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

Effect of Screening and Treatment for Gonorrhea and Chlamydia on HIV Incidence Among Men Who Have Sex With Men in the United States: A Modeling Analysis

BACKGROUND

Previous models have estimated the total population attributable fraction of Neisseria gonorrhoeae and Chlamydia trachomatis (NG/CT) on HIV incidence among men who have sex with men (MSM), but this does not represent realistic intervention effects. We estimated the potential impact of screening for NG/CT on downstream incidence of HIV among MSM.

METHODS

Using a network model, we estimated the effects of varying coverage levels for sexually transmitted infection screening among different priority populations: all sexually active MSM regardless of HIV serostatus, MSM with multiple recent (past 6 months) sex partners regardless of serostatus, MSM without HIV, and MSM with HIV. Under the assumption that all screening events included a urethral test, we also examined the effect of increasing the proportion of screening events that include rectal screening for NG/CT on HIV incidence.

RESULTS

Increasing annual NG/CT screening among sexually active MSM by 60% averted 4.9% of HIV infections over a 10-year period (interquartile range, 2.8%-6.8%). More HIV infections were averted when screening was focused on MSM with multiple recent sex partners: 60% coverage among MSM with multiple recent sex partners averted 9.8% of HIV infections (interquartile range, 8.1%-11.6%). Increased sexually transmitted infection screening among MSM without HIV averted more new HIV infections compared with the transmissions averted because of screening MSM with HIV, but fewer NG/CT tests were needed among MSM with HIV to avert a single new HIV infection.

CONCLUSIONS

Screening of NG/CT among MSM is expected to lead to modest but clinically relevant reductions in HIV incidence among MSM.

Novel strategies for prevention and treatment of antimicrobial resistance in sexually-transmitted infections

PURPOSE OF REVIEW

Antimicrobial resistance in sexually acquired infection (STI) pathogens is an important global public health threat. There is an urgent need for novel STI treatment and prevention strategies to tackle the rising incidence of STIs in high-income settings and the static progress in low- and middle-income settings over the past decade. The purpose of this review was to describe the research outlining the emergence of resistance in common STI pathogens and new strategies for their treatment and prevention.

RECENT FINDINGS

Rates of STIs have dramatically increased over the past decade. Further, antimicrobial resistance to first-line agents among key STI pathogens continues to emerge globally. Recent findings demonstrate promising results regarding the efficacy of novel antimicrobial treatment strategies for these pathogens, including several new, repurposed and unique combinations of antimicrobials. In addition, a number of new biomedical prevention strategies, such as antibacterial mouthwash and doxycycline chemoprophylaxis, are being investigated as novel prevention strategies for bacterial STIs.

SUMMARY

Significant progress has been made in the development of novel antimicrobials for the treatment of antimicrobial-resistant sexually acquired pathogens. However, due to the rapid development of resistance to antimicrobials demonstrated by these pathogens in the past, further research and development of effective prevention strategies should be prioritized.

Brazilian Protocol for Sexually Transmitted Infections, 2020: infections that cause cervicitis

Infections that cause cervicitis are a topic presented in the "Clinical Protocol and Therapeutic Guidelines for Comprehensive Care for People with Sexually Transmitted Infections", published by the Brazilian Ministry of Health in 2020. The document was developed based on scientific evidence and validated in discussions with experts. This article presents epidemiological and clinical aspects of infections that cause cervicitis and recommendations on screening, diagnosis, and treatment of affected people and their sexual partnerships. Also, it discusses strategies for surveillance, prevention, and control of these infections for health professionals and health service managers involved in the programmatic and operational management of sexually transmitted infections. Expanding access to diagnostic tests and early treatment are crucial for controlling the spread of pathogens that cause cervicitis. Associated factors to cervicitis: sexually active women younger than 25 years old, new or multiple sexual partners, partners with STI, previous history or presence of other STI, and irregular use of condoms.

