Chlamydia transmission: concurrency, reproduction number, and the epidemic trajectory

Wastewater surveillance beyond COVID-19: a ranking system for communicable disease testing in the tri-county Detroit area, Michigan, USA

Introduction

Throughout the coronavirus disease 2019 (COVID-19) pandemic, wastewater surveillance has been utilized to monitor the disease in the United States through routine national, statewide, and regional monitoring projects. A significant canon of evidence was produced showing that wastewater surveillance is a credible and effective tool for disease monitoring. Hence, the application of wastewater surveillance can extend beyond monitoring SARS-CoV-2 to encompass a diverse range of emerging diseases. This article proposed a ranking system for prioritizing reportable communicable diseases (CDs) in the Tri-County Detroit Area (TCDA), Michigan, for future wastewater surveillance applications at the Great Lakes Water Authority's Water Reclamation Plant (GLWA's WRP).

Methods

The comprehensive CD wastewater surveillance ranking system (CDWSRank) was developed based on 6 binary and 6 quantitative parameters. The final ranking scores of CDs were computed by summing the multiplication products of weighting factors for each parameter, and then were sorted based on decreasing priority. Disease incidence data from 2014 to 2021 were collected for the TCDA. Disease incidence trends in the TCDA were endowed with higher weights, prioritizing the TCDA over the state of Michigan.

Results

Disparities in incidences of CDs were identified between the TCDA and state of Michigan, indicating epidemiological differences. Among 96 ranked CDs, some top ranked CDs did not present relatively high incidences but were prioritized, suggesting that such CDs require significant attention by wastewater surveillance practitioners, despite their relatively low incidences in the geographic area of interest. Appropriate wastewater sample concentration methods are summarized for the application of wastewater surveillance as per viral, bacterial, parasitic, and fungal pathogens.

Discussion

The CDWSRank system is one of the first of its kind to provide an empirical approach to prioritize CDs for wastewater surveillance, specifically in geographies served by centralized wastewater collection in the area of interest. The CDWSRank system provides a methodological tool and critical information that can help public health officials and policymakers allocate resources. It can be used to prioritize disease surveillance efforts and ensure that public health interventions are targeted at the most potentially urgent threats. The CDWSRank system can be easily adopted to geographical locations beyond the TCDA.

How accurate is presumptive Chlamydia trachomatis treatment? A 6-month clinical audit of a walk-in sexual health service

Background Chlamydia trachomatis (chlamydia) is highly prevalent and is an important sexually transmitted infection as it can lead to increased risk of HIV seroconversion; and if left untreated, can cause infertility in women. Clinical guidelines recommend treating chlamydia presumptively when presenting symptomatically; however, clinicians are now questioning this due to increasing prevalence of antimicrobial resistance. Methods To determine the accuracy of presumptive chlamydia treatment practices at a walk-in sexual health service in regional Australia, we audited all same-day screen and treat presentations prescribed azithromycin over a 6-month period in 2018. Results A total of 325 cases were included in the analysis. Over half (54%) the presentations returned negative pathology for all pathogens investigated. One quarter (25%) of presentations were positive for chlamydia, and (4%) reported a dual infection. A further one fifth (20%) were negative for chlamydia but positive for another pathogen. More symptomatic males than females returned positive pathology for chlamydia (8% vs 4%). Conclusions While presumptive treatment is recommended in the current guidelines, our findings indicate this resulted in over-treatment. Considering the increasing resistance patterns for Mycoplasma genitalium, which include azithromycin, presumptive treatments need to balance immediate client care needs against long-term community antimicrobial resistance outcomes. This internal audit provided a feedback mechanism to the walk-in sexual service, enabling modification of practices to provide more precise, individual clinical care within the bounds of current STI guidelines, while balancing wider the objectives of antimicrobial stewardship.

Partnership dynamics in mathematical models and implications for representation of sexually transmitted infections: a review

Mathematical models of sexually transmitted disease (STI) are increasingly relied on to inform policy, practice, and resource allocation. Because STI transmission requires sexual contact between two or more people, a model's ability to represent the dynamics of sexual partnerships can influence the validity of findings. This ability is to a large extent constrained by the model type, as different modeling frameworks vary in their capability to capture patterns of sexual contact at individual, partnership, and network levels. In this paper, we classify models into three groups: compartmental, individual-based, and statistical network models. For each framework, we describe the basic model structure and discuss key aspects of sexual partnership dynamics: how and with whom partnerships are formed, partnership duration and dissolution, and temporal overlap in partnerships (concurrency). We illustrate the potential implications of accurately accounting for partnership dynamics, but these effects depend on characteristics of both the population and pathogen; the combined impact of these partnership and epidemiologic dynamics can be difficult to predict. While each of the reviewed model frameworks may be appropriate to inform certain research or policy questions, modelers and consumers of models should carefully consider the implications of sexual partnership dynamics for the questions under study.

Sexual Network Patterns and Their Association With Genital and Anal Human Papillomavirus Infection in Adolescent and Young Men

PURPOSE

This study aimed to determine individual- and partner-level factors associated with human papillomavirus (HPV) infection in vaccinated and unvaccinated men.

METHODS

A total of 747 men, aged 13-26 years, completed a survey of sexual behaviors and were tested for genital and perianal/anal HPV (36 types). Sexual network variables included recent and lifetime concurrency (being in more than one sexual relationship at the same time) and recent sex partner discordance (by race, ethnicity, age, and number of sexual partners). We determined individual-level and sexual network variables associated with ≥1 HPV type and HPV16/18, stratified by vaccination status, using separate multivariable logistic regression models.

RESULTS

Participants' mean age was 21.2 years; 64% were positive for ≥1 HPV type and 21% for HPV16/18. Factors associated with ≥1 HPV type in unvaccinated men included recruitment site and lifetime concurrency. Factors associated with ≥1 HPV type among vaccinated men included recruitment site, Chlamydia history, main male partner, number of lifetime female partners, and no condom use with female partner. Factors associated with HPV16/18 in unvaccinated men included race and partner concurrency. Factors associated with HPV16/18 in vaccinated men included ethnicity, main male partner, and recent concurrency.

CONCLUSIONS

Sexual network variables associated with HPV infection were different based on vaccination status and HPV type, suggesting risk factors for HPV infection may change as the proportion of vaccinated men increases. In addition, participant report of concurrency and not knowing whether one had practiced concurrency were consistent risk factors; clinicians should consider including concurrency in the sexual history to determine the risk of HPV.

Data-driven analysis of the simulations of the spread of COVID-19 under different interventions of China

Since February 2020, COVID-19 has spread rapidly to more than 200 countries in the world. During the pandemic, local governments in China have implemented different interventions to efficiently control the spread of the epidemic. Characterizing transmission of COVID-19 under some typical interventions is essential to help countries develop appropriate interventions. Based on the pre-symptomatic transmission patterns of COVID-19, we established a novel compartmental model: Susceptible-Infectious-Confirmed-Removed (SICR) model, which allowed the effective reproduction number to change over time, thus the effects of policies could be reasonably estimated. Using the epidemic data of Wuhan, Wenzhou, and Shenzhen, we migrated the corresponding estimated policy modes to South Korea, Italy, and the United States and simulated the potential outcomes for these countries when they adopted similar policy strategies to China. We found that the mild interventions implemented in Shenzhen were effective in controlling the epidemic in the early stage, while more stringent policies which were implemented in Wuhan and Wenzhou were necessary if the epidemic became severe and needed to be controlled in a short time.

