Reconceptualizing the HIV epidemiology and prevention needs of Female Sex Workers (FSW) in Swaziland

Quantifying the impact of cascade inequalities: a modelling study on the prevention impacts of antiretroviral therapy scale-up in Eswatini

Background

Inequalities in the antiretroviral therapy (ART) cascade across subpopulations remain an ongoing challenge in the global HIV response. Eswatini achieved the UNAIDS 95-95-95 targets by 2020, with differentiated programs to minimize inequalities across subpopulations, including for female sex workers (FSW) and their clients. We sought to estimate additional HIV infections expected in Eswatini if cascade scale-up had not been equal, and under which epidemic conditions these inequalities could have the largest influence.

Methods

Drawing on population-level and FSW-specific surveys in Eswatini, we developed a compartmental model of heterosexual HIV transmission which included eight subpopulations and four sexual partnership types. We calibrated the model to stratified HIV prevalence, incidence, and ART cascade data. Taking observed cascade scale-up in Eswatini as the base-case-reaching 95-95-95 in the overall population by 2020-we defined four counterfactual scenarios in which the population overall reached 80-80-90 by 2020, but where FSW, clients, both, or neither were disproportionately left behind, reaching only 60-40-80. We quantified relative additional cumulative HIV infections by 2030 in counterfactual vs base-case scenarios. We further estimated linear effects of viral suppression gap among FSW and clients on additional infections by 2030, plus effect modification by FSW/client population sizes, rates of turnover, and HIV prevalence ratios.

Results

Compared with the base-case scenario, leaving behind neither FSW nor their clients led to the fewest additional infections by 2030: median (95% credible interval) 14.9 (10.4, 18.4)% vs 26.3 (19.7, 33.0)% if both were left behind-a 73 (40, 149)% increase. The effect of lower cascade on additional infections was larger for clients vs FSW, and both effects increased with population size and relative HIV incidence.

Conclusions

Inequalities in the ART cascade across subpopulations can undermine the anticipated prevention impacts of cascade scale-up. As Eswatini has shown, addressing inequalities in the ART cascade, particularly those that intersect with high transmission risk, could maximize incidence reductions from cascade scale-up.

Adjusting for hidden biases in sexual behaviour data: a mechanistic approach

Background

Two required inputs to mathematical models of sexually transmitted infections are the average duration in epidemiological risk states (e.g., selling sex) and the average rates of sexual partnership change. These variables are often only available as aggregate estimates from published cross-sectional studies, and may be subject to distributional, sampling, censoring, and measurement biases.

Methods

We explore adjustments for these biases using aggregate estimates of duration in sex work and numbers of reported sexual partners from a published 2011 survey of female sex worker in Eswatini. We develop adjustments from first principles, and construct Bayesian hierarchical models to reflect our mechanistic assumptions about the bias-generating processes.

Results

We show that different mechanisms of bias for duration in sex work may "cancel out" by acting in opposite directions, but that failure to consider some mechanisms could over- or underestimate duration in sex work by factors approaching 2. We also show that conventional interpretations of sexual partner numbers are biased due to implicit assumptions about partnership duration, but that unbiased estimators of partnership change rate can be defined that explicitly incorporate a given partnership duration. We highlight how the unbiased estimator is most important when the survey recall period and partnership duration are similar in length.

Conclusions

While we explore these bias adjustments using a particular dataset, and in the context of deriving inputs for mathematical modelling, we expect that our approach and insights would be applicable to other datasets and motivations for quantifying sexual behaviour data.

The relationship between underage initiation of selling sex and depression among female sex workers in Eswatini

Background

Minors who sell sex are likely to have complex mental health needs that may persist into adulthood. This topic is understudied in sub-Saharan Africa. This study hypothesized that adult female sex workers in Eswatini who started selling sex as minors have a higher prevalence of depression than those who started as adults. We also examined correlates of depression and underage initiation of selling sex, including stigma and condom-related behaviors.

Methods

From October-December 2014, women aged 18 or older who sold sex in the past 12 months in Eswatini were recruited through venue-based sampling. Participants completed a survey including the 9-item Patient Health Questionnaire (PHQ-9) and a question about the age at which they first sold sex for money. T-tests, χ² tests and multivariable logistic regression were used to assess associations.

