Impact of improved treatment of sexually transmitted diseases on HIV infection in rural Tanzania: randomised controlled trial

Increased gonorrhoea and chlamydia testing did not increase case detection in an HIV clinical cohort 1999-2007

OBJECTIVES

Since 2003, US organisations have recommended universal screening, rather than targeted screening, of HIV-infected persons for gonorrhoea and chlamydia. The objective of this study was to determine whether wider testing resulting from these guidelines would produce an increase in gonorrhoea/chlamydia diagnoses.

METHODS

3283 patients receiving HIV care in 1999-2007 in the Johns Hopkins Hospital HIV clinic were studied. The two primary outcomes were the occurrence of any gonorrhoea/chlamydia testing in each year of care and the occurrence of any positive result(s) in years of testing. The proportion of all patients in care who were diagnosed with gonorrhoea/chlamydia was defined as the number of patients with positive results divided by the number of patients in care. Trends were analysed with repeated measures logistic regression.

RESULTS

The proportion of patients tested for gonorrhoea/chlamydia increased steadily from 0.12 in 1999 to 0.33 in 2007 (OR per year for being tested 1.17, 95% CI 1.15 to 1.19). The proportion positive among those tested decreased significantly after 2003 (OR per year 0.67, 95% CI 0.55 to 0.81). The proportion of all patients in care diagnosed with gonorrhoea/chlamydia therefore remained generally stable in 1999-2007 (OR per year 0.97, 95% CI 0.91 to 1.04).

CONCLUSIONS

Universal annual screening, as implemented, did not increase the proportion of all patients in care who were diagnosed with gonorrhoea/chlamydia. Similarly low implementation rates have been reported in cross-sectional studies. If future efforts to enhance implementation do not yield increases in diagnoses, then guidelines focusing on targeted screening of high-risk groups rather than universal screening may be warranted.

Factors associated with a clinician's offer of screening HIV-positive patients for sexually transmitted infections, including syphilis

This retrospective study assessed whether Quality Improvement Scotland national standards for the sexual health care offered to HIV-positive individuals are being met by the Edinburgh genitourinary (GU) medicine clinic; specifically whether HIV-positive patients are offered: (a) sexually transmitted infection (STI) screening annually and (b) syphilis testing six-monthly. The study also reviewed what factors were associated with a clinician's offer of STI screening and syphilis testing. Of the 509 patients seen within the study period, case notes documented that 64% were offered STI screens, and 69% were offered syphilis testing, results consistent with audits of services elsewhere. Sexual orientation (P < 0.0005), relationship status (P = 0.007) and receipt of antiretrovirals (P = 0.001) were independent predictors of clinician offer of STI screening, while gender (P < 0.0005) and receipt of antiretrovirals (P = 0.063) were independent predictors of offer of syphilis testing. Our results suggest that one explanation for clinicians failing to offer STI screens and syphilis serology testing is their (implicit) risk assessment that STI testing is not required in individual patients.

Intracluster correlation coefficients and coefficients of variation for perinatal outcomes from five cluster-randomised controlled trials in low and middle-income countries: results and methodological implications

Background

Public health interventions are increasingly evaluated using cluster-randomised trials in which groups rather than individuals are allocated randomly to treatment and control arms. Outcomes for individuals within the same cluster are often more correlated than outcomes for individuals in different clusters. This needs to be taken into account in sample size estimations for planned trials, but most estimates of intracluster correlation for perinatal health outcomes come from hospital-based studies and may therefore not reflect outcomes in the community. In this study we report estimates for perinatal health outcomes from community-based trials to help researchers plan future evaluations.

Methods

We estimated the intracluster correlation and the coefficient of variation for a range of outcomes using data from five community-based cluster randomised controlled trials in three low-income countries: India, Bangladesh and Malawi. We also performed a simulation exercise to investigate the impact of cluster size and number of clusters on the reliability of estimates of the coefficient of variation for rare outcomes.

Results

Estimates of intracluster correlation for mortality outcomes were lower than those for process outcomes, with narrower confidence intervals throughout for trials with larger numbers of clusters. Estimates of intracluster correlation for maternal mortality were particularly variable with large confidence intervals. Stratified randomisation had the effect of reducing estimates of intracluster correlation. The simulation exercise showed that estimates of intracluster correlation are much less reliable for rare outcomes such as maternal mortality. The size of the cluster had a greater impact than the number of clusters on the reliability of estimates for rare outcomes.

Conclusions

The breadth of intracluster correlation estimates reported here in terms of outcomes and contexts will help researchers plan future community-based public health interventions around maternal and newborn health. Our study confirms previous work finding that estimates of intracluster correlation are associated with the prevalence of the outcome of interest, the nature of the outcome of interest (mortality or behavioural) and the size and number of clusters. Estimates of intracluster correlation for maternal mortality need to be treated with caution and a range of estimates should be used in planning future trials.

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.

Quantifying sexual exposure to HIV within an HIV-serodiscordant relationship: development of an algorithm

BACKGROUND

The risk of acquiring HIV from a single sexual contact varies enormously reflecting biological and behavioural characteristics of both infected and uninfected partners. Accurate information on HIV transmission risk is required to construct evidence-based risk reduction practices for individuals, to direct the provision of prevention strategies at the population level, and enable the definition, quantification and comparison of true exposure in individuals termed 'exposed uninfected' within clinical trials.

METHODS

Following a systematic review of current literature on HIV transmission estimates, an HIV risk score was developed, incorporating weighted risk factors into a Bernoulli mathematical model, allowing quantification of overall risk of HIV acquisition within HIV-serodiscordant partnerships.

RESULTS

The HIV risk score enumerates the relative risk of HIV acquisition from HIV-positive partners incorporating the type and frequency of specific sex acts, the index case HIV plasma viral load and stage of disease, and the presence of genital ulcer disease in either partner and pregnancy, HSV-2 seropositivity, and circumcision status (men only) in the HIV-negative partner.

CONCLUSION

Key determinants of HIV exposure risk can be incorporated into a mathematical model in order to quantify individual relative risks of HIV acquisition. Such a model can facilitate comparisons within clinical trials of exposed uninfected individuals and facilitate interventions to reduce HIV transmission.

Guarding against an HIV epidemic within an Aboriginal community and cultural framework; lessons from NSW

The rate of HIV diagnosis in the Aboriginal and Torres Strait Islander population in Australia has been stable over the past 5 years. It is similar to the rate in non-Indigenous people overall, but there are major differences in the demographical and behaviour patterns associated with infection, with a history of injecting drug use and heterosexual contact much more prominent in Aboriginal people with HIV infection. Moreover there are a range of factors, such as social disadvantage, a higher incidence of sexually transmitted infections and poor access to health services that place Aboriginal people at special risk of HIV infection. Mainstream and Aboriginal community-controlled health services have an important role in preventing this epidemic. Partnerships developed within NSW have supported a range of services for Aboriginal people. There is a continuing need to support these services in their response to HIV, with a particular focus on Aboriginal Sexual Health Workers, to ensure that the prevention of HIV remains a high priority.

