Examining the Relationship Between Psychosocial Factors with Knowledge of HIV-Positive Status and Antiretroviral Therapy Exposure Among Adolescent Girls and Young Women Living with HIV in South Africa.

Adolescent girls and young women (AGYW) living with HIV have poor antiretroviral therapy (ART) outcomes. We examined the relationship between psychosocial factors with knowledge of HIV-positive status and antiretroviral therapy exposure among AGYW living with HIV in South Africa. Participants 15-24 years responded to a survey including socio-demographics, psychosocial factors, and HIV testing. Blood was collected to determine HIV status and ART exposure. Multivariable analyses were conducted using R. Of 568 participants with HIV, 356 had knowledge of their HIV-positive status. Social support from family [aOR 1.14 (95% CI 1.04-1.24)] or from a special person [aOR 1.12 (95% CI 1.02-1.23)] was associated with knowledge of HIV-positive status. Resilience [aOR 1.05 (95% CI 1.01-1.08)] was the only psychosocial factor associated with a higher odds of ART exposure. Social support and resilience may increase knowledge of HIV-positive status and ART exposure among South African AGYW.

Participation in an HIV prevention intervention and access to and use of contraceptives among young women: A cross sectional analysis in six South African districts.

OBJECTIVE: This study investigated whether young women's participation in a combination HIV-prevention intervention was associated with accessing and using condoms and other contraceptives. STUDY DESIGN: A cross-sectional household survey was conducted from 2017 to 2018 among a representative sample of young women aged 15-24 years old living in six South African districts in which the intervention was implemented. Cross-tabulations and multivariate regression analyses of weighted data were performed to examine access to and use of condoms and other contraceptives. RESULTS: In total 4399 young women participated, representing a 60.6% response rate. Of participants, 61.0% (n = 2685) reported accessing condoms and other contraceptives in the past year. Among those who ever had sex (n = 3009), 51.0% used condoms and 37.4% other contraceptives at last sex. Among 15-19 year old, participation in the combination intervention was positively associated with reporting contraceptive use other than condoms at last sex (Prevalence Ratio (PR): 1.36; 95% CI: 1.21-1.53) and reporting use of both condoms and other contraceptives at last sex (PR: 1.45; 95% CI: 1.26-1.68). No associations were observed in the age group 20-24. CONCLUSION: Our findings suggest that combination HIV prevention interventions may lead to increased access and use of condoms and other methods of contraception among adolescent women, but this needs to be confirmed in experimental studies. We need to test different or more intensive interventions to increase contraceptive use in young women aged 20-24. IMPLICATIONS: Participating in combination HIV prevention interventions that are delivered via multiple approaches may promote access to, and use of condoms and other methods of contraceptives among adolescent women, and thereby help reduce unintended pregnancies.

An Emerging Substance Use Epidemic: Recreational Use of HIV Pre-Exposure Prophylaxis and Treatment in South Africa.

South Africa has the largest HIV burden and treatment program in the world. Diversion of HIV prevention and treatment medication for recreational use-or nonmedical use for psychoactive effects-is a public health concern globally and in South Africa. Few South African studies examine recreational use of HIV antiretrovirals (ARVs). The objective of this article is to evaluate the prevalence of recreational ARV use and to identify risk and protective factors associated with use. Data are drawn from a cross-sectional household survey of N = 4399 adolescent girls and young women (AGYW) aged 15-24 years in six districts across South Africa where an evaluation of a South African combination HIV prevention for girls and young women was implemented. The use of ARVs to "get high" was reported by 8.3% of AGYW across all districts. Logistic regressions showed that those engaging in transactional sex were at two times higher odds of recreational ARV use [adjusted odds ratio (aOR) = 2.01; confidence interval (95% CI): 1.51-2.68]. Recreational ARV use was more likely among those who used pre-exposure prophylaxis (PrEP) (aOR = 2.17; 95% CI: 1.36-3.48); HIV-positive participants who were not on ARVs for treatment (aOR = 0.36; 95% CI: 0.18-0.68); and those who were not virally suppressed (aOR, no vs. yes = 2.84; 95% CI: 1.21-6.66). As ARVs become more widely available for prevention and treatment, it will be important to monitor and address the possible emergence of ARVs as a substance for misuse or abuse.