[Brazilian Protocol for Sexually Transmitted Infections 2020: infections that cause cervicitis]

Infections that cause cervicitis are a topic presented in the "Clinical Protocol and Therapeutic Guidelines for Comprehensive Care for People with Sexually Transmitted Infections", published by the Brazilian Ministry of Health in 2020. The document was developed based on scientific evidence and validated in discussions with experts. This article presents epidemiological and clinical aspects of infections that cause cervicitis, as well as recommendations on screening, diagnosis and treatment of affected people and their sexual partnerships. In addition, it discusses strategies for surveillance, prevention and control of these infections for health professionals and health service managers involved in the programmatic and operational management of sexually transmitted infections. Expanding access to diagnostic tests and early treatment are crucial for controlling the spread of pathogens that cause cevicitis.

Are Sexually Transmitted Infection/HIV Behavioral Interventions for Women of Color Culturally Grounded? A Review of the Literature

Although behavioral interventions for women of color have been shown to be effective in reducing sexually transmitted infections (STIs), STI/HIV rates continue to increase. To alleviate sexual health disparities, it is necessary to understand the cultural behaviors of the target population to design culturally grounded interventions. The purposes of our review were to examine the current state of STI/HIV behavioral interventions for women of color, determine how culture has been incorporated into interventions, and identify gaps in the literature. We reviewed 17 articles targeting women of color between the ages of 13 and 65 years. Findings suggest the need for interventions that are culturally grounded, group based, and delivered face-to-face and in multiple sessions to reduce STI/HIV risk behaviors. Although many of the studies were effective, we found three major gaps: (a) the need to examine intervention sustainability, (b) limitations in the adaption of theoretical frameworks, and (c) clarity in how to infuse culture into interventions.

Sexually transmitted infections and HIV in the era of antiretroviral treatment and prevention: the biologic basis for epidemiologic synergy

INTRODUCTION

HIV is a unique sexually transmitted infection (STI) that is greatly affected by other concomitant "classical" bacterial and viral STIs that cause genital ulcers and/or mucosal inflammation. STIs also serve as a marker for risky sexual behaviours. STIs increase infectiousness of people living with HIV by increasing the viral concentration in the genital tract, and by increasing the potential for HIV acquisition in people at risk for HIV. In addition, some STIs can increase blood HIV concentration and promote progression of disease. This review is designed to investigate the complex relationship between HIV and classical STIs.

DISCUSSION

Treatment of STIs with appropriate antibiotics reduces HIV in blood, semen and female genital secretions. However, community-based trials could not reliably reduce the spread of HIV by mass treatment of STIs. Introduction of antiretroviral agents for the treatment and prevention of HIV has led to renewed interest in the complex relationship between STIs and HIV. Antiretroviral treatment (ART) reduces the infectiousness of HIV and virtually eliminates the transmission of HIV in spite of concomitant or acquired STIs. However, while ART interrupts HIV transmission, it does not stop intermittent shedding of HIV in genital secretions. Such shedding of HIV is increased by STIs, although the viral copies are not likely replication competent or infectious. Pre-exposure prophylaxis (PrEP) of HIV with the combination of tenofovir disoproxil fumarate and emtricitabine (TDF/FTC) prevents HIV acquisition in spite of concomitant STIs.

CONCLUSIONS

STIs remain pandemic, and the availability of ART may have led to an increase in STIs, as fear of HIV has diminished. Classical STIs present a huge worldwide health burden that cannot be separated from HIV, and they deserve far more attention than they currently receive.

Institutional context and VCT practitioner narratives: possibilities and limitations for HIV prevention in Rio de Janeiro, Brazil

BACKGROUND

Voluntary Counseling and Testing (VCT) is an HIV prevention strategy that promotes the principles of confidentiality and informed consent. International research has highlighted VCT counselors' isolation from service planning and the contradictions they negotiate between local values and global testing recommendations. In Brazil, studies have identified many limitations, including counselors' difficulties to implement a vulnerability approach to HIV prevention as recommended in the country's national guidelines. These studies, however, have not considered the particularities of the institutional contexts where counselors work. This research addresses these gaps in the VCT literature by exploring how VCT services are organized and how counselors perceive and perform their practices in the state of Rio de Janeiro, Brazil.

