁺T cells [CD4⁺CCR5⁺CD161⁺ (p=0.02) and CD4⁺CCR5⁺CD95⁺ (p=0.001)].

Conclusion

This study shows that ASA use impacts the immune response in both the systemic and genital tract compartments. This could have major implications for the prevention of infectious diseases such as HIV, in which the virus targets activated T cells to establish an infection. This could inform guidelines on ASA use in women.

Clinical Trial Registration

ClinicalTrials.gov, identifier NCT02079077.

Pre-exposure prophylaxis for transgender women and men who have sex with men: qualitative insights from healthcare providers, community organization-based leadership and end users in coastal Kenya

Transgender women (TW) and men who have sex with men (MSM) in Kenya are disproportionately affected by human immunodeficiency virus (HIV) and would benefit substantially from pre-exposure prophylaxis (PrEP). We conducted focus group discussions (FGDs) with healthcare providers (HCPs) and TW/MSM leadership and in-depth interviews (IDIs) with PrEP-experienced MSM and TW to learn about perceived and actual barriers to PrEP programming. Eleven HCP and 10 TW/MSM leaders participated in FGDs before PrEP roll-out (January 2018) and 12 months later. Nineteen PrEP end-users (11 MSM and 8 TW) participated in IDIs. Topic guides explored PrEP knowledge, HIV acquisition risk, gender identity, motivation for PrEP uptake and adherence and PrEP-dispensing venue preferences. Braun and Clarke thematic analysis was applied. Four themes emerged: limited preparedness of HCPs to provide PrEP to TW and MSM, varied motivation for PrEP uptake and persistence among end users, lack of recognition of TW by HCPs and suggestions for PrEP programming improvement from all stakeholders. Providers' reluctance to prescribe PrEP to TW and distrust of TW towards providers calls for interventions to improve the capacity of service environments and staff HIV preventive care. Alternative locations for PrEP provision, including community-based sites, may be developed with TW/MSM leaders.

"I wish to remain HIV negative": Pre-exposure prophylaxis adherence and persistence in transgender women and men who have sex with men in coastal Kenya

BACKGROUND

Transgender women (TGW) and men who have sex with men (MSM) in sub-Saharan Africa have high HIV acquisition risks and can benefit from daily pre-exposure prophylaxis (PrEP). We assessed PrEP adherence by measuring tenofovir-diphosphate (TFV-DP) levels and explore motives for PrEP persistence in TGW and MSM.

METHODS

Participants were enrolled in a one-year PrEP programme and made quarterly visits irrespective of whether they were still using PrEP. At their month 6 visit, participants provided a dried blood spot to test for TFV-DP levels; protective levels were defined as those compatible with ≥4 pills per week (700-1249 fmol/punch). Before TFV-DP levels were available, a sub-set of these participants were invited for an in-depth interview (IDI). Semi-structured IDI topic guides were used to explore motives to uptake, adhere to, and discontinue PrEP. IDI data were analyzed thematically.

RESULTS

Fifty-three participants (42 MSM and 11 TGW) were enrolled. At month 6, 11 (20.7%) participants (8 MSM and 3 TGW) were lost to follow up or stopped taking PrEP. Any TFV-DP was detected in 62.5% (5/8) of TGW vs. 14.7% of MSM (5/34, p = 0.01). Protective levels were detected in 37.5% of TGW (3/8), but not in any MSM. Nineteen IDI were conducted with 7 TGW and 9 MSM on PrEP, and 1 TGW and 2 MSM off PrEP. Unplanned or frequent risky sexual risk behaviour were the main motives for PrEP uptake. Among participants on PrEP, TGW had a more complete understanding of the benefits of PrEP. Inconsistent PrEP use was attributed to situational factors. Motives to discontinue PrEP included negative reactions from partners and stigmatizing healthcare services.