Results

Overall, 43.1% of participants (332/770) had probable depression, and 16.6% (128/770) started selling sex as minors under the age of 18. Over half (55.5%, 71/128) of those who started selling sex as minors had depression. This was significantly higher than the 40.7% (261/642) prevalence of depression among participants who started selling sex as adults (p = 0.002). After adjusting for confounders, female sex workers who started selling sex as minors had higher odds of depression than those who started as adults (adjusted odds ratio [aOR] 1.70, 95% confidence interval 1.11-2.60).

Conclusion

Results highlight the need for trauma-informed and adolescent-friendly mental health services in settings free of stigma toward female sex workers in Eswatini.

Validating a measure of anticipated sex work-related stigma among male and female sex workers in Kenya

Sex workers face different types of sex work-related stigma, which may include anticipated, perceived, experienced, or internalized stigma. Sex work stigma can discourage health care seeking and hamper STI and HIV prevention and treatment efforts. There is a paucity of validated sex work-related stigma measures, and this limits the ability to study the stigma associated with sex work. A cross-sectional survey was conducted that measured anticipated sex work-related stigma among male and female sex workers in Kenya (N = 729). We examined the construct validity and reliability of the anticipated stigma items to establish a conceptually and statistically valid scale. Our analysis supported a 15-item scale measuring five anticipated sex work stigma domains: gossip and verbal abuse from family; gossip and verbal abuse from healthcare workers; gossip and verbal abuse from friends and community; physical abuse; and exclusion. The scale demonstrated good face, content, and construct validity. Reliability was good for all subscales and the overall scale. The scale demonstrated good model fit statistics and good standardized factor loadings. The availability of valid and reliable stigma measures will enhance efforts to characterize and address stigma among sex workers and ultimately support the protection, health and well-being of this vulnerable population.

Feasibility of oral HIV self-testing in female sex workers in Gaborone, Botswana

BACKGROUND

Oral HIV self-testing (HIVST) may be useful for increasing testing in persons at elevated risk of acquiring HIV.

METHODS

We conducted a pilot study to evaluate the feasibility (defined by uptake) of HIVST among FSW in Gaborone, Botswana. FSW age 18 years and above were recruited through a non-governmental organization serving FSW. FSW with unknown or negative HIV status at screening performed HIVST in the study clinic following brief training. FSW testing HIV-negative were each given two test kits to take home: one kit to perform unassisted HIVST and another to share with others. Feasibility (use) of HIVST (and sharing of test kits with others) was assessed in these women at a study visit four months later.

RESULTS

Two hundred FSW were screened. Their average age was 34 years (range 18-59), and 115 (58%) were HIV-positive. Eighty-five (42%) tested HIV-negative at entry and were eligible to take part in the HIVST pilot study. All 85 (100%) agreed to take home HIVST kits. Sixty-nine (81%) of these 85 participants had a follow-up visit, 56 (81%) of whom reported performing HIVST at a mean of three and half months after the initial visit. All 56 participants who performed HIVST reported negative HIVST results. Fifty (73%) of the 69 participants who took HIVST kits home shared them with others. Of the 50 women sharing HIVST kits, 25 (50%) shared with their non-client partners, 15 with a family member, 8 with friends, and 3 with a client. One participant did not test herself but shared both her test kits. Most participants 53/56 (95%) found oral HIVST very easy to use whilst 3/56 (5%) felt it was fairly easy.

CONCLUSION

Oral HIVST is feasible among FSW in Gaborone, Botswana. The majority of FSW used the HIVST kits themselves and also shared extra HIVST kits with other individuals.

Loss to follow-up among female sex workers in Zambia: findings from a five-year HIV-incidence cohort

HIV-incidence studies are used to identify at-risk populations for HIV-prevention trials and interventions, but loss to follow-up (LTFU) can bias results if participants who remain differ from those who drop out. We investigated the incidence of and factors associated with LTFU among Zambian female sex workers (FSWs) in an HIV-incidence cohort from 2012 to 2017. Enrolled participants returned at month one, month three and quarterly thereafter. FSWs were considered LTFU if they missed six consecutive months, or if their last visit was six months before the study end date. Of 420 FSWs, 139 (33%) were LTFU at a rate of 15.7 per 100 person years. In multivariable analysis, LTFU was greater for FSWs who never used alcohol, began sex work above the age of consent, and had a lower volume of new clients. Our study appeared to retain FSWs in most need of HIV-prevention services offered at follow-up.

