Determinants of the impact of sexually transmitted infection treatment on prevention of HIV infection: a synthesis of evidence from the Mwanza, Rakai, and Masaka intervention trials

Changes in Inflammatory Cytokine Levels in Rectal Mucosa Associated With Neisseria gonorrheae and/or Chlamydia trachomatis Infection and Treatment Among Men Who Have Sex With Men in Lima, Peru

BACKGROUND

Neisseria gonorrheae and Chlamydia trachomatis are associated with mucosal inflammation and human immunodeficiency virus 1 (HIV-1) transmission. We assessed levels of inflammatory cytokines in men who have sex with men (MSM) with and without rectal gonorrhea and/or chlamydia in Lima, Peru.

METHODS

We screened 605 MSM reporting condomless receptive anal intercourse for rectal N. gonorrheae/C. trachomatis using nucleic acid testing. We identified 101 cases of gonorrhea and/or chlamydia and randomly selected 50 N. gonorrheae/C. trachomatis positive cases and matched 52 negative controls. We measured levels of IL-1β, IL-6, IL-8, and TNF-α in rectal secretions. Tests for HIV-1, rectal N. gonorrheae/C. trachomatis, and mucosal cytokines were repeated after 3 and 6 months. Cytokine levels in cases and uninfected controls were compared using Wilcoxon rank-sum tests and linear regression.

RESULTS

MSM with gonorrhea/chlamydia had elevated levels of all cytokines in rectal mucosa compared with matched controls (all P values <.001). Following antibiotic treatment there were no significant differences in cytokine levels at 3- or 6-month follow-up evaluations (all P values >.05).

DISCUSSION

Rectal gonorrhea/chlamydia infection is associated with transient mucosal inflammation and cytokine recruitment. Our data provide proof of concept for rectal sexually transmitted infection screening as an HIV prevention strategy for MSM. Clinical Trials Registration. NCT03010020.

Comparison of the burden of self-reported bacterial sexually transmitted infections among men having sex with men across 68 countries on four continents

BACKGROUND

Men who have sex with men (MSM) are in general more vulnerable to sexually transmitted infections (STIs) than the heterosexual men population. However, surveillance data on STI diagnoses lack comparability across countries due to differential identification of MSM, diagnostic standards and methods, and screening guidelines for asymptomatic infections.

METHODS

We compared self-reported overall diagnostic rates for syphilis, gonorrhea, and chlamydia infections, and diagnostic rates for infections that were classified to be symptomatic in the previous 12 months from two online surveys. They had a shared methodology, were conducted in 68 countries across four continents between October 2017 and May 2018 and had 202,013 participants.

RESULTS

Using multivariable multilevel regression analysis, we identified age, settlement size, number of sexual partners, condom use for anal intercourse, testing frequency, sampling rectal mucosa for extragenital testing, HIV diagnosis, and pre-exposure prophylaxis use as individual-level explanatory variables. The national proportions of respondents screened and diagnosed who notified some or all of their sexual partners were used as country-level explanatory variables. Combined, these factors helped to explain differences in self-reported diagnosis rates between countries. The following differences were not explained by the above factors: self-reported syphilis diagnoses were higher in Latin America compared with Europe, Canada, Israel, Lebanon, and the Philippines (aORs 2.30 - 3.71 for symptomatic syphilis compared to Central-West Europe); self-reported gonorrhea diagnoses were lower in Eastern Europe and in Latin America compared with all other regions (aORs 0.17-0.55 and 0.34 - 0.62 for symptomatic gonorrhea compared to Central-West Europe); and self-reported chlamydia diagnoses were lower in Central East and Southeast Europe, South and Central America, and the Philippines (aORs 0.25 - 0.39 for symptomatic chlamydia for Latin American subregions compared to Central West Europe).

CONCLUSIONS

Possible reasons for differences in self-reported STI diagnosis prevalence likely include different background prevalence for syphilis and syndromic management without proper diagnosis, and different diagnostic approaches for gonorrhea and chlamydia.

Cross-sectional assessment of determinants of STIs among men who have sex with men and transgender women in Kigali, Rwanda

BACKGROUND

STIs among men who have sex with men (MSM) and transgender women (TGW) continue to increase. In Rwanda, STI management relies on syndromic management with limited empirical data characterising the burden of specific STIs among MSM/TGW. This study evaluated the prevalence of syphilis, Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) and associated factors among MSM/TGW in Kigali.

METHODS

From March to August 2018, 737 MSM/TGW >18 years were enrolled using respondent-driven sampling (RDS). Structured interviews and HIV/STI screening were conducted. Syphilis was screened with rapid plasma reagin confirmed by Treponema pallidum hemagglutination assay. CT/NG were tested by Cepheid GeneXpert. RDS-adjusted multivariable Poisson regression models with robust variance estimation were used to evaluate factors associated with any STI, and determinants of urethral and rectal STIs separately.

RESULTS

Prevalence of any STI was 20% (RDS adjusted: 16.7% (95% CI: 13.2% to 20.2%)). Syphilis was 5.7% (RDS adjusted: 6.8% (95% CI: 4.3% to 9.4%)). CT was 9.1% (RDS adjusted: 6.1% (95% CI: 3.9% to 8.4%)) and NG was 8.8% (RDS adjusted: 7.1% (95% CI: 4.9% to 9.2%)). STIs were more common among older MSM and those with HIV (p<0.05). Of CT infections, 67% were urethral, 27% rectal and 6% were dual site. For NG infections, 52% were rectal, 29% urethral and 19% were dual site. Overall, 25.8% (23 of 89) of those with confirmed STI and returned for their results were symptomatic at time of testing.STI symptoms in the previous year (adjusted prevalence ratio (aPR): 1.94 (95% CI: 1.26 to 2.98)) were positively associated with any STI. Being circumcised was negatively associated with any STI (aPR: 0.47 (95% CI: 0.31 to 0.73)). HIV was positively associated with rectal STIs (aPR: 3.50 (95% CI: 1.09 to 11.21)) but negatively associated with urethral STIs.

CONCLUSION

MSM/TGW, especially those living with HIV, are at high risk of STIs in Rwanda with the vast majority being asymptomatic. These data suggest the potential utility of active STI surveillance strategies using highly sensitive laboratory methods among those at high risk given the anatomical distribution and limited symptomatology of STIs observed among Rwandan MSM/TGW.

Estimating prevalence and incidence of sexually transmitted infections among South African women: Implications of combined impacts of risk factors

In addition to being the epicentre of the HIV epidemic, South Africa also has the highest burden of sexually transmitted infections (STIs) in the world. Therefore, understanding the most influential risk factors of STIs is a research priority. Using the data from 9948 women who resided in KwaZulu Natal, South Africa, we estimated the population attributable risk to quantify the combined impacts of the most influential factors on STI diagnosis. Overall STI prevalence was 20%, and STI incidence was 15 per 100 person-years. Four factors: age at sexual debut, single/not cohabiting, two or more sex partners and parity <3 were identified as the most influential risk factors for STI prevalence and incidence rates. However, these factors collectively associated with only 51% and 53% of the excess STI prevalence and incidence rates, respectively. These relatively modest impacts provide empirical evidence for the significant impacts of unmeasured factors on STIs. Culturally and socially appropriate prevention programs may be more effective to target those at highest risk of STIs.