CONCLUSION

While MSM evinced greater adherence challenges in this PrEP programme, almost 40% of TGW were protected by PrEP. Given high HIV incidences in TGW these findings hold promise for TGW PrEP programming in the region.

Characterization of the Genital Mucosa Immune Profile to Distinguish Phases of the Menstrual Cycle: Implications for HIV Susceptibility

BACKGROUND

Inflammation and immune activation are key factors in sexual transmission of human immunodeficiency virus (HIV). We sought to define the impact of hormonal cycling on the mucosal immune environment and HIV risk in sex workers with a natural menstrual cycle.

METHODS

We compared soluble mucosal immune factors and cervical mononuclear cells during hormone titer-defined phases of the menstrual cycle among 37 sex workers from Nairobi, Kenya. Systemic and mucosal samples were collected 14 days apart to distinguish the follicular and luteal phases of the menstrual cycle, and phases were confirmed by hormone measurements. Vaginal concentrations of 19 immune modulators and cervical T-cell activation markers were measured.

RESULTS

The follicular phase signature was characterized by an elevated CCL2 level, decreased interleukin 1α and interleukin 1β cervical concentrations, and a significant increase in the proportion of CD4+ T cells that expressed CD69. The genital concentration of CCL2 was the best marker to distinguish the follicular from the luteal phase in univariate and multivariate analyses and remained independent of elevated genital inflammation and bacterial vaginosis.

CONCLUSION

The follicular phase of the menstrual cycle was associated with an elevated CCL2 level and retention of resident memory CD4+ T cells, which has implications for increased susceptibility to HIV infection.

PrEP interest and HIV-1 incidence among MSM and transgender women in coastal Kenya

INTRODUCTION

There is emerging data on HIV-1 incidence among MSM in sub-Saharan Africa (SSA), but no known estimate of HIV-1 incidence among transgender women (TGW) in the region has yet been reported. We assessed HIV-1 incidence and pre-exposure prophylaxis (PrEP) interest in men who have sex with men exclusively (MSME), men who have sex with men and women (MSMW) and TGW in coastal Kenya.

METHODS

HIV-1-seronegative individuals who had participated in an HIV testing study in 2016 were traced and retested in 2017 according to Kenyan guidelines. All participants were assigned male sex at birth and had male sex partners; additional data on gender identity and sexual orientation were obtained. We assessed the factors associated with HIV-1 acquisition using Poisson regression and calculated HIV-1 incidence in MSME, MSMW and TGW. PrEP interest was assessed through focus group discussions to characterize subcategories' perceived PrEP needs.

RESULTS

Of the 168 cohort participants, 42 were classified as MSME, 112 as MSMW and 14 as TGW. Overall, HIV-1 incidence was 5.1 (95% confidence interval (CI): 2.6 to 9.8) per 100 person-years (PY): 4.5 (95% CI: 1.1 to 17.8] per 100 PY among MSME, 3.4 (95% CI: 1.3 to 9.1) per 100 PY among MSMW and 20.6 (95% CI: 6.6 to 63.8] per 100 PY among TGW. HIV-1 acquisition was associated with exclusive receptive anal intercourse (aIRR 13.0, 95% CI 1.9 to 88.6), history of an STI in preceding six months (aIRR 10.3, 95% CI 2.2 to 49.4) and separated/divorced marital status (aIRR 8.2 (95%: 1.1 to 62.2). Almost all (98.8%) participants were interested in initiating PrEP. MSME and TGW felt that PrEP would lead to increases in condomless anal or group sex.

CONCLUSIONS

TGW had a very high HIV-1 incidence compared with MSME and MSMW. Subcategories of MSM anticipated different PrEP needs and post-PrEP risk behaviour. Further studies should assess if TGW may have been wrongly categorized as MSM in other HIV-1 incidence studies in the region.

