Association between participant self-report and biological outcomes used to measure sexual risk behavior in human immunodeficiency virus-1-seropositive female sex workers in Mombasa, Kenya

MORTALITY RISK INFORMATION, SURVIVAL EXPECTATIONS AND SEXUAL BEHAVIOURS

We investigate the impact of a randomised information intervention about population-level mortality on health investment and subjective health expectations. Our focus is on risky sex in a high-HIV-prevalence environment. Treated individuals are less likely to engage in risky sexual practices one year after the intervention, with, for example, an 8% increase in abstinence. We collected detailed data on individuals' subjective expectations about their own and population survival, as well as other important health outcomes. Our findings emphasise the significance of integrating subjective expectation data in field experiments to identify the pathways that lead to behavioural change.

Brief Report: Incidence and Correlates of Pregnancy in HIV-Positive Kenyan Sex Workers

INTRODUCTION

The incidence of pregnancy in female sex workers (FSWs) living with HIV is not well characterized.

METHODS

Current and former FSWs living with HIV and enrolled in a prospective cohort study in Mombasa, Kenya, were followed monthly to ascertain sexual behavior and underwent quarterly pregnancy testing. Pregnancies were considered planned, mistimed, or unwanted according to fertility desires and pregnancy intentions. Cox proportional hazards models were used to estimate hazard ratios (HRs) of the association between characteristics and incident pregnancy.

RESULTS

Two hundred seventy-nine FSWs were eligible (October 2012-April 2017). Most women had a nonpaying, regular partner (83.2%, 232/279), were not using modern nonbarrier contraception (69.5%, 194/279), and did not desire additional children (70.6%, 197/279). Of 34 first incident pregnancies [5.8/100 person-years (p-y); 95% confidence interval (CI): 4.1 to 8.0], 91.2% (n = 31) were unintended. The incidences of planned (5.7/100 p-y, n = 3), mistimed (10.4/100 p-y, n = 9), and unwanted pregnancies (4.9/100 p-y, n = 22) were similar (P = 0.15). In univariable analysis, oral contraceptive pill use (versus no contraception), having a nonpaying, regular partner, transactional sex, vaginal washing, condomless sex, and higher sex frequency were associated with an increased pregnancy risk. Older age was associated with a lower pregnancy risk. In multivariable analysis, having a nonpaying, regular partner (adjusted HR 4.0, 95% CI: 1.2 to 14.1) and age ≥40 years (aHR 0.2, 95% CI: 0.0 to 0.9) remained significantly associated with a higher and lower pregnancy risk, respectively.

CONCLUSION

In this cohort of HIV-positive FSWs, most pregnancies were unintended. Identifying FSWs' fertility desires and pregnancy intentions could facilitate efforts to increase contraceptive use and implement safer conception strategies.

Incidence of unintended pregnancy among female sex workers in low-income and middle-income countries: a systematic review and meta-analysis

OBJECTIVES

To determine the incidence of unintended pregnancy among female sex workers (FSWs) in low-income and middle-income countries (LMICs).

DESIGN

We searched MEDLINE, PsychInfo, Embase and Popline for papers published in English between January 2000 and January 2016, and Web of Science and Proquest for conference abstracts. Meta-analysis was performed on the primary outcomes using random effects models, with subgroup analysis used to explore heterogeneity.

PARTICIPANTS

Eligible studies targeted FSWs aged 15-49 years living or working in an LMIC.

OUTCOME MEASURES

Studies were eligible if they provided data on one of two primary outcomes: incidence of unintended pregnancy and incidence of pregnancy where intention is undefined. Secondary outcomes were also extracted when they were reported in included studies: incidence of induced abortion; incidence of birth; and correlates/predictors of pregnancy or unintended pregnancy.