HIV prevalence, sexual risk behaviours and HIV testing among female sex workers in three cities in Sri Lanka: Findings from respondent-driven sampling surveys

Sri Lanka has a low-level HIV epidemic. This study aims to provide evidence on HIV, syphilis and hepatitis B (HBV) prevalence, sexual risk behaviours and utilisation of HIV prevention interventions among female sex workers (FSW) in the cities Colombo, Galle, and Kandy. Using respondent-driven sampling (RDS), we recruited a total of 458 FSW in Colombo, 360 in Galle and 362 in Kandy from November 2017 to March 2018. Participants provided biological specimens for testing for infections and completed a behavioural questionnaire. We found no HIV nor HBV infections in Galle and Kandy, and low HIV (0.4%) and HBV surface antigen (0.6%) prevalence in Colombo. FSW in Colombo had higher positivity on Treponema pallidum-particle agglutination test (8.4%) compared to Galle (2.0%) and Kandy (2.5%). About two thirds of FSW heard of HIV in each of the cities. Around 90% of FSW used condom at last sex with a client in both Colombo and Galle, but considerably less in Kandy (57.1%). However, lower proportion of FSW used condoms every time during sex with clients in the past 30 day: 22.9% of FSW in Colombo, 26.6% in Kandy and 68.4% in Galle. Across cities, 17.5%-39.5% of FSW reported being tested for HIV in the past 12 months or knowing HIV positive status. The commonest reasons for never testing for HIV was not knowing where to test (54.2% in Colombo, 41.8% in Galle, 48.1% in Kandy) followed by inconvenient testing location (23.7% in Colombo and 31.1% in Kandy). HIV has not yet been firmly established among FSW in three cities in Sri Lanka, but the vulnerability towards HIV and STIs is substantial. HIV interventions should be intensified by expanding community-based HIV testing approaches, increasingawareness of HIV risks and addressing socio-structural vulnerabilities of FSW to HIV.

Contribution of high risk groups' unmet needs may be underestimated in epidemic models without risk turnover: A mechanistic modelling analysis

Background

Epidemic models of sexually transmitted infections (STIs) are often used to characterize the contribution of risk groups to overall transmission by projecting the transmission population attributable fraction (tPAF) of unmet prevention and treatment needs within risk groups. However, evidence suggests that STI risk is dynamic over an individual’s sexual life course, which manifests as turnover between risk groups. We sought to examine the mechanisms by which turnover influences modelled projections of the tPAF of high risk groups.

Methods

We developed a unifying, data-guided framework to simulate risk group turnover in deterministic, compartmental transmission models. We applied the framework to an illustrative model of an STI and examined the mechanisms by which risk group turnover influenced equilibrium prevalence across risk groups. We then fit a model with and without turnover to the same risk-stratified STI prevalence targets and compared the inferred level of risk heterogeneity and tPAF of the highest risk group projected by the two models.

Results

The influence of turnover on group-specific prevalence was mediated by three main phenomena: movement of previously high risk individuals with the infection into lower risk groups; changes to herd effect in the highest risk group; and changes in the number of partnerships where transmission can occur. Faster turnover led to a smaller ratio of STI prevalence between the highest and lowest risk groups. Compared to the fitted model without turnover, the fitted model with turnover inferred greater risk heterogeneity and consistently projected a larger tPAF of the highest risk group over time.

Implications

If turnover is not captured in epidemic models, the projected contribution of high risk groups, and thus, the potential impact of prioritizing interventions to address their needs, could be underestimated. To aid the next generation of tPAF models, data collection efforts to parameterize risk group turnover should be prioritized.

•

A new framework for parameterizing turnover in risk groups is developed.

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Mechanisms by which turnover influences sexually transmitted infection (STI), prevalence in risk groups are examined.

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Turnover reduces the ratio of equilibrium STI prevalence in high vs low risk groups.

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Inferred risk heterogeneity is higher when fitting transmission models with turnover.

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Ignoring turnover in risk could underestimate the transmission population attributable fraction (tPAF), of high risk groups to the overall epidemic.

Acceptability of oral HIV self-testing among female sex workers in Gaborone, Botswana

Background

HIV prevalence among female sex workers (FSW) in sub-Saharan Africa is much higher than in the general population. HIV self-testing (HIVST) may be useful for increasing testing rates in FSW.

Methods

We conducted semi-structured in-depth interviews among FSW, nurses and lay counsellors providing services to FSWs in Botswana. We aimed to gain understanding of perceived acceptability, anticipated barriers, and preferred approaches to HIVST among FSW. Interviews were audio-recorded, transcribed and translated. Transcripts were reviewed and coded independently by two investigators; high inter-coder agreement was achieved (Kappa = 0.80).