Sexual Concurrency and Contraceptive Use Among Young Adult Women

Leveraging 2.5 years of weekly data from the Relationship Dynamics and Social Life Study, we investigate the relationship between young women's sexual concurrency and their contraceptive behavior. Specifically, we (1) examine whether young women changed their contraceptive use when switching from one to multiple concurrent sexual partners in the same week; (2) explore the uniformity of contraceptive responses to concurrency across relationship context; and (3) compare the contraceptive behaviors of never-concurrent women with those of ever-concurrent women in weeks when they were not concurrent. Nearly one in five sexually active young women had sex with two or more people in the same week. When they were concurrent, these women's odds of using any contraception increased threefold, and their odds of using condoms increased fourfold. This pattern of contraceptive adjustments was the same across relationship characteristics, such as duration and exclusivity. Yet when they were not concurrent, ever-concurrent women were less likely to use any contraception and used condoms less consistently than women who were never concurrent. We discuss these findings in the context of ongoing debates about the role of sexual concurrency in STI transmission dynamics.

Factors associated with concurrent sexual partnerships among men who have sex with men in Yangon, Myanmar

Men who have sex with men (MSM) are considered to be one of the groups most at risk of contracting HIV. However, to date, information regarding MSM's sexual behaviors and the risk factors for their concurrent sexual partnerships (CSP) have not been known in Myanmar. This study aimed to identify factors associated with CSP among MSM.A cross-sectional study was conducted from September to October 2011 in Yangon, Myanmar. In total, 353 males who had self-reported sex with men were recruited using respondent-driven sampling method. Descriptive statistics and multivariate logistic regression analysis were performed. In total, 61.0% of the MSM reported having CSP. MSM who practiced sex trading in the past six months (adjusted odds ratio8.32; 95% confidence interval [CI]: 2.30-30.10), MSM who had diagnosed with STIs/HIV (AOR 6.71; 95% CI: 4.78-9.28), and MSM who engaged in unprotected insertive anal sex (AOR 1.27; 95% CI: 1.02-1.45) were more likely to have CSP. In contrast, MSM who used condoms consistently during the past six months (AOR = 0.27; 95% CI: 0.08-0.94), MSM who had a regular job (AOR = 0.21; 95% CI: 0.06-0.74), and MSM who initiated sexual activities later in their lives (AOR = 0.08; 95% CI: 0.03-0.25) were less likely to have CSP. Concurrent sexual partnerships are common among MSM in Myanmar. Findings suggest that interventions should focus on MSM who diagnosed with STIs/HIV, do not have regular jobs, and initiated their sexual activities at an early age.

Differential sexual network connectivity offers a parsimonious explanation for population-level variations in the prevalence of bacterial vaginosis: a data-driven, model-supported hypothesis

BACKGROUND

The prevalence of bacterial vaginosis (BV) and vaginal microbiota types varies dramatically between different populations around the world. Understanding what underpins these differences is important, as high-diversity microbiotas associated with BV are implicated in adverse pregnancy outcomes and enhanced susceptibility to and transmission of sexually transmitted infections.

MAIN TEXT

We hypothesize that these variations in the vaginal microbiota can, in part, be explained by variations in the connectivity of sexual networks. We argue: 1) Couple-level data suggest that BV-associated bacteria can be sexually transmitted and hence high sexual network connectivity would be expected to promote the spread of BV-associated bacteria. Epidemiological studies have found positive associations between indicators of network connectivity and the prevalence of BV; 2) The relationship between BV prevalence and STI incidence/prevalence can be parsimoniously explained by differential network connectivity; 3) Studies from other mammals are generally supportive of the association between network connectivity and high-diversity vaginal microbiota.

CONCLUSION

To test this hypothesis, we propose a combination of empirical and simulation-based study designs.

It's the network, stupid: a population's sexual network connectivity determines its STI prevalence

There is little consensus as to why sexually transmitted infections (STIs), including HIV and bacterial vaginosis (BV) are more prevalent in some populations than others. Using a broad definition of sexual network connectivity that includes both structural and conductivity-related factors, we argue that the available evidence suggests that high prevalence of traditional STIs, HIV and BV can be parsimoniously explained by these populations having more connected sexual networks. Positive feedback, whereby BV and various STIs enhance the spread of other STIs, then further accentuates the spread of BV, HIV and other STIs. We review evidence that support this hypothesis and end by suggesting study designs that could further evaluate the hypothesis, as well as implications of this hypothesis for the prevention and management of STIs.

It's the network, stupid: a population's sexual network connectivity determines its STI prevalence

There is little consensus as to why sexually transmitted infections (STIs), including HIV and bacterial vaginosis (BV) are more prevalent in some populations than others. Using a broad definition of sexual network connectivity that includes both structural and conductivity-related factors, we argue that the available evidence suggests that high prevalence of traditional STIs, HIV and BV can be parsimoniously explained by these populations having more connected sexual networks. Positive feedback, whereby BV and various STIs enhance the spread of other STIs, then further accentuates the spread of BV, HIV and other STIs. We review evidence that support this hypothesis and end by suggesting study designs that could further evaluate the hypothesis, as well as implications of this hypothesis for the prevention and management of STIs.

But Everyone is Doing It (Sort of)! Perceived Sexual Risks in the Social Environment and the Impact on Homeless Youth Engagement in Concurrent Sexual Relationships

Although homeless youth are likely to engage in concurrent sexual relationships and doing so can accelerate HIV transmission, the issue of sexual concurrency (i.e., having sexual partnerships that overlap in time) has received scarce attention in this vulnerable population. The literature that exists tends to focus on individuals' characteristics that may be associated with concurrency and overlooks the influence of their social environment. Informed by the risk amplification and abatement model (RAAM), this study explored the association between pro-social and problematic social network connections, and sexual concurrency among homeless youth using drop-in center services (N = 841). Nearly 37% of youth engaged in concurrency. Partially consistent with the RAAM, regression analyses showed that affiliation with more problematic ties (i.e., having more network members who practice concurrency and unprotected sex) was associated with greater sexual concurrency. Programs addressing HIV risk among homeless youth in drop-in centers should consider the role youths' network composition may play in concurrency.