Using safe, affordable and accessible non-steroidal anti-inflammatory drugs to reduce the number of HIV target cells in the blood and at the female genital tract

INTRODUCTION

At its basic level, HIV infection requires a replication-competent virus and a susceptible target cell. Elevated levels of vaginal inflammation has been associated with the increased risk of HIV infection as it brings highly activated HIV target cells (CCR5+CD4+ T cells; CCR5+CD4+CD161+ Th17 T cells) to the female genital tract (FGT) where they interact with HIV. Decreased HIV risk has been associated with a phenotype of decreased immune activation, called immune quiescence, described among Kenyan female sex workers who were intensely exposed to HIV yet remain uninfected. Current prevention approaches focus on limiting viral access. We took the novel HIV prevention approach of trying to limit the number of HIV target cells in the genital tract by reducing inflammation using safe, affordable and globally accessible anti-inflammatory drugs.

METHODS

We hypothesized that the daily administration of low doses of acetylsalicylic acid (ASA 81 mg) or hydroxychloroquine (HCQ 200 mg) would reduce inflammation thereby decreasing HIV target cells at the FGT. Low-risk HIV seronegative women from Nairobi, Kenya were randomized for six weeks therapy of ASA (n = 37) or HCQ (n = 39) and tested to determine the impact on their systemic and mucosal immune environment.

RESULTS

The results showed that HCQ use was associated with a significant reduction in the proportion of systemic T cells that were CCR5+CD4+ (p = 0.01) and Th17 (p = 0.01). In the ASA arm, there was a 35% and 28% decrease in the proportion of genital T cells that were CD4+CCR5+ (p = 0.017) and Th17 (p = 0.04) respectively. Proteomic analyses of the cervical lavage showed ASA use was associated with significantly reduced amount of proteins involved in the inflammatory response and cell recruitment at the mucosa, although none of the individual proteins passed multiple comparison correction. These changes were more apparent in women with Lactobacillus dominant microbiomes.

CONCLUSION

Together, these data indicate that taking low-dose ASA daily was associated with significant reduction in HIV target cells at the FGT. This study provides proof-of-concept for a novel HIV-prevention approach that reducing inflammation using safe, affordable and globally accessible non-steroidal anti-inflammatory agents is associated with significant reduction in the proportion of HIV-target cells at the FGT.

CD161 identifies polyfunctional Th1/Th17 cells in the genital mucosa that are depleted in HIV-infected female sex workers from Nairobi, Kenya

CD161 identifies a subset of circulating Th17 cells that are depleted in the blood and gut of HIV-infected individuals. In the female reproductive tract (FRT), the pattern of CD161 expression on CD4⁺ cells remains unknown. Here, we characterized CD161 expression in the FRT of Kenyan female sex workers (FSW). Compared to the blood, CD161⁺CD4⁺ T cells were enriched in the FRT of uninfected FSWs. These cells were depleted in FRT of HIV-infected FSWs. Cervical CD161⁺ cells harboured an activated phenotype (CD69, CD95, HLA-DR) with elevated expression of tissue-homing markers (CCR6, β7 integrin) and HIV co-receptor (CCR5). Mitogen-stimulated production of IL-17 confirmed the Th17 commitment of CD161⁺CD4⁺ T cells in the FRT with a predominance of polyfunctional Th1/Th17 cells. Here, we showed that the expression of CD161 on CD4+T cells is modulated at the FRT, but still identified a highly activated cellular subset, which differentiates into pro-inflammatory Th1/Th17 cells, expresses multiple HIV susceptibility markers and are depleted in HIV-infected individuals. The use of CD161 as a biomarker of HIV targets in the FRT reduces the need for functional assessment of cells and could have important implications in better understanding HIV pathogenesis and Th17 fate in the FRT of high-risk women.

The Impact of Sex Work Interruption on Blood-Derived T Cells in Sex Workers from Nairobi, Kenya

BACKGROUND

Unprotected sexual intercourse exposes the female genital tract (FGT) to semen-derived antigens, which leads to a proinflammatory response. Studies have shown that this postcoital inflammatory response can lead to recruitment of activated T cells to the FGT, thereby increasing risk of HIV infection.

