Adaora A. Adimora

Bacterial vaginosis and HIV acquisition: A meta-analysis of published studies

Objectives:To assess and summarize the published literature on the extent to which bacterial vaginosis may increase the risk of HIV acquisition. Design:Meta-analysis of published studies. Methods:Medline and other electronic databases were systematically searched for eligible publications. The association between bacterial vaginosis and incident HIV was separately analyzed from that between bacterial vaginosis and prevalent HIV. The latter was further analyzed, stratified by bacterial vaginosis diagnostic method, HIV risk profile of the study population, and whether or not adjusted estimates were presented. Results:Twenty-three eligible publications were identified, including a total of 30 739 women. Bacterial vaginosis was associated with an increased risk of HIV acquisition in HIV-incidence studies (relative risk = 1.6, 95% confidence interval: 1.2, 2.1). All but one of 21 HIV-prevalence studies reported estimates above the null. The latter results were heterogeneous and showed some evidence of funnel plot asymmetry, precluding the estimation of a single summary measure. The association between bacterial vaginosis and HIV in prevalence studies appeared stronger for women without high-risk sexual behavior. Conclusion:Bacterial vaginosis was consistently associated with an increased risk of HIV infection. High bacterial vaginosis prevalence may result in a high number of HIV infections being attributable to bacterial vaginosis. More prospective studies are needed to accurately evaluate the role of bacterial vaginosis in HIV acquisition in low-risk versus high-risk women. Furthermore, randomized clinical trials may be worth considering to determine the effect of bacterial vaginosis control measures on HIV acquisition.

Concurrent Sexual Partnerships Among Men in the United States

OBJECTIVES We sought to determine the prevalence, distribution, and correlates of US mens involvement in concurrent sexual partnerships, a sexual network pattern that speeds population dissemination of HIV. METHODS For this analysis, we compared sexual partnership dates of 4928 male respondents in the 2002 National Survey of Family Growth to determine the prevalence of concurrent sexual partnerships and evaluated associations between concurrency and demographic risk characteristics. RESULTS Approximately 11% of men had concurrent sexual partnerships during the preceding year. Concurrency was associated with being unmarried (odds ratio [OR] = 4.59; 95% confidence interval [CI] = 2.54, 8.29), non-Hispanic Black (OR=2.56; 95% CI=1.61, 4.07) or Hispanic (OR=2.25; 95% CI=1.32, 3.85) race/ethnicity, and incarceration during the past year (OR=2.10; 95% CI=1.18, 3.74). Men with concurrent sexual partnerships were also more likely to report drug or alcohol intoxication during sexual intercourse (OR=2.10; 95% CI=1.37, 3.21), nonmonogamous female sexual partners (OR=6.11; 95% CI=4.10, 9.11), and history of sexual intercourse with a man (OR = 1.93; 95% CI = 1.09, 3.42), than those without concurrent partnerships. CONCLUSIONS The higher concurrency prevalence in various groups, dense sexual networks, and mixing between high-risk subpopulations and the general population may be important factors in the US epidemic of heterosexual HIV infection.

Hiv and African Americans in the Southern United States: Sexual Networks and Social Context

Background: Heterosexual HIV transmission among African Americans in the rural southern United States has climbed in recent years. Concurrent partnerships and bridge populations have emerged as key elements in the spread of sexually transmitted infections (STIs). Goal: The goal of this study was to examine published empiric data and other literature concerning the extent of these network patterns and their relationship to the socioeconomic context among African Americans in the rural South. Study Design: The authors conducted a review of public health, medical, and social sciences literature. Results: In areas of the rural South with high STI rates, there is extensive concurrency with evidence of dense sexual networks and bridging among the general population, core group members, and other high-risk subpopulations. Qualitative research reveals socioeconomic factors that support these network patterns: low ratio of men to women, economic oppression, racial discrimination, and high incarceration rates of black men. Conclusion: Concurrency and bridging likely contribute to increased heterosexual HIV transmission among blacks in the South; contextual factors promote these network patterns in this population.

Heterosexually Transmitted Hiv Infection Among African Americans in North Carolina

Context: Rates of heterosexually transmitted HIV infection among African Americans in the southeastern United States greatly exceed those for whites. Objective: Determine risk factors for heterosexually transmitted HIV infection among African Americans. Methods: Population-based case-control study of black men and women, aged 18-61 years, reported to the North Carolina state health department with a recent diagnosis of heterosexually transmitted HIV infection and age- and gender-matched controls randomly selected from the state driver s license file. A lower-risk stratum of respondents was created to identify transmission risks among people who denied high-risk behaviors. Results: Most case subjects reported annual household income <

Contextual factors and the black-white disparity in heterosexual HIV transmission.