The evolving HIV/AIDS response and the urgent tasks ahead

AIDS continues to outpace the science, financing, prevention, and treatment efforts of the past quarter-century. There have been different epochs along the evolutionary timeline of the global AIDS response, from the discovery of HIV to the threat posed by the current economic crisis. This timeline serves as a reference to how we have arrived where we are today, in the hope that understanding our past will help us set the course for a more efficient and effective future response.

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.

Population-based biomedical sexually transmitted infection control interventions for reducing HIV infection

BACKGROUND

The transmission of sexually transmitted infections (STIs) is closely related to the sexual transmission of human immunodeficiency virus (HIV). Similar risk behaviours, such as frequent unprotected intercourse with different partners, place people at high risk of HIV and STIs, and there is clear evidence that many STIs increase the likelihood of HIV transmission. STI control, especially at the population or community level, may have the potential to contribute substantially to HIV prevention.This is an update of an existing Cochrane review. The review's search methods were updated and its inclusion and exclusion criteria modified so that the focus would be on one well-defined outcome. This review now focuses explicitly on population-based biomedical interventions for STI control, with change in HIV incidence being an outcome necessary for a study's inclusion.

OBJECTIVES

To determine the impact of population-based biomedical STI interventions on the incidence of HIV infection.

SEARCH STRATEGY

We searched PubMed, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science/Social Science, PsycINFO, and Literatura Latino Americana e do Caribe em Ciências da Saúde (LILACS), for the period of 1 January1980 - 16 August 2010. We initially identified 6003 articles and abstracts. After removing 776 duplicates, one author (TH) removed an additional 3268 citations that were clearly irrelevant. Rigorously applying the inclusion criteria, three authors then independently screened the remaining 1959 citations and abstracts. Forty-six articles were chosen for full-text scrutiny by two authors. Ultimately, four studies were included in the review.We also searched the Aegis database of conference abstracts, which includes the Conference on Retroviruses and Opportunistic Infections (CROI), the International AIDS Conference (IAC), and International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention (IAS) meetings from their inception dates (1993, 1985 and 2001, respectively) through 2007. We manually searched the web sites of those conferences for more recent abstracts (up to 2010, 2010 and 2009, respectively)  In addition to searching the clinical trials registry at the US National Institutes of Health, we also used the metaRegister of Controlled Trials.We checked the reference lists of all studies identified by the above methods.

SELECTION CRITERIA

Randomised controlled trials involving one or more biomedical interventions in general populations (as opposed to occupationally or behaviourally defined groups, such as sex workers) in which the unit of randomisation was either a community or a treatment facility and in which the primary outcome was incident HIV infection. The term "community" was interpreted to include a group of villages, an arbitrary geographical division, or the catchment population of a group of health facilities.

DATA COLLECTION AND ANALYSIS

Three authors (BN, LB, TH) independently applied the inclusion criteria to potential studies, with any disagreements resolved by discussion. Trials were examined for completeness of reporting. Data were abstracted independently using a standardised abstraction form.

MAIN RESULTS

We included four trials. One trial evaluated mass treatment of all individuals in a particular community. The other three trials evaluated various combinations of improved syndromic STI management in clinics, STI counselling, and STI treatment.In the mass treatment trial in rural southwestern Uganda, after three rounds of treatment of all community members for STIs, the adjusted rate ratio (aRR) of incident HIV infection was 0.97 (95% CI 0.81 - 1.2), indicating no effect of the intervention. The three STI management intervention studies were all conducted in rural parts of Africa. One study, in northern Tanzania, showed that the incidence of HIV infection in the intervention groups (strengthened syndromic management of STIs in primary care clinics) was 1.2% compared with 1.9% in the control groups (aRR = 0.58, 95% CI 0.42 - 0.79), corresponding to a 42% reduction (95% CI 21.0% - 58.0%) in HIV incidence in the intervention group. Another study, conducted in rural southwestern Uganda, showed that the aRR of behavioural intervention and STI management compared to control on HIV incidence was 1.00 (95% CI 0.63 - 1.58). In the third STI management trial, in eastern Zimbabwe, there was no effect of the intervention on HIV incidence (aRR = 1.3, 95% CI 0.92 - 1.8). These are consistent with data from the mass treatment trial showing no intervention effect. Overall, pooling the data of the four studies showed no significant effect of any intervention (rate ratio [RR] = 0.97, 95% CI 0.78 - 1.2).Combining the mass treatment trial and one of the STI management trials, we find that there is a significant 12.0% reduction in the prevalence of syphilis for those receiving a biomedical STI intervention (RR 0.88, 95% CI 0.80 - 0.96). For gonorrhoea, we find a statistically significant 51.0% reduction in its prevalence in those receiving any of these interventions (RR 0.49, 95% CI 0.31 - 0.77). Finally, for chlamydia, we found no significant difference between any biomedical intervention and control (RR 1.03, 95% CI 0.77 - 1.4).

AUTHORS' CONCLUSIONS

We failed to confirm the hypothesis that STI control is an effective HIV prevention strategy. Improved STI treatment services were shown in one study to reduce HIV incidence in an environment characterised by an emerging HIV epidemic (low and slowly rising prevalence), where STI treatment services were poor and where STIs were highly prevalent; Incidence was not reduced in two other settings. There is no evidence for substantial benefit from a presumptive treatment intervention for all community members. There are, however, other compelling reasons why STI treatment services should be strengthened, and the available evidence suggests that when an intervention is accepted it can substantially improve quality of services provided.

Advances in the prevention of heterosexual transmission of HIV/AIDS among women in the United States

Despite recent advances in testing and treatment, the incidence of HIV/AIDS in the United States has remained stagnant with an estimated 56,300 new infections every year. Women account for an increasing proportion of the epidemic. The vulnerability of women to HIV stems from both increased biologic susceptibility to heterosexual transmission and also the social, economic, and structural disadvantages they often confront. This review describes the main reasons for the increased vulnerability of U.S. women to HIV transmission with particular emphasis on specific highrisk groups including: non-Hispanic blacks, women who use drugs, women with a history of incarceration, and victims of intimate partner violence. Although behavioral approaches to HIV prevention may be effective, pragmatic implementation is often difficult, especially for women who lack sociocultural capital to negotiate condoms with their male partners. Recent advances in HIV prevention show promise in terms of female-initiated interventions. These notably include female condoms, non-specific vaginal microbicides, and antiretroviral oral and vaginal pre-exposure prophylaxis. In this review, we will present evidence in support of these new female-initiated interventions while also emphasizing the importance of advocacy and the political support for these scientific advances to be successful.