Results

We interviewed five care providers whose average age was 40 years (SD = 2,64, range = 37–43); three nurses and two counsellors. Thirty FSW were interviewed, with mean age 34 years (range = 20–52). Most (27; 90%) FSW expressed great interest in using HIVST kits. Facilitators of HIVST were: awareness of own risky sexual behaviours, desire to stay healthy, and perceived autonomy over one’s healthcare decisions. Perceived advantages of HIVST included convenience, privacy, and perception of decreased stigma. Identified barriers to HIVST included lack of knowledge about the HIVST kit, fear of testing due to anticipated stigma, mistrust of the test’s accuracy, doubt of self-competency to perform HIVST, and concerns about not linking to care. Assisting someone to test was noted as good for providing emotional support, but there were concerns about confidentiality breaches. Providers expressed concerns over low literacy among FSWs which could affect comprehension of testing instructions, and competency to perform testing and interpret results. Participants’ recommendations for implementation of HIVST included: ensuring wide dissemination of information on HIVST, engaging peers in information-sharing and education, making test kits accessible in FSW-friendly centres, and having clear instructions for linkage to healthcare and support.

Conclusion

HIVST shows high acceptability among FSWs in Gaborone Botswana, with providers expressing some concerns. Implementation should be peer-driven with healthcare provider oversight.

Characterizing Multi-level Determinants of HIV Prevalence Among Female Sex Workers in Maseru and Maputsoe, Lesotho

Lesotho has a broadly generalized HIV epidemic with nearly one in three reproductive-aged women living with HIV. Given this context, there has been limited research on specific HIV risks. In response, this study aimed to characterize the burden of HIV and multi-level correlates of HIV infection amongst female sex workers (FSW) in Lesotho. Respondent driven sampling was used to recruit 744 FSW from February to September 2014 in Maseru and Maputsoe, Lesotho. Robust Poisson regression was used to model weighted prevalence ratios (PR) for HIV, leveraging a modified social ecological model. The HIV prevalence among participants was 71.9% (534/743), with a mean age of 26.8 (SD 7.2). Both individual and structural determinants involving stigma were significantly associated with HIV. Women with the highest enacted stigma score (≥ 5) had a 26% higher prevalence of HIV than individuals that did not experience any stigma (PR 1.26, 95% CI 1.01, 1.57). These data reinforce the extraordinarily high burden of HIV borne by FSW even in the context of the generalized HIV epidemic observed in Lesotho and across southern Africa. Moreover, stigma represents a structural determinant that is fundamental to an effective HIV response for FSW in Lesotho.

Prevalence and correlates of anal intercourse among female sex workers in eSwatini

INTRODUCTION

As HIV is very effectively acquired during condomless receptive anal intercourse (AI) with serodiscordant and viremic partners, the practice could contribute to the high prevalence among female sex workers (FSW) in eSwatini (formerly known as Swaziland). We aim to estimate the proportion reporting AI (AI prevalence) among Swazi FSW and to identify the correlates of AI practice in order to better inform HIV prevention interventions among this population.

METHODS

Using respondent-driven sampling (RDS), 325 Swazi FSW were recruited in 2011. We estimated the prevalence of AI and AI with inconsistent condom use in the past month with any partner type, and inconsistent condom use during AI and vaginal intercourse (VI) by partner type. Univariate and multivariable logistic regression models were used to identify behavioural and structural correlates associated with AI and AI with inconsistent condom use.

RESULTS

RDS-adjusted prevalence of AI and AI with inconsistent condom use was high, at 44%[95% confidence interval (95%CI):35-53%]) and 34%[95%CI:26-42%], respectively and did not vary by partner type. HIV prevalence was high in this sample of FSW (70%), but knowledge that AI increases HIV acquisition risk low, with only 10% identifying AI as the riskiest sex act. Those who reported AI were more likely to be better educated (adjusted odds ratio(aOR) = 1.92[95%CI:1.03-3.57]), to have grown up in rural areas (aOR = 1.90[95%CI:1.09-3.32]), have fewer new clients in the past month (aOR = 0.33[95%CI:0.16-0.68]), and for last sex with clients to be condomless (aOR = 2.09[95%CI:1.07-4.08]). Although FSW reporting AI in past month were more likely to have been raped (aOR = 1.95[95%CI:1.05-3.65]) and harassed because of being a sex worker (aOR = 2.09[95%CI:1.16-3.74]), they were also less likely to have ever been blackmailed (aOR = 0.50[95%CI:0.25-0.98]) or been afraid to walk in public places (aOR = 0.46[95%CI:0.25-0.87]). Correlates of AI with inconsistent condom use were similar to those of AI.