RESULTS

Twenty-five eligible studies were identified from 3866 articles. Methodological quality was low overall. Unintended pregnancy incidence showed high heterogeneity (I²>95%), ranging from 7.2 to 59.6 per 100 person-years across 10 studies. Study design and duration were found to account for heterogeneity. On subgroup analysis, the three cohort studies in which no intervention was introduced had a pooled incidence of 27.1 per 100 person-years (95% CI 24.4 to 29.8; I²=0%). Incidence of pregnancy (intention undefined) was also highly heterogeneous, ranging from 2.0 to 23.4 per 100 person-years (15 studies).

CONCLUSIONS

Of the many studies examining FSWs' sexual and reproductive health in LMICs, very few measured pregnancy and fewer assessed pregnancy intention. Incidence varied widely, likely due to differences in study design, duration and baseline population risk, but was high in most studies, representing a considerable concern for this key population. Evidence-based approaches that place greater importance on unintended pregnancy prevention need to be incorporated into existing sexual and reproductive health programmes for FSWs.

PROSPERO REGISTRATION NUMBER

CRD42016029185.

A Prospective Cohort Study of Fertility Desire, Unprotected Sex, and Detectable Viral Load in HIV-Positive Female Sex Workers in Mombasa, Kenya

BACKGROUND

Little is known about fertility desire in HIV-positive female sex workers. Fertility desire could increase HIV transmission risk if it was associated with condomless sex or lower adherence to antiretroviral therapy.

METHODS

A prospective cohort study was conducted among 255 HIV-positive female sex workers in Mombasa, Kenya. Using generalized estimating equations, fertility desire was evaluated as a risk factor for semen detection in vaginal secretions by prostate-specific antigen (PSA) test, a biomarker of condomless sex, detectable plasma viral load (VL), and HIV transmission potential, defined as visits with positive PSA and detectable VL.

RESULTS

The effect of fertility desire on PSA detection varied significantly by nonbarrier contraception use (P-interaction < 0.01). At visits when women reported not using nonbarrier contraception, fertility desire was associated with higher risk of semen detection [82/385, 21.3% vs. 158/1007, 15.7%; adjusted relative risk (aRR) 1.58, 95% confidence interval (CI): 1.12 to 2.23]. However, when women used nonbarrier contraception, fertility desire was associated with lower risk of PSA detection (10/77, 13.0% vs. 121/536, 22.6%; aRR 0.58, 95% CI: 0.35 to 0.94). Fertility desire was not associated with detectable VL (31/219, 14.2% vs. 128/776, 16.5%; aRR 0.82, 95% CI: 0.46 to 1.45) or higher absolute risk of transmission potential (10/218, 4.6% vs. 21/769, 2.7%; adjusted risk difference = 0.011, 95% CI -0.031 to 0.050).

CONCLUSIONS

Fertility desire was associated with higher risk of biological evidence of semen exposure when women were not using nonbarrier contraceptives. Low HIV transmission potential regardless of fertility desire suggests that the combination of condoms and antiretroviral therapy adherence was effective.

Association between non-barrier modern contraceptive use and condomless sex among HIV-positive female sex workers in Mombasa, Kenya: A prospective cohort analysis

Background

As access to antiretroviral therapy in sub-Saharan Africa continues to expand, more women with HIV can expect to survive through their reproductive years. Modern contraceptives can help women choose the timing and spacing of childbearing. However, concerns remain that women with HIV who use non-barrier forms of modern contraception may engage in more condomless sex because of their decreased risk of unintended pregnancy. We examined whether non-barrier modern contraceptive use by HIV-positive female sex workers was associated with increased frequency of recent condomless sex, measured by detection of prostate-specific antigen (PSA) in vaginal secretions.

Methods

Women who were HIV-positive and reported transactional sex were included in this analysis. Pregnant and post-menopausal follow-up time was excluded, as were visits at which women reported trying to get pregnant. At enrollment and quarterly follow-up visits, a pelvic speculum examination with collection of vaginal secretions was conducted for detection of PSA. In addition, women completed a structured face-to-face interview about their current contraceptive methods and sexual risk behavior at enrollment and monthly follow-up visits. Log-binomial generalized estimating equations regression was used to test for associations between non-barrier modern contraceptive use and detection of PSA in vaginal secretions and self-reported condomless sex. Data from October 2012 through September 2014 were included in this analysis.