METHODS

This is a case study of VCT services in the state of Rio de Janeiro. The research design included individual structured interviews with seven VCT service coordinators and twenty individual semi-structured interviews with VCT counselors. Participants were sampled according to gender, undergraduate degree and work trajectory to capture a diverse range counselor narratives.

RESULTS

The VCT services were relatively homogenous in terms of functioning and had a similar restricted roll of activities including individual counseling and occasional external prevention activities with groups vulnerable to HIV. All VCT services reported reductions in staff size. Some counselors used dialogical practices to build trust, guarantee confidentiality and adjust their practices in accordance with their clients' values and practices. Others emphasized imperative messages or focused on risk and individual responsibility. Connections between how counselors perceive their practices and the organization of their work environment were observed.

CONCLUSIONS

Due to the importance of counseling as a prevention strategy we recommend rethinking the relationship between counselors' practices and the organization of VCT services. The challenges brought about by the expansion of "test and treat" programs globally and other social and symbolic aspects of the HIV epidemic, such as gender inequalities, must also be taken into account. Further reflection is also needed on the relationship between counseling guidelines and practices within the vulnerability approach to HIV prevention.

Sexually transmitted infections: challenges ahead

WHO estimated that nearly 1 million people become infected every day with any of four curable sexually transmitted infections (STIs): chlamydia, gonorrhoea, syphilis, and trichomoniasis. Despite their high global incidence, STIs remain a neglected area of research. In this Commission, we have prioritised five areas that represent particular challenges in STI treatment and control. Chlamydia remains the most commonly diagnosed bacterial STI in high-income countries despite widespread testing recommendations, sensitive and specific non-invasive testing techniques, and cheap effective therapy. We discuss the challenges for chlamydia control and evidence to support a shift from the current focus on infection-based screening to improved management of diagnosed cases and of chlamydial morbidity, such as pelvic inflammatory disease. The emergence and spread of antimicrobial resistance in Neisseria gonorrhoeae is globally recognised. We review current and potential future control and treatment strategies, with a focus on novel antimicrobials. Bacterial vaginosis is the most common vaginal disorder in women, but current treatments are associated with frequent recurrence. Recurrence after treatment might relate to evidence that suggests sexual transmission is integral to the pathogenesis of bacterial vaginosis, which has substantial implications for the development of effective management approaches. STIs disproportionately affect low-income and middle-income countries. We review strategies for case management, focusing on point-of-care tests that hold considerable potential for improving STI control. Lastly, STIs in men who have sex with men have increased since the late 1990s. We discuss the contribution of new biomedical HIV prevention strategies and risk compensation. Overall, this Commission aims to enhance the understanding of some of the key challenges facing the field of STIs, and outlines new approaches to improve the clinical management of STIs and public health.

Programs of the preventive interventions against sexually transmitted infections in the high-risk subpopulations

A review article highlights the practical issues of design, implementation and effectiveness estimation of STI prevention programs aimed to correct the behavior leading to infection. the importance of epidemiological modeling method for the organization of preventive interventions is discussed. the prospects of the multidisciplinary behavioral approach to STI prevention are demonstrated.

Partner Services in Sexually Transmitted Disease Prevention Programs: A Review

BACKGROUND

Partner services have been a mainstay of public health sexually transmitted disease (STD) prevention programs for decades. The principal goals are to interrupt transmission and reduce STD morbidity and sequelae. In this article, we review current literature with the goal of informing STD prevention programs.