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.

How the circumcision solution in Africa will increase HIV infections

The World Health Organization and UNAIDS have supported circumcision as a preventive for HIV infections in regions with high rates of heterosexually transmitted HIV; however, the circumcision solution has several fundamental flaws that undermine its potential for success. This article explores, in detail, the data on which this recommendation is based, the difficulty in translating results from high risk adults in a research setting to the general public, the impact of risk compensation, and how circumcision compares to existing alternatives. Based on our analysis it is concluded that the circumcision solution is a wasteful distraction that takes resources away from more effective, less expensive, less invasive alternatives. By diverting attention away from more effective interventions, circumcision programs will likely increase the number of HIV infections.

Interventions to modify sexual risk behaviours for preventing HIV in homeless youth

BACKGROUND

Homeless youth are at high risk for HIV infection as a consequence of risky sexual behaviour. Interventions for homeless youth are challenging. Assessment of the effectiveness of interventions to modify sexual risk behaviours for preventing HIV in homeless youth is needed.

OBJECTIVES

To evaluate and summarize the effectiveness of interventions for modifying sexual risk behaviours and preventing transmission of HIV among homeless youth.

SEARCH STRATEGY

We searched electronic databases (CENTRAL, MEDLINE, EMBASE, AIDSearch, Gateway, PsycInfo, LILACS), reference lists of eligible articles, international health agency publication lists, and clinical trial registries. The search was updated January 2010. We contacted authors of published reports and other key role players.

SELECTION CRITERIA

Randomised studies of interventions to modify sexual risk behaviour (biological, self-reporting of sexual-risk behaviour or health-seeking behaviour) in homeless youth (12-24 years).

DATA COLLECTION AND ANALYSIS

Data from eligible studies were extracted by two reviewers. We assessed risk of bias per the Cochrane Collaborations tool. None of the eligible studies reported any primary biological outcomes for this review. Reports of self-reporting sexual risk behaviour outcomes varied across studies precluding calculation of summary measures of effect; we present the outcomes descriptively for each study. We contacted authors for missing or ambiguous data.

MAIN RESULTS

We identified three eligible studies after screening a total of 255 unique records. All three were performed in the United States of America and recruited substance-abusing male and female adolescents (total N=615) through homeless shelters into randomised controlled trials of independent and non-overlapping behavioural interventions. The three trials differed in theoretical background, delivery method, dosage (number of sessions,) content and outcome assessments. Overall, the variability in delivery and outcomes precluded estimation of summary of effect measures. We assessed the risk of bias to be high for each of the studies. Whilst some effect of the interventions on outcome measures were reported, heterogeneity and lack of robustness in these studies necessitate caution in interpreting the effectiveness of these interventions. 

AUTHORS' CONCLUSIONS

The body of evidence does not permit conclusions on the impact of interventions to modify sexual risk behaviour in homeless youth; more research is required. While the psychosocial and contextual factors that fuel sexual risk behaviours among homeless youth challenge stringent methodologies of RCT's, novel ways for program delivery and trial retention are in need of development. Future trials should comply with rigorous methodology in design, delivery, outcome measurement and reporting.

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.

Sexually transmissible infections among female sex workers in Manado, Indonesia, using a multiplex polymerase chain reaction-based reverse line blot assay

Background: Sexually transmissible infections (STIs) remain highly prevalent, and HIV is increasing, among female sex workers (FSWs) in Indonesia. Our aim was to determine the prevalence of, and risk factors for, STIs among FSWs in Manado, Indonesia. Methods: We recruited FSWs mainly at their workplace: they completed a questionnaire and provided a urine sample and self-collected vaginal swab. Samples were tested using multiplex polymerase chain reaction, followed by reverse line blot hybridisation. Results: We recruited 221 FSWs, (median age: 25 years). During the previous 3 months, 30% reported never using condoms; only 2.7% always used condoms. Of 217 women with urine samples, 49% had a ‘curable STI’: 10.6% with gonorrhoea, 26.7% with chlamydia, 12.4% with Mycoplasma genitalium and 22.6% with trichomoniasis. Independent risk factors for gonorrhoea were: domiciled outside North Sulawesi (P = 0.001) and age 16–25 years (P = 0.02); for chlamydia: no prior history of STI symptoms (P = 0.003) and age 16–25 years (P = 0.02); for Mycoplasma genitalium: number of clients on last day of sex work (P = 0.004); for trichomoniasis: number of clients per week (P = 0.04). When these four infections were grouped as any ‘curable STI’, independent associations were: number of clients on the last day of sex work (P = 0.001), age 16–25 years (P = 0.02) and sex working for fewer than 2 years (P = 0.03). Conclusions: This is the first report of M. genitalium infection in Indonesia. The high prevalence of STIs and low condom use among these FSWs suggest their vulnerability to the HIV epidemic in Indonesia. They need enhanced interventions, including outreach screening, and periodic presumptive treatment.

Effects of periodic presumptive treatment on three bacterial sexually transmissible infections and HIV among female sex workers in Port Moresby, Papua New Guinea

Background Sexually transmissible infections (STI) are common in female sex workers (FSW). Aim: To determine if 3-monthly periodic presumptive treatments (PPT) would reduce the prevalence of STI in FSW. Methods: In a cohort study conducted between November 2003 and September 2004, FSW were enrolled, counselled and interviewed. Informed consent was obtained. Testing by using polymerase chain reaction (PCR) for Chlamydia trachomatis (Ct), Neisseria gonorrhoeae (Ng) and Trichomonas vaginalis (Tv), and serology for HIV were performed at baseline and final follow-up visits. Each FSW received 3-monthly oral amoxicillin, probenecid, a combination of amoxicillin and clavulanic acid, and azithromycin. Tinidazole was administered once. Results: The cohort consisted of 129 FSW at baseline and 71 at final follow-up visit. Of these 71 FSW, there was a significant decline in the proportion with positive PCR results for Ct from 38% to 16% (P = 0.001), Ng from 56% to 23% (P = <0.001) and Tv from 62% to 30% (P = <0.001) between baseline and the final follow-up visit. HIV prevalence increased from 15% to 21% (P = 0.125). Conclusions: PPT was statistically effective in reducing STI but rates rebounded rapidly. Several new HIV infections occurred. If PPT is to be very effective in FSW where the prevalence of STI is so high, then 100% condom use with clients and regular sexual partners (RSP), and high rates of notification of RSP would be required if low incidence and prevalence of STI were to be achievable.

The prevalence of sexually transmitted infections in Papua New Guinea: a systematic review and meta-analysis

BACKGROUND

The potential for an expanded HIV epidemic in Papua New Guinea (PNG) demands an effective, evidence-based and locally-appropriate national response. As sexually transmitted infections (STIs) may be important co-factors in HIV transmission nationally, it is timely to conduct a systematic review of STI prevalences to inform national policy on sexual health and HIV/STI prevention.