Results

Overall, 314 women contributed 1,583 quarterly examination visits. There was minimal difference in PSA detection at contraceptive-exposed versus contraceptive-unexposed visits (adjusted relative risk [aRR] 1.28, 95% confidence interval [95% CI] 0.93–1.76). There was a higher rate of self-reported condomless sex at visits where women reported using modern contraceptives, but this difference was not statistically significant after adjustment for potential confounding factors (aRR 1.59, 95% CI 0.98–2.58).

Conclusion

Non-barrier methods of modern contraception were not associated with increased risk of objective evidence of condomless sex.

A Prospective Cohort Study of Intimate Partner Violence and Unprotected Sex in HIV-Positive Female Sex Workers in Mombasa, Kenya

We conducted a prospective cohort study to test the hypothesis that intimate partner violence (IPV) is associated with unprotected sex in HIV-positive female sex workers in Mombasa, Kenya. Women completed monthly visits and quarterly examinations. Any IPV in the past year was defined as ≥1 act of physical, sexual, or emotional violence by the current or most recent emotional partner ('index partner'). Unprotected sex with any partner was measured by self-report and prostate specific antigen (PSA) test. Recent IPV was associated with significantly higher risk of unprotected sex (adjusted relative risk [aRR] 1.91, 95 % CI 1.32, 2.78, p = 0.001) and PSA (aRR 1.54, 95 % CI 1.17, 2.04, p = 0.002) after adjusting for age, alcohol use, and sexual violence by someone besides the index partner. Addressing IPV in comprehensive HIV programs for HIV-positive women in this key population is important to improve wellbeing and reduce risk of sexual transmission of HIV.

HIV Prevalence, Estimated Incidence, and Risk Behaviors Among People Who Inject Drugs in Kenya

OBJECTIVE

HIV infection in sub-Saharan Africa increasingly occurs among people who inject drugs (PWID). Kenya is one of the first to implement a national needle and syringe program. Our study undertook a baseline assessment as part of evaluating needle and syringe program in a seek, test, treat, and retain approach.

METHODS

Participants enrolled between May and December 2012 from 10 sites. Respondent-driven sampling was used to reach 1785 PWID for HIV-1 prevalence and viral load determination and survey data.

RESULTS

Estimated HIV prevalence, adjusted for differential network size and recruitment relationships, was 14.5% in Nairobi (95% CI: 10.8 to 18.2) and 20.5% in the Coast region (95% CI: 17.3 to 23.6). Viral load (log10 transformed) in Nairobi ranged from 1.71 to 6.12 (median: 4.41; interquartile range: 3.51-4.94) and in the Coast from 1.71 to 5.88 (median: 4.01; interquartile range: 3.44-4.72). Using log10 viral load 2.6 as a threshold for HIV viral suppression, the percentage of HIV-infected participants with viral suppression was 4.2% in Nairobi and 4.6% in the Coast. Heroin was the most commonly injected drug in both regions, used by 93% of participants in the past month, typically injecting 2-3 times/day. Receptive needle/syringe sharing at last injection was more common in Nairobi (23%) than in the Coast (4%). Estimated incidence among new injectors was 2.5/100 person-years in Nairobi and 1.6/100 person-years in the Coast.

CONCLUSIONS

The HIV epidemic is well established among PWID in both Nairobi and Coast regions. Public health scale implementation of combination HIV prevention has the potential to greatly limit the epidemic in this vulnerable and bridging population.

A 15-year study of the impact of community antiretroviral therapy coverage on HIV incidence in Kenyan female sex workers

OBJECTIVE

To test the hypothesis that increasing community antiretroviral therapy (ART) coverage would be associated with lower HIV incidence in female sex workers (FSWs) in Mombasa District, Kenya.

DESIGN

Prospective cohort study.

METHODS

From 1998 to 2012, HIV-negative FSWs were asked to return monthly for an interview regarding risk behavior and testing for sexually transmitted infections including HIV. We evaluated the association between community ART coverage and FSW's risk of becoming HIV infected using Cox proportional hazards models adjusted for potential confounding factors.