CONCLUSIONS

AI is commonly practised and condom use is inconsistent among Swazi FSW. Sex act data are needed to determine how frequently AI is practiced. Interventions to address barriers to condom use are needed, as are biomedical interventions that reduce acquisition risk during AI.

Obligations of motherhood in shaping sex work, condom use, and HIV care among Swazi female sex workers living with HIV

Parental obligations influence sexual behaviour among female sex workers (FSW) and may serve as a risk or protective factor for HIV acquisition. How these obligations affect behaviours beyond HIV prevention, including HIV care, is understudied. We analysed 25 interviews conducted with 11 mothers who sell sex and are living with HIV, and 4 key informants as part of a larger study examining the positive health, dignity, and prevention needs of FSW in eSwatini. Despite awareness of HIV reinfection, FSW initiated sex work and engaged in condomless sex due to financial pressures of providing for children. While women attributed having condomless sex to their obligations as a provider, motherhood also served as motivation to engage in HIV care. Further, FSW described children as a source of support in HIV care. Children reminded mothers to take their medications, prepared food to take with medications, and assisted with travel to the clinic.

'We must treat them like all the other people': Evaluating the Integrated Key Populations Sensitivity Training Programme for Healthcare Workers in South Africa

Background

Sensitisation training can reduce judgemental and discriminatory attitudes amongst healthcare workers. The ‘Integrated Key Populations Sensitivity Training Programme for Healthcare Workers in South Africa’ aimed to improve access to appropriate and non-judgemental health services for ‘key populations’, specifically men who have sex with men, sex workers and people who use drugs, through the sensitisation of healthcare workers.

Objectives

The aim of this study was to evaluate the effects of the integrated key population sensitisation training intervention for healthcare workers, conducted between 2013 and 2014 in South Africa.

Methods

This study used a combination of qualitative and quantitative methods. Qualitative methods compared attitudes between healthcare workers who received the training intervention and those who did not. Quantitative methods were used to compare similar changes in awareness amongst healthcare workers before and after receiving the training. We explored shifts in attitudes towards key populations, changes in awareness of health issues related to stigma, discrimination, and changes in capacity to manage sexual health and HIV risk behaviours, including substance use and anal sex.

Results

The findings indicate that the training intervention resulted in a shift in attitudes, increased empathy for key populations, a reduction in negative and discriminatory moral-based judgements towards key populations and their behaviours, and increased self-perceived capacity to provide appropriate health services to key populations. Over 70% of healthcare workers trained in this programme strongly agreed that this intervention helped to increase awareness of psychosocial vulnerabilities of key populations, and address stigmatising attitudes.

Conclusion

The findings suggest that sensitisation training increases healthcare workers’ knowledge and awareness about specific HIV-related health needs and psychosocial vulnerabilities of key populations, reduces moralising and judgemental attitudes, and results in healthcare workers feeling more skilled to provide appropriate and sensitive services.

Development and reliability of metrics to characterize types and sources of stigma among men who have sex with men and female sex workers in Togo and Burkina Faso

Background

Stigma is a multifaceted concept that potentiates Human Immunodeficiency Virus and sexually transmitted infection acquisition and transmission risks among key populations, including men who have sex with men (MSM) and female sex workers (FSW). Despite extensive stigma literature, limited research has characterized the types and sources of stigma reported by key populations in Sub-Saharan Africa.

Methods

This study leveraged data collected from 1356 MSM and 1383 FSW in Togo and Burkina Faso, recruited via respondent-driven sampling. Participants completed a survey instrument including stigma items developed through systematic reviews and synthesis of existing metrics. Using exploratory factor analysis with promax oblique rotation, 16 items were retained in a stigma metric for MSM and 20 in an FSW stigma metric. To assess the measures’ convergent validity, their correlations with expected variables were examined through bivariate logistic regression models.