The role of sexual networks in studies of how BV and STIs increase the risk of subsequent reinfection

Prior studies have demonstrated that both bacterial vaginosis (BV) and sexually transmitted infections (STIs) are strong independent risk factors for subsequent STI. In observational studies of this biological enhancement (BE) hypothesis, it is important to adjust for the risk of STI exposure so that the independent effect of BE can be assessed. We sought to model if two markers of local sexual network (partner concurrency and cumulative number of STIs) represented residual confounding in the models of risk for subsequent infection in a study that screened 3620 women for STIs every 3 months for a year. Mixed-effects logistic regression was used to calculate the odds ratios for an incident diagnosis of Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis and BV following a diagnosis of any of these four at the prior visit, controlling for the cumulative number of STIs and partner concurrency variables. We found that partner concurrency and cumulative number of STIs were each associated with incident infection, and in general, controlling for these variables reduced the strength of the association between prior and incident infections. We conclude that the frequently found association between prior and incident STIs is associated with both BE and sexual network structure.

Incident Trichomonas vaginalis Is Associated With Partnership Concurrency: A Longitudinal Cohort Study

BACKGROUND

Sexual partner concurrency (PC) has been shown to be a risk factor for a number of sexually transmitted infections but it is unknown if it is a risk factor for Trichomonas vaginalis (TV).

OBJECTIVE

We assess if there is an association between PC and incident TV infection.

STUDY DESIGN

We used mixed effects logistic regression to assess the association between PC and incident TV in the Longitudinal Study of Vaginal Flora, a cohort study of 3620 women followed quarterly for 5 visits.

RESULTS

Trichomonas vaginalis was more common in those reporting definite/possible/unknown PC (15.6%/15.0%/18.3%) than those reporting no PC (5.2%; P < 0.001 for all 3 comparisons). After controlling for a range of confounders, incident TV remained associated with reporting that one's partner definitely (adjusted odds ratio, 5.4; 95% confidence interval, 3.7-8.0) and possibly (adjusted odds ratio, 3.4; 95% confidence interval, 2.2-5.1) engaged in PC in the preceding period.

CONCLUSIONS

Partner concurrency was associated with incident TV infection.

Recently released Black men's perceptions of the impact of incarceration on sexual partnering

Evidence suggests that men with recent histories of incarceration are more likely to engage in high-risk sexual activity, however there is limited research exploring how having been recently released from prison might impact men's sexual risk behaviours or sexual partnering. This qualitative study explores the ways in which exposure to incarceration impacts the dynamics of sexual partnering among recently released Black men in Baltimore, USA. In-depth interviews were conducted with 19 recently released Black men between 21-45 years of age living in the city. Data were analysed using a combination of inductive and deductive approaches. Participants reported that women living in the neighbourhoods to which they returned found recently released men to be highly desirable sexual partners because they offered increased potential for sexual gratification, were perceived as healthier than other sexual partners in their communities and represented opportunities for attaining financial stability and the potential for establishing romantic partnerships. As a result, men reported they had more opportunities for sex and more power to negotiate sex with women. Recently released Black men's perceptions of their own sexual desirability among women raise important implications regarding power in the sexual relationships of recently released men that may increase HIV- and sexually transmitted infection-related risk for recently released men and their sexual partners.

Epidemic potential by sexual activity distributions

For sexually transmitted infections like HIV to propagate through a population, there must be a path linking susceptible cases to currently infectious cases. The existence of such paths depends in part on the degree distribution. Here, we use simulation methods to examine how two features of the degree distribution affect network connectivity: Mean degree captures a volume dimension, while the skewness of the upper tail captures a shape dimension. We find a clear interaction between shape and volume: When mean degree is low, connectivity is greater for long-tailed distributions, but at higher mean degree, connectivity is greater in short-tailed distributions. The phase transition to a giant component and giant bicomponent emerges as a positive function of volume, but it rises more sharply and ultimately reaches more people in short-tail distributions than in long-tail distributions. These findings suggest that any interventions should be attuned to how practices affect both the volume and shape of the degree distribution, noting potential unanticipated effects. For example, policies that primarily affect high-volume nodes may not be effective if they simply redistribute volume among lower degree actors, which appears to exacerbate underlying network connectivity.

Sexual Behavior and Sexually Transmitted Infections Among Swingers: Results From an Online Survey in Belgium

Swingers are couples practicing consensual extradyadic heterosexual relations. This subculture is defined by venues and online communities. This study aimed to assess swingers' lifestyle, sexual health, and history of testing for sexually transmitted infections (STIs) and to review risk factors for sexual risk behavior and STI transmission. An online survey was distributed through venues, chat websites, and dating websites. Most of 480 swingers starting the survey completed it (n = 392, 81.6%). Women (n = 146) reported more frequent swinging (p = 0.013), same-sex contacts (p < 0.001), and more sex under influence of alcohol (p < 0.001). Men (n = 334) reported more anal sex (p = 0.002) and condomless vaginal sex (p = 0.004). Of respondents tested, 25.7% ever received an STI diagnosis. Using logistical regression, being male, older, single, and party drug use were associated with sexual risk behavior (p = 0.009). Higher frequency of swinging was associated with an STI diagnosis (p = 0.036). Swingers were sexually active, reported factors associated with sexual risk behavior, and were more diagnosed with an STI compared to the general population. Many swingers were tested for STIs. Nonetheless, implementation of tailored testing strategies should be considered given their elevated risk for STI acquisition.

Experiences of structural vulnerability among exotic dancers in Baltimore, Maryland: Co-occurring social and economic antecedents of HIV/STI risk

BACKGROUND

Women who grow up in economic scarcity often face limited opportunities for upward mobility, as a result of challenges securing stable housing, quality education, and steady employment. Chronic instability may limit the capacity of women to protect themselves against HIV/STI-related harm when engaging in sexual activity or drug use. Characterizing the structural contexts that facilitate HIV/STI risk among women are critical to effective design and implementation of drug and sexual harm reduction interventions.

METHODS

Semi-structured in-depth interviews were completed with 25 female exotic dancers working in Baltimore City and County exotic dance clubs July 2014-May 2015. Using thematic analysis, interviews were examined to understand the nature of structural vulnerability experienced by dancers during their early lives through the initial months of exotic dancing, including an examination of the roles of drug use and social relationships in engagement of sexual risk behavior.

RESULTS

Dancers depicted early experiences of social and economic disadvantage, which accumulated through early adulthood. Substance use emerged as an important subject for the majority of women, operating cyclically as both precursor to and product of accumulating social and economic hardship. Dancers revealed social strategies that buffered the effects of structural vulnerability and minimized exposure to workplace-related drug and sexual harms.

CONCLUSION

This study provides insight on an understudied group of at-risk women with a unique demographic profile. Findings illustrate how the effects of structural vulnerability, substance abuse, social strategies, and opportunities for economic gain through sexual services in the workplace converge to produce varying levels of HIV/STI risk among exotic dancers.

Pair formation models for sexually transmitted infections: A primer

For modelling sexually transmitted infections, duration of partnerships can strongly influence the transmission dynamics of the infection. If partnerships are monogamous, pairs of susceptible individuals are protected from becoming infected, while pairs of infected individuals delay onward transmission of the infection as long as they persist. In addition, for curable infections re-infection from an infected partner may occur. Furthermore, interventions based on contact tracing rely on the possibility of identifying and treating partners of infected individuals. To reflect these features in a mathematical model, pair formation models were introduced to mathematical epidemiology in the 1980's. They have since been developed into a widely used tool in modelling sexually transmitted infections and the impact of interventions. Here we give a basic introduction to the concepts of pair formation models for a susceptible-infected-susceptible (SIS) epidemic. We review some results and applications of pair formation models mainly in the context of chlamydia infection.