RESULTS

One thousand, four hundred and four FSWs contributed 4335 woman-years of follow-up, with 145 acquiring HIV infection (incidence 3.35/100 woman-years). The ART rollout began in 2003. By 2012, an estimated 52% of HIV-positive individuals were receiving treatment. Community ART coverage was inversely associated with HIV incidence (adjusted hazard ratio 0.77; 95% confidence interval 0.61-0.98; P = 0.03), suggesting that each 10% increase in coverage was associated with a 23% reduction in FSWs' risk of HIV acquisition. Community ART coverage had no impact on herpes simplex virus type-2 incidence (adjusted hazard ratio 0.97; 95% confidence interval 0.79-1.20; P = 0.8).

CONCLUSION

Increasing general population ART coverage was associated with lower HIV incidence in FSWs. The association with HIV incidence, but not herpes simplex virus type-2 incidence, suggests that the effect of community ART coverage may be specific to HIV. Interventions such as preexposure prophylaxis and antiretroviral-containing microbicides have produced disappointing results in HIV prevention trials with FSWs. These results suggest that FSWs' risk of acquiring HIV infection might be reduced through the indirect approach of increasing ART coverage in the community.

Epidemic impacts of a community empowerment intervention for HIV prevention among female sex workers in generalized and concentrated epidemics

Introduction

Sex workers have endured a high burden of HIV infection in and across HIV epidemics. A comprehensive, community empowerment-based HIV prevention intervention emphasizes sex worker organization and mobilization to address HIV risk and often includes community-led peer education, condom distribution, and other activities. Meta-analysis of such interventions suggests a potential 51% reduction in inconsistent condom use. Mathematical modeling exercises provide theoretical insight into potential impacts of the intervention on HIV incidence and burden in settings where interventions have not yet been implemented.

Methods

We used a deterministic model, Goals, to project the impact on HIV infections when the community empowerment interventions were scaled up among female sex workers in Kenya, Thailand, Brazil, and Ukraine. Modeling scenarios included expansion of the comprehensive community empowerment-based HIV prevention intervention from baseline coverage over a 5-year period (5–65% in Kenya and Ukraine; 10–70% in Thailand and Brazil), while other interventions were held at baseline levels. A second exercise increased the intervention coverage simultaneously with equitable access to ART for sex workers. Impacts on HIV outcomes among sex workers and adults are observed from 2012–2016 and, compared to status quo when all interventions are held constant.

Results

Optimistic but feasible coverage (65%–70%) of the intervention demonstrated a range of impacts on HIV: 220 infections averted over 5 yrs. among sex workers in Thailand, 1,830 in Brazil, 2,220 in Ukraine, and 10,800 infections in Kenya. Impacts of the intervention for female sex workers extend to the adult population, cumulatively averting 730 infections in Thailand to 20,700 adult infections in Kenya. Impacts vary by country, influenced by HIV prevalence in risk groups, risk behaviors, intervention use, and population size.

Discussion

A community empowerment approach to HIV prevention and access to universal ART for female sex workers is a promising human rights-based solution to overcoming the persistent burden of HIV among female sex workers across epidemic settings.

Estimating the impact of reducing violence against female sex workers on HIV epidemics in Kenya and Ukraine: a policy modeling exercise

PROBLEM

Female sex workers (FSWs) worldwide suffer disproportionate burdens of HIV and gender-based violence. Despite evidence linking these threats, little is known about the potential HIV epidemic impact of reducing abuse.

METHOD OF STUDY

The Goals model approximated the impact of reducing violence against FSWs on HIV epidemics in Ukraine and Kenya, measured by reductions in new infections among FSWs and adults. Cumulative infections averted over a 5-year period, in which violence declined was calculated, relative to a status quo with no reduction. Projections held HIV interventions constant at baseline levels; subsequently, scenarios adjusted for planned expansion of antiretroviral therapy (ART) coverage.

