The epidemiology of HIV infection among female sex workers in Nairobi, Kenya: A structural determinants and life-course perspective.

High HIV prevalence among female sex workers (FSWs) is heavily influenced by structural determinants (e.g. criminalisation of sex work; violence) and significant life events (e.g. orphanhood, teenage pregnancy). This study aims to understand the epidemiology of HIV among FSWs in Nairobi, Kenya using a structural determinants and life-course perspective. Baseline cross-sectional survey data were collected June-December 2019 for the Maisha Fiti study with 1003 FSWs (aged 18-45 years). Odds ratios and 95% confidence intervals were estimated using multivariable logistic regression with a hierarchical modelling approach. HIV prevalence was 28.0%, and increased with age (<25 years 5.7%, 25-34 years 19.0%, ≥35 years 40.6%). In adjusted analyses, HIV seroprevalence was associated with childhood and adolescence including violence from militia or soldiers (AOR = 1.60; 95%CI:1.00-2.53), young age at sexual debut (≤15 years old vs. ≥18 years AOR = 0.57; 95%CI:0.39-0.84) and teenage pregnancy (AOR = 1.37; 95%CI:1.00-1.88). For adulthood the factors included lower SES score (lowest vs. highest tertile AOR = 0.63; 95%CI:0.40-0.98); reduced housing insecurity (AOR = 0.52; 95%CI:0.54-0.79); lower alcohol/drug use score (AOR = 0.44; 95%CI:0.31-0.61); and a longer duration of selling sex (0-5 years vs. ≥11 years AOR = 2.35; 95%CI:1.44-3.82). Among HIV-negative FSWs, prevalence of HIV risk factors was high (recent hunger 32.3%; internalised 67.7% and experienced 66.0% sex work stigma; recent police arrest 30.1%; recent physical or sexual violence 65.6%, condomless last sex intimate partner 71.1%; harmful alcohol or substance use 49.1%). Only 24.6% of HIV-negative FSWs reported taking PrEP. Taken together, adverse events in childhood and adolescence were associated with increased odds of living with HIV, and were more strongly associated with HIV serostatus than adulthood structural or behavioural risk factors. HIV-negative FSWs remain at high risk of HIV acquisition. This study highlights the importance of addressing adverse events throughout the life course to reduce HIV risk, and the need to continue multi-level HIV prevention and treatment efforts.

Childhood and adolescent factors shaping vulnerability to underage entry into sex work: a quantitative hierarchical analysis of female sex workers in Nairobi, Kenya.

OBJECTIVE: To explore factors associated with early age at entry into sex work, among a cohort of female sex workers (FSWs) in Nairobi, Kenya. BACKGROUND: Younger age at sex work initiation increases the risk of HIV acquisition, condom non-use, violence victimisation and alcohol and/or substance use problems. This study aimed to understand factors in childhood and adolescence that shape the vulnerability to underage sex work initiation. DESIGN: Building on previous qualitative research with this cohort, analysis of behavioural-biological cross-sectional data using hierarchical logistic regression. PARTICIPANTS AND MEASURES: FSWs aged 18-45 years were randomly selected from seven Sex Workers Outreach Programme clinics in Nairobi, and between June and December 2019, completed a baseline behavioural-biological survey. Measurement tools included WHO Adverse Childhood Experiences, Alcohol, Smoking and Substance Involvement Screening Test and questionnaires on sociodemographic information, sexual risk behaviours and gender-based violence. Descriptive statistics and logistic regression were conducted using hierarchical modelling. RESULTS: Of the 1003 FSWs who participated in the baseline survey (response rate 96%), 176 (17.5%) initiated sex work while underage (<18 years). In the multivariable analysis, factors associated with entering sex work while underage included incomplete secondary school education (aOR=2.82; 95% CI=1.69 to 4.73), experiencing homelessness as a child (aOR=2.20; 95% CI=1.39 to 3.48), experiencing childhood physical or sexual violence (aOR=1.85; 95% CI=1.09 to 3.15), young age of sexual debut (≤15 years) (aOR=5.03; 95% CI=1.83 to 13.79) and being childless at time of sex work initiation (aOR=9.80; 95% CI=3.60 to 26.66). CONCLUSIONS: Lower education level and childhood homelessness, combined with sexual violence and sexual risk behaviours in childhood, create pathways to underage initiation into sex work. Interventions designed for girls and young women at these pivotal points in their lives could help prevent underage sex work initiation and their associated health, social and economic consequences.