Prevalence and Risk Factors for Rectal and Urethral Sexually Transmitted Infections From Self-Collected Samples Among Young Men Who Have Sex With Men Participating in the Keep It Up! 2.0 Randomized Controlled Trial

BACKGROUND

Despite recommendations that sexually active men who have sex with men be regularly tested for sexually transmitted infections (STIs) and that testing reflect anatomical sites of potential exposure, regular testing is not widely performed, especially for rectal STIs. As such, little is known about the prevalence of rectal and urethral STIs among young men who have sex with men (YMSM).

METHODS

The current study examined the prevalence and risk factors for rectal and urethral chlamydia and gonorrhea in a sample of 1113 YMSM ages 18 to 29 years (mean, 24.07 years). Before participating in a randomized controlled trial for an online human immunodeficiency virus prevention program (Keep It Up! 2.0), participants completed self-report measures and self-collected urine and rectal samples. Participants mailed samples to a laboratory for nucleic acid amplification testing. Viability of self-collected samples was examined as a potential method to increase STI screening for MSM without access to STI testing clinics.

RESULTS

Results indicated that 15.1% of participants tested positive for an STI, 13.0% for a rectal STI, 3.4% for a urethral STI, and 1.2% for both rectal and urethral STIs. Rectal chlamydia was significantly more common (8.8%) than rectal gonorrhea (5.0%). Rectal STIs were higher among black YMSM compared with white YMSM. Additionally, rectal STIs were positively associated with condomless receptive anal sex with casual partners.

CONCLUSIONS

Findings call attention to the need for health care providers to test YMSM for rectal STIs. This study also demonstrates the viability of including self-collected samples for STI testing in an eHealth program.

Contact structure, mobility, environmental impact and behaviour: the importance of social forces to infectious disease dynamics and disease ecology

Human factors, including contact structure, movement, impact on the environment and patterns of behaviour, can have significant influence on the emergence of novel infectious diseases and the transmission and amplification of established ones. As anthropogenic climate change alters natural systems and global economic forces drive land-use and land-cover change, it becomes increasingly important to understand both the ecological and social factors that impact infectious disease outcomes for human populations. While the field of disease ecology explicitly studies the ecological aspects of infectious disease transmission, the effects of the social context on zoonotic pathogen spillover and subsequent human-to-human transmission are comparatively neglected in the literature. The social sciences encompass a variety of disciplines and frameworks for understanding infectious diseases; however, here we focus on four primary areas of social systems that quantitatively and qualitatively contribute to infectious diseases as social-ecological systems. These areas are social mixing and structure, space and mobility, geography and environmental impact, and behaviour and behaviour change. Incorporation of these social factors requires empirical studies for parametrization, phenomena characterization and integrated theoretical modelling of social-ecological interactions. The social-ecological system that dictates infectious disease dynamics is a complex system rich in interacting variables with dynamically significant heterogeneous properties. Future discussions about infectious disease spillover and transmission in human populations need to address the social context that affects particular disease systems by identifying and measuring qualitatively important drivers.This article is part of the themed issue 'Opening the black box: re-examining the ecology and evolution of parasite transmission'.

An Empiric HIV Risk Scoring Tool to Predict HIV-1 Acquisition in African Women

Supplemental Digital Content is Available in the Text.

Objective:

To develop and validate an HIV risk assessment tool to predict HIV acquisition among African women.

Design:

Data were analyzed from 3 randomized trials of biomedical HIV prevention interventions among African women (VOICE, HPTN 035, and FEM-PrEP).

Methods:

We implemented standard methods for the development of clinical prediction rules to generate a risk-scoring tool to predict HIV acquisition over the course of 1 year. Performance of the score was assessed through internal and external validations.

Results:

The final risk score resulting from multivariable modeling included age, married/living with a partner, partner provides financial or material support, partner has other partners, alcohol use, detection of a curable sexually transmitted infection, and herpes simplex virus 2 serostatus. Point values for each factor ranged from 0 to 2, with a maximum possible total score of 11. Scores ≥5 were associated with HIV incidence >5 per 100 person-years and identified 91% of incident HIV infections from among only 64% of women. The area under the curve (AUC) for predictive ability of the score was 0.71 (95% confidence interval [CI]: 0.68 to 0.74), indicating good predictive ability. Risk score performance was generally similar with internal cross-validation (AUC = 0.69; 95% CI: 0.66 to 0.73) and external validation in HPTN 035 (AUC = 0.70; 95% CI: 0.65 to 0.75) and FEM-PrEP (AUC = 0.58; 95% CI: 0.51 to 0.65).

Conclusions:

A discrete set of characteristics that can be easily assessed in clinical and research settings was predictive of HIV acquisition over 1 year. The use of a validated risk score could improve efficiency of recruitment into HIV prevention research and inform scale-up of HIV prevention strategies in women at highest risk.

Opportunities and barriers to STI testing in community health centres in China: a nationwide survey

BACKGROUND

China has strengthened its primary care workforce and implemented a wide network of community health centres (CHCs). However, STI testing and management are not currently included in the 'Essential Package of Primary Health Care in China'. Legislation change to encourage STI service delivery would be important, but it is also critical to determine if there are also provider-related opportunities and barriers for implementing effective STI programmes through CHCs if future legislation were to change.

METHODS

A national representative survey was conducted between September and December 2015 in a stratified random sample of 180 CHCs based in 20 cities in China. Primary care practitioners (PCPs) provided information on current experiences of STI testing as well as the barriers and facilitators for STI testing in CHCs. Multivariate logistic regression was conducted to determine factors associated with PCPs performing STI testing.

RESULTS

3580 out of 4146 (86%) invited PCPs from 158 CHCs completed the survey. The majority (85%, 95% CI 84% to 87%) of doctors stated that STI testing was an important part of healthcare. However, less than a third (29%, 95% CI 27% to 31%) would perform an STI test if the patients asked. Barriers for performing STI testing included lack of training, concerns about reimbursement, concerns about damage to clinics' reputations and the stigma against key populations. Respondents who reported that they would perform an STI test were likely to be younger, received a bachelor degree or higher, received specific training in STIs, believed that STI test was an important part of healthcare or had resources to perform STI testing.

CONCLUSIONS

There is potential for improving STI management in China through upskilling the primary care workforce in CHCs. Specific training in STIs is needed, and other structural, logistical and attitudinal barriers are needed to be addressed.

Estimating prevalence trends in adult gonorrhoea and syphilis in low- and middle-income countries with the Spectrum-STI model: results for Zimbabwe and Morocco from 1995 to 2016

Objective

To develop a tool for estimating national trends in adult prevalence of sexually transmitted infections by low- and middle-income countries, using standardised, routinely collected programme indicator data.

Methods

The Spectrum-STI model fits time trends in the prevalence of active syphilis through logistic regression on prevalence data from antenatal clinic-based surveys, routine antenatal screening and general population surveys where available, weighting data by their national coverage and representativeness. Gonorrhoea prevalence was fitted as a moving average on population surveys (from the country, neighbouring countries and historic regional estimates), with trends informed additionally by urethral discharge case reports, where these were considered to have reasonably stable completeness. Prevalence data were adjusted for diagnostic test performance, high-risk populations not sampled, urban/rural and male/female prevalence ratios, using WHO's assumptions from latest global and regional-level estimations. Uncertainty intervals were obtained by bootstrap resampling.