Bypassing the 'rapid-clearance-in-males-buffer': A fourth mechanism to explain how concurrency enhances STI spread

A number of sexually transmitted infections (STIs) persist for a considerably shorter period in the male urethra than the vagina. If the gap between sequential partnerships is longer than the duration of STI colonization in males, then this would protect future female partners from this STI in a setting of serial monogamy. If, however, males have more than one partner at a time (concurrency), then this would enable the STI to bypass this gap/buffer. We therefore propose bypassing the rapid-clearance-in-males-buffer as a fourth mechanism, whereby concurrency could enhance the spread of STIs.

Anxiety and depression strongly associated with sexual risk behaviors among networks of young men in Dar es Salaam, Tanzania

This study tested the association between mental health scores and sexual risk behaviors among male members of social groups known as "camps" in Dar es Salaam, Tanzania. Anxiety and depression were measured using the HSCL-25 and condom use and sexual partner concurrency were assessed through self-report. A total of 1113 sexually active men with an average age of 27 years were included in the analyses. Higher anxiety and depression scores were significantly associated with both condom use (Anxiety AOR = 0.58, 95% CI: 0.44, 0.77; Depression AOR = 0.60, 95% CI: 0.47, 0.77) and concurrency (Anxiety AOR = 2.32, 95% CI: 1.73, 3.12; Depression AOR = 2.08, 95% CI: 1.60, 2.70). The results of this study provide information salient to the development of effective HIV prevention interventions targeting populations with high burdens of anxiety and depression. The feasibility and effect of integrating mental health promotion activities into HIV prevention interventions should be explored.

Optimizing Partner Notification Programs for Men Who Have Sex with Men: Factorial Survey Results from South China

Background

Syphilis is prevalent among men who have sex with men (MSM) in China. Syphilis partner notification (PN) programs targeting MSM has been considered as one of effective strategies to prevention and control of the infection in the population. We examined willingness and preferences for PN among MSM to measure feasibility and optimize uptake.

Methods

Participation in a syphilis PN program was measured using a factorial survey from both the perspective of the index patient and the partner. Respondents were recruited from April-July 2011 using convenience sampling at two sites—a MSM sexually transmitted disease (STD) clinic and a MSM community based organization (CBO). Respondents first evaluated three factorial survey vignettes to measure probability of participation and then an anonymous sociodemographic questionnaire. A two-level mixed linear model was fitted for the factorial survey analysis.

Results

In 372 respondents with mean age (± SD) 28.5 (± 6.0) years, most were single (82.0%) and closeted gays (66.7%). The Internet was the most frequent place to search for sex. Few (31.2%) had legal names for casual partners, but most had instant messenger (86.5%) and mobile phone numbers (77.7%). The mean probability of participation in a syphilis PN program was 64.5% (± 32.4%) for index patients and 63.7% (± 32.6%) for partners. Referral of the partner to a private clinic or MSM CBO for follow-up decreased participation compared to the local Center for Disease Control and Prevention (CDC) or public STD clinic.

Conclusions

Enhanced PN services may be feasible among MSM in South China. Internet and mobile phone PN may contact partners untraceable by traditional PN. Referral of partners to the local CDC or public STD clinic may maximize PN participation.

Partner concurrency and HIV infection risk in South Africa

BACKGROUND

The relationship between concurrent sexual partnerships and HIV risk is not fully understood. Evidence on the relationship between partner concurrency (one's sexual partner has another partner) and individual HIV risk is limited. In this study, the relationship between reported sexual partner concurrency and the risk of HIV infection was explored among South Africans.

METHODS

Data from the third South African national HIV survey were used. In this survey, performed in 2008, questionnaires and HIV tests were administered to a nationally representative sample of 15031 persons. Bivariate analysis and multiple logistic regression were used to evaluate the relationship between partner concurrency and HIV serostatus. Spearman's correlation was used to test the association between the prevalence of HIV and partner concurrency by race in women.

RESULTS

The relationship between HIV prevalence and partner concurrency varied by race. At a cross-racial level there was a positive association between HIV prevalence and partner concurrency for women (rho=0.95, p=0.05). Among coloured, white, and Indian persons, HIV prevalence and partner concurrency rates were too low to allow further statistical testing. In the bivariate analysis, black African women who reported partner concurrency had a higher prevalence of HIV (36% (95% confidence interval (CI) 29.7-42.0) vs. 23% (95% CI 19.6-26.1), p<0.001). After controlling for demographic, social, biological, and behavioural variables, the association remained statistically significant (adjusted odds ratio (aOR) 1.4, p=0.04). The association was stronger among 15-29-year-old black African women (aOR 1.8, p=0.03) than among women aged 30 years and older (aOR 1.3, p=0.36).

CONCLUSIONS

These results suggest that partner concurrency may increase the HIV infection risk for black South African women, and in particular, for younger women.

Correlation between Trichomonas vaginalis and Concurrency: An Ecological Study

Objective. There is a large variation in the prevalence of Trichomonas vaginalis (TV) between different countries and between racial groups within countries. Sexual partner concurrency may play a role. We investigate the correlation between the prevalence of sexual partner concurrency and TV prevalence. Methods. Spearman's correlation to assess relationship between TV prevalence in women and point prevalence of concurrency in men in (1) 11 countries with comparable data (concurrency data from WHO Survey and TV prevalence data from Global Burden of Disease estimates) and (2) three racial groups in the United States (Add Health Study). Results. The prevalence of TV and concurrency was positively correlated in the international (rho = 0.84, P = 0.001) and USA study (rho = 1.0, P < 0.001). Conclusion. Prospective longitudinal studies that include measures of partner behavior are required to definitively establish the role of concurrency in the spread of TV.

Changes in Sexual Behavior and Attitudes Across Generations and Gender Among a Population-Based Probability Sample From an Urbanizing Province in Thailand

Thailand has undergone rapid modernization with implications for changes in sexual norms. We investigated sexual behavior and attitudes across generations and gender among a probability sample of the general population of Nonthaburi province located near Bangkok in 2012. A tablet-based survey was performed among 2,138 men and women aged 15-59 years identified through a three-stage, stratified, probability proportional to size, clustered sampling. Descriptive statistical analysis was carried out accounting for the effects of multistage sampling. Relationship of age and gender to sexual behavior and attitudes was analyzed by bivariate analysis followed by multivariate logistic regression analysis to adjust for possible confounding. Patterns of sexual behavior and attitudes varied substantially across generations and gender. We found strong evidence for a decline in the age of sexual initiation, a shift in the type of the first sexual partner, and a greater rate of acceptance of adolescent premarital sex among younger generations. The study highlighted profound changes among young women as evidenced by a higher number of lifetime sexual partners as compared to older women. In contrast to the significant gender gap in older generations, sexual profiles of Thai young women have evolved to resemble those of young men with attitudes gradually converging to similar sexual standards. Our data suggest that higher education, being never-married, and an urban lifestyle may have been associated with these changes. Our study found that Thai sexual norms are changing dramatically. It is vital to continue monitoring such changes, considering the potential impact on the HIV/STIs epidemic and unintended pregnancies.