Conducting Violence and Mental Health Research with Female Sex Workers during the COVID-19 Pandemic: Ethical Considerations, Challenges, and Lessons Learned from the Maisha Fiti Study in Nairobi, Kenya.

Conducting violence and mental health research during the COVID-19 pandemic with vulnerable groups such as female sex workers (FSWs) required care to ensure that participants and the research team were not harmed. Potential risks and harm avoidance needed to be considered as well as ensuring data reliability. In March 2020, COVID-19 restrictions were imposed in Kenya during follow-up data collection for the Maisha Fiti study (n = 1003); hence data collection was paused. In June 2020, the study clinic was re-opened after consultations with violence and mental health experts and the FSW community. Between June 2020 and January 2021, data were collected in person and remotely following ethical procedures. A total of 885/1003 (88.2%) FSWs participated in the follow-up behavioural-biological survey and 47/47 (100%) participated in the qualitative in-depth interviews. A total of 26/885 (2.9%) quantitative surveys and 3/47 (6.4%) qualitative interviews were conducted remotely. Researching sensitive topics like sex work, violence, and mental health must guarantee study participants' safety and privacy. Collecting data at the height of COVID-19 was crucial in understanding the relationships between the COVID-19 pandemic, violence against women, and mental health. Relationships established with study participants during the baseline survey-before the pandemic-enabled us to complete data collection. In this paper, we discuss key issues involved in undertaking violence and mental health research with a vulnerable population such as FSWs during a pandemic. Lessons learned could be useful to others researching sensitive topics such as violence and mental health with vulnerable populations.

Violence across the Life Course and Implications for Intervention Design: Findings from the Maisha Fiti Study with Female Sex Workers in Nairobi, Kenya.

We examined violence experiences among Female Sex Workers (FSWs) in Nairobi, Kenya, and how these relate to HIV risk using a life course perspective. Baseline behavioural-biological surveys were conducted with 1003 FSWs June-December 2019. Multivariable logistic regression models were used to estimate the adjusted odds ratio (AOR) and 95% confidence intervals (CI) for associations of life course factors with reported experience of physical or sexual violence in the past 6 months. We found substantial overlap between violence in childhood, and recent intimate and non-intimate partner violence in adulthood, with 86.9% reporting one or more types of violence and 18.7% reporting all three. Recent physical or sexual violence (64.9%) was independently associated with life course factors, including a high WHO Adverse Childhood Experiences (ACE) score (AOR = 7.92; 95% CI:4.93-12.74) and forced sexual debut (AOR = 1.97; 95% CI:1.18-3.29), as well as having an intimate partner (AOR = 1.67; 95% CI:1.25-2.23), not having an additional income to sex work (AOR = 1.54; 95% CI:1.15-2.05), having four or more dependents (AOR = 1.52; 95% CI:0.98-2.34), recent hunger (AOR = 1.39; 95% CI:1.01-1.92), police arrest in the past 6 months (AOR = 2.40; 95% CI:1.71-3.39), condomless last sex (AOR = 1.46; 95% CI:1.02-2.09), and harmful alcohol use (AOR = 3.34; 95% CI:1.74-6.42). Interventions that focus on violence prevention during childhood and adolescence should help prevent future adverse trajectories, including violence experience and HIV acquisition.