METHODOLOGY/PRINCIPAL FINDINGS

We undertook a systematic review and meta-analysis of HIV and STI prevalences in PNG, reported in peer-reviewed and non-peer-reviewed publications for the period 1950-2010. Prevalence estimates were stratified by study site (community or clinic-based), geographic area and socio-demographic characteristics. The search strategy identified 105 reports, of which 25 studies (10 community-based; 10 clinic-based; and 5 among self-identified female sex workers) reported STI prevalences and were included in the systematic review. High prevalences of chlamydia, gonorrhoea, syphilis and trichomonas were reported in all settings, particularly among female sex workers, where pooled estimates of 26.1%, 33.6%, 33.1% and 39.3% respectively were observed. Pooled HIV prevalence in community-based studies was 1.8% (95% CI:1.2-2.4) in men; 2.6% (95% CI:1.7-3.5) in women; and 11.8% (95% CI:5.8-17.7) among female sex workers.

CONCLUSIONS/SIGNIFICANCE

The epidemiology of STIs and HIV in PNG shows considerable heterogeneity by geographical setting and sexual risk group. Prevalences from community-based studies in PNG were higher than in many other countries in the Asia-Pacific. A renewed focus on national STI/HIV surveillance priorities and systems for routine and periodic data collection will be essential to building effective culturally-relevant behavioural and biomedical STI/HIV prevention programs in PNG.

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 prevention research: taking stock and the way forward

Previous papers in this supplement have reviewed the evidence of the effectiveness of alternative HIV prevention methods from randomized controlled trials and other studies. This paper draws together the main conclusions from these reviews. A conceptual framework is presented that maps the proximal and distal determinants of sexual HIV transmission and helps to identify the stages in the causal pathway at which each intervention approach acts. The advances, gaps and challenges emerging from the reviews of individual intervention methods are summarized and cross-cutting themes identified. Approximately 90% of HIV prevention trials have found no effect on HIV incidence and we explore the alternative explanations for the large number of 'flat' trials. We conclude that there is no single explanation for these flat results, which may be due to interventions that are ineffective or inappropriately targeted or implemented, or to factors related to the design or conduct of trials. We examine the lessons from these flat results and provide recommendations on what should be done differently in future trials. HIV prevention remains of critical importance in an era of expanded delivery of antiretroviral therapy. In future HIV prevention research, it is important that resources are used as efficiently as possible to provide rigorous evidence of the effectiveness of a wider array of complementary prevention tools.

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.

A process evaluation of the scale up of a youth-friendly health services initiative in northern Tanzania

Background

While there are a number of examples of successful small-scale, youth-friendly services interventions aimed at improving reproductive health service provision for young people, these projects are often short term and have low coverage. In order to have a significant, long-term impact, these initiatives must be implemented over a sustained period and on a large scale. We conducted a process evaluation of the 10-fold scale up of an evaluated youth-friendly services intervention in Mwanza Region, Tanzania, in order to identify key facilitating and inhibitory factors from both user and provider perspectives.

Methods

The intervention was scaled up in two training rounds lasting six and 10 months. This process was evaluated through the triangulation of multiple methods: (i) a simulated patient study; (ii) focus group discussions and semi-structured interviews with health workers and trainers; (iii) training observations; and (iv) pre- and post-training questionnaires. These methods were used to compare pre- and post-intervention groups and assess differences between the two training rounds.

Results

Between 2004 and 2007, local government officials trained 429 health workers. The training was well implemented and over time, trainers' confidence and ability to lead sessions improved. The district-led training significantly improved knowledge relating to HIV/AIDS and puberty (RR ranged from 1.06 to 2.0), attitudes towards condoms, confidentiality and young people's right to treatment (RR range: 1.23-1.36). Intervention health units scored higher in the family planning and condom request simulated patient scenarios, but lower in the sexually transmitted infection scenario than the control health units. The scale up faced challenges in the selection and retention of trained health workers and was limited by various contextual factors and structural constraints.

Conclusions

Youth-friendly services interventions can remain well delivered, even after expansion through existing systems. The scaling-up process did affect some aspects of intervention quality, and our research supports others in emphasizing the need to train more staff (both clinical and non-clinical) per facility in order to ensure youth-friendly services delivery. Further research is needed to identify effective strategies to address structural constraints and broader social norms that hampered the scale up.

A qualitative study of participant adherence in a randomized controlled trial of herpes suppressive therapy for HIV prevention in Tanzania

Poor participant adherence to treatment may contribute to lack of impact in some biomedical HIV prevention trials. This qualitative study explored adherence in a randomized controlled trial of herpes suppressive therapy to reduce HIV acquisition and infectivity among 1305 Tanzanian women. The trial found participants completed 72% of visits on treatment; 52-56% of women on treatment had > or = 90% adherence by pill count estimate; and between six and nine months 30/86 (35%) of urine samples from acyclovir recipients tested acyclovir negative, and 7/86 (8%) from placebo recipients tested acyclovir positive. Twenty in-depth interviews (IDIs) were conducted after 30 months with respondents randomly selected from "acyclovir negative" acyclovir recipients and "acyclovir positive" placebo recipients, or by preliminary pill count adherence categories ("under users," "good users," and "over users"). Almost all respondents reported appropriate adherence and positive trial attitudes, e.g., trusting staff, appreciating services, perceiving pills as beneficial. Fourteen understood placebo use, and six understood the trial purpose. Notably, 5/9 acyclovir recipients and 1/11 placebo recipients believed their pills had treated pre-existing sexually transmitted infections. Limited understanding did not negatively affect reported adherence. Reported adherence problems usually related to illness, travel, and/or family obligations (e.g., husband's disapproval). "Acyclovir positive" placebo recipients denied taking other participants' pills. The IDIs also did not resolve discrepant reports of pill loss or theft. Biomedical HIV interventions often have strong behavioral components that require close attention during intervention development, trial design, and process and impact evaluation. This study identified topics which warrant further consideration, including: information reinforcement and comprehension assessment throughout a trial for long-term participant understanding; involving partners in adherence promotion activities; strategizing with participants to maintain adherence during familial illnesses or other crises; and close monitoring, identification, and follow-up of (1) individuals with discrepant biological tests, and (2) other sources of the treatment in the trial area. Methodological research is also needed to improve adherence measures.