16,000, history of sexually transmitted diseases, and high-risk behaviors, including crack cocaine use and sex partners who injected drugs or used crack cocaine. However, 27% of case subjects (and 69% of control subjects) denied high-risk sexual partners or behavior. Risk factors for HIV infection in this subset of participants were less than high school education (adjusted odds ratio [OR] 5.0; 95% CI: 2.2, 11.1), recent concern about having enough food for themselves or their family (OR 3.7; 1.5, 8.9), and having a sexual partner who was not monogamous during the relationship with the respondent (OR 2.9; 1.3, 6.4). Conclusion: Although most heterosexually transmitted HIV infection among African Americans in the South is associated with established high-risk characteristics, poverty may be an underlying determinant of these behaviors and a contributor to infection risk even in people who do not have high-risk behaviors.

Understanding and responding to disparities in HIV and other sexually transmitted infections in African Americans

ABSTRACT African-Americans have the highest rates of human immunodeficiency virus (HIV) transmission, including heterosexual transmission, in the United States. Although numerous factors probably contribute to the extreme racial disparity, reasons for its persistence remain poorly explained. Mathematical modeling demonstrates that concurrent sexual partnerships speed transmission of HIV through sexual networks more effectively than does serial monogamy, for the same total number of sexual partners. This paper examines the evidence that the social and economic environment for many African-Americans discourages long-term monogamy and promotes concurrent sexual partnerships, which may, in turn, fuel the HIV epidemic in this population.

Social context of sexual relationships among rural African Americans.

Although these health disparities are not unique to STIs; their nature, pattern, and distribution are complex. This complexity is not solely a result of individual risk behaviours. Increasing evidence indicates that disease epidemics, and, consequently, disparities in morbidity rates, are outcomes of the functioning of systems.

The relationship between condom use and herpes simplex virus acquisition

Background Reasons for the strikingly increased rates of HIV and other sexually transmitted infections (STIs) among African Americans in the rural Southeastern United States remain unclear. Investigators have devoted little attention to the potential influence of the social and economic context on sexual behaviors. Goal To examine the potential influence of these contextual factors on behaviors that promote the transmission of STIs. Study Design Focus group interviews in which African Americans from rural North Carolina discussed life in their communities and contextual factors affecting sexual behavior. Results Respondents reported pervasive economic and racial oppression, lack of community recreation, boredom, and resultant substance abuse. Many perceived a shortage of black men because of their higher mortality and incarceration rates compared with whites, and believed this male shortage to be partly responsible for the concurrent sexual partnerships that they perceived as widespread among unmarried persons. Conclusion Contextual features including racism, discrimination, limited employment opportunity, and resultant economic and social inequity may promote sexual patterns that transmit STIs.

Concurrent sexual partnerships among African Americans in the rural south.