Syndemic of factors that shape the early lives of women who enter into sex work: a qualitative methods study from Nairobi, Kenya.

OBJECTIVE: To explore the structural and social co-factors that shape the early lives of women who enter sex work in Nairobi, Kenya. DESIGN: Thematic analysis of qualitative data collected as part of the Maisha Fiti study among female sex workers (FSWs) in Nairobi. PARTICIPANTS AND MEASURES: FSWs aged 18-45 years were randomly selected from seven Sex Workers Outreach Programme clinics in Nairobi and participated in baseline behavioural-biological surveys. Participants in this qualitative study were randomly selected from the Maisha Fiti study cohort and were interviewed between October 2019 and July 2020. Women described their lives from childhood, covering topics including sex work, violence and financial management. RESULTS: 48 out of 1003 Maisha Fiti participants participated in the in-depth qualitative interviews. FSWs described how physical and sexual violence, poverty and incomplete education in their childhood and adolescence intertwined with early pregnancy, marriage, intimate partner violence and relationship breakdown in their adolescence and early adulthood. The data analysis found clear syndemic relationships between these risk factors, particularly childhood violence, poverty and incomplete education and highlighted pathways leading to financial desperation and caring for dependents, and subsequent entry into sex work. Women perceived sex work as risky and most would prefer alternative work if possible, but it provided them with some financial independence and agency. CONCLUSIONS: This is the first study in Kenya to qualitatively explore the early lives of sex workers from a syndemic perspective. This method identified the pivotal points of (1) leaving school early due to poverty or pregnancy, (2) breakdown of early intimate relationships and (3) women caring for dependents on their own. Complex, multi-component structural interventions before these points could help increase school retention, reduce teenage pregnancy, tackle violence, support young mothers and reduce entry into sex work and the risk that it entails by expanding livelihood options.

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.

Feasibility of conducting HIV prevention trials among key populations in Nairobi, Kenya.

OBJECTIVE: To assess the feasibility of conducting HIV prevention trials among key populations in Nairobi, Kenya. BACKGROUND: HIV prevention trials require the inclusion of those at high risk of HIV infection and their informed decision to take part and remain in the clinical trial to the end is crucial. In Kenya key populations including men who have sex with men (MSM) and female sex workers (FSW) are, disproportionately, at high risk of HIV infection when compared to the general population. Few trials testing biomedical prevention products against HIV have enrolled Kenyan FSW and MSM. METHODS: We performed simulated vaccine efficacy trial (SiVET) using licensed hepatitis B vaccines as substitutes for a HIV vaccine candidate and included randomization for those immune to hep B. The SiVET was an observational study designed to mimic the rigors of a clinical trial; we assessed HIV risk, provided risk counselling and prevention tools and performed HIV testing at baseline and periodically until the end of the trial. MSM and FSW were enrolled at a ratio of 4:1. Volunteers were assigned to either hepatitis B vaccine or placebo. RESULTS: Recruitment took approximately 24 months between Sep 2015 and Sep 2017. Of the 368 volunteers screened, 250 (200 MSM and 50 FSW) were enrolled. Reasons for exclusion at screening included: being positive for HIV (n = 7), hepatitis (n = 14), other pre-existing medical conditions (n = 41), eligible but chose not to enrol (n = 47). Most of the volunteers adhered to study procedures and attended their study visits within the study window. These include volunteers who received the second vaccination 244 (98%), the third vaccination 228 (91%) and, the final study visit 217 (87%). The reasons volunteers discontinued from the study early included: relocation and loss to follow up (n = 14). A total of 8 cases of HIV infection were observed in 174.5 Person Years at Risk (PYAR), all among MSM, including 5 seroconversions identified at the last study visit, for a HIV incidence of 4.58 cases/ 100 PYAR, among MSM enrolled in the study. CONCLUSION: Our findings suggest that it is possible to conduct HIV prevention trials among key populations in Nairobi with a good adherence to a vaccine efficacy trial schedule. Despite HIV prevention efforts, we also noted a high incidence of HIV infection. This demonstrates the need for effective HIV prevention products in these populations.