Effect of treating co-infections on HIV-1 viral load: a systematic review

Co-infections contribute to HIV-related pathogenesis and often increase viral load in HIV-infected people. We did a systematic review to assess the effect of treating key co-infections on plasma HIV-1-RNA concentrations in low-income countries. We identified 18 eligible studies for review: two on tuberculosis, two on malaria, six on helminths, and eight on sexually transmitted infections, excluding untreatable or non-pathogenic infections. Standardised mean plasma viral load decreased after the treatment of co-infecting pathogens in all 18 studies. The standardised mean HIV viral-load difference ranged from -0.04 log(10) copies per mL (95% CI -0.24 to 0.16) after syphilis treatment to -3.47 log(10) copies per mL (95% CI -3.78 to -3.16) after tuberculosis treatment. Of 14 studies with variance data available, 12 reported significant HIV viral-load differences before and after treatment. Although many of the viral-load reductions were 1.0 log(10) copies per mL or less, even small changes in plasma HIV-RNA concentrations have been shown to slow HIV progression and could translate into population-level benefits in lowering HIV transmission risk.

Effectiveness and safety of tenofovir gel, an antiretroviral microbicide, for the prevention of HIV infection in women

The Centre for the AIDS Program of Research in South Africa (CAPRISA) 004 trial assessed the effectiveness and safety of a 1% vaginal gel formulation of tenofovir, a nucleotide reverse transcriptase inhibitor, for the prevention of HIV acquisition in women. A double-blind, randomized controlled trial was conducted comparing tenofovir gel (n = 445 women) with placebo gel (n = 444 women) in sexually active, HIV-uninfected 18- to 40-year-old women in urban and rural KwaZulu-Natal, South Africa. HIV serostatus, safety, sexual behavior, and gel and condom use were assessed at monthly follow-up visits for 30 months. HIV incidence in the tenofovir gel arm was 5.6 per 100 women-years (person time of study observation) (38 out of 680.6 women-years) compared with 9.1 per 100 women-years (60 out of 660.7 women-years) in the placebo gel arm (incidence rate ratio = 0.61; P = 0.017). In high adherers (gel adherence > 80%), HIV incidence was 54% lower (P = 0.025) in the tenofovir gel arm. In intermediate adherers (gel adherence 50 to 80%) and low adherers (gel adherence < 50%), the HIV incidence reduction was 38 and 28%, respectively. Tenofovir gel reduced HIV acquisition by an estimated 39% overall, and by 54% in women with high gel adherence. No increase in the overall adverse event rates was observed. There were no changes in viral load and no tenofovir resistance in HIV seroconverters. Tenofovir gel could potentially fill an important HIV prevention gap, especially for women unable to successfully negotiate mutual monogamy or condom use.

Contribution of sexually transmitted infections to the sexual transmission of HIV

PURPOSE OF REVIEW

We review recent evidence about the link between sexually transmitted infections (STI) and HIV transmission and consider implications for control programmes.

RECENT FINDINGS

New studies and meta-analyses confirm the association of HIV acquisition and transmission with recent STIs, although there is considerable heterogeneity between organisms and populations. Much of the recent evidence relates to herpes simplex virus type 2 (HSV-2), for which the population-attributable risk percentage (PAR%) for HSV-2 is between 25 and 35 in Africa. Mathematical models show how transmission attributable to STI varies with HIV epidemic phase, and HSV-2 becomes increasingly important as the epidemic matures. HSV-2 suppressive therapy reduces HIV concentrations in plasma and the genital tract in people coinfected with HSV-2, in part due to direct inhibition of HIV reverse transcriptase. Recent trials of HSV-2 suppressive therapy have not shown an impact on the risk of HIV acquisition, nor in controlling transmission from dually infected people to their serodiscordant heterosexual partners.

SUMMARY

Although there is a plausible link between STI and HIV risk, intervention studies continue to be disappointing. This fact does not disprove a causal link, but mechanisms of action and the design and implementation of interventions need to be better understood.

Long-term biological and behavioural impact of an adolescent sexual health intervention in Tanzania: follow-up survey of the community-based MEMA kwa Vijana Trial

BACKGROUND

The ability of specific behaviour-change interventions to reduce HIV infection in young people remains questionable. Since January 1999, an adolescent sexual and reproductive health (SRH) intervention has been implemented in ten randomly chosen intervention communities in rural Tanzania, within a community randomised trial (see below; NCT00248469). The intervention consisted of teacher-led, peer-assisted in-school education, youth-friendly health services, community activities, and youth condom promotion and distribution. Process evaluation in 1999-2002 showed high intervention quality and coverage. A 2001/2 intervention impact evaluation showed no impact on the primary outcomes of HIV seroincidence and herpes simplex virus type 2 (HSV-2) seroprevalence but found substantial improvements in SRH knowledge, reported attitudes, and some reported sexual behaviours. It was postulated that the impact on "upstream" knowledge, attitude, and reported behaviour outcomes seen at the 3-year follow-up would, in the longer term, lead to a reduction in HIV and HSV-2 infection rates and other biological outcomes. A further impact evaluation survey in 2007/8 ( approximately 9 years post-intervention) tested this hypothesis.

METHODS AND FINDINGS

This is a cross-sectional survey (June 2007 through July 2008) of 13,814 young people aged 15-30 y who had attended trial schools during the first phase of the MEMA kwa Vijana intervention trial (1999-2002). Prevalences of the primary outcomes HIV and HSV-2 were 1.8% and 25.9% in males and 4.0% and 41.4% in females, respectively. The intervention did not significantly reduce risk of HIV (males adjusted prevalence ratio [aPR] 0.91, 95%CI 0.50-1.65; females aPR 1.07, 95%CI 0.68-1.67) or HSV-2 (males aPR 0.94, 95%CI 0.77-1.15; females aPR 0.96, 95%CI 0.87-1.06). The intervention was associated with a reduction in the proportion of males reporting more than four sexual partners in their lifetime (aPR 0.87, 95%CI 0.78-0.97) and an increase in reported condom use at last sex with a non-regular partner among females (aPR 1.34, 95%CI 1.07-1.69). There was a clear and consistent beneficial impact on knowledge, but no significant impact on reported attitudes to sexual risk, reported pregnancies, or other reported sexual behaviours. The study population was likely to have been, on average, at lower risk of HIV and other sexually transmitted infections compared to other rural populations, as only youth who had reached year five of primary school were eligible.

