Antonio Gerbase

Priority interventions to reduce HIV transmission in sex work settings in sub-Saharan Africa and delivery of these services

Virtually no African country provides HIV prevention services in sex work settings with an adequate scale and intensity. Uncertainty remains about the optimal set of interventions and mode of delivery.

Periodic presumptive treatment of curable sexually transmitted infections among sex workers: a systematic review

Background:Unprotected sex work remains a major driver of HIV/sexually transmitted infection (STI) epidemics in many countries. STI treatment can lower disease burden, complications and prevalence of HIV cofactors. Periodic presumptive treatment (PPT) has been used with sex workers to reduce their high burden of largely asymptomatic STIs. The objective of this review is to assess benefits and harms of PPT among female sex workers. Methods:We searched MEDLINE for studies related to sex work and STIs during 1990–2010, extracted data from eligible studies in duplicate and conducted meta-analysis by study design using random effects models. Results:Two thousand, three hundred and fifteen articles were screened, 18 studies met inclusion criteria and 14 were included in meta-analyses. One published randomized controlled trial (RCT) reported significant reductions of gonorrhoea (Neisseria gonorrhoeae) [rate ratio (RR) 0.46, 95% confidence interval (CI) 0.31–0.68] and chlamydia (Chlamydia trachomatis) (RR 0.38, 95%CI 0.26–0.57), but no effect on serologic syphilis (RR 1.02, 95%CI 0.54–1.95). Similar results were seen for N. gonorrhoeae and C. trachomatis in pooled analyses, including data from one unpublished RCT and across study designs, and correlated with initial prevalence (R2 = 0.155). One observational study reported genital ulcer disease (GUD) declines in sex workers, and two reported impact among male client populations for N. gonorrhoeae [odds ratio (OR) 0.60, 95% CI 0.38–0.94], C. trachomatis (OR 0.47, 95% CI 0.31–0.71) and GUD (OR 0.21, 95% CI 0.11–0.42). No studies reported evidence of risk compensation or antibiotic resistance. Conclusion:PPT can reduce prevalence of gonorrhoea, chlamydia and ulcerative STIs among sex workers in whom prevalence is high. Sustained STI reductions can be achieved when PPT is implemented together with peer interventions and condom promotion. Additional benefits may include impact on STI and HIV transmission at population level.

Impact of High-Risk Sex and Focused Interventions in Heterosexual HIV Epidemics: A Systematic Review of Mathematical Models

Background The core-group theory of sexually transmitted infections suggests that targeting prevention to high-risk groups (HRG) could be very effective. We aimed to quantify the contribution of heterosexual HRGs and the potential impact of focused interventions to HIV transmission in the wider community. Methods We systematically identified studies published between 1980 and 2011. Studies were included if they used dynamical models of heterosexual HIV transmission, incorporated behavioural heterogeneity in risk, and provided at least one of the following primary estimates in the wider community (a) the population attributable fraction (PAF) of HIV infections due to HRGs, or (b) the number per capita or fraction of HIV infections averted, or change in HIV prevalence/incidence due to focused interventions. Findings Of 267 selected articles, 22 were included. Four studies measured the PAF, and 20 studies measured intervention impact across 265 scenarios. In low-prevalence epidemics (≤5% HIV prevalence), the estimated impact of sex-worker interventions in the absence of risk compensation included: 6–100% infections averted; 0.9–6.2 HIV infections averted per 100,000 adults; 11–94% and 4–47% relative reduction in prevalence and incidence respectively. In high-prevalence epidemics (>5% HIV prevalence), sex-worker interventions were estimated to avert 6.8–40% of HIV infections and up to 564 HIV infections per 100,000 adults, and reduce HIV prevalence and incidence by 13–27% and 2–14% respectively. In both types of epidemics, greater heterogeneity in HIV risk was associated with a larger impact on the fraction of HIV infections averted and relative reduction in HIV incidence. Conclusion Focused interventions, as estimated by mathematical models, have the potential to reduce HIV transmission in the wider community across low- and high-prevalence regions. However, considerable variability exists in estimated impact, suggesting that a targeted approach to HIV prevention should be tailored to local epidemiological context.