RESULTS

An approximate 25% reduction in incident HIV infections among FSWs was observed when physical or sexual violence was reduced; cumulative infections averted were 21,200 and 4700 in Kenya and Ukraine, respectively. Similar percent reductions were observed assuming ART coverage expansion, with approximately 18,200 and 4400 infections averted among FSWs in Kenya and Ukraine. New infections were also averted in the general population.

CONCLUSION

Reducing violence against FSWs appears to impart significant reductions in new infections among FSWs and in the general adult population in both generalized and concentrated epidemics. Limitations provide direction to improve the precision of future estimates.

Loss to follow-up as a competing risk in an observational study of HIV-1 incidence

OBJECTIVE

Conventional survival estimates may be biased if loss to follow-up (LTF) is associated with the outcome of interest. Our goal was to assess whether the association between sexual risk behavior and HIV-1 acquisition changed after accounting for LTF with competing risks regression.

METHODS

HIV-1-seronegative women who enrolled in a Kenyan sex worker cohort from 1993-2007 were followed prospectively and tested for HIV at monthly clinic visits. Our primary predictor was self-reported sexual risk behavior in the past week, analyzed as a time-dependent covariate. Outcomes included HIV-1 acquisition and LTF. We analyzed the data using Cox proportional hazards regression and competing risks regression, in which LTF was treated as a competing event.

RESULTS

A total of 1,513 women contributed 4,150 person-years (py), during which 198 (13.1%) acquired HIV-1 infection (incidence, 4.5 per 100 py) and 969 (64.0%) were LTF (incidence, 23.4 per 100 py). After adjusting for potential confounders, women reporting unprotected sex with multiple partners were less likely to be lost to follow-up (adjusted sub-hazard ratio (aSHR) 0.50, 95% confidence interval (CI) 0.32-0.76, relative to no sexual activity). The risk of HIV-1 acquisition after reporting unprotected sex with multiple partners was similar with Cox regression (adjusted hazard ratio (aHR) 2.41, 95% CI 1.36-4.27) and competing risks regression (aSHR 2.47, 95% CI 1.33-4.58).

CONCLUSIONS

Unprotected sex with multiple partners was associated with higher HIV-1 acquisition risk, but lower attrition. This differential attrition did not substantially bias Cox regression estimates when compared to competing risks regression results.

Incidence and correlates of Chlamydia trachomatis infection in a high-risk cohort of Kenyan women

BACKGROUND

In Africa, data on Chlamydia trachomatis infection are scarce because reliable diagnosis is costly and not widely available. Our objective was to evaluate the incidence and correlates of C. trachomatis infection among high-risk Kenyan women.

METHODS

We conducted prospective cohort analyses using data from a cohort of women who reported transactional sex. C. trachomatis testing was performed using the Gen-Probe Aptima GC/CT Detection System. We used Andersen-Gill proportional hazards modeling to evaluate correlates of C. trachomatis.

RESULTS

Between August 2006 and December 2010, 865 women contributed 2011 person-years of observation. Sixty-four women experienced 101 episodes of C. trachomatis infection (incidence rate, 5.0/100 person-years). There was a large difference in incidence by age group: those younger than 25 years had an incidence of 27.6 per 100 person-years (95% confidence interval [CI], 16.3-46.5), those 25 to 34 years old had an incidence of 8.4 per 100 person-years (95% CI, 6.4-11.0), and those 35 years and older had an incidence of 2.6 per 100 person-years (95% CI, 1.8-3.6). In multivariate analyses, younger age (<25 and 25-34 years vs. ≥35 years; hazard ratio [HR], 8.5 [95% CI, 4.1-17.7] and 2.9 [95% CI, 1.7-5.0], respectively), depot medroxyprogesterone acetate use (HR, 1.8; 95% CI, 1.1-3.0), and recent Neisseria gonorrhoeae infection (HR, 3.3; 95% CI, 1.5-7.4) were significantly associated with increased risk of acquiring C. trachomatis infection.