Remote methods for research on violence against women and children: lessons and challenges from research during the COVID-19 pandemic.

Collecting data to understand violence against women and children during and after the COVID-19 pandemic is essential to inform violence prevention and response efforts. Although researchers across fields have pivoted to remote rather than in-person data collection, remote research on violence against women, children and young people poses particular challenges. As a group of violence researchers, we reflect on our experiences across eight studies in six countries that we redesigned to include remote data collection methods. We found the following areas were crucial in fulfilling our commitments to participants, researchers, violence prevention and research ethics: (1) designing remote data collection in the context of strong research partnerships; (2) adapting data collection approaches; (3) developing additional safeguarding processes in the context of remote data collection during the pandemic; and (4) providing remote support for researchers. We discuss lessons learnt in each of these areas and across the research design and implementation process, and summarise key considerations for other researchers considering remote data collection on violence.

Harmful Alcohol and Drug Use Is Associated with Syndemic Risk Factors among Female Sex Workers in Nairobi, Kenya.

Background: Female Sex Workers (FSWs) are at high risk of harmful alcohol and other drug use. We use quantitative data to describe the prevalence of alcohol and other drug use and identify associated occupational and socio-economic risk factors, and aim to elucidate patterns of alcohol and drug use through information drawn from qualitative data. Methods: Maisha Fiti was a mixed-method longitudinal study conducted in 2019 among a random sample of FSWs in Nairobi, Kenya. We used baseline date from the behavioural−biological survey, which included the WHO Alcohol, Smoking and Substance Involvement Screening Test that measures harmful alcohol and other drug use in the past three months (moderate/high risk score: >11 for alcohol; >4 for other drugs). In-depth interviews were conducted with 40 randomly selected FSWs. Findings: Of 1003 participants, 29.9% (95%CI 27.0−32.6%) reported harmful (moderate/high risk) alcohol use, 21.5% harmful amphetamine use (95%CI 19.1−24.1%) and 16.9% harmful cannabis use (95%CI 14.7−19.2%). Quantitative analysis found that harmful alcohol, cannabis and amphetamine use were associated with differing risk factors including higher Adverse Childhood Experience (ACE) scores, street homelessness, food insecurity (recent hunger), recent violence from clients, reduced condom use, depression/anxiety and police arrest. Qualitative interviews found that childhood neglect and violence were drivers of entry into sex work and alcohol use, and that alcohol and cannabis helped women cope with sex work. Conclusions: There is a need for individual and structural-level interventions, tailored for FSWs, to address harmful alcohol and other drug use and associated syndemic risks including ACEs, violence and sexual risk behaviours.

Experiences and challenges in sexual health service access among men who have sex with men in Kenya.

Men who have sex with men (MSM) in Kenya bear a heavy burden of HIV/STIs and are a priority population in the national HIV/AIDS response, yet remain criminalised and stigmatised within society. HIV pre-exposure prophylaxis (PrEP) offers an opportunity to significantly impact the HIV epidemic, as does the concept of U = U, whereby those who are living with HIV and on treatment are uninfectious when their viral load has been suppressed so as to be undetectable. However, the value of such innovations will not be realised without sufficient understanding of, and respect for, the sexual health service provision needs of MSM. This paper describes findings from 30 in-depth interviews with MSM living in Nairobi that explored engagement with sexual health service providers, barriers to access and perceived opportunities to improve service design and delivery. Findings indicate concern relating to the professionalism of some staff working within public hospitals as well as feelings that many sexual health services were not considered safe spaces for the discussion of MSM-specific sexual behaviour. Diverse views were expressed relating to comfort in public, community and private sexual health services as well as how these are and should be organised.

Longitudinal experiences and risk factors for common mental health problems and suicidal behaviours among female sex workers in Nairobi, Kenya.