Attitudes Towards Power in Relationships and Sexual Concurrency Within Heterosexual Youth Partnerships in Baltimore, MD

Sexual concurrency may increase risk for HIV/STIs among youth. Attitudes about gender roles, including power balances within sexual partnerships, could be a driver. We examined this association among Baltimore youth (N = 352), aged 15-24. Data were collected from February, 2011 to May, 2013. We examined whether index concurrency in male-reported partnerships (N = 221) and sex partner's concurrency in female-reported partnerships (N = 241) were associated with youth's attitudes towards relationship power. Males with more equitable beliefs about power were less likely to report index concurrency. Females with more equitable beliefs were more likely to report sex partner's concurrency. The relationship was significant in main and casual partnerships among females and main partnerships among males. The strongest associations were detected among middle-socioeconomic status (SES) males and low-SES and African American females. Implementing interventions that recognize the complex relationship between socioeconomic context, partner dynamics, gender, and sexual behavior is an important step towards reducing HIV/STI risk among youth.

Association of perceived partner non-monogamy with prevalent and incident sexual concurrency

OBJECTIVES

Concurrency is suggested as an important factor in sexually transmitted infection transmission and acquisition, though little is known regarding factors that may predict concurrency initiation. We examined the association between perception of a partner's non-monogamy (PPNM) and simultaneous or subsequent concurrency among at-risk heterosexual young adults in the Los Angeles area.

METHODS

We used Poisson regression models to estimate the relationship between PPNM and incident concurrency among 536 participants participating in a cohort study, interviewed at 4-month periods during 1 year. Concurrency was defined as an overlap in reported sexual partnership dates; PPNM was defined as believing a partner was also having sex with someone else.

RESULTS

Participants (51% female; 30% non-Hispanic white, 28% non-Hispanic black, 27% Hispanic/Latino) had a mean age of 23 years and lifetime median of nine sex partners. At each interview (baseline, 4-month, 8-month and 12-month), 4-month concurrency prevalence was, respectively, 38.8%, 27.4%, 23.1% and 24.5%. Four-month concurrency incidence at 4, 8 and 12 months was 8.5%, 10.6% and 17.8%, respectively. Participants with recent PPNM were more likely to initiate concurrency (crude 4-month RR=4.6; 95% CI 3.0, 7.0; adjusted 4-month RR=4.0, 95% CI 2.6 to 6.1).

CONCLUSIONS

Recent PPNM was associated with incident concurrency. Among young adults, onset of concurrency may be stimulated, relatively quickly, by the PPNM. Programmes which promote relationship communication skills and explicit monogamy expectations may help reduce concurrency.

Social place as a location of potential core transmitters-implications for the targeted control of sexually transmitted disease transmission in urban areas

PURPOSE

Places are an important determinant of risk for sexually transmitted infection (STI) acquisition and transmission. We sought to identify social places that are critical for targeted STI control activities. The objective of this study was to determine whether sex partner meeting places characterized by drug markets, sex markets, and separately, drug and/or sex markets were more likely to have potential core transmitters as compared with other sex partner meeting places in one urban setting.

METHODS

In 2008-2009, heterosexual sex partner places or venues were identified in Baltimore, MD using a venue-based study approach.

RESULTS

A total of 1334 participants aged 18 to 35 years were enrolled at 85 venues. In those participants, 39 potential core transmitters were identified and 31% of venues had at least one potential core transmitter. In final age-adjusted and gender-adjusted models, core transmitters were significantly more likely to be identified at drug markets (OR = 1.37; 95% CI = 1.23-1.53), sex markets (OR = 1.27; 95% CI = 1.14-1.41), and drug and/or sex markets (OR = 1.49; 95% CI = 1.32-1.68).

CONCLUSIONS

This study identified key characteristics of venues, such as drug and sex market activity, that may be important in identifying places for the targeted control of STI transmission.

Chlamydia trachomatis infection in young adults - association with concurrent partnerships and short gap length between partners

BACKGROUND

Sexually transmitted infections (STIs) continue to be highly prevalent in young people. New understanding of sexual risk behaviour is essential for future preventive initiatives. Studies based on self-reported STI history indicate that gap length between sexual partnerships is an important determinant in STI transmission, but little is known about the impact of concurrent partnerships and short gap length. This study aimed to examine the significance of concurrent partnerships and short gap length between serially monogamous partnerships in Chlamydia trachomatis-infected individuals compared to the general population.

METHODS

A Danish cross-sectional study was conducted among individuals aged 15-29 years with a verified C. trachomatis infection and a sample of the background population. Participants answered a web-based questionnaire on sexual behaviour. Associations were identified in multivariate analyses.

RESULTS

In total, 36% of the included young adults reported that they had two or more partners within the last year. Concurrent partnerships were frequent (46%), and the gap length between serially monogamous partnerships tended to be short (median gap length, 64 days, interquartile interval (IQI) = 31, 122). A strong association was found between concurrent partnerships (odds ratio (OR) = 12.5, 95% confidence interval (CI) = 7.7-20.4), short gap length between serially monogamous partnerships (OR = 10.0, 95% CI = 5.7-17.4) and having a verified C. trachomatis infection.

CONCLUSIONS

C. trachomatis infection was strongly associated with concurrent partnerships or short gap length between serially monogamous partnerships. These findings have considerable implications for public health policy. Both types of risk factors should be considered in future preventive interventions aiming to reduce the spread of C. trachomatis infections.

Evaluating a Brief, Video-Based Sexual Risk Reduction Intervention and Assessment Reactivity with STI Clinic Patients: Results from a Randomized Controlled Trial

We report results from a randomized controlled trial designed to evaluate the efficacy of a video-based sexual risk reduction intervention and to measure assessment reactivity. Patients (N = 1010; 56 % male; 69 % African American) receiving care at a sexually transmitted infection (STI) clinic were assigned to one of four conditions formed by crossing assessment condition (i.e., sexual health vs. general health) with intervention condition (i.e., sexual risk reduction intervention vs. general health promotion). After completing their assigned baseline assessment, participants received their assigned intervention, and subsequently returned for follow-up assessments at 3, 6, 9, and 12 months. Participants in all conditions reduced their self-reported sexual risk behavior, and the incidence of new STIs declined from baseline through the follow-ups; however, there was no effect of intervention or assessment condition. We conclude that further risk reduction will require more intensive interventions, especially in STI clinics that already provide excellent clinical care.