OBJECTIVE

The purpose of this study was to evaluate the impact of sex work on activation and memory phenotypes of peripheral T cells among female sex workers (FSW) from Nairobi, Kenya.

SUBJECTS

Thirty FSW were recruited from the Pumwani Sex Workers Cohort, 10 in each of the following groups: HIV-exposed seronegative (at least 7 years in active sex work), HIV positive, and New Negative (HIV negative, less than 3 years in active sex work). Blood was obtained at three different phases (active sex work, abstinence from sex work-sex break, and following resumption of sex work). Peripheral blood mononuclear cells were isolated and stained for phenotypic markers (CD3, CD4, CD8, and CD161), memory phenotype markers (CD45RA and CCR7), activation markers (CD69, HLA-DR, and CD95), and the HIV coreceptor (CCR5). T-cell populations were compared between groups.

RESULTS

In HIV-positive women, CD8+CCR5+ T cells declined at the sex break period, while CD4+CD161+ T cells increased when returning to sex work. All groups showed no significant changes in systemic T-cell activation markers following the interruption of sex work, however, significant reductions in naive CD8+ T cells were noted. For each of the study points, HIV positives had higher effector memory and CD8+CD95+ T cells and lower naive CD8+ T cells than the HIV-uninfected groups.

CONCLUSIONS

Interruption of sex work had subtle effects on systemic T-cell memory phenotypes.

Elevated expression of LAG-3, but not PD-1, is associated with impaired iNKT cytokine production during chronic HIV-1 infection and treatment

Background

LAG-3 is a potent negative regulator of the immune response but its impact in HIV infection in poorly understood. Unlike exhaustion markers such as PD-1, Tim-3, 2B4 and CD160, LAG-3 is poorly expressed on bulk and antigen-specific T cells during chronic HIV infection and its expression on innate lymphocyte subsets is not well understood. The aim of this study was to assess LAG-3 expression and association with cellular dysfunction on T cells, NK cells and iNKT cells among a cohort of healthy and HIV-infected female sex workers in Nairobi, Kenya.

Results

Ex vivo LAG-3 expression was measured by multiparametric flow cytometry, and plasma cytokine/chemokine concentrations measured by bead array. Although LAG-3 expression on bulk T cells was significantly increased among HIV-infected women, the proportion of cells expressing the marker was extremely low. In contrast, LAG-3 was more highly expressed on NK and iNKT cells and was not reduced among women treated with ART. To assess the functional impact of LAG-3 on iNKT cells, iNKT cytokine production was measured in response to lipid (αGalCer) and PMA/Io stimulation by both flow cytometry and cytokine bead array. iNKT cytokine production is profoundly altered by both HIV infection and treatment, and LAG-3, but not PD-1, expression is associated with a reduction in iNKT IFNγ production.

Conclusions

LAG-3 does not appear to mediate T cell exhaustion in this African population, but is instead expressed on innate lymphocyte subsets including iNKT cells. HIV infection alters iNKT cytokine production patterns and LAG-3 expression is uniquely associated with iNKT dysfunction. The continued expression of LAG-3 during treatment suggests it may contribute to the lack of innate immune reconstitution commonly observed during ART.

Electronic supplementary material

The online version of this article (doi:10.1186/s12977-015-0142-z) contains supplementary material, which is available to authorized users.

Enrichment of LAG-3, but not PD-1, on double negative T cells at the female genital tract

PROBLEM

The expression of inhibitory markers such as LAG-3 and PD-1 on T lymphocytes regulates immune function. Their expression at the genital mucosa is poorly understood, but regulation of immune activation at the female genital tract likely controls susceptibility to sexually transmitted infections.

METHOD OF STUDY

Cervical mononuclear cells were phenotyped by flow cytometry. Concentrations of cytokines were determined in cervical-vaginal lavage samples by bead array.