Background: Female sex workers (FSWs) are at high risk of mental health problems and suicide risk. Few longitudinal studies have examined risk factors for poor mental health among FSWs. Methods: Maisha Fiti is a longitudinal study among FSWs randomly selected from Sex Worker Outreach Programme clinics across Nairobi. Behavioural-biological survey data were collected at baseline (n = 1003, June-December 2019), midline (n = 366) (Jan-March 2020) and endline (n = 877) (June 2020-Jan 2021). Women reporting mental health problems were offered counselling services. Multivariable mixed logistic regression models were used to examine factors associated with mental health problems and suicidal behaviours. Results: There was a decline in the proportion of women reporting any mental health problem (depression and/or anxiety and/or PTSD) (baseline: 29.9%, midline: 13.3%, endline: 11.8%). There was strong evidence that any mental health problem was associated with recent hunger (aOR 1.99; 95% CI 1.37-2.88) and recent violence from non-intimate partners (2.23; 95% CI 1.55-3.19). Recent suicidal behaviour prevalence was similar across survey rounds (baseline: 10.2%; midline: 10.2%; endline: 10.4%), and was associated with recent violence from non-intimate partners (aOR 1.96; 95% CI 1.31-2.95), recent hunger (aOR 1.69; 95% CI 1.15-2.47) and having an additional employment to sex work (aOR 1.50; 95% CI 1.00-2.23). Conclusions: Our study found a decline in mental health problems but high levels of persistent suicidal behaviours among FSWs. Syndemic risk factors including food insecurity and violence were longitudinally associated with mental health problems and recent suicidal behaviours. There is a need for accessible mental health services for FSWs, alongside structural interventions addressing poverty and violence.

Prevalence and correlates of common mental health problems and recent suicidal thoughts and behaviours among female sex workers in Nairobi, Kenya.

BACKGROUND: Adverse childhood experiences (ACEs), poverty, violence and harmful alcohol/substance use are associated with poor mental health outcomes, but few studies have examined these risks among Female Sex Workers (FSWs). We examine the prevalence and correlates of common mental health problems including suicidal thoughts and behaviours among FSWs in Kenya. METHODS: Maisha Fiti is a longitudinal study among FSWs randomly selected from Sex Worker Outreach Programme (SWOP) clinics across Nairobi. Baseline behavioural-biological survey (n = 1003) data were collected June-December 2019. Mental health problems were assessed using the Patient Health Questionnaire (PHQ-9) for depression, the Generalised Anxiety Disorder tool (GAD-7) for anxiety, the Harvard Trauma Questionnaire (HTQ-17) for Post-Traumatic Stress Disorder (PTSD) and a two-item tool to measure recent suicidal thoughts/behaviours. Other measurement tools included the WHO Adverse Childhood Experiences (ACE) score, WHO Violence Against Women questionnaire, and the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST). Descriptive statistics and multivariable logistic regression were conducted using a hierarchical modelling approach. RESULTS: Of 1039 eligible FSWs, 1003 FSWs participated in the study (response rate: 96%) with mean age 33.7 years. The prevalence of moderate/severe depression was 23.2%, moderate/severe anxiety 11.0%, PTSD 14.0% and recent suicidal thoughts/behaviours 10.2% (2.6% suicide attempt, 10.0% suicidal thoughts). Depression, anxiety, PTSD and recent suicidal thoughts/behaviours were all independently associated with higher ACE scores, recent hunger (missed a meal in last week due to financial difficulties), recent sexual/physical violence and increased harmful alcohol/substance. PTSD was additionally associated with increased chlamydia prevalence and recent suicidal thoughts/behaviours with low education and low socio-economic status. Mental health problems were less prevalent among women reporting social support. CONCLUSIONS: The high burden of mental health problems indicates a need for accessible services tailored for FSWs alongside structural interventions addressing poverty, harmful alcohol/substance use and violence. Given the high rates of ACEs, early childhood and family interventions should be considered to prevent poor mental health outcomes.