Early Sexual Debut and the Effects on Well-Being among South African Adolescent Girls and Young Women Aged 15 to 24 Years.

We compared first sex experiences and wellbeing of adolescent girls and young women (AGYW) who had an early sexual debut (age < 15) with those who had later sexual debut. We conducted a representative household survey among AGYW aged 15-24 years in six districts in South Africa. Of 3009 AGYW who had ever had sex, 8.9% reported early sexual debut. Early sexual debut was associated with coercion at first sex and a lower average well-being score compared with a later debut. Interventions which aim to delay early sexual debut may positively affect well-being.

The role of age-mixing patterns in HIV transmission dynamics: Novel hypotheses from a field study in Cape Town, South Africa.

BACKGROUND: Age-disparate relationships are thought to put young women at increased risk of HIV, though current evidence is inconclusive. Studying population-level age-mixing patterns as well as individual-level measures of age difference variation may provide insight into the persistence and magnitude of the epidemic in South Africa. METHODS: We used data from a survey in Cape Town (n = 506) to describe age-mixing dynamics in the four population strata of HIV negative and HIV positive male and female participants. Mixed-effects models were used to calculate the average increase in partner age for each year increase in age of participant, the average partner age for 15 year olds, and the between-subject and the within-subject standard deviation of partner ages. We conducted 2000 bootstrap replications of the models. Using negative binomial models, we also explored whether HIV status was associated with participants having a larger range in partner ages. RESULTS: HIV positive women had large variability in partner ages at the population level, and at the individual level had nearly three times the expected range of partner ages compared to HIV negative women. This pattern may increase the potential for HIV transmission across birth cohorts and may partially explain the persistence of the epidemic in South Africa. Young men, who have been previously absent from the age-disparity discourse, also choose older partners who may be putting them at increased risk of HIV infection due to the high HIV prevalence among older age categories of women.

Partner age differences and associated sexual risk behaviours among adolescent girls and young women in a cash transfer programme for schooling in Malawi.

BACKGROUND: Age disparities in sexual relationships have been proposed as a key risk factor for HIV transmission in Sub-Saharan Africa, but evidence remains inconclusive. The SIHR study, a cluster randomised trial of a cash transfer programme in Malawi, found that young women in the intervention groups were less likely to have had a sexual partner aged 25 or older, and less likely to test positive for HIV and HSV-2 at follow-up compared to control groups. We examined the hypotheses that girls in the intervention groups had smaller age differences than control groups and that large age differences were associated with relationship-level HIV transmission risk factors: inconsistent condom use, sex frequency, and relationship duration. METHODS: We conducted an analysis of schoolgirls in the Schooling, Income, and Health Risk (SIHR) study aged 13-22 at baseline (n = 2907). We investigated the effects of study arm, trial stage and participant age on age differences in sexual relationships using a linear mixed-effects model. Cumulative-link mixed-effects models were used to estimate the effect of relationship age difference on condom use and sex frequency, and a Cox proportional hazard model was used to estimate the effect of relationship age difference on relationship duration. We controlled for the girl's age, number of partners, study group and study round. RESULTS: Girls receiving cash transfers, on average, had smaller age differences in relationships compared to controls, though the estimated difference was not statistically significant (- 0.43 years; 95% CI: -1.03, 0.17). The older the participant was, the smaller her age differences (- 0.67 per 4-year increase in age; 95% CI: -0.99, - 0.35). Among controls, after the cash transfers had ended the average age difference was 0.82 years larger than during the intervention (95% CI: 0.43, 1.21), suggesting a possible indirect effect of the study on behaviour in the community as a whole. Across treatment groups, larger age differences in relationships were associated with lower levels of condom use, more frequent sex, and longer relationship durations. CONCLUSIONS: Cash-transfer programmes may prevent HIV transmission in part by encouraging young women to form age-similar relationships, which are characterised by increased condom use and reduced sex frequency. The benefits of these programmes may extend to those who are not directly receiving the cash.

Age differences between sexual partners, behavioural and demographic correlates, and HIV infection on Likoma Island, Malawi.