Results

One factor, experienced stigma, included actions that were carried out by multiple types of perpetrators and included being arrested, verbally harassed, blackmailed, physically abused, tortured, or forced to have sex. Other factors were differentiated by source of stigma including healthcare workers, family and friends, or police. Specifically, stigma from healthcare workers loaded on two factors: experienced healthcare stigma included being denied care, not treated well, or gossiped about by healthcare workers and anticipated healthcare stigma included fear of or avoiding seeking healthcare. Stigma from family and friends included feeling excluded from family gatherings, gossiped about by family, or rejected by friends. Stigma from police included being refused police protection and items related to police confiscation of condoms. The Cronbach’s alpha ranged from 0.71–0.82. Median stigma scores, created for each participant by summing the number of affirmative responses to each stigma item, among MSM were highest in Ouagadougou and among FSW were highest in both Ouagadougou and Bobo-Dioulasso. Validation analyses demonstrated higher stigma was generally significantly associated with suicidal ideation, disclosure of involvement in sex work or same-sex practices, and involvement in organizations for MSM or FSW.

Conclusions

Taken together, these data suggest promising reliability and validity of metrics for measuring stigma affecting MSM and FSW in multiple urban centers across West Africa.

Syphilis among Female Sex Workers: Results of Point-of-Care Screening during a Cross-Sectional Behavioral Survey in Burkina Faso, West Africa

Background

Syphilis among female sex workers (FSW) remains a public health concern due to its potential impact on their health and the possibility of transmission to their clients, partners, and children. Recent data on the prevalence of syphilis in the population in West Africa are scarce. The objective of this study was to measure the seroprevalence of syphilis serological markers among female sex workers in Burkina Faso.

Methods

We conducted a cross-sectional survey among FSW between February 2013 and May 2014. Participants were recruited using respondent-driven sampling (RDS) methods in five cities of Burkina Faso (Ouagadougou, Bobo-Dioulasso, Koudougou, Ouahigouya, and Tenkodogo). FSW were enrolled and screened for syphilis using a syphilis serological rapid diagnostic test. Data from all cities were analyzed with Stata version 14.0.

Results

A total of 1045 FSW were screened for syphilis. Participants' mean age was 27.2 ± 0.2 years. The syphilis serological markers were detected in 5.6% (95% CI: 4.4–7.2) of the participants whereas active syphilis was seen in 1.4% (95% CI: 0.9–2.4). RDS weighted prevalence of syphilis serological markers and active syphilis by city were, respectively, estimated to be 0.0% to 11.0% (95% CI: 8.1–14.7) and 0.0% to 2.2% (95% CI: 1.1–4.4). No syphilis markers were found among Ouahigouya FSW. Low education level and high number of clients were factors associated with syphilis markers among the FSW.

Conclusion

The prevalence of syphilis markers was high during this study among FSW. This highlights the need to reinforce the comprehensive preventive measures and treatment of syphilis in this population.

The Prevalence and Correlates of Physical and Sexual Violence Affecting Female Sex Workers in Swaziland

Female sex workers (FSW) have a heightened vulnerability to violence and negative sexual/reproductive health outcomes. Limited research has examined how experiencing physical and sexual violence (PSV) mediates risk for poor health outcomes among FSW in Swaziland. The present analyses aim to contribute to literature linking violence with poor health outcomes, high-risk behaviors, and reduced health service-seeking among FSW. Data were analyzed from a cross-sectional study conducted in Swaziland between July and September 2011 with 325 adult women who reported exchanging sex for money, goods, or favors in the last 12 months, recruited through respondent-driven sampling (RDS). Logistic regression was used to assess the relationship between PSV and ancillary violence/abuse exposures, risk behaviors, and sexual/reproductive and mental health outcomes. PSV was conceptualized as either ever having been beaten up as a result of selling sex or ever being forced to have sex since the age of 18, or both. Prevalence of PSV in this sample was 59.0% in crude estimation, and 48.4% (95% confidence interval [CI]:[39.2,57.6]) with RDS weighting. Separate RDS-weighted estimates of being beaten up as a result of sex work and ever being forced to have sex were 32.4% (95%CI=[24.4,40.4]) and 33.1% (95%CI =[25.0,41.2%]), respectively. Experiencing PSV was associated with being blackmailed (adjusted odds ratio [aOR]= 1.93, 95%CI= [1.07,3.52]), non-injection drug use in the last 12 months (aOR= 1.84, 95%CI= [1.02,3.33]), and feeling afraid to seek health services as a result of selling sex (aOR = 1.74, 95%CI= [1.01,2.99]). Given these findings, violence prevention strategies should be prioritized in programs that address Swazi FSW health, empowerment, and safety.