HIV burden and correlates of infection among transfeminine people and cisgender men who have sex with men in Nairobi, Kenya: an observational study.

BACKGROUND: Transgender people are disproportionately affected by HIV and other sexually transmitted infections (STIs) worldwide, and culturally competent prevention and treatment services are often unavailable or inaccessible. Despite recent improvements in national HIV responses for many key populations in east Africa, evidence of effective responses informed by transgender sexual health needs is sparse. We aimed to assess gender identity among men and transgender people who have sex with men in Kenya, and to explore its associations with sexual health-related outcomes, risk behaviours, and uptake of HIV prevention and care interventions. METHODS: We did a cross-sectional study in Nairobi, Kenya, and recruited adult cisgender men and transfeminine people who reported having sex with men, through respondent-driven sampling. Inclusion criteria were possession of a valid study coupon, being aged 18 years or older, having male sex assignment at birth or male gender identification currently, living within 50 km of Nairobi, and having had consensual anal or oral sexual activity with a man in the previous 12 months. Seed participants were identified by three community organisations that provide targeted health-care services to gay, bisexual, or other men who have sex with men (MSM) communities in Nairobi. We assessed gender identity, sociodemographics, sexual behaviour, and HIV prevention and care uptake, by self-completed survey. Participants were tested for HIV, syphilis, and rectal and urethral gonorrhoea and chlamydia. We compared prevalence of sexual health outcomes, risk behaviour, and HIV prevention and care service uptake among transfeminine and cisgender participants, using multivariable robust Poisson regression models, with gender identity as the independent variable. FINDINGS: Between May 4 and Dec 8, 2017, we enrolled 618 participants. Six participants did not answer the questions on sex assigned at birth and gender identity and so were excluded from the analyses. 522 (sample-weighted percentage 86%) of 612 participants were classified as cisgender men, 70 (11%) as transfeminine, and three (<1%) as transmasculine. 17 participants (2%) did not identify as male, female, or transgender. Compared with cisgender men, transfeminine people were more likely to be HIV-positive (28 [41%] of 70 transfeminine vs 151 [25%] of 521 cisgender men; p=0·0009) and to report current symptoms consistent with a rectal STI (eight [16%] of 67 vs 38 [7%] of 518; p=0·014). Transfeminine people reported higher numbers of recent male sexual partners (22 [27%] of 70 transfeminine people reported four or more male sexual partners in the past 3 months vs 112 [13%] of 522 cisgender men; p=0·042) and were more likely to report condomless anal intercourse with men (43 [62%] of 70 vs 208 [39%] of 522; p=0·0009) and receptive anal intercourse (54 [76%] of 70 vs 252 [46%] of 522; p<0·0001) in the past 3 months, and transactional sex with men (42 [57%] of 69 vs 240 [42%] of 518; p=0·023) and experience of sexual assault (16 [23%] of 69 vs 65 [11%] of 520; p=0·019) in the past 12 months. Use of pre-exposure prophylaxis and post-exposure prophylaxis was low in both groups. INTERPRETATION: Transfeminine people who have sex with men have a higher burden of HIV and associated risk behaviours compared with cisgender MSM in the same context, yet their uptake of prevention and care services is poor. Policies should acknowledge the specific needs of transfeminine people as distinct from cisgender MSM, and support health-care providers to address these needs. FUNDING: Evidence for HIV Prevention in Southern Africa (EHPSA), UK Aid.

Online socializing among men who have sex with men and transgender people in Nairobi and Johannesburg and implications for public health-related research and health promotion: an analysis of qualitative and respondent-driven sampling survey data.