Patterns of age differences between sexual partners - "age-mixing" - may partially explain the magnitude of HIV epidemics in Sub-Saharan Africa. However, evidence of age-disparity as a risk factor for HIV remains mixed. We used data from a socio-centric study of sexual behaviour in Malawi to quantify the age-mixing pattern and to find associations between relationship characteristics and age differences for 1,922 participants. Three age difference measures were explored as predictors of prevalent HIV infection. We found that for each year increase in male participant age, the average age difference with their partners increased by 0.26 years, while among women it remained approximately constant around 5 years. Women in the study had larger within-individual variation in partner ages compared to men. Spousal partnerships and never using a condom during sex were associated with larger age differences in relationships of both men and women. Men who were more than five years younger than their partners had 5.39 times higher odds (95% CI: 0.93-31.24) of being HIV-infected than men 0-4 years older. The relationship between HIV-infection and age-asymmetry may be more complex than previously described. The role that women play in HIV transmission should not be under-estimated, particularly in populations with large within-individual variation in partner ages.

Characterizing Herbal Medicine Use for Noncommunicable Diseases in Urban South Africa.

Economic challenges associated with noncommunicable diseases (NCDs) and the sociocultural outlook of many patients especially in Africa have increased dependence on traditional herbal medicines (THMs) for these diseases. A cross-sectional descriptive study designed to determine the prevalence of and reasons for THM use in the management of NCDs among South African adults was conducted in an urban, economically disadvantaged area of Cape Town, South Africa. In a cohort of 1030 participants recruited as part of the existing Prospective Urban and Rural Epidemiological (PURE) study, 456 individuals were identified. The overall prevalence of THM use was 27%, of which 61% was for NCDs. Participants used THM because of a family history (49%) and sociocultural beliefs (33%). Hypertensive medication was most commonly used concurrently with THM. Healthcare professionals need to be aware of the potential dualistic use of THM and conventional drugs by patients, as this could significantly influence health outcomes. Efforts should be made to educate patients on the potential for drug/herb interactions.

Spatial heterogeneity in projected leprosy trends in India.

BACKGROUND: Leprosy is caused by infection with Mycobacterium leprae and is characterized by peripheral nerve damage and skin lesions. The disease is classified into paucibacillary (PB) and multibacillary (MB) leprosy. The 2012 London Declaration formulated the following targets for leprosy control: (1) global interruption of transmission or elimination by 2020, and (2) reduction of grade-2 disabilities in newly detected cases to below 1 per million population at a global level by 2020. Leprosy is treatable, but diagnosis, access to treatment and treatment adherence (all necessary to curtail transmission) represent major challenges. Globally, new case detection rates for leprosy have remained fairly stable in the past decade, with India responsible for more than half of cases reported annually. METHODS: We analyzed publicly available data from the Indian Ministry of Health and Family Welfare, and fit linear mixed-effects regression models to leprosy case detection trends reported at the district level. We assessed correlation of the new district-level case detection rate for leprosy with several state-level regressors: TB incidence, BCG coverage, fraction of cases exhibiting grade 2 disability at diagnosis, fraction of cases in children, and fraction multibacillary. RESULTS: Our analyses suggest an endemic disease in very slow decline, with substantial spatial heterogeneity at both district and state levels. Enhanced active case finding was associated with a higher case detection rate. CONCLUSIONS: Trend analysis of reported new detection rates from India does not support a thesis of rapid progress in leprosy control.

Concurrent partnerships in Cape Town, South Africa: race and sex differences in prevalence and duration of overlap.

INTRODUCTION: Concurrent partnerships (CPs) have been suggested as a risk factor for transmitting HIV, but their impact on the epidemic depends upon how prevalent they are in populations, the average number of CPs an individual has and the length of time they overlap. However, estimates of prevalence of CPs in Southern Africa vary widely, and the duration of overlap in these relationships is poorly documented. We aim to characterize concurrency in a more accurate and complete manner, using data from three disadvantaged communities of Cape Town, South Africa. METHODS: We conducted a sexual behaviour survey (n = 878) from June 2011 to February 2012 in Cape Town, using Audio Computer-Assisted Self-Interviewing to collect sexual relationship histories on partners in the past year. Using the beginning and end dates for the partnerships, we calculated the point prevalence, the cumulative prevalence and the incidence rate of CPs, as well as the duration of overlap for relationships begun in the previous year. Linear and binomial regression models were used to quantify race (black vs. coloured) and sex differences in the duration of overlap and relative risk of having CPs in the past year. RESULTS: The overall point prevalence of CPs six months before the survey was 8.4%: 13.4% for black men, 1.9% for coloured men, 7.8% black women and 5.6% for coloured women. The median duration of overlap in CPs was 7.5 weeks. Women had less risk of CPs in the previous year than men (RR 0.43; 95% CI: 0.32-0.57) and black participants were more at risk than coloured participants (RR 1.86; 95% CI: 1.17-2.97). CONCLUSIONS: Our results indicate that in this population the prevalence of CPs is relatively high and is characterized by overlaps of long duration, implying there may be opportunities for HIV to be transmitted to concurrent partners.