RESULTS

LAG-3 expression was significantly elevated at the genital mucosa and was associated with expression of CCR5 and CD69. Double negative (DN) T cells expressed the highest levels of LAG-3, but not PD-1, and were more activated than other T lymphocytes.

CONCLUSION

The elevated expression of LAG-3 at the genital tract suggests it may regulate T-cell activation, and identify cells susceptible to HIV infection. The enrichment of LAG-3 on DN T cells suggests LAG-3 may contribute to the immunoregulatory activity of these cells.

Effect of baseline HIV disease parameters on CD4+ T cell recovery after antiretroviral therapy initiation in Kenyan women

BACKGROUND

Antiretroviral therapy (ART) for HIV infection reconstitutes the immune system and improves survival. However, the rate and extent of CD4+ T cell recovery varies widely. We assessed the impact of several factors on immune reconstitution in a large Kenyan cohort.

METHODOLOGY/PRINCIPAL FINDINGS

HIV-infected female sex workers from a longitudinal cohort, with at least 1 year of pre-ART and 6 months of post-ART follow-up (n = 79), were enrolled in the current study. The median pre-ART follow-up was 4,040 days. CD4 counts were measured biannually and viral loads where available. The median CD4 count at ART initiation was 180 cells/ul, which increased to 339 cells/ul at the most recent study visit. The rate of CD4+ T cell increase on ART was 7.91 cells/month (mean = 13, range -25.92 to 169.4). LTNP status prior to ART initiation did not associate with the rate of CD4 recovery on ART. In univariate analyses, associations were observed for CD4 recovery rate and duration of pre-ART immunosuppression (r = -0.326, p = 0.004) and CD4 nadir (r = 0.284, p = 0.012). In multivariate analysis including age, CD4 nadir, duration of HIV infection, duration of pre-ART immunosuppression, and baseline viral load, only CD4 nadir (p = 0.007) and not duration of immunosuppression (p = 0.87) remained significantly associated with the rate of CD4 recovery.

CONCLUSIONS/SIGNIFICANCE

These data suggest that prior duration of immune suppression does not predict subsequent recovery once ART is initiated and confirm the previous observation that the degree of CD4 depletion prior to ART initiation is the most important determinant of subsequent immune reconstitution.

Behavioural effects of infant and child mortality on fertility in Kenya

This paper analyses the behavioural effects of infant and child mortality on birth intervals in Kenya. Analysing the behavioural effects of infant and child mortality on fertility independent of its biological effects has been considered a difficult task. In this paper, a procedure for analysing these effects separately is developed and applied to the 1989 Kenya Demographic and Health Survey (KDHS) data. The results of the analysis suggests that women in Kenya adopt various strategies such as curtailing the duration of breastfeeding, increasing frequency of coitus, and to a lesser extent use of contraception in order to replace infant or children who have died or to insure against those who are likely to die. These findings suggest the existence of behavioural effects of infant and child mortality on fertility in Kenya.

Adolescent knowledge, values, and coping strategies: implications for health in sub-Saharan Africa

PURPOSE

The purposes of this study were to investigate the experiences and knowledge of adolescents living in an urban center in Kenya and to understand how the decisions they make affect their physical and psychological health.

METHODS

A sample of 216 adolescents was drawn and they met weekly in small groups with trained facilitators for a period of 6 months. A research team monitored the developments of the groups and the topics they discussed. The findings were corroborated by the adolescents.

RESULTS

It was found that adolescents were primarily concerned with developing a coherent and consistent set of personal values which would govern their behavior. Unfortunately, they could not always achieve those values and they resorted to dysfunctional coping strategies which were injurious to their health.

CONCLUSIONS

The role of the adolescent in developing countries is complex and poorly defined. In a period of unprecedented change, an urgent and comprehensive review is necessary by all sections of society if the health of this group is to improve.