Results

Estimated syphilis prevalence (in men and women) declined from 1.9% (95% CI 1.1% to 3.4%) in 2000 to 1.5% (1.3% to 1.8%) in 2016 in Zimbabwe, and from 1.5% (0.76% to 1.9%) to 0.55% (0.30% to 0.93%) in Morocco. At these time points, gonorrhoea estimates for women aged 15–49 years were 2.5% (95% CI 1.1% to 4.6%) and 3.8% (1.8% to 6.7%) in Zimbabwe; and 0.6% (0.3% to 1.1%) and 0.36% (0.1% to 1.0%) in Morocco, with male gonorrhoea prevalences 14% lower than female prevalence.

Conclusions

This epidemiological framework facilitates data review, validation and strategic analysis, prioritisation of data collection needs and surveillance strengthening by national experts. We estimated ongoing syphilis declines in both Zimbabwe and Morocco. For gonorrhoea, time trends were less certain, lacking recent population-based surveys.

Combination HIV prevention options for young women in Africa

Although the number of new HIV infections has declined by over 30% in the past decade, the number of people who acquire HIV each year remains unacceptably high. In 2014 the Joint United Nations Programme on HIV/AIDS (UNAIDS) estimated that there were about 2 million new HIV infections. The virus continues to spread, particularly in key populations, such as men who have sex with men (MSM), transgender individuals, sex workers and people who inject drugs. In Africa, young women have the highest HIV incidence rates. Scaling up known efficacious HIV prevention strategies for these groups at high risk is therefore a high priority. HIV prevention has generally been targeted at HIV-negative individuals or in some instances, entire communities. Prevention efforts are, however, shifting from a narrow focus on HIV-uninfected persons to a continuum of prevention that includes both HIV-negative and HIV-positive individuals. Given that a single HIV prevention intervention is unlikely to be able to alter the epidemic trajectory as HIV epidemics in communities are complex and comprise a mosaic of different risk factors and different routes of transmission, there is need to provide combination prevention. Hence, a mix of behavioural, biomedical and structural HIV prevention options is likely to be needed to alter the course of the HIV epidemic. The combination of HIV prevention interventions needed will vary depending on cultural context, the population targeted and the stage of the epidemic. This paper reviews the available HIV prevention strategies for young women and discusses new HIV prevention approaches in development.

Chlamydia and Gonorrhea in HIV-Infected Pregnant Women and Infant HIV Transmission

BACKGROUND

Sexually transmitted infections (STIs) such as Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) can lead to adverse pregnancy and neonatal outcomes. The prevalence of STIs and its association with HIV mother-to-child transmission (MTCT) were evaluated in a substudy analysis from a randomized, multicenter clinical trial.

METHODOLOGY

Urine samples from HIV-infected pregnant women collected at the time of labor and delivery were tested using polymerase chain reaction testing for the detection of CT and NG (Xpert CT/NG; Cepheid, Sunnyvale, CA). Infant HIV infection was determined by HIV DNA polymerase chain reaction at 3 months.

RESULTS

Of the 1373 urine specimens, 249 (18.1%) were positive for CT and 63 (4.6%) for NG; 35 (2.5%) had both CT and NG detected. Among 117 cases of HIV MTCT (8.5% transmission), the lowest transmission rate occurred among infants born to CT- and NG-uninfected mothers (8.1%) as compared with those infected with only CT (10.7%) and both CT and NG (14.3%; P = 0.04). Infants born to CT-infected mothers had almost a 1.5-fold increased risk for HIV acquisition (odds ratio, 1.47; 95% confidence interval, 0.9-2.3; P = 0.09).

CONCLUSIONS

This cohort of HIV-infected pregnant women is at high risk for infection with CT and NG. Analysis suggests that STIs may predispose to an increased HIV MTCT risk in this high-risk cohort of HIV-infected women.

Barriers to Bacterial Sexually Transmitted Infection Testing of HIV-Infected Men Who Have Sex With Men Engaged in HIV Primary Care

BACKGROUND

Approximately 15% of HIV-infected men who have sex with men (MSM) engaged in HIV primary care have been diagnosed as having a sexually transmitted infection (STI) in the past year, yet STI testing frequency remains low.

METHODS

We sought to quantify STI testing frequencies at a large, urban HIV care clinic, and to identify patient- and provider-related barriers to increased STI testing. We extracted laboratory data in aggregate from the electronic medical record to calculate STI testing frequencies (defined as the number of HIV-infected MSM engaged in care who were tested at least once over an 18-month period divided by the number of MSM engaged in care). We created anonymous surveys of patients and providers to elicit barriers.

RESULTS

Extragenital gonorrhea and chlamydia testing was low (29%-32%), but the frequency of syphilis testing was higher (72%). Patients frequently reported high-risk behaviors, including drug use (16.4%) and recent bacterial STI (25.5%), as well as substantial rates of recent testing (>60% in prior 6 months). Most (72%) reported testing for STI in HIV primary care, but one-third went elsewhere for "easier" (42%), anonymous (21%), or more frequent (16%) testing. HIV primary care providers lacked testing and treatment knowledge (25%-32%) and cited lack of time (68%), discomfort with sexual history taking and genital examination (21%), and patient reluctance (39%) as barriers to increased STI testing.

CONCLUSION

Sexually transmitted infection testing in HIV care remains unacceptably low. Enhanced education of providers, along with strategies to decrease provider time and increase patient ease and frequency of STI testing, is needed.

The Effect of High Rates of Bacterial Sexually Transmitted Infections on HIV Incidence in a Cohort of Black and White Men Who Have Sex with Men in Atlanta, Georgia

Data reporting sexually transmitted infection (STI) incidence rates among HIV-negative U.S. men who have sex with men (MSM) are lacking. In addition, it is difficult to analyze the effect of STI on HIV acquisition given that sexual risk behaviors confound the relationship between bacterial STIs and incident HIV. The InvolveMENt study was a longitudinal cohort of black and white HIV-negative, sexually active MSM in Atlanta who underwent routine screening for STI and HIV and completed behavioral questionnaires. Age-adjusted incidence rates were calculated for urethral and rectal Chlamydia (CT), gonorrhea (GC), and syphilis, stratified by race. Propensity-score-weighted Cox proportional hazards models were used to estimate the effect of STI on HIV incidence and calculate the population attributable fraction (PAF) for STI. We included 562 HIV-negative MSM with 843 person-years of follow-up in this analysis. High incidence rates were documented for all STIs, particularly among black MSM. Having a rectal STI was significantly associated with subsequent HIV incidence in adjusted analyses (aHR 2.7; 95% CI 1.2, 6.4) that controlled for behavioral risk factors associated with STI and HIV using propensity score weights. The PAF for rectal STI was 14.6 (95% CI 6.8, 31.4). The high incidence of STIs among Atlanta MSM and the association of rectal STI with HIV acquisition after controlling for behavioral risk underscore the importance of routine screening and treatment for STIs among sexually active MSM. Our data support targeting intensive HIV prevention interventions, such as preexposure chemoprophylaxis (PrEP), for Atlanta MSM diagnosed with rectal STIs.