Serosorting and HIV/STI Infection among HIV-Negative MSM and Transgender People: A Systematic Review and Meta-Analysis to Inform WHO Guidelines

We conducted a systematic review and meta-analysis to assess the association between serosorting and HIV infection, sexually transmitted infections (STIs), and quality of life among men who have sex with men (MSM) and transgender people. Two reviewers independently screened abstracts and abstracted data. Meta-analyses were conducted using random effects models. Of 310 citations reviewed, 4 observational studies, all with MSM, met inclusion criteria. Compared to consistent condom use, serosorting was associated with increased risk of HIV (3 studies, odds ratio (OR): 1.80, 95% confidence interval (CI):1.21–2.70) and bacterial STIs (1 study, OR: 1.62, 95% CI: 1.44–1.83). Compared to no condom use, serosorting was associated with reduced risk of HIV (3 studies, OR: 0.46, 95% CI: 0.25–0.83) and bacterial STIs (1 study, OR: 0.81, 95% CI: 0.73–0.91). Among HIV-negative MSM, condom use appears to be more protective against HIV and STIs than serosorting and should be encouraged. However, serosorting may be better than no condom use as a harm reduction strategy.

Using GRADE methodology for the development of public health guidelines for the prevention and treatment of HIV and other STIs among men who have sex with men and transgender people

BackgroundThe World Health Organization (WHO) Department of HIV/AIDS led the development of public health guidelines for delivering an evidence-based, essential package of interventions for the prevention and treatment of HIV and other sexually transmitted infections (STIs) among men who have sex with men (MSM) and transgender people in the health sector in low- and middle-income countries. The objective of this paper is to review the methodological challenges faced and solutions applied during the development of the guidelines.MethodsThe development of the guidelines followed the WHO guideline development process, which utilizes the GRADE approach. We identified, categorized and labeled the challenges identified in the guidelines development process and described the solutions through an interactive process of in-person and electronic communication.ResultsWe describe how we dealt with the following challenges: (1) heterogeneous and complex interventions; (2) paucity of trial data; (3) selecting outcomes of interest; (4) using indirect evidence; (5) integrating values and preferences; (6) considering resource use; (7) addressing social and legal barriers; (8) wording of recommendations; and (9) developing global guidelines.ConclusionWe were able to successfully apply the GRADE approach for developing recommendations for public health interventions. Applying the general principles of the approach while carefully considering specific challenges can enhance both the process and the outcome of guideline development.

Sexually transmitted diseases in Latin America and the Caribbean

Las enfermedades de transmision sexual (ETS) constituyen un problema de salud publica con importantes consecuencias y secuelas que incluyen la enfermedad inflamatoria pelvica, la infertilidad, el carcinoma cervical y los desenlaces adversos del embarazo. En la ultima decada, la estrecha asociacion entre la presencia de ETS y el aumento del riesgo de transmision sexual del virus de la inmunodeficiencia humana ha renovado el interes por la prevencion y control de las ETS. Sin embargo, en America Latina y el Caribe, la informacion epidemiologica sobre la magnitud del problema de las ETS es escasa y, en general, esta limitada a un pequeno numero de estudios y a datos oficiales incompletos de los paises de la zona. Tras una cuidadosa revision de la literatura y un analisis de los datos que posee la Organizacion Mundial de la Salud sobre cada pais, hemos estimado la prevalencia e incidencia en America Latina y el Caribe de cuatro ETS curables (sifilis, gonorrea, infeccion por clamidias y tricomoniasis) en hombres y mujeres de 15 a 49 anos de edad. Para ello se utilizaron parametros tales como la duracion de la infeccion, la estimacion de los pacientes tratados frente a los no tratados y los datos de poblacion. En 1996, el numero estimado de casos en America Latina y el Caribe fue de 1,3 millones para la sifilis, de 7,1 millones para la gonorrea, de 10,0 millones para las infecciones clamidiales y de 17,7 millones para la tricomoniasis. Con una cifra estimada total que, en el mejor de los casos, es superior a 36 millones de casos anuales, las ETS tratables parecen constituir un importante problema de salud publica en la zona.