The association between timing of initiation of antenatal care and stillbirths: a retrospective cohort study of pregnant women in Cape Town, South Africa.

BACKGROUND: There is renewed interest in stillbirth prevention for lower-middle income countries. Early initiation of and properly timed antenatal care (ANC) is thought to reduce the risk of many adverse birth outcomes. To this end we examined if timing of the first ANC visit influences the risk of stillbirth. METHODS: We conducted an analysis of a retrospective cohort of women (n = 34,671) with singleton births in a public perinatal service in Cape Town, South Africa. The main exposure was the gestational age at the first ANC visit. Bivariable analyses examining maternal characteristics by stillbirth status and gestational age at the first ANC visit, were conducted. Logistic regression, adjusting for maternal characteristics, was conducted to determine the risk of stillbirth. RESULTS: Of the 34,671 women who initiated ANC, 27,713 women (80%) were retained until delivery. The population stillbirth rate was 4.3 per 1000 births. The adjusted models indicated there was no effect of gestational age at first ANC visit on stillbirth outcomes when analyzed as a continuous variable (aOR 1.01; 95% CI: 0.99-1.04) or in trimesters (2nd Trimester aOR 0.78, 95% CI: 0.39-1.59; 3rd Trimester OR 1.03, 95% CI: 0.50-2.13, both with 1st Trimester as reference category). The findings were unchanged in sensitivity analyses of unobserved outcomes in non-retained women. CONCLUSION: The timing of a woman's first ANC visit may not be an important determinant of stillbirths in isolation. Further research is required to examine how quality of care, incorporating established, effective biomedical interventions, influences outcomes in this setting.

Assessing the Validity and Appropriateness of Audio Computer-Assisted Self-Interviews in Urban; Disadvantaged Cape Town Communities

Those who study sexual behaviour often rely on self-reported information from surveys. However; results from surveys may be inaccurate due to social desirability bias (SDB). One way to combat SDB is to change the mode of inquiry. Typically surveys are conducted using face-to-face-interviewing. The use of audio computer-assisted self-interviewing (ACASI) has been proposed as a better alternative. There is evidence from Africa; that use of ACASI may elicit more adequate reporting of sensitive sexual behaviours. Here we describe a sexual behaviour survey we conducted in three disadvantaged communities of Cape Town using ACASI methods

Is younger really safer? A qualitative study of perceived risks and benefits of age-disparate relationships among women in Cape Town, South Africa.

Young women in age-asymmetric relationships may be at an elevated risk for acquisition of HIV, since relationships with older men are also correlated with other risk behaviors like less condom use. Qualitative studies have shown that women are motivated to participate in these relationships for money and emotional support. However, there is a paucity of research on women's perceived risks of these relationships, particularly in South Africa. To this end, we conducted in-depth interviews with 23 women recruited from three urban communities in Cape Town. A thematic question guide was used to direct the interviews. Thematic content analysis was used to explore women's perceived risks of age-disparate and non-age-disparate relationships, the benefits of dating older men, and risk perceptions that influence decisions around beginning or ending a relationship. A plurality of women thought that dating an older man does not bring any adverse consequences, although some thought that older men do not use condoms and may be involved in concurrent partnerships. Many women were less inclined to date same-age or younger men, because they were viewed as being disrespectful and abusive. This study points to the need for more awareness raising about the risks of age-disparate relationships. In addition to these initiatives, there is an urgent need to implement holistic approaches to relationship health, in order to curb intimate partner violence, improve gender equity and make non-age-disparate relationships more attractive.

Coital frequency and condom use in monogamous and concurrent sexual relationships in Cape Town, South Africa.