CONCLUSIONS

The high incidence of C. trachomatis among younger high-risk women suggests the need for screening as an important public health intervention for this population.

Safety and adherence to intermittent pre-exposure prophylaxis (PrEP) for HIV-1 in African men who have sex with men and female sex workers

BACKGROUND

Little is known about safety of and adherence to intermittent HIV PrEP regimens, which may be more feasible than daily dosing in some settings. We present safety and adherence data from the first trial of an intermittent PrEP regimen among Kenyan men who have sex with men (MSM) and female sex workers (FSW).

METHODS/PRINCIPAL FINDINGS

MSM and FSW were randomized to daily oral FTC/TDF or placebo, or intermittent (Monday, Friday and within 2 hours after sex, not to exceed one dose per day) oral FTC/TDF or placebo in a 2:1:2:1 ratio; volunteers were followed monthly for 4 months. Adherence was assessed with the medication event monitoring system (MEMS). Sexual activity data were collected via daily text message (SMS) queries and timeline followback interviews with a one-month recall period. Sixty-seven men and 5 women were randomized into the study. Safety was similar among all groups. Median MEMS adherence rates were 83% [IQR: 63-92] for daily dosing and 55% [IQR:28-78] for fixed intermittent dosing (p = 0.003), while adherence to any post-coital doses was 26% [IQR:14-50]. SMS response rates were low, which may have impaired measurement of post-coital dosing adherence. Acceptability of PrEP was high, regardless of dosing regimen.

CONCLUSIONS/SIGNIFICANCE

Adherence to intermittent dosing regimens, fixed doses, and in particular coitally-dependent doses, may be more difficult than adherence to daily dosing. However, intermittent dosing may still be appropriate for PrEP if intracellular drug levels, which correlate with prevention of HIV acquisition, can be attained with less than daily dosing and if barriers to adherence can be addressed. Additional drug level data, qualitative data on adherence barriers, and better methods to measure sexual activity are necessary to determine whether adherence to post-coital PrEP could be comparable to more standard regimens.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00971230.

Burden of HIV among female sex workers in low-income and middle-income countries: a systematic review and meta-analysis

BACKGROUND

Female sex workers are a population who are at heightened risk of HIV infection secondary to biological, behavioural, and structural risk factors. However, three decades into the HIV pandemic, understanding of the burden of HIV among these women remains limited. We aimed to assess the burden of HIV in this population compared with that of other women of reproductive age.

METHODS

We searched PubMed, Embase, Global Health, SCOPUS, PsycINFO, Sociological Abstracts, CINAHL (Cumulative Index to Nursing and Allied Health Literature), Web of Science, and POPLine for studies of female sex workers in low-income and middle-income countries published between Jan 1, 2007, and June 25, 2011. Studies of any design that measured the prevalence or incidence of HIV among female sex workers, even if sex workers were not the main focus of the study, were included. Meta-analyses were done with the Mantel-Haenszel method with a random-effects model characterising an odds ratio for the prevalence of HIV among female sex workers compared with that for all women of reproductive age.

FINDINGS

Of 434 selected articles and surveillance reports, 102 were included in the analyses, representing 99,878 female sex workers in 50 countries. The overall HIV prevalence was 11·8% (95% CI 11·6-12·0) with a pooled odds ratio for HIV infection of 13·5 (95% CI 10·0-18·1) with wide intraregional ranges in the pooled HIV prevalence and odds ratios for HIV infection. In 26 countries with medium and high background HIV prevalence, 30·7% (95% CI 30·2-31·3; 8627 of 28,075) of sex workers were HIV-positive and the odds ratio for infection was 11·6 (95% CI 9·1-14·8).

INTERPRETATION

Although data characterising HIV risk among female sex workers is scarce, the burden of disease is disproportionately high. These data suggest an urgent need to scale up access to quality HIV prevention programmes. Considerations of the legal and policy environments in which sex workers operate and actions to address the important role of stigma, discrimination, and violence targeting female sex workers is needed.

FUNDING

The World Bank, UN Population Fund.