METHODS

We searched the literature for systematic reviews. We found 9 reviews published between 2005 and 2014 (covering 108 studies). The reviews varied by study inclusion criteria (e.g., study methods, geographic location, and infections). We abstracted major conclusions and recommendations from the reviews.

RESULTS

Conclusions and recommendations were divided into patient referral interventions and provider referral interventions. For patient referral, there was evidence supporting the use of expedited partner therapy and interactive counseling, but not purely didactic instruction. Provider referral through Disease Intervention Specialists was efficacious and particularly well supported for HIV. For other studies, modeling data and testing outcomes showed that partner notification in general reached high-prevalence populations. Reviews also suggested more focus on using technology and population-level implementation strategies. However, partner services may not be the most efficient means to reach infected persons.

CONCLUSIONS

Partner services programs constitute a large proportion of program STD prevention activities. Value is maximized by balancing a portfolio of patient and provider referral interventions and by blending partner notification interventions with other STD prevention interventions in overall partner services program structure. Sexually transmitted disease prevention needs program-level research and development to generate this portfolio.

Bottlenecks in HIV-1 transmission: insights from the study of founder viruses

HIV-1 infection typically results from the transmission of a single viral variant, the transmitted/founder (T/F) virus. Studies of these HIV-1 variants provide critical information about the transmission bottlenecks and the selective pressures acting on the virus in the transmission fluid and in the recipient tissues. These studies reveal that T/F virus phenotypes are shaped by stochastic and selective forces that restrict transmission and may be targets for prevention strategies. In this Review, we highlight how studies of T/F viruses contribute to a better understanding of the biology of HIV-1 transmission and discuss how these findings affect HIV-1 prevention strategies.

Public health interventions to control syphilis

Syphilis control strategies are old, but interventions have changed and there is now a more scientific approach to evidence of effectiveness. We searched PubMed using 'syphilis control' to identify papers that measured the effectiveness of interventions. We also included novel approaches and comprehensive responses to outbreaks. Few papers used high-quality research methodology and fewer evaluated impact on prevalence or incidence; most assessed intermediate outcomes. Syphilis can often be controlled by a combination of case finding, treatment and education. However, outbreaks are unique and ongoing evaluation is needed to see if interventions are producing intended intermediate outcomes at reasonable costs.

Young age at first intercourse and subsequent risk-taking behaviour: An epidemiological study of more than 20,000 Danish men from the general population

Aim: First intercourse at the age of 14 years or younger is usually considered high-risk behaviour for sexually transmitted infections (STIs). It has been linked to other types of risky behaviour in women, while conflicting results have been obtained for men. The aim of the study was to estimate the prevalence of first intercourse at a young age in various birth cohorts of men and to determine any association with later risky behaviour. Methods: We studied 22,979 randomly selected men aged 18–45 years from the Danish general male population who responded to a self-administered questionnaire. Multiple sexual partners over a lifetime, multiple new sexual partners within the past 6 months, intercourse with a commercial sex worker, having an STI, binge drinking and current smoking were considered risky behaviour. Results: First intercourse at the age of 14 years or younger was more prevalent in younger (14%) than in older (10%) birth cohorts and among men with shorter schooling. Young age at sexual debut was associated with a more than twofold increase in the risks for subsequent risky behaviour. Conclusions: More than 10% of Danish men first had sex at an early age, and this was closely related to subsequent risk-taking behaviour.