INTRODUCTION: A decreased frequency of unprotected sex during episodes of concurrent relationships may dramatically reduce the role of concurrency in accelerating the spread of HIV. Such a decrease could be the result of coital dilution - the reduction in per-partner coital frequency from additional partners - and/or increased condom use during concurrency. To study the effect of concurrency on the frequency of unprotected sex, we examined sexual behaviour data from three communities with high HIV prevalence around Cape Town, South Africa. METHODS: We conducted a cross-sectional survey from June 2011 to February 2012 using audio computer-assisted self-interviewing to reconstruct one-year sexual histories, with a focus on coital frequency and condom use. Participants were randomly sampled from a previous TB and HIV prevalence survey. Mixed effects logistic and Poisson regression models were fitted to data from 527 sexually active adults reporting on 1210 relationship episodes to evaluate the effect of concurrency status on consistent condom use and coital frequency. RESULTS: The median of the per-partner weekly average coital frequency was 2 (IQR: 1-3), and consistent condom use was reported for 36% of the relationship episodes. Neither per-partner coital frequency nor consistent condom use changed significantly during episodes of concurrency (aIRR=1.05; 95% confidence interval (CI): 0.99-1.24 and aOR=1.01; 95% CI: 0.38-2.68, respectively). Being male, coloured, having a tertiary education, and having a relationship between 2 weeks and 9 months were associated with higher coital frequencies. Being coloured, and having a relationship lasting for more than 9 months, was associated with inconsistent condom use. CONCLUSIONS: We found no evidence for coital dilution or for increased condom use during concurrent relationship episodes in three communities around Cape Town with high HIV prevalence. Given the low levels of self-reported consistent condom use, our findings suggest that if the frequency of unprotected sex with each of the sexual partners is sustained during concurrent relationships, HIV-positive individuals with concurrent partners may disproportionately contribute to onward HIV transmission.

Evaluating audio computer assisted self-interviews in urban South African communities: evidence for good suitability and reduced social desirability bias of a cross-sectional survey on sexual behaviour.

BACKGROUND: Efficient HIV prevention requires accurate identification of individuals with risky sexual behaviour. However, self-reported data from sexual behaviour surveys are prone to social desirability bias (SDB). Audio Computer-Assisted Self-Interviewing (ACASI) has been suggested as an alternative to face-to-face interviewing (FTFI), because it may promote interview privacy and reduce SDB. However, little is known about the suitability and accuracy of ACASI in urban communities with high HIV prevalence in South Africa. To test this, we conducted a sexual behaviour survey in Cape Town, South Africa, using ACASI methods. METHODS: Participants (n = 878) answered questions about their sexual relationships on a touch screen computer in a private mobile office. We included questions at the end of the ACASI survey that were used to assess participants' perceived ease of use, privacy, and truthfulness. Univariate logistic regression models, supported by multivariate models, were applied to identify groups of people who had adverse interviewing experiences. Further, we constructed male-female ratios of self-reported sexual behaviours as indicators of SDB. We used these indicators to compare SDB in our survey and in recent FTFI-based Demographic and Health Surveys (DHSs) from Lesotho, Swaziland, and Zimbabwe. RESULTS: Most participants found our methods easy to use (85.9%), perceived privacy (96.3%) and preferred ACASI to other modes of inquiry (82.5%) when reporting on sexual behaviours. Unemployed participants and those in the 40-70 year old age group were the least likely to find our methods easy to use (OR 0.69; 95% CI: 0.47-1.01 and OR 0.37; 95% CI: 0.23-0.58, respectively). In our survey, the male-female ratio for reporting >2 sexual partners in the past year, a concurrent relationship in the past year, and > 2 sexual partners in a lifetime was 3.4, 2.6, and 1.2, respectively- far lower than the ratios observed in the Demographic and Health Surveys. CONCLUSIONS: Our analysis suggests that most participants in our survey found the ACASI modality to be acceptable, private, and user-friendly. Moreover, our results indicate lower SDB than in FTFI techniques. Targeting older and unemployed participants for ACASI training prior to taking the survey may help to improve their perception of ease and privacy.

Effectiveness of a peer-led HIV prevention intervention in secondary schools in Rwanda: results from a non-randomized controlled trial.