CONCLUSIONS

SRH knowledge can be improved and retained long-term, but this intervention had only a limited effect on reported behaviour and no significant effect on HIV/STI prevalence. Youth interventions integrated within intensive, community-wide risk reduction programmes may be more successful and should be evaluated.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00248469

Randomized controlled trials of interventions to prevent sexually transmitted infections: learning from the past to plan for the future

Globally, sexually transmitted infections (STIs) represent a significant source of morbidity and disproportionately impact the health of women and children. The number of randomized controlled trials testing interventions to prevent STIs has dramatically increased over time. To assess their impact, the authors conducted a systematic review of interventions to prevent sexual transmission or acquisition of STIs other than human immunodeficiency virus, published in the English-language, peer-reviewed literature through December 2009. Ninety-three papers reporting data from 74 randomized controlled trials evaluating 75 STI prevention interventions were identified. Eight intervention modalities were used: behavioral interventions (36% of interventions), vaginal microbicides (16%), vaccines (16%), treatment (11%), partner services (9%), physical barriers (5%), male circumcision (5%), and multicomponent (1%). Overall, 59% of interventions demonstrated efficacy in preventing infection with at least 1 STI. Treatment interventions and vaccines for viral STIs showed the most consistently positive effects. Male circumcision protected against viral STIs and possibly trichomoniasis. Almost two-thirds of behavioral interventions were effective, but the magnitude of effects ranged broadly. Partner services yielded similarly mixed results. In contrast, vaginal microbicides and physical barrier methods demonstrated few positive effects. Future STI prevention efforts should focus on enhancing adherence within interventions, integrating new technologies, ensuring sustainable behavior change, and conducting implementation research.

Gonorrhoea and chlamydia testing rates of HIV-infected men: low despite guidelines

OBJECTIVES

Screening HIV-infected men for gonorrhoea (GC) and chlamydia (CT) may decrease HIV transmission and reduce the incidence of pelvic inflammatory disease in female partners. This study determined GC/CT testing rates in a clinical HIV cohort before and after 2003 when the US Centers for Disease Control and Prevention issued guidelines for GC/CT screening.

METHODS

First GC/CT testing episodes were identified for all men enrolling in a Baltimore HIV clinic from 1999 to 2007. Multivariate Cox and logistic regression were used to assess clinical and demographic factors associated with being tested and with having a positive result.

RESULTS

Among 1110 men, the rate of GC/CT testing upon clinic enrollment increased from 4.0% prior to 2003 to 16.5% afterwards, and the rate of ever being tested increased from 34.2% to 49.1% (p<0.001 for both comparisons). Among men with same sex contact, 10% of first testing episodes included extragenital sites. Among the 342 men ever-tested, 5.2% had positive results on first testing. Predictors of testing included enrolling after 2003, younger age, frequent visits and black race. Predictors of a positive test result included CD4 count ≥ 200 cells/mm(3) and younger age.

CONCLUSIONS

GC/CT testing rates among men increased substantially after the 2003 guidelines but remain low. Disseminating existing evidence for GC/CT screening and promoting operational interventions to facilitate it are warranted.

Preventing HIV infection in women: a global health imperative

Women account for approximately one-half of all human immunodeficiency virus (HIV) infections worldwide. Sexual transmission is the dominant mode of HIV transmission to women, and there is a concomitant associated epidemic of transmission to infants. The majority of HIV infections in women are in sub-Saharan Africa, with a disproportionate burden in young women <25 years of age. Acquisition and prevention of HIV infection in women is complex and influenced by biological, behavioral, and structural factors. Efforts to reduce the incidence of HIV infection among women in sub-Saharan African could play a substantial role in altering global trajectories of HIV infection. Increasing access to sexual and reproductive health services, addressing gender-based violence and social instability, reducing poverty and the need to engage in sex for survival, and encouraging greater male responsibility are critical short-to-medium-term interventions. Efforts to find a microbicide and HIV vaccine need to be matched with efforts to deepen understanding of acquisition of HIV in the female genital tract to inform development of targeted molecules for prevention of HIV infection.

Recent syphilis infection prevalence and risk factors among male low-income populations in coastal Peruvian cities

BACKGROUND

The objective of this study was to examine the epidemiology of syphilis among high-risk socially marginalized populations in urban, coastal Peru, to quantify the prevalence of recent syphilis infection and identify risk factors.

METHODS

Survey data and serologic specimens were collected from a population-based sample of 3 populations: men who have sex with only men (MSOM), socially marginalized heterosexual men, and socially marginalized women. Syphilis prevalence was determined for each population, and multivariate analysis was used to analyze risk factors for recent syphilis infection among the MSOM and among the socially marginalized men.

RESULTS

The prevalence of recent syphilis infection was 10.5% among the MSOM, 1.5% among the socially marginalized men, and 2.0% among the women. Among both MSOM and the socially marginalized men, recent syphilis infection was significantly associated with Herpes simplex virus Type 2 infection (prevalence ratio = 1.96; 95% confidence interval, 1.03-3.74, and PR = 3.72; 95% CI, 2.12-6.53, respectively). Recent syphilis infection was also significantly associated with HIV infection among the socially marginalized men (PR = 11.13; 95% CI, 4.50-27.51) and with the number of sexually active years among the MSOM (PR = 1.05, 95% CI, 1.01-1.10).

CONCLUSIONS

All 3 groups included in this study exhibited a high prevalence of recent syphilis infection, with recent infection being most prevalent among the MSOM. These findings demonstrate the need for more effective syphilis control services among those populations, to decrease syphilis-associated morbidity, transmission of syphilis, and the potential transmission of HIV.

Rectal gonorrhea and chlamydia reinfection is associated with increased risk of HIV seroconversion

INTRODUCTION

HIV infection continues to disproportionately affect men who have sex with men (MSM). Identification of modifiable risk factors for HIV infection among MSM is critical for effective prevention.

METHODS

We examined the relationship between number of prior rectal Neisseria gonorrhoeae (GC) or Chlamydia trachomatis (CT) infections and HIV seroconversion in a retrospective cohort of HIV-uninfected MSM diagnosed with a rectal infection. Number of rectal CT or GC infections in the prior 2 years was the primary exposure. Univariate and multivariate Cox proportional hazards models were used to estimate the association between prior rectal infections and HIV seroconversion.

RESULTS

A total of 541 MSM were observed for a total of 1197.96 person-years. Overall, 27 (4.99%) of the MSM became infected with HIV, for an estimated annual incidence of 2.25% [95% confidence interval (CI): 1.49 to 3.26]. In multivariate analysis, an early syphilis diagnosis in the past 2 years (hazard ratio = 4.04, 95% CI: 1.19 to 13.79) and 2 prior CT or GC rectal infections in the past 2 years (hazard ratio = 8.85, 95% CI: 2.57 to 30.40) were associated with incident HIV.

CONCLUSIONS

Among MSM infected with rectal GC or CT, a history of 2 additional prior rectal infections was associated with an 8-fold increased risk of HIV infection. HIV-uninfected MSM with multiple rectal infections represent a population in need of innovative HIV-prevention interventions.

Weighing the gold in the gold standard: challenges in HIV prevention research

OBJECTIVE(S)

Few HIV prevention interventions have been evaluated in randomized controlled trials (RCTs). We examined design, implementation, and contextual considerations that may limit detection of a positive or adverse effect in HIV prevention trials.

DESIGN

A systematic review of late phase RCTs for prevention of sexual transmission of HIV that randomly allocated intervention and comparison groups; evaluated interventions to prevent sexual transmission in nonpregnant populations; and reported HIV incidence as the primary or secondary outcome.