Rush to judgment: the STI-treatment trials and HIV in sub-Saharan Africa

INTRODUCTION

The extraordinarily high incidence of HIV in sub-Saharan Africa led to the search for cofactor infections that could explain the high rates of transmission in the region. Genital inflammation and lesions caused by sexually transmitted infections (STIs) were a probable mechanism, and numerous observational studies indicated several STI cofactors. Nine out of the ten randomized controlled trials (RCTs), however, failed to demonstrate that treating STIs could lower HIV incidence. We evaluate all 10 trials to determine if their design permits the conclusion, widely believed, that STI treatment is ineffective in reducing HIV incidence.

DISCUSSION

Examination of the trials reveals critical methodological problems sufficient to account for statistically insignificant outcomes in nine of the ten trials. Shortcomings of the trials include weak exposure contrast, confounding, non-differential misclassification, contamination and effect modification, all of which consistently bias the results toward the null. In any future STI-HIV trial, ethical considerations will again require weak exposure contrast. The complexity posed by HIV transmission in the genital microbial environment means that any future STI-HIV trial will face confounding, non-differential misclassification and effect modification. As a result, it is unlikely that additional trials would be able to answer the question of whether STI control reduces HIV incidence.

CONCLUSIONS

Shortcomings in published RCTs render invalid the conclusion that treating STIs and other cofactor infections is ineffective in HIV prevention. Meta-analyses of observational studies conclude that STIs can raise HIV transmission efficiency two- to fourfold. Health policy is always implemented under uncertainty. Given the known benefits of STI control, the irreparable harm from not treating STIs and the likely decline in HIV incidence resulting from STI control, it is appropriate to expand STI control programmes and to use funds earmarked for HIV prevention to finance those programmes.

Physicians' perceived barriers to management of sexually transmitted infections in Vietnam

Background

Sexually transmitted infections (STIs) are a public health problem in Vietnam with sub-optimal care in medical practice. Identifying practitioners’ perceived barriers to STI care is important to improve care for patients with STIs.

Methods

A cross-sectional survey was conducted among 451 physicians. These physicians were dermatology and venereology (D&V) doctors, obstetrical/gynaecological (Ob/Gyn) doctors, general practitioners, and assistant doctors working in health facilities at provincial, district and communal levels in three provinces in Vietnam.

Results

Almost all (99%) respondents mentioned at least one barrier to STI care. The barriers were “lack of STI training” (57%), “lack of professional resources” (41%), “lack of time” (38%), “lack of reimbursement” (21%), “lack of privacy/confidentiality” (17%), “lack of counselling” (15%), and “not the role of primary care provider” (7%). Multivariable logistic regression analysis showed that “lack of professional resources” was associated with respondents being in medical practice for ten years or under (vs. 11–20 years), and working at district or communal health facilities (vs. provincial facilities); “lack of time” were associated with respondents being female, seeing more than 30 patients a week (vs. <15 patients/week); and “lack of privacy/confidentiality” was associated with physicians’ seeing more than 30 patients a week (vs. <15 patients/week).

Conclusion

The study has identified several barriers to STI care in medical practice in Vietnam. Results of the study can be used to improve areas in STI care including policy and practice implications.

Evidence-based public health: not only whether it works, but how it can be made to work practicably at scale

Because public health must operate at scale in widely diverse, complex situations, randomized controlled trials (RCTs) have limited utility for public health. Other methodologies are needed. A key conceptual backbone is a detailed “theory of change” to apply appropriate evidence for each operational component. Synthesizing patterns of findings across multiple methodologies provides key insights. Programs operating successfully across a variety of settings can provide some of the best evidence. Challenges include judging the quality of such evidence and assisting programs to apply it. WHO and others should shift emphasis from RCTs to more relevant evidence when assessing public health issues.

Looking upstream to prevent HIV transmission: can interventions with sex workers alter the course of HIV epidemics in Africa as they did in Asia?

BACKGROUND

High rates of partner change in 'upstream' sex work networks have long been recognized to drive 'downstream' transmission of sexually transmitted infections (STIs). We used a stochastic microsimulation model (STDSIM) to explore such transmission dynamics in a generalized African HIV epidemic.

METHODS

We refined the quantification of sex work in Kisumu, Kenya, from the 4-cities study. Interventions with sex workers were introduced in 2000 and epidemics projected to 2020. We estimated the contribution of sex work to transmission, and modelled standard condom and STI interventions for three groups of sex workers at feasible rates of use and coverage.

RESULTS

Removing transmission from sex work altogether would have resulted in 66% lower HIV incidence (range 54-75%) and 56% lower prevalence (range 44-63%) after 20 years. More feasible interventions reduced HIV prevalence from one-fifth to one-half. High rates of condom use in sex work had the greatest effect, whereas STI treatment contributed to HIV declines at lower levels of condom use. Interventions reaching the 40% of sex workers with most clients reduced HIV transmission nearly as much as less targeted approaches attempting to reach all sex workers. Declines were independent of antiretroviral therapy rollout and robust to realistic changes in parameter values.

CONCLUSION

'Upstream' transmission in sex work remains important in advanced African HIV epidemics even in the context of antiretroviral therapy. As in concentrated Asian epidemics, feasible condom and STI interventions that reach the most active sex workers can markedly reduce the size of HIV epidemics. Interventions targeting 'transactional' sex with fewer clients have less impact.

Genital schistosomiasis and its unacknowledged role on HIV transmission in the STD intervention studies

Treatment of sexually transmitted infections (STIs) has been hypothesised to decrease HIV transmission. Although observational studies show an association between STIs and HIV, only one prospective randomised controlled trial (RCT) has confirmed this. Female genital schistosomiasis can cause genital lesions, accompanied by bloody discharge, ulcers or malodorous discharge. Genital schistosomiasis is common, starts before puberty and symptoms can be mistaken for STIs. Three observational studies have found an association between schistosomiasis and HIV. Genital lesions that develop in childhood are chronic. This paper sought to explore the possible effects of schistosomiasis on the RCTs of STI treatment for HIV prevention.

In the study sites, schistosomiasis was a likely cause of genital lesions. The studies recruited women that may have had genital schistosomal lesions established in childhood. Schistosomiasis endemic areas with different prevalence levels may have influenced HIV incidence in intervention and control sites differently, and some control group interventions may have influenced the impact of schistosomiasis on the study results. Schistosomiasis is a neglected cause of genital tract disease. It may have been an independent cause of HIV incidence in the RCTs of STI treatment for HIV prevention and may have obscured the findings of these trials.

Vulnerability to HIV infection among female drug users in Kathmandu Valley, Nepal: a cross-sectional study

Background

Women who use drugs are extremely vulnerable to HIV and sexually transmitted infections (STIs), but studies on risk behaviours and HIV infection among female drug users are limited in Nepal.

Methods

In this cross-sectional study conducted between September 2010 and May 2011, HIV prevalence and risk factors for HIV infection were investigated among female drug users recruited in drop-in centres, parks and streets in the Kathmandu Valley. The participants completed face-to-face interviews for a structured questionnaire, HIV pre-test counselling, specimen collection for HIV test and they were provided with their results at post-test counselling.