INTRODUCTION: There is little published literature about gay, bisexual and other men who have sex with men and transgender individuals (MSM and TG)'s use of social media in sub-Saharan Africa, despite repressive social and/or criminalizing contexts that limit access to physical HIV prevention. We sought to describe MSM and TG's online socializing in Nairobi and Johannesburg, identifying the characteristics of those socializing online and those not, in order to inform the development of research and health promotion in online environments. METHODS: Respondent-driven sampling surveys were conducted in 2017 in Nairobi (n = 618) and Johannesburg (n = 301) with those reporting current male gender identity or male sex assigned at birth and sex with a man in the last 12 months. Online socializing patterns, sociodemographic, sexual behaviour and HIV-testing data were collected. We examined associations between social media use and sociodemographic characteristics and sexual behaviours among all, and only those HIV-uninfected, using logistic regression. Analyses were RDS-II weighted. Thirty qualitative interviews were conducted with MSM and TG in each city, which examined the broader context of and motivations for social media use. RESULTS: Most MSM and TG had used social media to socialize with MSM in the last month (60% Johannesburg, 71% Nairobi), mostly using generic platforms (e.g. Facebook), but also gay-specific (e.g. Grindr). HIV-uninfected MSM and TG reporting riskier recent sexual behaviours had raised odds of social media use in Nairobi, including receptive anal intercourse (adjusted OR = 2.15, p = 0.006), buying (aOR = 2.24, p = 0.015) and selling sex with men (aOR = 2.17, p = 0.004). Evidence for these associations was weaker in Johannesburg, though socializing online was associated with condomless anal intercourse (aOR = 3.67, p = 0.003) and active syphilis (aOR = 13.50, p = 0.016). Qualitative findings indicated that while online socializing can limit risk of harm inherent in face-to-face interactions, novel challenges were introduced, including context collapse and a fear of blackmail. CONCLUSIONS: Most MSM and TG in these cities socialize online regularly. Users reported HIV acquisition risk behaviours, yet this space is not fully utilized for sexual health promotion and research engagement. Effective, safe and acceptable means of using online channels to engage with MSM/TG that account for MSM and TG's strategies and concerns for managing online security should now be explored, as complements or alternatives to existing outreach.

Willingness to participate in future HIV vaccine trials among men who have sex with men and female sex workers living in Nairobi, Kenya.

OBJECTIVE: To evaluate factors associated with willingness to participate in future HIV vaccine trials among men who have sex with men and female sex workers living in Nairobi, Kenya. BACKGROUND: Working with 'key populations', those at elevated risk of HIV acquisition, is important to conduct efficient HIV prevention trials. In Nairobi Kenya, HIV infection is higher in men who have sex with men (MSM) and female sex workers (FSW) than in the general adult population, hence the need to establish if they would be willing to participate in future HIV vaccine trials. METHODS: We administered a structured questionnaire to MSM and FSW enrolled in a simulated vaccine efficacy trial (SiVET). The SiVET was an observational study designed to mimic the rigors of a clinical trial to assess HIV risk characteristics at baseline. After 12-15 months of follow-up, a structured questionnaire was administered to evaluate hypothetical willingness to participate in future HIV vaccine trials. RESULTS: Of 250 persons (80% MSM by design) enrolled in SiVET, 214 attended the final study visit and 174 (81%) of them expressed hypothetical willingness to participate in future HIV vaccine trials. These were 82% of MSM and 80% of FSW of those who attended the final study visit. Having a very good experience in the SiVET trial predicted willingness to participate in future HIV vaccine trials. Motivating factors for participation included a desire to receive education about HIV (59%) and to receive healthcare (57%). CONCLUSIONS: Our data demonstrate high willingness among key populations in Kenya, to participate in future HIV vaccine trials after completing participation in a SiVET. The findings suggest that these groups might be a reliable target population for consideration in future HIV vaccine trials. Assessment of willingness to participate in these populations provides important information that may help to inform future education and recruitment efforts for vaccine trials. Improving the research experience for members of key populations could impact their willingness to participate in HIV vaccine trials.