Partner Incarceration and African-American Women's Sexual Relationships and Risk: A Longitudinal Qualitative Study

Racialized mass incarceration is associated with racial/ethnic disparities in HIV and other sexually transmitted infections (STIs) in the US. The purpose of this longitudinal qualitative study was to learn about the processes through which partner incarceration affects African-American women's sexual risk. Four waves of in-depth qualitative interviews were conducted in 2010-2011 with 30 women in Atlanta, Georgia (US) who had recently incarcerated partners. Approximately half the sample misused substances at baseline. Transcripts were analyzed using grounded theory. For over half the sample (N = 19), partner incarceration resulted in destitution, and half of this group (N = 9) developed new partnerships to secure shelter or food; most misused substances. Other women (N = 9) initiated casual relationships to meet emotional or sexual needs. When considered with past research, these findings suggest that reducing incarceration rates among African-American men may reduce HIV/STIs among African-American women, particularly among substance-misusing women, as might rapidly linking women with recently incarcerated partners to housing and economic support and drug treatment.

A network-level explanation for the differences in HIV prevalence in South Africa's racial groups

Analyses of individual-level risk factors have not been able to adequately explain why HIV has spread so extensively in southern Africa and why this has occurred especially within certain racial or ethnic groups. Using data from a longitudinal study of a representative sample of adolescents aged 14-22 living in Cape Town, South Africa, this article presents evidence of how differences in individual-level risk factors as well as sexual network structures between different racial or ethnic groups may help explain the differential spread of HIV in South Africa. Particular emphasis is placed on how levels of partner concurrency, respondent concurrency, mutual concurrency, serial concurrency and numbers of sexual partners and an average early age of sexual debut combine in different ways in the different racial or ethnic groups to create networks of sexual partnerships that differ in the density of their interconnections and hence potential for HIV spread. These network-level differences offer a potential explanation for the observed generalised HIV epidemic seen among the population of black South Africans.

Why do some South African ethnic groups have very high HIV rates and others not?

The differences in HIV prevalence between South Africa's racial/ethnic groups (19.9%, 3.2%, and 0.5% among 15-49-year-old blacks, coloureds and whites, respectively) are as big as those between the countries with the highest and lowest levels of HIV prevalence worldwide. These large racial/ethnic differences are largely determined by different sexual network structures. In networks among black South Africans, sexual partnerships are more likely to be arranged concurrently - a configuration that leads to exponential increases in the spread of HIV. An examination of the historical origins of polygamy (where it is normative for partnerships to be arranged concurrently) and monogamy (serial or lifetime) reveals that it is the practice of universal monogamy in stratified societies which is the outlier. The ideology and practice of universal monogamy originated in Europe as the result of several factors, most prominently conflicts between the Christian Church and the nobility. After its imposition in Europe, the European colonial project would see this ideology disseminated around the world. Under the influence of liberalism it would mutate into a secular and unacknowledged value-programme of monogamy as a universal norm. This value-programme and practice of monogamy (mostly serial) is still the norm for white South Africans; thus, this sexual behaviour 'spandrel' (by-product of other historical processes) is a large contributor to the lower levels of HIV prevalence among whites. In pre-colonial African societies, polygyny was normative, and the Christian value-programme of monogamy never achieved the hegemonic status it did in Europe and other areas of conquest. Married black African men who converted to Christianity were no less likely to have additional sexual partners, but only more likely to conceal them. The ongoing secrecy about having concurrent partners has contributed to the connectedness of sexual networks among black Africans at large and in this manner has contributed to the rapid spread of HIV.

Individual, partner, and partnership level correlates of anal sex among youth in Baltimore City

Anal sex is an efficient mode of STI transmission and studies indicate that anal sex is common among heterosexuals, including adolescents. We examined the association between individual, partner, and sexual partnership-level characteristics with anal sex among a household survey of 263 individuals aged 15-24 years in Baltimore City, Maryland. We used weighted multiple logistic regression to examine correlates of anal sex in a heterosexual partnership by gender. Twenty-nine percent of males and 15% of females reported anal sex in a partnership in the past 6 months. For males, anal sex was associated with having two or more partners in the past 3 months (AOR = 13.93, 95% CI 3.87-50.12), having been tested for HIV (AOR = 0.30, 95% CI 0.12-0.72), and oral sex with a partner (AOR = 8.79, 95% CI 1.94-39.78). For females, anal sex was associated with reporting having a main partner (AOR = 6.74, 95% CI 1.74-23.65), partner meeting place (AOR = 3.03, 95% CI 1.04-8.82), partner history of STI (AOR = 0.20, 95% CI 0.05-0.85), and oral sex with a partner (AOR = 8.47, 95% CI 1.08-66.25). Anal sex was associated with inconsistent condom use for both males (OR = 5.77, 95% CI 1.68-19.79) and females (OR = 5.16, 95% CI 1.46-18.30). We conclude that anal sex is a prevalent risk behavior among heterosexual youth and is associated with a range of factors at the individual and partnership levels. These findings provide support for comprehensive sex education that includes information about anal sex; findings from this study can inform public health campaigns targeting youth at risk for STIs.

Elevated sexual risk behaviors among postincarcerated young African American males in the South

The dramatic racial disparities in the rates of HIV/STIs(sexually transmitted infections) among African Americans make understanding broader structural factors that increase the risk for HIV/STIs crucial. The current study of young 564 African American men attending STI clinics investigated whether those who had ever been incarcerated reported recent sexual behaviors relatively more risky than their counterparts who had never been incarcerated. Participants were recruited from clinics treating STIs in three southern U.S. cities. Males 15 to 23 years of age who identified as Black/African American and reported recent (past 2 months) sexual activity were eligible. Linear mixed-effects models and generalized estimating equation models were used to assess associations between baseline incarceration history and sexual risk behavior over a 6-month follow-up period. Mean age was 19.6 years (SD = 1.87). At baseline, 240 (42.6%) men reported history of incarceration. Incarceration history predicted several risk behaviors over a 6-month follow-up period. Compared with those with no incarceration history, men previously incarcerated reported a desire to conceive a pregnancy (β = .40, p = .02), were less likely to have used a condom at last sex act (odds ratio = .91, p = .02) and were more likely to have used drugs and alcohol before sex in the past 2 months (β = .69, p < .001; β = .41, p < .001). A history of incarceration may influence the sexual risk behavior of young African American males. Prevention programs and interventions should intensify support for postincarceration African American males to help mitigate this behavior.

A new approach to measuring partnership concurrency and its association with HIV risk in couples

Empirical estimates of the association between concurrent partnerships (CP) and HIV risk are affected by non-sampling errors in survey data on CPs, e.g., because respondents misreport the extent of their CPs. We propose a new approach to measuring CPs in couples, which permits assessing how respondent errors affect estimates of the association between CPs and HIV risk. Each couple member is asked (1) to report whether s/he has engaged in CPs and (2) to assess whether his/her partner has engaged in CPs, since their couple started. Cross-tabulating these data yields multiple classifications (with varying combinations of sensitivity/specificity) of the CPs of each couple member. We then measure the association between CPs and HIV outcomes according to each classification. The resulting range of estimates is an indicator of the uncertainty associated with respondent errors. We tested this approach using data on 520 matched couples drawn from the Likoma Network Study. Results suggest that existing tests of the concurrency hypothesis are affected by significant uncertainty.