METHODS

PubMed/MEDLINE, other electronic databases, and electronic conference proceedings of recent HIV/AIDS-related conferences were searched to identify published or unpublished trials meeting the inclusion criteria. Descriptive, methodological, and contextual factors were abstracted from each trial.

RESULTS

The review included 37 HIV prevention RCTs reporting on 39 unique interventions. Only six RCTs, all evaluating biomedical interventions, demonstrated definitive effects on HIV incidence. Five of the six RCTs significantly reduced HIV infection: all three male circumcision trials, one trial of sexually transmitted infection treatment and care, and one vaccine trial. One microbicide trial of nonoxynol-9 gel produced adverse results. Lack of statistical power, poor adherence, and diluted versions of the intervention in comparison groups may have been important issues for the other trials that demonstrated 'flat' results.

CONCLUSION

Almost 90% of HIV prevention trials had 'flat' results, which may be attributable to trial design and/or implementation. The HIV prevention community must not only examine evidence from significant RCTs, but must also examine flat trials and address design and implementation issues that limit detection of an effect.

Population-based seroprevalence of HSV-2 and syphilis in Andhra Pradesh state of India

BACKGROUND

Understanding the prevalence and risk factors for common causes of ulcerative genital disease in the general population would inform current STI syndromic management and HIV testing strategies in high HIV prevalence regions of India.

METHODS

Persons 15-49 years old from 32 rural and 34 urban clusters were sampled using a stratified random method to represent adults in the high HIV prevalence Guntur district in Andhra Pradesh state. Interviews were conducted and dry blood spots were collected on 12,617 study participants. Testing for HSV-2 and syphilis was performed.

RESULTS

Adjusted HSV-2 and syphilis seroprevalence rates were 4.70% and 2.08% for men and 7.07% and 1.42% for women. For men, tattooing, >3 lifetime sex partners, tobacco use, and sex with men in the past 6 months were associated with HSV-2 or syphilis (ORs, 1.66-2.95, p < 0.05). Male circumcision was positively associated with HSV-2 infection (OR, 1.37, p = 0.028) though this could be due to residual confounding. In women, greater than one lifetime partner remained significantly associated with HSV-2 in multivariate analysis (OR, 2.61; 95% CI, 1.39-4.87). Among all behavioral risk factors and other covariates in women and men, HIV infection exhibited the strongest association with HSV-2 and syphilis (ORs, 8.2-14.2, p < 0.001). The proportion of individuals with HSV-2 who were HIV infected was less than the proportion with syphilis who were HIV infected (11.8% vs. 22.7%; p = 0.001).

CONCLUSIONS

Nearly one in four persons surveyed in this population-based study that were seroprevalent for syphilis, were also HIV infected. Common population risk factors for syphilis, HSV-2 and HIV and high rates of co-seroprevalence suggest that HIV testing, STI testing and service strategies for these would benefit from direct linkage in India.

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.

The impact of male circumcision on HIV transmission

PURPOSE

Adult male circumcision is currently being implemented as an HIV prevention strategy worldwide. We reviewed the literature on adult male circumcision in the prevention of HIV.

MATERIALS AND METHODS

A MEDLINE search was used to identify current literature addressing HIV and male circumcision. The data from that literature were reviewed and summarized.

RESULTS

Three randomized, controlled trials demonstrate that circumcising adult males reduces the incidence of HIV by 50% to 60%. Adult male circumcision does not seem to have an adverse impact on sexual function. Epidemiological and economic modeling suggests that adult male circumcision can potentially be a highly cost-effective strategy for HIV prevention.

CONCLUSIONS

Safe, high quality, low cost adult male circumcision services should be made available to regions with a high HIV incidence as part of a comprehensive HIV prevention package.

Cluster randomized trials for HIV prevention

PURPOSE OF REVIEW

This paper reviews cluster randomized trials for HIV prevention, focusing on the unique aspects of such trials and describes key cluster randomized trials for HIV prevention from the past decade. Relevant methodological issues are also reviewed.

RECENT FINDINGS

Three cluster randomized trials evaluating sexually transmitted infection control as an HIV prevention tool have given mixed results. Recent modeling studies suggest that the differences are due to differences in the underlying populations rather than design differences. Two trials have shown reduced HIV incidence in intervention target groups without showing a community-wide effect. Areas of active methodological research include ensuring baseline comparability between arms in cluster randomized trials with relatively few clusters, and measuring incidence when the intervention may require time to be fully effective. Innovative approaches to measuring incidence based on so-called 'detuned assays' may be relevant to this problem.

SUMMARY

Cluster randomized trials are qualitatively different from individually randomized trials. As the intervention population may differ from the assessment population, cluster randomized trials of infectious diseases can estimate both direct and indirect intervention effects. Most cluster randomized trial interventions involve behavioral or social components, so the generalizability of results to other settings is often difficult. Modeling studies can aid in the interpretation of results.

Sexually transmitted infections among HIV-1-discordant couples

Introduction

More new HIV-1 infections occur within stable HIV-1-discordant couples than in any other group in Africa, and sexually transmitted infections (STIs) may increase transmission risk among discordant couples, accounting for a large proportion of new HIV-1 infections. Understanding correlates of STIs among discordant couples will aid in optimizing interventions to prevent HIV-1 transmission in these couples.

Methods

HIV-1-discordant couples in which HIV-1-infected partners were HSV-2-seropositive were tested for syphilis, chlamydia, gonorrhea, and trichomoniasis, and HIV-1-uninfected partners were tested for HSV-2. We assessed sociodemographic, behavioral, and biological correlates of a current STI.

Results

Of 416 couples enrolled, 16% were affected by a treatable STI, and among these both partners were infected in 17% of couples. A treatable STI was found in 46 (11%) females and 30 (7%) males. The most prevalent infections were trichomoniasis (5.9%) and syphilis (2.6%). Participants were 5.9-fold more likely to have an STI if their partner had an STI (P<0.01), and STIs were more common among those reporting any unprotected sex (OR = 2.43; P<0.01) and those with low education (OR = 3.00; P<0.01). Among HIV-1-uninfected participants with an HSV-2-seropositive partner, females were significantly more likely to be HSV-2-seropositive than males (78% versus 50%, P<0.01).

Conclusions

Treatable STIs were common among HIV-1-discordant couples and the majority of couples affected by an STI were discordant for the STI, with relatively high HSV-2 discordance. Awareness of STI correlates and treatment of both partners may reduce HIV-1 transmission.

Trial Registration

ClinicalTrials.gov NCT00194519

HIV prevention cost-effectiveness: a systematic review

BACKGROUND

After more than 25 years, public health programs have not been able to sufficiently reduce the number of new HIV infections. Over 7,000 people become infected with HIV every day. Lack of convincing evidence of cost-effectiveness (CE) may be one of the reasons why implementation of effective programs is not occurring at sufficient scale. This paper identifies, summarizes and critiques the CE literature related to HIV-prevention interventions in low- and middle-income countries during 2005-2008.