Passive sentinel surveillance system for sexually transmitted diseases in primary healthcare sites in Ethiopia, 1991–3

Background: In 1989 the ministry of health of Ethiopia launched an STD control programme to strengthen the STD case management capabilities at public health centres and hospitals. The programme included the introduction of a syndrome based system for notification of STD cases. We here report the data originated by the syndromic case reporting system under programme conditions. Methods: 35 (17%) of the total 225 hospitals and public health centres of Ethiopia were included in the programme. Information relevant to the years 1991 to 1993 was analysed at mid 1994. Results: 32 clinical sites (91% of the total) provided at least one monthly report. The proportion of monthly reports received was 65% of those due, ranging from 51% in 1991 to 73% in 1992 and 42% in 1993. A total of 77 294 consultations for STD related symptoms were recorded, including 70 200 new cases, 6588 repeated consultations, and 506 partners of STD patients. Among first attendant patients 38 459 (52.7%) were males with a male to female ratio of 1:1. Urethral discharge and vaginal discharge were the leading cause of consultation among males (58%) and females (64%) respectively. The frequency of genital ulcer diseases was 26% among males and 15% among females. Inguinal adenopathy in the absence of genital ulcers was also frequent, accounting for 10% of consulting males and 5% of females. Based on Gram stain, gonorrhoea was identified in 64% of the cases of urethral discharge, while trichomoniasis and candidiasis were identified by wet mount in 28% and 16% of the cases of vaginal discharge respectively. Conclusions: STDs are a common cause of consultation at public health centre sites in Ethiopia. A syndromic case reporting system proved to be efficient and produced valuable information to initiate assessment of the problem and to set up bases for monitoring trends of STD morbidity.

O1-S06.01 Impact of targeted interventions in HIV epidemics as predicted by mathematical models: a systematic review

Background Mathematical modelling of sexually transmitted infections suggests that targeting intervention (TI) to high-risk heterosexual risk groups (HRG) who have disproportionately high exposure and potential for transmission within populations can be very effective. We reviewed HIV transmission modelling studies to better understand the potential impact of TIs or the contribution of HRG to overall HIV transmission across geographical regions and epidemic phases. Methods We systematically searched PubMed with relevant key words to identify publications that used dynamical models of heterosexual HIV transmission, and then searched papers to identify studies that incorporated heterogeneity in risk, and provided estimates of the population attributable fraction of HIV infections due to HRGs (PAF), or fraction of infections prevented (PF) or change in prevalence due to TIs. Results Of 917 titles, 283 were excluded on abstract review. Of 634 papers searched, 96 modelled heterogeneity, of which 26 were included. Six studies used non-regionalised models, 9 studied generalised epidemics (GE) in sub-Saharan Africa, nine studied concentrated epidemics (CE) in Asia, West Africa, Japan, and Europe, and two studied both epidemic types. The PAF of HRGs ranged from 13% to 17% in mature GEs with an HIV prevalence of 16%–22% across three studies. Five models explored TIs in GEs and predicted a PF of 12%–73% and a 0%–27% reduction in prevalence with >50% coverage of commercial partnerships. Ten studies modelled TIs in CEs, with overall HIV prevalence at the mature phase between 0.7% and 3.5%, and suggested that TIs could reduce prevalence by 14%–30%, with PFs of 25%–48% if >75% coverage of commercial partnerships. With <50% coverage of commercial partnerships, 1 study demonstrated a 14% reduction in prevalence at 10 years, and two studies predicted a PF between 13% and 20%. The PF of TIs implemented early in a CE with high coverage ranged between 27% and 97%. Two studies predicted that additional TIs (pre-exposure prophylaxis) associated with high levels of risk compensation in mature epidemic settings could reverse positive gains already made by increased condom use see Abstract O1-S06.01 table 1. Abstract O1-S06.01 Table 1 Summary of published modelling results on targeted intervention among heterosexual higher-risk groups Population attributable fraction, % (years) Prevented fraction %, (years post-intervention) Change in prevalence %, (years post-intervention) Generalised epidemics  Early – 12 (4) 0 (1)  Mature 13 (4), 8–17 (20) 73 (1), 35 (10) 4–27 (10) Concentrated epidemics  Early – 70 (1), 27(4), 85–97(10) 41–58 (10), 58–89 (30)  Mature 40 (1) 25–30 (1), 10–48 (10), 40 (11) 30 (5), 14 (10) Conclusion Modelling studies suggest that TIs have the potential to reduce HIV in the overall population in generalised and concentrated epidemics. The relative impact of TIs depends on coverage, epidemic phase, differential risk between HRGs and remainder of the population, and the time-scale of outcome measurement.