Toward global prevention of sexually transmitted infections (STIs): the need for STI vaccines

An estimated 499 million curable sexually transmitted infections (STIs; gonorrhea, chlamydia, syphilis, and trichomoniasis) occurred globally in 2008. In addition, well over 500 million people are estimated to have a viral STI such as herpes simplex virus type 2 (HSV-2) or human papillomavirus (HPV) at any point in time. STIs result in a large global burden of sexual, reproductive, and maternal-child health consequences, including genital symptoms, pregnancy complications, cancer, infertility, and enhanced HIV transmission, as well as important psychosocial consequences and financial costs. STI control strategies based primarily on behavioral primary prevention and STI case management have had clear successes, but gains have not been universal. Current STI control is hampered or threatened by several behavioral, biological, and implementation challenges, including a large proportion of asymptomatic infections, lack of feasible diagnostic tests globally, antimicrobial resistance, repeat infections, and barriers to intervention access, availability, and scale-up. Vaccines against HPV and hepatitis B virus offer a new paradigm for STI control. Challenges to existing STI prevention efforts provide important reasons for working toward additional STI vaccines. We summarize the global epidemiology of STIs and STI-associated complications, examine challenges to existing STI prevention efforts, and discuss the need for new STI vaccines for future prevention efforts.

The evolving sexual health paradigm: transforming definitions into sexual health practices

Sexual health is an evolving paradigm that integrates a positive approach to sexuality with existing public health policy and practice for reducing the burdens of sexually transmitted infections, including those due to HIV. The sexual health paradigm rests in commitment to sexual rights, sexual knowledge, sexual choice, and sexual pleasure, as well as key elements of sexuality addressed by sexual desire, sexual arousal, and sexual function, and sexual behaviors. The sexual health paradigm offers new approaches to supporting general health and well being while reducing the burdens of sexual diseases and their consequences.

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.

Prevention of sexually transmitted infections in urban communities (Peru PREVEN): a multicomponent community-randomised controlled trial

BACKGROUND

Previous community-randomised trials of interventions to control sexually transmitted infections (STIs) have involved rural settings, were rarely multicomponent, and had varying results. We aimed to assess the effect of a multicomponent intervention on curable STIs in urban young adults and female sex workers (FSWs).

METHODS

In this community-randomised trial, baseline STI screening was done between August, and November, 2002, in random household samples of young adults (aged 18-29 years) and in FSWs in Peruvian cities with more than 50,000 inhabitants. Geographically separate cities were selected, matched into pairs, and randomly allocated to intervention or control groups with an S-PLUS program. Follow-up surveys of random samples were done after 2 years and 3 years. The intervention comprised four modalities: strengthened STI syndromic management by pharmacy workers and clinicians; mobile-team outreach to FSWs for STI screening and pathogen-specific treatment; periodic presumptive treatment of FSWs for trichomoniasis; and condom promotion for FSWs and the general population. Individuals in control cities received standard care. The composite primary endpoint was infection of young adults with Chlamydia trachomatis, Trichomonas vaginalis, or Neisseria gonorrhoeae, or syphilis seroreactivity. Laboratory workers and the data analyst were masked, but fieldworkers, the Peruvian study team, and participants in the outcome surveys were not. All analyses were done by intention to treat. This trial is registered, ISRCTN43722548.

FINDINGS

We did baseline surveys of 15,261 young adults in 24 Peruvian cities. Of those, 20 geographically separate cities were matched into pairs, in each of which one city was assigned to intervention and the other to standard of care. In the 2006 follow-up survey, data for the composite primary outcome were available for 12,930 young adults. We report a non-significant reduction in prevalence of STIs in young adults, adjusted for baseline prevalence, in intervention cities compared with control cities (relative risk 0·84, 95% CI 0·69-1·02; p=0·096). In subgroup analyses, significant reductions were noted in intervention cities in young adult women and FSWs.

INTERPRETATION

Syndromic management of STIs, mobile-team outreach to FSWs, presumptive treatment for trichomoniasis in FSWs, and condom promotion might reduce the composite prevalence of any of the four curable STIs investigated in this trial.

FUNDING

Wellcome Trust and Burroughs Wellcome Fund, National Institutes of Health, Center for AIDS Research, CIPRA, and USAID-Peru.