Assessment of a new web-based sexual concurrency measurement tool for men who have sex with men

BACKGROUND

Men who have sex with men (MSM) are the most affected risk group in the United States' human immunodeficiency virus (HIV) epidemic. Sexual concurrency, the overlapping of partnerships in time, accelerates HIV transmission in populations and has been documented at high levels among MSM. However, concurrency is challenging to measure empirically and variations in assessment techniques used (primarily the date overlap and direct question approaches) and the outcomes derived from them have led to heterogeneity and questionable validity of estimates among MSM and other populations.

OBJECTIVE

The aim was to evaluate a novel Web-based and interactive partnership-timing module designed for measuring concurrency among MSM, and to compare outcomes measured by the partnership-timing module to those of typical approaches in an online study of MSM.

METHODS

In an online study of MSM aged ≥18 years, we assessed concurrency by using the direct question method and by gathering the dates of first and last sex, with enhanced programming logic, for each reported partner in the previous 6 months. From these methods, we computed multiple concurrency cumulative prevalence outcomes: direct question, day resolution / date overlap, and month resolution / date overlap including both 1-month ties and excluding ties. We additionally computed variants of the UNAIDS point prevalence outcome. The partnership-timing module was also administered. It uses an interactive month resolution calendar to improve recall and follow-up questions to resolve temporal ambiguities, combines elements of the direct question and date overlap approaches. The agreement between the partnership-timing module and other concurrency outcomes was assessed with percent agreement, kappa statistic (κ), and matched odds ratios at the individual, dyad, and triad levels of analysis.

RESULTS

Among 2737 MSM who completed the partnership section of the partnership-timing module, 41.07% (1124/2737) of individuals had concurrent partners in the previous 6 months. The partnership-timing module had the highest degree of agreement with the direct question. Agreement was lower with date overlap outcomes (agreement range 79%-81%, κ range .55-.59) and lowest with the UNAIDS outcome at 5 months before interview (65% agreement, κ=.14, 95% CI .12-.16). All agreements declined after excluding individuals with 1 sex partner (always classified as not engaging in concurrency), although the highest agreement was still observed with the direct question technique (81% agreement, κ=.59, 95% CI .55-.63). Similar patterns in agreement were observed with dyad- and triad-level outcomes.

CONCLUSIONS

The partnership-timing module showed strong concurrency detection ability and agreement with previous measures. These levels of agreement were greater than others have reported among previous measures. The partnership-timing module may be well suited to quantifying concurrency among MSM at multiple levels of analysis.

Health-seeking behaviors among HIV-negative, high-risk black women living in an urban southern city

This study explores the HIV health information-seeking behavior among Black women living in a southern urban city in the United States. Interviews were conducted with 50 Black women to explore their HIV health-seeking behavior, self-efficacy, and locus of control. Results indicate that despite the multiple HIV risk factors faced by the women a majority of them did not seek out HIV health information. Policy implications for HIV prevention education are discussed.

Measuring prevalence and correlates of concurrent sexual partnerships among young sexually active men in Kisumu, Kenya

Our objectives were to: (1) compare multiple measures of partnership concurrency, including the UNAIDS-recommended definition and (2) describe the prevalence and correlates of concurrent sexual partnerships among young Kenyan men. We analyzed 10,907 lifetime partnerships of 1,368 men ages 18-24 years enrolled in a randomized trial of male circumcision to reduce HIV-1 incidence in Kisumu. Partnership concurrency was determined by overlapping dates and examined over varying recall periods and assumptions. The lifetime prevalence of concurrency was 77 %. Sixty-one percent of all partnerships were concurrent and factors associated with concurrency differed by partner type. Point prevalence of concurrency at the time of the interview was consistently the highest and UNAIDS-recommended definition was the most conservative (25 vs. 18 % at baseline, respectively). Estimates of concurrency were influenced by methods for definition and measurement. Regardless of definition, concurrent partnerships are frequent in this population of young, sexually active men in high HIV prevalence Kisumu, Kenya.

Reciprocal sex partner concurrency and STDs among heterosexuals at high-risk of HIV infection

Inconsistent findings on the relationship of sex partner concurrency to infection with HIV and other sexually transmitted diseases (STDs) may result from differences in how sex partner concurrency is conceptualized. We examine the relationship of reciprocal sex partner concurrency (RSPC) to diagnosed STDs among heterosexuals. Heterosexually active adults (N = 717) were recruited for a cross-sectional study using respondent-driven sampling (RDS) from high-HIV-risk areas in New York City (NYC, 2006-2007) and interviewed about their sexual risk behaviors, number of sex partners, last sex partners, and STD diagnoses (prior 12 months). RSPC was when both the participant and her/his last sex partner had sex with other people during their sexual relationship. Odds ratios (OR), adjusted odds ratios (aOR), and 95 % confidence intervals (95%CI) were estimated by logistic regression. The sample was 52.4 % female, 74.3 % Black; median age was 40 years. RSPC was reported by 40.7 % and any STD diagnoses by 23.4 %. Any STDs was reported by 31.5 % of those reporting RSPC vs. 17.9 % of those who did not (OR = 2.11, 95%CI = 1.49-3.0). Any STDs was independently associated with RSPC (aOR = 1.54, 95%CI = 1.02-2.32), female gender (aOR = 2.15, 95%CI = 1.43-3.23), having more than three sex partners (aOR = 1.72, 95%CI = 1.13-2.63), and unprotected anal sex (aOR = 1.65, 95%CI = 1.12-2.42). Heterosexuals in high-HIV-risk neighborhoods in sexual partnerships that involve RSPC are at greater risk of STDs and, potentially, HIV. RSPC, in addition to sexual risk behaviors and the number of sex partners, may facilitate the heterosexual spread of HIV through STD cofactors and linkage into larger STD/HIV sexual transmission networks.

From coitus to concurrency: sexual partnership characteristics and risk behaviors of 15-19 year old men recruited from urban venues in Tanzania

Understanding the uptake and patterns of sexual partnerships of adolescent males reveals their risky behaviors that could persist into adulthood. Using venue-based sampling, we surveyed 671 male youth ages 15-19 from an urban Tanzanian neighborhood about their sexual partnerships during the past 6 months. The proportion of males who had ever had sex increased with age (21 % at age 15; 70 % at age 17; 94 % at age 19), as did the proportion who engaged in concurrency (5 % at age 15; 28 % at age 17; 44 % at age 19). Attendance at ≥2 social venues per day and meeting a sexual partner at a venue was associated with concurrency. Concurrency was associated with alcohol consumption before sex among 18-19 year olds and with not being in school among 15-17 year olds. We find that concurrency becomes normative over male adolescence. Venue-based sampling may reach youth vulnerable to developing risky sexual partnership patterns.