Sampling Key Populations for HIV Surveillance: Results From Eight Cross-Sectional Studies Using Respondent-Driven Sampling and Venue-Based Snowball Sampling

BACKGROUND

In using regularly collected or existing surveillance data to characterize engagement in human immunodeficiency virus (HIV) services among marginalized populations, differences in sampling methods may produce different pictures of the target population and may therefore result in different priorities for response.

OBJECTIVE

The objective of this study was to use existing data to evaluate the sample distribution of eight studies of female sex workers (FSW) and men who have sex with men (MSM), who were recruited using different sampling approaches in two locations within Sub-Saharan Africa: Manzini, Swaziland and Yaoundé, Cameroon.

METHODS

MSM and FSW participants were recruited using either respondent-driven sampling (RDS) or venue-based snowball sampling. Recruitment took place between 2011 and 2016. Participants at each study site were administered a face-to-face survey to assess sociodemographics, along with the prevalence of self-reported HIV status, frequency of HIV testing, stigma, and other HIV-related characteristics. Crude and RDS-adjusted prevalence estimates were calculated. Crude prevalence estimates from the venue-based snowball samples were compared with the overlap of the RDS-adjusted prevalence estimates, between both FSW and MSM in Cameroon and Swaziland.

RESULTS

RDS samples tended to be younger (MSM aged 18-21 years in Swaziland: 47.6% [139/310] in RDS vs 24.3% [42/173] in Snowball, in Cameroon: 47.9% [99/306] in RDS vs 20.1% [52/259] in Snowball; FSW aged 18-21 years in Swaziland 42.5% [82/325] in RDS vs 8.0% [20/249] in Snowball; in Cameroon 15.6% [75/576] in RDS vs 8.1% [25/306] in Snowball). They were less educated (MSM: primary school completed or less in Swaziland 42.6% [109/310] in RDS vs 4.0% [7/173] in Snowball, in Cameroon 46.2% [138/306] in RDS vs 14.3% [37/259] in Snowball; FSW: primary school completed or less in Swaziland 86.6% [281/325] in RDS vs 23.9% [59/247] in Snowball, in Cameroon 87.4% [520/576] in RDS vs 77.5% [238/307] in Snowball) than the snowball samples. In addition, RDS samples indicated lower exposure to HIV prevention information, less knowledge about HIV prevention, limited access to HIV prevention tools such as condoms, and less-reported frequency of sexually transmitted infections (STI) and HIV testing as compared with the venue-based samples. Findings pertaining to the level of disclosure of sexual practices and sexual practice-related stigma were mixed.

CONCLUSIONS

Samples generated by RDS and venue-based snowball sampling produced significantly different prevalence estimates of several important characteristics. These findings are tempered by limitations to the application of both approaches in practice. Ultimately, these findings provide further context for understanding existing surveillance data and how differences in methods of sampling can influence both the type of individuals captured and whether or not these individuals are representative of the larger target population. These data highlight the need to consider how program coverage estimates of marginalized populations are determined when characterizing the level of unmet need.

Promise and pitfalls of pre-exposure prophylaxis for female sex workers

PURPOSE OF REVIEW

We explore the potential benefits of integrating preexposure prophylaxis (PrEP) into combination HIV prevention for female sex workers (FSWs) and the likely challenges to implementation.

RECENT FINDINGS

Evidence for the biological effectiveness of PrEP in women who can adhere to daily dosing is strong. FSWs in many countries bear the brunt of the HIV epidemic. Current combination prevention approaches enable many FSWs to remain HIV-free, but in some settings FSWs are unable to mitigate their risk. PrEP provides a new prevention tool for these women. To benefit, HIV-negative FSWs need to perceive that they are at risk, be motivated and able to take PrEP daily and to attend health services for prescription refill and clinical monitoring. FSWs face particular structural challenges to PrEP uptake and use, including stigmatizing health services; fear of disclosure to other FSWs and clients; fear of the authorities; lack of social support; substance use; unplanned travel and risk compensation many of which can be addressed through combination prevention approaches.

SUMMARY

For those FSWs who are unable to mitigate their HIV risk, PrEP, if adequately supported and integrated with combination prevention, may empower them to remain HIV-free.