Sexually Transmitted Infection (STI) screening, case and contact treatment, and condom promotion resulting in STI reduction two years later in rural Malawi

As part of a longitudinal cohort study in rural Malawi in 2000, 469 men and 758 women were asked to respond to a series of surveys, were tested for gonorrhea and chlamydia, and received their results and treatment, if applicable, for themselves and up to 2 partners if positive for either sexually transmitted infection (STI). Two years later, in 2002, 328 men and 525 women were again asked to respond to survey questions, tested again for gonorrhea and chlamydia, and were also tested for HIV--of these, 247 men and 453 women had also given urine samples in 2000. In 2000, the gonorrhea and chlamydia prevalence was 6.2% and 5.8% among men, and 3.6% and 4.9% among women. Two years later, prevalence of gonorrhea and chlamydia was 0.7% and 1.4% among men, and 1.3% and 1.1% among women. Although we did not test for HIV in the first round, the HIV prevalence in 2002 was 19.2%. The implications of the findings are discussed in the context of interventions for STI prevention and to reduce HIV transmission in sub-Saharan Africa.

Effect of treatment assignment on intravaginal cleansing in a randomized study of the diaphragm with candidate microbicide

BACKGROUND

Intravaginal cleansing may predispose women to adverse health outcomes and may interfere with the effectiveness and safety of female-initiated methods for preventing sexually transmitted infections (STIs). In a 4-week randomized study of 192 Malagasy sex workers, we evaluated associations between self-reported intravaginal cleansing and randomization assignment: diaphragm with viscous candidate microbicide gel (Acidform™, TOPCAD, Chicago, IL, licensed to Instead, Coppell, TX), diaphragm with placebo hydroxyethylcellulose gel (HEC, ReProtect LLC, Baltimore, MD), Acidform alone, or HEC alone.

METHODS

Women were counseled to avoid intravaginal cleansing and were blinded to gel assignment. We evaluated changes in self-reported intravaginal cleansing across the study and assessed the effects of treatment assignment and covariates on frequent (more than once daily) intravaginal cleansing. Significant predictors in domain-specific models were evaluated in an all-domain multiple regression model.

RESULTS

The proportion of women reporting intravaginal cleansing decreased from baseline (97%) to week 1 (82%) (p < 0.001). Self-reported frequent intravaginal cleansing decreased from baseline (87% to 56%) during the same time period (p < 0.001). In adjusted analyses, the Acidform-diaphragm group had 60% lower odds of frequent intravaginal cleansing during the study (odds ratio [OR] 0.4, 95% confidence interval [CI] 0.2-0.8) compared to the control group (HEC only). HEC-diaphragm and Acidform only users did not differ from controls. Living on the coast of Madagascar, not cohabiting, frequent intravaginal cleansing at enrollment, and high coital frequency predicted frequent intravaginal cleansing during follow-up.

CONCLUSIONS

Gel characteristics and the diaphragm's presence likely influenced women's cleansing. Viscous gel delivered by a cervical barrier (such as a diaphragm) may minimize the likelihood of frequent intravaginal cleansing.

Pre-exposure prophylaxis state of the science: empirical analogies for research and implementation

Pre-exposure prophylaxis (PrEP) has the potential to become a powerful biomedical approach to HIV prevention; however, its success depends on behavioral and social factors that may determine its appropriate use. This article is designed to facilitate interdisciplinary empirical analogies relevant to PrEP implementation, reviewing behavioral and social science findings that may provide lessons critical to the success of PrEP as a biomedical-behavioral prevention strategy. As we prepare for the dissemination of new biomedical approaches to HIV prevention, integrating the state of the science across disciplines may result in innovative strategies for implementation that can enhance their success.

Epidemiologic approaches to global health

In this introduction to volume 32 of Epidemiologic Reviews, the authors highlight the diversity and complexity of global health concerns, and they frame the 12 articles included in this issue within the diverse topics of research in this emerging and ever-expanding field. The authors emphasize the need for ongoing research related to the methods used in global health and for comprehensive surveillance, and they offer suggestions for future directions in global health research.