Patterns and predictors of multiple sexual partnerships among newly arrived Latino migrant men

Multiple sexual partnerships (MSP), both concurrent and serial short gap, are thought to increase the risk of HIV and sexually transmitted infection (STI) acquisition and transmission. In this study we evaluate potential individual and environmental risk factors for engaging in MSP in a cohort of newly arrived Latino migrant men (LMM) in New Orleans, LA, USA. Participants were surveyed at three time points over a nine-month period to examine factors associated with MSP. Of the 113 men, 32.5 % reported ever MSP. In 290 observations, 19.5 % of men had concurrent, and 15.0 % had serial short gap partnerships in at least one interviews. Substance was associated with MSP, OR (95 % CI) 2.00 (1.16, 3.45) whereas belonging to a community organization was found to be protective, OR 0.32 (0.17, 0.59). Interventions to reduce substance use and promote social connection are needed to prevent a potential HIV/STI epidemic in this population.

Partner-concurrency associated with herpes simplex virus 2 infection in young South Africans

Whilst much is known about the individual-level risk factors for herpes simplex virus 2 (HSV-2) infection, little is known about why only some populations develop generalized HSV-2 epidemics. This study aims to assess the extent to which partner-concurrency (a factor which operates at both the partnership- and network-level) may be responsible. We utilized multivariate logistic regression to analyse the relationship between HSV-2 seropositivity and potential risk factors in data from a representative cross-sectional survey of 14-24 year olds from a township in South Africa conducted in 1999. The overall prevalence of HSV-2 was 53.3% amongst women and 17% amongst men. For men, four factors remained significantly associated with HSV-2 infection in the multivariate regression analysis: total number of sex acts, being a migrant labourer, Zulu ethnicity and being human immunodeficiency virus (HIV) positive. For women, eight factors were associated with HSV-2 infection: increasing age, partner-concurrency (having a partner who had other partners), an older partner, total number of sex acts, using hormonal contraception, Xhosa ethnicity, syphilis seropositivity and being HIV positive. We conclude that partner-concurrency is associated with increased HSV-2 seropositivity in women.

Serial monogamy and biologic concurrency: measurement of the gaps between sexual partners to inform targeted strategies

Having multiple sexual partners concurrently increases the risk of transmission of a sexually transmitted infection. Even if partnerships do not overlap, transmission potential exists when the gap between partnerships is shorter than the remaining infectious period. In the present article, we quantify the gap between partners to assess transmission potential using data collected by a cross-sectional survey of 2,203 genitourinary medicine clinic patients in England in 2009. Questionnaires asked about patients' 3 most recent partnerships. Gaps were calculated as time (days) between the last sexual encounter with a former partner and the first sexual encounter with the next partner. Among 1,875 patients who reported 1 or more partners in the previous 3 months, 47.6% of men and 27.7% of women reported 2 or more partners. Forty-two percent of the gaps were negative (i.e., partnerships that were concurrent); the median gaps were -7 and -17 days for men and women, respectively (i.e., overlaps were 7 and 17 days for men and women, respectively). Although half of the gaps were positive (serially monogamous partnerships), many were of short duration; the median gaps were 14 and 24 days for men and women, respectively. In over half of the gaps, condoms were used inconsistently with one or both partners, and in one-quarter, condoms were never used with either partner. There is thus a high potential for sexually transmitted infections, as even if partnerships are not behaviorally concurrent, they may be biologically concurrent. These data have important implications for designing and targeting effective health promotion messages.

The spatial and temporal association of neighborhood drug markets and rates of sexually transmitted infections in an urban setting

This study examined temporal and spatial relationships between neighborhood drug markets and gonorrhea among census block groups from 2002 to 2005. This was a spatial, longitudinal ecologic study. Poisson regression was used with adjustment in final models for socioeconomic status, residential stability and vacant housing. Increased drug market arrests were significantly associated with a 11% increase gonorrhea (adjusted relative risk (ARR) 1.11; 95% CI 1.05, 1.16). Increased drug market arrests in adjacent neighborhoods were significantly associated with a 27% increase in gonorrhea (ARR 1.27; 95% CI 1.16, 1.36), independent of focal neighborhood drug markets. Increased drug market arrests in the previous year in focal neighborhoods were not associated with gonorrhea (ARR 1.04; 95% CI 0.98, 1.10), adjusting for focal and adjacent drug markets. While the temporal was not supported, our findings support an associative link between drug markets and gonorrhea. The findings suggest that drug markets and their associated sexual networks may extend beyond local neighborhood boundaries indicating the importance of including spatial lags in regression models investigating these associations.

Symptoms of sexually transmitted infections and care-seeking behaviors of male clients of female sex workers in Bangladesh

BACKGROUND

In Bangladesh, male clients (MCs) of female sex workers (FSWs) represent diverse occupational categories from different socioeconomic strata, and they are considered a bridging group to transmit sexually transmitted infections (STIs) to their spousal and nonspousal female partners. This study aimed to better understand sexual behaviors, STI symptoms, and care-seeking behaviors among MCs of FSWs in Bangladesh.

METHODS

A cross-sectional study was conducted among MCs from November 2005 to July 2006 in 3 types of sex trade settings in Bangladesh. Of 1565 MCs included in this study, 531 were from brothels, 515 from hotels, and 519 from street-based settings.

RESULTS

Among the MCs, 32.2% reported having had STI symptoms within the last 1 year before the interview and 81.5% sought care for those symptoms. Among those who reported symptoms, 44.5% received treatment from pharmacies, 37.4% received treatment from qualified medical professionals, 8.6%, received treatment from nongovernment organization clinics, and 7.8% went to herbal providers. Male clients who had only 1 to 4 years of schooling were 2.4 times more likely to have STI symptoms (adjusted odds ratio [OR], 2.4; 95% confidence interval [CI], 1.5-3.8) compared with the MCs having 10 or more years of schooling. The MCs who had sex with more than 3 nonmarital sexual partners in the last month were 2 times more likely to have STI symptoms (adjusted OR, 2.0; 95% CI, 1.4-2.8). The MCs who used condoms consistently in their non-marital sexual contacts were significantly less likely (adjusted OR, 0.4; 95% CI, 0.3-0.6) to have STI symptoms.

CONCLUSIONS

Reported risk behaviors, STI symptoms and care-seeking behavior suggest that MCs are a potential risk group for transmission of HIV and STIs. The study findings underscore the need to target HIV/STI prevention intervention for MCs, which are predominantly geared toward FSWs.

Racial/ethnic differences in patterns of sexual risk behavior and rates of sexually transmitted infections among female young adults

OBJECTIVES

We examined patterns of sexual behavior and risk for sexually transmitted infections (STIs) in young adulthood for Black, Hispanic, and White females.

METHODS

We used a nationally representative sample of 7015 female young adults from wave III of the National Longitudinal Study of Adolescent Health. Sexual risk items assessed behaviors occurring in the previous 6 years and past year to determine classes of sexual risk and links to STIs in young adulthood.

RESULTS

Latent class analysis revealed 3 sexual risk classes for Black and Hispanic youths and 4 sexual risk classes for White youths. The moderate and high risk classes had the highest probabilities of risky sexual partners, inconsistent condom use, and early age of sexual initiation, which significantly increased odds for STIs compared with recent abstainers.

CONCLUSIONS

We found different classes of sexual behavior by race/ethnicity, with Black and Hispanic young women most at risk for STIs in young adulthood. Preventive efforts should target younger adolescents and focus on sexual partner behavior.