Sexually transmitted infection screening uptake and knowledge of sexually transmitted infection symptoms among female sex workers participating in a community randomised trial in Peru

This study aims to evaluate condom use, sexually transmitted infection (STI) screening, and knowledge of STI symptoms among female sex workers in Peru associated with sex work venues and a community randomised trial of STI control. One component of the Peru PREVEN intervention conducted mobile-team outreach to female sex workers to reduce STIs and increase condom use and access to government clinics for STI screening and evaluation. Prevalence ratios were calculated using multivariate Poisson regression models with robust standard errors, clustering by city. As-treated analyses were conducted to assess outcomes associated with reported exposure to the intervention. Care-seeking was more frequent in intervention communities, but differences were not statistically significant. Female sex workers reporting exposure to the intervention had a significantly higher likelihood of condom use, STI screening at public health clinics, and symptom recognition compared to those not exposed. Compared with street- or bar-based female sex workers, brothel-based female sex workers reported significantly higher rates of condom use with last client, recent screening exams for STIs, and HIV testing. Brothel-based female sex workers also more often reported knowledge of STIs and recognition of STI symptoms in women and in men. Interventions to promote STI detection and prevention among female sex workers in Peru should consider structural or regulatory factors related to sex work venues.

The HIV Care Continuum among Female Sex Workers: A Key Population in Lilongwe, Malawi

OBJECTIVE

The HIV care continuum among female sex workers (FSW), a key population, has not been well characterized, especially within the generalized epidemics of sub-Saharan Africa. This was the first study to characterize the HIV care continuum among FSW in Lilongwe, Malawi.

METHODS

From July through September 2014, we used venue-based sampling to enroll 200 adult FSW in Lilongwe, Malawi into a cross-sectional evaluation assessing HIV care continuum outcomes. Seropositive FSW, identified using HIV rapid testing, received rapid CD4 counts in addition to viral loads using dried blood spots. We calculated proportions of HIV-infected FSW who had history of care, were on ART, and had suppressed viral load and we used Poisson regression to estimate the associations of demographic characteristics and transmission risk behaviors with each outcome.

RESULTS

HIV seroprevalence was 69% (n = 138). Among all FSW the median age was 24 years (IQR: 22-28). Among the 20% who were newly diagnosed and reported previously testing negative, the median time since last HIV test was 11 months (interquartile range: 3-17). The majority (69%) of HIV-infected FSW had a history of HIV care, 52% reported current ART use, and 45% were virally suppressed. Of the FSW who reported current ART use, 86% were virally suppressed. Transmission risk behaviors were not associated with continuum outcomes.

CONCLUSIONS

FSW in Lilongwe were predominately young and have a high HIV prevalence. Only half of HIV-infected FSW reported current ART use, but the majority of those on ART were virally suppressed. To reduce ongoing transmission and improve health outcomes, increased HIV testing, care engagement, and ART coverage is urgently needed among FSW. Universal testing and treatment strategies for all FSW in Malawi must be strongly considered.

Feasible, Efficient and Necessary, without Exception - Working with Sex Workers Interrupts HIV/STI Transmission and Brings Treatment to Many in Need

BACKGROUND AND OVERVIEW

High rates of partner change in sex work-whether in professional, 'transactional' or other context-disproportionately drive transmission of HIV and other sexually transmitted infections. Several countries in Asia have demonstrated that reducing transmission in sex work can reverse established epidemics among sex workers, their clients and the general population. Experience and emerging research from Africa reaffirms unprotected sex work to be a key driver of sexual transmission in different contexts and regardless of stage or classification of HIV epidemic. This validation of the epidemiology behind sexual transmission carries an urgent imperative to realign prevention resources and scale up effective targeted interventions in sex work settings, and, given declining HIV resources, to do so efficiently. Eighteen articles in this issue highlight the importance and feasibility of such interventions under four themes: 1) epidemiology, data needs and modelling of sex work in generalised epidemics; 2) implementation science addressing practical aspects of intervention scale-up; 3) community mobilisation and 4) the treatment cascade for sex workers living with HIV.

CONCLUSION

Decades of empirical evidence, extended by analyses in this collection, argue that protecting sex work is, without exception, feasible and necessary for controlling HIV/STI epidemics. In addition, the disproportionate burden of HIV borne by sex workers calls for facilitated access to ART, care and support. The imperative for Africa is rapid scale-up of targeted prevention and treatment, facilitated by policies and action to improve conditions where sex work takes place. The opportunity is a wealth of accumulated experience working with sex workers in diverse settings, which can be tapped to make up for lost time. Elsewhere, even in countries with strong interventions and services for sex workers, an emerging challenge is to find ways to sustain them in the face of declining global resources.