Results

A total of 269 female drug users were recruited, of whom 28% (n = 77) were found HIV positive; the majority (78%, n = 211) being injecting drug users and aged below 25 years (57%, n = 155). Nearly half (n = 137) of the total participants had shared needles or syringes in the past month, and 131 and 102 participants were involved in commercial or casual sex respectively with only half or less of them having had used condoms in the last 12 months. In multivariate analysis the variables associated with HIV infection included: (a) older age; (b) history of school attendance; (c) frequency of sharing of injection instruments; and (d) unsafe sex with commercial or casual partners.

Conclusions

HIV was highly prevalent among female drug users in the Kathmandu Valley, with its risk being strongly associated not only with unsafe injection practice but also with unsafe sexual behaviours. Awareness raising programmes and preventive measures such as condom distribution, needle or syringe exchange or methadone maintenance therapy should be urgently introduced in this neglected subpopulation.

Individual-based simulation models of HIV transmission: reporting quality and recommendations

BACKGROUND

Individual-based modeling is a growing technique in the HIV transmission and prevention literature, but insufficient attention has been paid to formally evaluate the quality of reporting in this field. We present reporting recommendations for individual-based models for HIV treatment and prevention, assess the quality of reporting in the existing literature, and comment on the contribution of this model type to HIV policy and prediction.

METHODS

We developed reporting recommendations for individual-based HIV transmission mathematical models, and through a systematic search, used them to evaluate the reporting in the existing literature. We identified papers that employed individual-based simulation models and were published in English prior to December 31, 2012. Articles were included if the models they employed simulated and tracked individuals, simulated HIV transmission between individuals in a particular population, and considered a particular treatment or prevention intervention. The papers were assessed with the reporting recommendations.

FINDINGS

Of 214 full text articles examined, 32 were included in the evaluation, representing 20 independent individual-based HIV treatment and prevention mathematical models. Manuscripts universally reported the objectives, context, and modeling conclusions in the context of the modeling assumptions and the model's predictive capabilities, but the reporting of individual-based modeling methods, parameterization and calibration was variable. Six papers discussed the time step used and one discussed efforts to maintain internal validity in coding.

CONCLUSION

Individual-based models represent detailed HIV transmission processes with the potential to contribute to inference and policy making for many different regions and populations. The rigor in reporting of assumptions, methods, and calibration of individual-based models focused on HIV transmission and prevention varies greatly. Higher standards for reporting of statistically rigorous calibration and model assumption testing need to be implemented to increase confidence in existing and future modeling results.

Can combination prevention strategies reduce HIV transmission in generalized epidemic settings in Africa? The HPTN 071 (PopART) study plan in South Africa and Zambia

The HIV Prevention Trials Network (HPTN) is conducting the HPTN 071 (PopART) study in 21 communities in Zambia and South Africa with support from a consortium of funders. HPTN 071 (PopART) is a community-randomized trial of a combination prevention strategy to reduce HIV incidence in the context of the generalized epidemic of southern Africa. The full PopART intervention strategy is anchored in home-based HIV testing and facilitated linkage of HIV-infected persons to care through community health workers and universal antiretroviral therapy for seropositive persons regardless of CD4+ cell count or HIV viral load. To further reduce the risk of HIV acquisition among uninfected individuals, the study aims to expand voluntary medical male circumcision, diagnosis and treatment of sexually transmitted infections, behavioral counseling, and condom distribution. The full PopART intervention strategy also incorporates promotion of other interventions designed to reduce HIV and tuberculosis transmission, including optimization of the prevention of mother-to-child HIV transmission and enhanced individual and public health tuberculosis services. Success for the PopART strategy depends on the ability to increase coverage for the study interventions whose uptake is a necessary antecedent to a prevention effect. Processes will be measured to assess the degree of penetration of the interventions into the communities. A randomly sampled population cohort from each community will be used to measure the impact of the PopART strategy on HIV incidence over 3 years. We describe the strategy being tested and progress to date in the HPTN 071 (PopART) study.

Reported changes in sexual behaviour and human papillomavirus knowledge in Peruvian female sex workers following participation in a human papillomavirus vaccine trial

Summary

Limited data exist on the effect of clinical trial participation on sexual behavioural change. Two hundred female sex workers working in Lima, Peru received human papillomavirus (HPV) vaccine in either the standard (0, 2, 6 months) or modified (0, 3, 6 months) schedule. Participants received comprehensive screening and treatment for sexually transmitted infections (STIs), counselling on safe sex practices, education about HPV and the HPV vaccine, contraceptives (oral and condoms) and family planning at each visit. We assessed vaccine completion rates, change in sexual practices, and changes in HPV knowledge before and after participation in the vaccine trial. There were high rates of vaccine completion, 91% overall. The estimated number of reported new and total clients over a 30-day period decreased significantly ( P < 0.001). Knowledge about HPV and HPV-related disease increased among all participants. In addition, all participants listed at least one preventive strategy during the month 7 follow-up survey.

Combination prevention: new hope for stopping the epidemic

HIV research has identified approaches that can be combined to be more effective in transmission reduction than any 1 modality alone: delayed adolescent sexual debut, mutual monogamy or sexual partner reduction, correct and consistent condom use, pre-exposure prophylaxis with oral antiretroviral drugs or vaginal microbicides, voluntary medical male circumcision, antiretroviral therapy (ART) for prevention (including prevention of mother to child HIV transmission [PMTCT]), treatment of sexually transmitted infections, use of clean needles for all injections, blood screening prior to donation, a future HIV prime/boost vaccine, and the female condom. The extent to which evidence-based modalities can be combined to prevent substantial HIV transmission is largely unknown, but combination approaches that are truly implementable in field conditions are likely to be far more effective than single interventions alone. Analogous to PMTCT, "treatment as prevention" for adult-to-adult transmission reduction includes expanded HIV testing, linkage to care, antiretroviral coverage, retention in care, adherence to therapy, and management of key co-morbidities such as depression and substance use. With successful viral suppression, persons with HIV are far less infectious to others, as we see in the fields of sexually transmitted infection control and mycobacterial disease control (tuberculosis and leprosy). Combination approaches are complex, may involve high program costs, and require substantial global commitments. We present a rationale for such investments and cite an ongoing research agenda that seeks to determine how feasible and cost-effective a combination prevention approach would be in a variety of epidemic contexts, notably that in a sub-Saharan Africa.

Association between herpes simplex virus type 2 and HIV-1 in a population of married couples from Dakar, Senegal

Numerous studies suggest that herpes simplex virus type 2 (HSV-2) increases the risk of HIV-1 infection but recent clinical trials of HSV-2 suppressive therapy failed to show an effect. We assessed the putative association between HSV-2 and HIV-1 in a population of HIV-concordant-negative, HIV-1-discordant and HIV-1-concordant-positive married couples from Dakar, Senegal. In agreement with previous studies, we observed a strong overall association between HSV-2 and HIV-1 (odds ratio 4.61; P < 0.001). However, this association was mainly determined by a low HSV-2 prevalence in HIV-concordant-negative couples compared with HIV-1-discordant and HIV-1-concordant-positive couples (23% versus 59% and 66%, respectively; P < 0.001). We observed no further differences in HSV-2 prevalence between HIV-1-discordant and HIV-1-concordant-positive couples (59% and 66%, respectively; P = 0.483). Neither the index (59% versus 62%, P = 1.000) nor recipient partners (41% versus 63%, P = 0.131) in HIV-1-discordant and HIV-1-concordant-positive couples showed significant differences in HSV-2 prevalence. HSV-2 does not constitute a clear risk factor for HIV-1 infection in this population.