METHODS

Systematic identification of publications was conducted through several methods: electronic databases, internet search of international organizations and major funding/implementing agencies, and journal browsing. Inclusion criteria included: HIV prevention intervention, year for publication (2005-2008), setting (low- and middle-income countries), and CE estimation (empirical or modeling) using outcomes in terms of cost per HIV infection averted and/or cost per disability-adjusted life year (DALY) or quality-adjusted life year (QALY).

RESULTS

We found 21 distinct studies analyzing the CE of HIV-prevention interventions published in the past four years (2005-2008). Seventeen CE studies analyzed biomedical interventions; only a few dealt with behavioral and environmental/structural interventions. Sixteen studies focused on sub-Saharan Africa, and only a handful on Asia, Latin America and Eastern Europe. Many HIV-prevention interventions are very cost effective in absolute terms (using costs per DALY averted), and also in country-specific relative terms (in cost per DALY measured as percentage of GDP per capita).

CONCLUSION

There are several types of interventions for which CE studies are still not available or insufficient, including surveillance, abstinence, school-based education, universal precautions, prevention for positives and most structural interventions. The sparse CE evidence available is not easily comparable; thus, not very useful for decision making. More than 25 years into the AIDS epidemic and billions of dollars of spending later, there is still much work to be done both on costs and effectiveness to adequately inform HIV prevention planning.

Behavioral mechanisms in HIV epidemiology and prevention: past, present, and future roles

In the 1980s, behavioral variations across geographically and socially defined populations were the central focus of AIDS research, and behavior change was seen as the primary means of controlling HIV epidemics. Today, biological mechanisms--especially other sexually transmitted infections, antiretroviral therapy, and male circumcision--predominate in HIV epidemiology and prevention. We describe several reasons for this shift in emphasis. Although the shift is understandable, we argue for a sustained focus on behavioral mechanisms in HIV research in order to realize the theoretical promise of interventions targeting the biological aspects of HIV risk. We also provide evidence to suggest that large reductions in HIV prevalence may be accomplished by small changes in behavior. Moreover, we contend that behavioral mechanisms will find their proper place in HIV epidemiology and prevention only when investigators adopt a conceptual model that treats prevalence as a determinant as well as an outcome of behavior and that explicitly recognizes the dynamic interdependence between behavior and other epidemiological and demographic parameters.

A systematic review of the quality of trials evaluating biomedical HIV prevention interventions shows that many lack power

PURPOSE

Several randomized, controlled trials (RCTs) have tested strategies to prevent sexual acquisition of HIV infection, but their quality has been variable. We aimed to identify, describe, and evaluate the quality of RCTs studying biomedical interventions to prevent HIV acquisition by sexual transmission.

METHOD

We conducted a systematic review to identify all RCTs evaluating the efficacy of biomedical HIV prevention interventions. We assessed seven generic and content-specific quality components important in HIV prevention trials, factors influencing study power, co-interventions provided, and trial ethics.

RESULTS

We identified 26 eligible RCTs. The median number of quality components judged to be in adequate or unclear was 3 (range 1-4) in 1992-1998, 3 (range 1-4) in 1999-2003, and 0 (range0-2) in 2004-2008 (p < .001). Common problems that may have biased results included low retention (median 84%), poor adherence to interventions requiring on going use (median < or =78%), and lower HIV incidence than expected a priori (in 8 of 11 trials where evaluable).

CONCLUSION

Reporting of trials of biomedical HIV prevention interventions has improved over time. However, quality improvement is needed in several key areas that influence study power, including participant retention, adherence to interventions, and estimation of expected HIV incidence.

Sexual transmission of HIV-1

HIV-1 transmission occurs in a limited number of ways all of which are preventable. Overall, the risk of HIV-1 transmission following a single sexual exposure is low especially in comparison with other sexually transmitted infections (STIs); with estimates of the average probability of male to female HIV-1 transmission only 0.0005-0.0026 per coital act. The risk of acquiring HIV-1 from a single contact varies enormously and is dependant upon the infectiousness of the HIV-1 positive individual and the susceptibility to HIV-1 of their sexual partner. An understanding of the determinants of HIV-1 transmission is important not only to assess the infection risk to an individual when exposed to the virus (e.g. to determine the provision of post exposure prophylaxis), but also to make accurate predictions on the potential spread of HIV-1 infection in a population and to direct appropriate targeted prevention strategies. In this review article we summarise the current literature on the major worldwide source of HIV-1 acquisition, sexual transmission. This article forms part of a special issue of Antiviral Research marking the 25th anniversary of antiretroviral drug discovery and development, Vol 85, issue 1, 2010.

Disentangling contributions of reproductive tract infections to HIV acquisition in African Women

OBJECTIVE

: To estimate the effects of reproductive tract infections (RTIs) on HIV acquisition among Zimbabwean and Ugandan women.

METHODS

: A multicenter prospective observational cohort study enrolled 4439 HIV-uninfected women aged 18 to 35 attending family planning clinics in Zimbabwe and Uganda. Participants were interviewed, and tested for HIV and RTIs every 3 months for 15 to 24 months. They received HIV risk reduction counseling, male condoms, and treatment for curable RTIs.

RESULTS

: Despite HIV risk reduction counseling and regular screening and treatment for RTIs, the HIV incidence did not decline during the study. Positive HSV-2 serostatus at baseline (hazard ratio [HR] = 3.69, 95% confidence interval = 2.45-5.55), incident HSV-2 (HR = 5.35, 3.06-9.36), incident Neisseria gonorrhoeae (HR = 5.46, 3.41-8.75), and altered vaginal flora during the study (bacterial vaginosis [BV]: HR = 2.12, 1.50-3.01; and intermediate flora: HR = 2.02, 1.39-2.95) were independently associated with HIV acquisition after controlling for demographic and behavioral covariates and other RTIs (Treponema pallidum, Chlamydia trachomatis, Trichomonas vaginalis, and vaginal yeasts). For N. gonorrhoeae, C. trachomatis, T. vaginalis, and vaginal yeasts, the risk of HIV acquisition increased when the infection was identified at the visit before the HIV-detection visit or with the duration of infection. Population attributable risk percent (PAR%) calculations show that HSV-2 contributes most to acquisition of new HIV infections (50.4% for baseline HSV-2 and 7.9% for incident HSV-2), followed by altered vaginal flora (17.2% for bacterial vaginosis and 11.8% for intermediate flora).

CONCLUSIONS

: A substantial proportion of new HIV infections in Zimbabwean and Ugandan women are attributable to RTIs, particularly HSV-2 and altered vaginal flora.