BACKGROUND: While the HIV epidemic is levelling off in sub-Saharan Africa, it remains at an unacceptably high level. Young people aged 15-24 years remain particularly vulnerable, resulting in a regional HIV prevalence of 1.4% in young men and 3.3% in young women. This study assesses the effectiveness of a peer-led HIV prevention intervention in secondary schools in Rwanda on young people's sexual behavior, HIV knowledge and attitudes. METHODS: In a non-randomized longitudinal controlled trial, fourteen schools were selected in two neighboring districts in Rwanda Bugesera (intervention) and Rwamagana (control). Students (n = 1950) in eight intervention and six control schools participated in three surveys (baseline, six and twelve months in the intervention). Analysis was done using linear and logistic regression using generalized estimation equations adjusted for propensity score. RESULTS: The overall retention rate was 72%. Time trends in sexual risk behavior (being sexually active, sex in last six months, condom use at last sex) were not significantly different in students from intervention and control schools, nor was the intervention associated with increased knowledge, perceived severity or perceived susceptibility. It did significantly reduce reported stigma. CONCLUSIONS: Analyzing this and other interventions, we identified several reasons for the observed limited effectiveness of peer education: 1) intervention activities (spreading information) are not tuned to objectives (changing behavior); 2) young people prefer receiving HIV information from other sources than peers; 3) outcome indicators are not adequate and the context of the relationship in which sex occurs and the context in which sex occurs is ignored. Effectiveness of peer education may increase through integration in holistic interventions and redefining peer educators' role as focal points for sensitization and referral to experts and services. Finally, we argue that a narrow focus on sexual risks will never significantly turn the tide.

Age-disparate relationships and implications for STI transmission among young adults in Cape Town, South Africa.

OBJECTIVES: To estimate the prevalence of age-disparate (AD) relationships among young black and coloured adults in Cape Town (South Africa) and determine socio-demographic predictors and individual and relationship characteristics of women in these relationships. METHODS: A secondary analysis of the Cape Area Panel Study (N = 1960) data was conducted. Descriptive statistics were used to quantify the age-mixing pattern and logistic regression was used to identify significant socio-demographic and behavioural correlates of AD relationships. RESULTS: Prevalence of AD relationships was high in both black (36%) and coloured (28%) women. The average age difference between male respondents and their partners increased with age. Young, black women who spent fewer nights under the same roof in one week, had a deceased parent, and were not currently attending classes were more likely to be in an AD relationship. Reports of sexually-transmitted infection (STI) symptoms in the last month and unprotected sex were more common among women in AD relationships. CONCLUSIONS: AD relationships are common among young women in Cape Town. Home and family stability is preventative of young women engaging in AD relationships. Therefore, holistic, societal interventions may reduce AD relationships, which are a risk factor for STIs.

Age-disparity, sexual connectedness and HIV infection in disadvantaged communities around Cape Town, South Africa: a study protocol.

BACKGROUND: Crucial connections between sexual network structure and the distribution of HIV remain inadequately understood, especially in regard to the role of concurrency and age disparity in relationships, and how these network characteristics correlate with each other and other risk factors. Social desirability bias and inaccurate recall are obstacles to obtaining valid, detailed information about sexual behaviour and relationship histories. Therefore, this study aims to use novel research methods in order to determine whether HIV status is associated with age-disparity and sexual connectedness as well as establish the primary behavioural and socio-demographic predictors of the egocentric and community sexual network structures. METHOD/DESIGN: We will conduct a cross-sectional survey that uses a questionnaire exploring one-year sexual histories, with a focus on timing and age disparity of relationships, as well as other risk factors such as unprotected intercourse and the use of alcohol and recreational drugs. The questionnaire will be administered in a safe and confidential mobile interview space, using audio computer-assisted self-interview (ACASI) technology on touch screen computers. The ACASI features a choice of languages and visual feedback of temporal information. The survey will be administered in three peri-urban disadvantaged communities in the greater Cape Town area with a high burden of HIV. The study communities participated in a previous TB/HIV study, from which HIV test results will be anonymously linked to the survey dataset. Statistical analyses of the data will include descriptive statistics, linear mixed-effects models for the inter- and intra-subject variability in the age difference between sexual partners, survival analysis for correlated event times to model concurrency patterns, and logistic regression for association of HIV status with age disparity and sexual connectedness. DISCUSSION: This study design is intended to facilitate more accurate recall of sensitive sexual history data and has the potential to provide substantial insights into the relationship between key sexual network attributes and additional risk factors for HIV infection. This will help to inform the design of context-specific HIV prevention programmes.