Declining sexually transmitted infections among female sex workers: the results of an HIV and sexually transmitted infection prevention strategy in Honduras, 2006-08

In 2006, we implemented an HIV and sexually transmitted infection (STI) prevention programme for female sex workers (FSWs) in three Honduran cities. All FSW attending STI clinics underwent regular examinations and STI testing. Information on condom use with different partners was collected at each visit. After three years, we detected a significant decline in the prevalence of syphilis from 2.3% at the first screening to 0.0% at the third screening (P = 0.05), and of chlamydia, from 6.1% to 3.3% (P = 0.01). No changes were observed in the prevalence of gonorrhoea or trichomoniasis. The cumulative HIV prevalence remained constant (P = 0.44). Reports of condom use with clients increased from 93.8% to 98.9% (P < 0.001). The implementation of an HIV/STI prevention programme in FSW has contributed to increases in condom use with clients and the reduction in syphilis and chlamydia prevalence. The intervention should be strengthened and considered as part of a national health policy strategy.

The role of sexually transmitted infections in the evolution of the South African HIV epidemic

OBJECTIVES

To assess the extent to which sexually transmitted infections (STIs) have contributed to the spread of HIV in South Africa and to estimate the extent to which improvements in STI treatment have reduced HIV incidence.

METHODS

A mathematical model was used to simulate interactions between HIV and six other STIs (genital herpes, syphilis, chancroid, gonorrhoea, chlamydial infection and trichomoniasis) as well as bacterial vaginosis and vaginal candidiasis. The effects of STIs on HIV transmission probabilities were assumed to be consistent with meta-analytic reviews of observational studies, and the model was fitted to South African HIV prevalence data.

RESULTS

The proportion of new HIV infections in adults that were attributable to curable STIs reduced from 39% (uncertainty range: 24-50%) in 1990 to 14% (8-18%) in 2010, while the proportion of new infections attributable to genital herpes increased. Syndromic management programmes are estimated to have reduced adult HIV incidence by 6.6% (3.3-10.3%) between 1994 and 2004, by which time syndromic management coverage was 52%. Had syndromic management been introduced in 1986, with immediate achievement of 100% coverage and a doubling of the rate of health seeking, HIV incidence would have reduced by 64% (36-82%) over the next decade, but had the same intervention been delayed until 2004, HIV incidence would have reduced by only 5.5% (2.8-9.0%).

CONCLUSIONS

Sexually transmitted infections have contributed significantly to the spread of HIV in South Africa, but STI control efforts have had limited impact on HIV incidence because of their late introduction and suboptimal coverage.

Antiretroviral-based microbicides and oral pre-exposure prophylaxis for HIV prevention

Numerous HIV prevention options have been tested, with limited success. Microbicides have been the focus of research specifically targeted to prevent new infections among women. After decades of research using non-HIV-specific microbicides, we now have proof of concept for antiretroviral-based microbicides. Issues of drug resistance, frequency of HIV testing and adherence to treatment remain to be explored. Drugs used for HIV treatment and with good safety profiles have been shown to provide protection to men who have sex with men. Ethical issues surrounding cost, access, future design of HIV prevention trials and composition of the prevention package offered to trial participants remain. The role of advocacy and market research will be crucial to ensure effective interventions are accessed and supported. There is renewed hope in the HIV prevention field with collective efforts needed to ensure we get the new prevention tools and options into the hands of men and women at risk of HIV infection. The purpose of this paper is to provide a review of existing research and identify issues for future enquiry.

Combination HIV prevention: significance, challenges, and opportunities

No single HIV prevention strategy will be sufficient to control the HIV pandemic. However, a growing number of interventions have shown promise in partially protecting against HIV transmission and acquisition, including knowledge of HIV serostatus, behavioral risk reduction, condoms, male circumcision, needle exchange, treatment of curable sexually transmitted infections, and use of systemic and topical antiretroviral medications by both HIV-infected and uninfected persons. Designing the optimal package of interventions that matches the epidemiologic profile of a target population, delivering that package at the population level, and evaluating safety, acceptability, coverage, and effectiveness, all involve methodological challenges. Nonetheless, there is an unprecedented opportunity to develop "prevention packages" that combine various arrays of evidence-based strategies, tailored to the needs of diverse subgroups and targeted to achieve high coverage for a measurable reduction in population-level HIV transmission. HIV prevention strategies that combine partially effective interventions should be scaled up and evaluated.

The relative contribution of viral and bacterial sexually transmitted infections on HIV acquisition in southern African women in the Methods for Improving Reproductive Health in Africa study

We assess the relative contribution of viral and bacterial sexually transmitted infections (STIs) on HIV acquisition among southern African women in a nested case-control study within the Methods for Improving Reproductive Health in Africa (MIRA) trial. Cases were women with incident HIV infection; controls were HIV-uninfected at the time of case seroconversion selected in a 1 to 3 case to control ratio (risk-set sampling), matched on study site and time of follow-up. Conditional logistic regression models were used to calculate adjusted odds ratios (AORs) and population-attributable fractions (PAF). Among 4948 enrolled women, we analysed 309 cases and 927 controls. The overall HIV incidence rate was 4.0 per 100 women-years. The incidence of HIV infection was markedly higher in women who had prevalent Herpes simplex virus type 2 (HSV-2) (AOR: 2.14; 95% confidence interval [CI]: 1.55–2.96), incident HSV-2 (AOR: 4.43; 95% CI: 1.77–11.05) and incident Neisseria gonorrhoeae (AOR: 6.92; 95% CI: 3.01–15.90). The adjusted PAF of HIV incidence for prevalent HSV-2 was 29.0% (95% CI: 16.8–39.3), for incident HSV-2 2.1% (95% CI: 0.6–3.6) and for incident N. gonorrhoeae 4.1% (95% CI: 2.5–5.8). Women's greatest risk factors for HIV acquisition were incident bacterial and viral STIs. Women-centred interventions aimed at decreasing HIV incidence in young African women need to address these common co-morbid conditions.

Correlates of HIV-1 genital shedding in Tanzanian women

Background

Understanding the correlates of HIV shedding is important to inform strategies to reduce HIV infectiousness. We examined correlates of genital HIV-1 RNA in women who were seropositive for both herpes simplex virus (HSV)-2 and HIV-1 and who were enrolled in a randomised controlled trial of HSV suppressive therapy (aciclovir 400 mg b.i.d vs. placebo) in Tanzania.

Methodology

Samples, including a cervico-vaginal lavage, were collected and tested for genital HIV-1 and HSV and reproductive tract infections (RTIs) at randomisation and 6, 12 and 24 months follow-up. Data from all women at randomisation and women in the placebo arm during follow-up were analysed using generalised estimating equations to determine the correlates of cervico-vaginal HIV-1 RNA detection and load.

Principal Findings

Cervico-vaginal HIV-1 RNA was detected at 52.0% of 971 visits among 482 women, and was independently associated with plasma viral load, presence of genital ulcers, pregnancy, bloody cervical or vaginal discharge, abnormal vaginal discharge, cervical ectopy, Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, an intermediate bacterial vaginosis score and HSV DNA detection. Similar factors were associated with genital HIV-1 RNA load.

Conclusions

RTIs were associated with increased presence and quantity of genital HIV-1 RNA in this population. These results highlight the importance of integrating effective RTI treatment into HIV care services.

The impact of mobility on HIV control: a modelling study

Mobility is associated with HIV due to more risky sexual behaviour of mobile groups such as travellers and migrants. Limited participation of such groups may reduce the effectiveness of HIV interventions disproportionally. The established STDSIM model, which simulates transmission and control of HIV and STD, was extended to simulate mobility patterns based on data from Tanzania. We explored the impact of non-participation of mobile groups (travellers and recent migrants) on the effectiveness of two interventions: condom promotion and health education aiming at partner reduction. If mobile groups do not participate, the effectiveness of both interventions could be reduced by 40%. The impact of targeting travellers with a combined HIV campaign is close to that of a general population intervention. In conclusion, it is important to account for possible non-participation of migrants and travellers. If non-participation is substantial, impact of interventions can be greatly improved by actively approaching these people.

Viral surface glycoproteins, gp120 and gp41, as potential drug targets against HIV-1: brief overview one quarter of a century past the approval of zidovudine, the first anti-retroviral drug

The first anti-HIV drug, zidovudine (AZT), was approved by the FDA a quarter of a century ago, in 1985. Currently, anti-HIV drug-combination therapies only target HIV-1 protease and reverse transcriptase. Unfortunately, most of these molecules present numerous shortcomings such as viral resistances and adverse effects. In addition, these drugs are involved in later stages of infection. Thus, it is necessary to develop new drugs that are able to block the first steps of viral life cycle. Entry of HIV-1 is mediated by its two envelope glycoproteins: gp120 and gp41. Upon gp120 binding to cellular receptors, gp41 undergoes a series of conformational changes from a non-fusogenic to a fusogenic conformation. The fusogenic core of gp41 is a trimer-of-hairpins structure in which three C-terminal helices pack against a central trimeric-coiled coil formed by three N-terminal helices. The formation of this fusogenic structure brings the viral and cellular membranes close together, a necessary condition for membrane fusion to occur. As gp120 and gp41 are attractive targets, the development of entry inhibitors represents an important avenue of anti-HIV drug therapy. The present review will focus on some general considerations about HIV, the main characteristics of gp120, gp41 and their inhibitors, with special emphasis on the advances of computational approaches employed in the development of bioactive compounds against HIV-1 entry process.

Interactions of HIV, other sexually transmitted diseases, and genital tract inflammation facilitating local pathogen transmission and acquisition

Despite several decades of clinical trials assessing the impact of etiological treatment of sexually transmitted diseases (STDs) to decrease HIV acquisition and transmission, almost all of these trials have not proven to be efficacious. Increasing evidence suggests that specific STD treatment alone may not be sufficient to alter the genital tract inflammatory milieu that is created by STDs. This paper examines the associations between STDs and HIV susceptibility and infectiousness, and considers the role of chronic and refractory inflammation to create an environment that potentiates HIV and STD transmission and acquisition by reviewing biological, observational, and clinical trial data.

Epidemiological synergy of Trichomonas vaginalis and HIV in Zimbabwean and South African women

BACKGROUND

Trichomonas vaginalis (T. vaginalis) is the most common nonviral sexually transmitted infection in the world. Despite the coexisting global epidemics of T. vaginalis and HIV, little attention has focused on the emerging evidence that T. vaginalis increases susceptibility to, and potentially transmission of, HIV.

METHODS

We evaluated T. vaginalis infection in the context of a multisite, randomized controlled trial amongst women in South Africa and Zimbabwe, to determine first, if risk of HIV acquisition was increased among women recently infected with T. vaginalis, and second, if risk of T. vaginalis acquisition was increased among women infected with HIV.

RESULTS

After controlling for potential confounders, participants infected with T. vaginalis were more likely to test positive for HIV at their following visit, compared to participants uninfected with T. vaginalis (adjusted hazard ratio = 2.05; 95% CI, 1.05-4.02). Similarly, HIV-positive participants were twice as likely to have acquired T. vaginalis infection at the following visit, compared to HIV-negative participants (adjusted hazard ratio = 2.12; 95% CI, 1.35-3.32).

CONCLUSIONS

We found an increased risk of both HIV acquisition associated with T. vaginalis infection and risk of T. vaginalis acquisition associated with HIV infection. This bidirectional relationship represents a potentially important factor in sustaining the HIV epidemic in populations where T. vaginalis is endemic.

Treatment of sexually transmitted infections for HIV prevention: end of the road or new beginning?

Observational and biological data provide compelling evidence of the importance of sexually transmitted infections (STIs) in HIV transmission, but only one of nine intervention trials has shown an effect. This article reviews the observational studies, critically examines the nine randomized controlled trials evaluating the impact of STI treatment interventions on HIV incidence, and discusses implications for HIV prevention policy, programs and future research. The role of other vaginal infections is also briefly considered. In aggregate, the evidence strongly supports the concept that STI treatment prevents HIV infection. However, issues in trial design and conduct, including HIV epidemic phase, STI prevalence, intervention in comparison groups, and power have affected five of the six trials of treatment of curable STIs. In the three herpes intervention trials, antivirals for HSV suppression were insufficiently potent to alleviate persistent genital inflammation in HIV-negative HSV2-positive persons, and the reduction in HIV levels in HIV-positive persons was insufficient to reduce HIV transmission. It is time for a new phase of exploration of how, when, and in whom to include STI control as a key component of HIV prevention, driven by basic research to elucidate the mechanisms by which STIs and vaginal infections facilitate HIV transmission. From a policy perspective, treatment of curable STIs is an essential part of primary healthcare and is a cheap, simple, and effective intervention when appropriately targeted and delivered. It should be promoted as an essential component of HIV control programs in communities in which the burden of STIs is substantial.

HIV vaccines: current status worldwide and in Africa

Since HIV-1 was identified, development of a preventive vaccine has been a major goal. Significant progress toward that goal has been made by 2010. In macaques, a vigorous T effector cell response has protected some animals from disease caused by simian immunodeficiency virus (SIV). Broadly, neutralizing human anti-HIV antibodies have been isolated and their structures, and targets are rapidly being elucidated. For the first time an AIDS vaccine has shown modest protective efficacy in a human clinical trial. To reach the final goal, there is a need for a coordinated global effort, including a range of approaches including novel high-throughput screening techniques, X-ray crystallography, and monoclonal antibody isolation, analysis of T cell responses and their impact on disease progression, human epidemiology, as well as targeted studies in nonhuman primates. African research teams as well as cohorts of healthy volunteers and HIV-infected individuals have contributed to HIV vaccine research and development in many important ways. It is essential that this work continue to speed the development and deployment of a vaccine suitable for African populations.

The effect of syndromic management interventions on the prevalence of sexually transmitted infections in South Africa

OBJECTIVES

Few studies have assessed the effect of syndromic management interventions on the prevalence of sexually transmitted infections (STIs) at a population level. This study aims to determine the effect of syndromic management protocols that have been introduced in South Africa since 1994.

STUDY DESIGN

A mathematical model of sexual behaviour patterns in South Africa was used to model the incidence of HIV, genital herpes, syphilis, chancroid, gonorrhoea, chlamydial infection, trichomoniasis, bacterial vaginosis and vaginal candidiasis. Assumptions about health seeking behaviour and treatment effectiveness were based on South African survey data. The model was fitted to available STI prevalence data.

MAIN OUTCOME MEASURES

Reductions in STI prevalence due to syndromic management.

RESULTS

Between 1995 and 2005, there were significant reductions in the prevalence of syphilis, chancroid, gonorrhoea, trichomoniasis and chlamydial infection. In women aged between 15 and 49, syndromic management resulted in a 33% (95% CI: 23-43%) decline in syphilis prevalence, a 6% (95% CI: 3-11%) reduction in gonorrhoea prevalence, a 5% (95% CI: 1-13%) reduction in the prevalence of bacterial vaginosis and a substantial decline in chancroid. However, syndromic management did not significantly reduce the prevalence of other STIs. For all STIs, much of the modelled reduction in STI prevalence between 1995 and 2005 can be attributed to either increased condom usage or AIDS mortality.

CONCLUSIONS

Syndromic management of STIs can be expected to decrease the prevalence of curable STIs that tend to become symptomatic, but has little effect on the prevalence of STIs that are mostly asymptomatic.

Periconception pre-exposure prophylaxis to prevent HIV transmission: benefits, risks, and challenges to implementation

HIV-serodiscordant couples face complicated choices between fulfilling reproductive desire and risking HIV transmission to their partners and children. Sexual HIV transmission can be dramatically reduced through artificial insemination and sperm washing; however, most couples cannot access these resources. We propose that periconception pre-exposure prophylaxis (PrEP) could offer an important, complementary therapy to harm reduction counseling programs that aim to decrease HIV transmission for couples who choose to conceive. In this paper, we describe the potential benefits of periconception PrEP and define critical points of clarification prior to implementation of PrEP as part of a reproductive health program. We consider sexual transmission risk, current risk reduction options, PrEP efficacy, cost, adherence, resistance, fetal toxicity, and impact of PrEP counseling on entry into health services. We address PrEP in the context of other periconception HIV-prevention strategies, including antiretroviral treatment of the HIV-infected partner. We conclude that, should PrEP prove safe and efficacious in ongoing trials, periconception PrEP may offer a useful approach to minimize risk of HIV transmission for individuals of reproductive age in HIV-endemic countries.

Re-thinking global health sector efforts for HIV and tuberculosis epidemic control: promoting integration of programme activities within a strengthened health system

BACKGROUND

The global financial crisis threatens global health, particularly exacerbating diseases of inequality, e.g. HIV/AIDS, and diseases of poverty, e.g. tuberculosis. The aim of this paper is to reconsider established practices and policies for HIV and tuberculosis epidemic control, aiming at delivering better results and value for money. This may be achieved by promoting greater integration of HIV and tuberculosis control programme activities within a strengthened health system.

DISCUSSION

HIV and tuberculosis share many similarities in terms of their disease burden and the recommended stratagems for their control. HIV and tuberculosis programmes implement similar sorts of control activities, e.g. case finding and treatment, which depend for success on generic health system issues, including vital registration, drug procurement and supply, laboratory network, human resources, and financing. However, the current health system approach to HIV and tuberculosis control often involves separate specialised services. Despite some recent progress, collaboration between the programmes remains inadequate, progress in obtaining synergies has been slow, and results remain far below those needed to achieve universal access to key interventions. A fundamental re-think of the current strategic approach involves promoting integrated delivery of HIV and tuberculosis programme activities as part of strengthened general health services: epidemiological surveillance, programme monitoring and evaluation, community awareness of health-seeking behavior, risk behaviour modification, infection control, treatment scale-up (first-line treatment regimens), drug-resistance surveillance, containing and countering drug-resistance (second-line treatment regimens), research and development, global advocacy and global partnership. Health agencies should review policies and progress in HIV and tuberculosis epidemic control, learn mutual lessons for policy development and scaling up interventions, and identify ways of joint planning and joint funding of integrated delivery as part of strengthened health systems.

SUMMARY

As both a danger and an opportunity, the global financial crisis may entail disaster or recovery for global health sector efforts for HIV and tuberculosis epidemic control. Review of policies and progress in control paves the way for identification of synergies between the two programmes, within strengthened health services. The silver lining in the global economic crisis could be better control of the HIV and tuberculosis epidemics, better overall health system performance and outcomes, and better value for money.

Can we reduce the spread of HIV infection by suppressing herpes simplex virus type 2 infection?

Overwhelming evidence from observational epidemiological studies indicates that herpes simplex virus type 2 (HSV-2) infection enhances the risk of acquiring HIV infection. Studies of genital shedding of HIV have suggested that HSV-2 infection also increases the onward transmission of HIV-1 by HIV/HSV-2 co-infected patients. Several randomized controlled trials were initiated to assess the impact of HSV-2 suppressive therapy on the acquisition of HIV infection by HSV-2 infected men and women, and on the onward transmission of HIV by HSV-2/HIV co-infected men and women. In the past 2 years the results of these trials have been published. HSV-2 suppressive therapy was not found to have any effect on HIV acquisition nor on onward transmission of HIV. However, suppressive therapy with acyclovir was found to slow down disease progression in HIV/HSV-2 co-infected patients. The effect was rather modest and cost-effectiveness studies are needed to assess whether HSV-2 suppressive therapy has a place in the management of HIV-1 infected patients, especially in low and middle income countries.

Control of sexually transmitted infections and prevention of HIV transmission: mending a fractured paradigm

Control of sexually transmitted infections (STIs) is feasible, leads to improved sexual and reproductive health and contributes to preventing HIV transmission. The most advanced HIV epidemics have developed under conditions of poor STI control, particularly where ulcerative STIs were prevalent. Several countries that have successfully controlled STIs have documented stabilization or reversal of their HIV epidemics. STI control is a public health outcome measured by reduced incidence and prevalence. The means to achieve this include: (i) targeting and outreach to populations at greatest risk; (ii) promoting and providing condoms and other means of prevention; (iii) effective clinical interventions; (iv) an enabling environment; and (v) reliable data. Clinical services include STI case management, screening and management of STIs in sex partners. Syndromic case management is effective for most symptomatic curable STIs and screening strategies exist to detect some asymptomatic infections. Presumptive epidemiologic treatment of sex partners and sex workers complement efforts to interrupt transmission and reduce prevalence. Clinical services alone are insufficient for control since many people with STIs do not attend clinics. Outreach and peer education have been effectively used to reach such populations. STI control requires effective interventions with core populations whose rates of partner change are high enough to sustain transmission. Effective, appropriate targeting is thus necessary and often sufficient to reduce prevalence in the general population. Such efforts are most effective when combined with structural interventions to ensure an enabling environment for prevention. Reliable surveillance and related data are critical for designing and evaluating interventions and for assessing control efforts.