Context We need other means to reduce the risk for transmitting genital herpes (herpes simplex virus type 2 [HSV-2]). Are condoms effective? Content In a trial of an ineffective HSV-2 vaccine, 1843 participants were divided into 3 groups according to the frequency of condom use (for 0% to 25%, 25% to 75%, and >75% to 100% of sexual acts). Frequent condom users had fewer HSV-2 infections. Compared with participants in the next lowest category, participants in a category had a 26% lower risk for HSV-2 infection. Limitation In this observational cohort study, many unmeasured factors could also contribute to altered rates of HSV-2 acquisition. Conclusion Condom use is associated with a lower rate of acquisition of HSV-2. The Editors Genital herpes is a common sexually transmitted infection that can be transmitted during episodes of recurrent lesions and during subclinical shedding (1). In the absence of an effective vaccine, condoms have been routinely recommended for prevention of transmission, and a recent study showed that daily antiviral therapy also decreases the risk for transmission of herpes simplex virus type 2 (HSV-2) in discordant couples (2, 3). In a previous study of monogamous HSV-2discordant couples who were enrolled in an ineffective candidate HSV-2 vaccine trial, we showed that condoms protect women from HSV-2 infection (4). However, very few cases of genital HSV-2 occurred among men who were sexual partners of women infected with HSV-2, precluding definitive conclusions about the effectiveness of condoms for prevention of transmission to men. We present data from a concurrent trial of the candidate vaccine among HSV-2seronegative persons attending sexually transmitted disease clinics (5). A total of 1862 participants were enrolled in this study; 85 cases of genital herpes were documented in men, and 33 cases were documented in women. We analyzed the effect of condom use on HSV acquisition in this prospectively followed cohort of men and women. Methods Study Sample Participants included in this analysis took part in a randomized, double-blind, placebo-controlled efficacy trial of a candidate subunit HSV-2 vaccine that was subsequently shown to be ineffective (5). The trial involved 22 centers located at sexually transmitted disease clinics and enrolled 1862 participants. Initial serologic testing was done at screening; participants who were seronegative for HIV and HSV-2 and reported 4 or more sexual partners in the past year or 1 or more sexually transmitted diseases in the past year were eligible to enroll. The effectiveness of condom use among the 528 discordant couples enrolled in a parallel vaccine study was reported previously (4, 5). Participants were enrolled and followed for 18 months, during which they were evaluated at 11 study visits. At enrollment, we collected demographic information and information about sexual history. At each study visit, we took blood samples and recorded the following information about sexual history, which described behavior since the last visit: frequency of sexual activities, defined as vaginal or anal intercourse; frequency of condom use; number of partners; number of new partners; and number of partners with a known history of genital herpes. The information regarding number of partners was gender-specific. In addition, participants were counseled routinely about safer sexual behavior and were offered condoms at each study visit. Genitourinary signs and symptoms were evaluated as needed at additional interim visits. Laboratory Methods The Western blot assay done at the University of Washington, Seattle, Washington, established HSV serologic status at study entry and was used to document seroconversion (6). Type-specific cultures using standard techniques were done at local study sites. Statistical Analysis Acquisition of HSV-2 was defined by seroconversion on the Western blot assay or by a positive culture for HSV-2. Time to HSV-2 acquisition was defined as the number of days from screening to the first positive culture for HSV-2 or as the midpoint between the last negative result of the HSV-2 antibody test and the first positive result of the HSV-2 antibody test. In this analysis of condom use and HSV acquisition, we included the time from screening to enrollment in the study, whereas in the vaccine trial participants were followed beginning at enrollment. Thus, our report includes 109 participants who were not included in the efficacy analysis of the original vaccine trial. Twenty of these participants seroconverted to HSV-2 during the screening period before enrollment, and 89 were lost to follow-up after enrollment. Participants who did not acquire HSV-2 were censored at the last blood draw taken during the study or at enrollment if they did not report any sexual activity thereafter. Participants who reported no sexual activity for the entire time from screening to study termination were excluded from the analysis because they were not at risk for HSV-2 infection. Participants with follow-up longer than 65 days beyond the 18 months specified in the protocol (3%) were censored at day 605. Participants who were seronegative for HSV type 1 (HSV-1) and HSV-2 at screening were included in the analysis of HSV-1. Time to HSV-1 acquisition was defined as the number of days from screening to the first positive culture for HSV-1 or the midpoint between the last negative result of the HSV-1 antibody test and the first positive result of the HSV-1 antibody test. Participants who did not acquire HSV-1 were censored at the last blood draw or at enrollment if they did not report any sexual activity thereafter. Participants who reported no sexual activity for the duration of the study were excluded from the analysis of HSV-1. KaplanMeier curves, log-rank tests, and univariate and multivariate Cox regression models were used to determine baseline risk factors associated with HSV-2 acquisition. To relate sexual behavior to HSV-2 acquisition during the study, we constructed time-dependent covariate Cox regression models. The analysis time was divided into four 150-day intervals, and information about sexual history collected at interim visits was used to calculate covariate summaries for each period. Because continuous variables did not satisfy the assumption of a linear effect in the log hazard, they were categorized. Our choice for the cut-points was motivated by maintaining equal numbers of participants in each category (for example, age was split at the median value, 27 years), by consistency with observed risk patterns, or by interpretation considerations. Frequency of sexual activity was expressed as the average number of sexual acts per week in the time period, calculated by averaging the reported estimates over the visits for each interval. This average was then categorized as greater than 2 versus 2 or fewer to correspond to observed risk patterns. Use of condoms during the study period was described categorically in each interval (used for 0% to 25%, for 25% to 75%, or for >75% of sexual acts). This grouped linear parameterization was chosen to remain consistent with published analyses (4) while allowing a doseresponse relationship, assuming constant change in the risk with increasing category of condom use. The use of condoms was not evaluated during intervals for which the participants did not report any sexual activity. The number of partners reported was summarized for each period and was modeled in a binary fashion. Partner cut-points were chosen for interpretation reasons to describe ways in which this patient group may differ from monogamous couples who were studied in a previously published report addressing condom use and infection with HSV (4). Total number of partners was modeled as more than 1 versus 1 or fewer, and both new partners and partners with a history of genital herpes were modeled as any versus none. These analyses did not adjust for receipt of placebo versus receipt of vaccine, because this factor was not statistically significant in acquisition of HSV and did not influence the covariates of interest for this study. An interaction term between condom use and gender was used to check the hypothesis of a difference in the effect of condoms by gender and to provide gender-specific estimates of condom use. Two-sided P values for model covariates were calculated by using the likelihood ratio test. The same methods were used to explore baseline risk factors and time-varying risk factors for time to infection with HSV-1. Poisson regression was used to provide P values for comparisons involving incidence rates. Tests for changes in sexual behavior with time used generalized estimating equations. Statistical analyses were done by using Stata statistical software (version 8.1, Stata Corp., College Station, Texas). Role of the Funding Source The funding for the analyses for this study was provided by federal grants; design, data analysis, and interpretation were done at the University of Washington. The initial clinical trial was funded by Chiron Corporation. This study was supported in part by National Institutes of Health Herpes Program Project Grant AI-30731 and Centers for Disease Control and Prevention Research Initiative UR6/CCU017828-02. Results Of the 1862 participants who enrolled for the vaccine trial, 19 did not report any sexual activity during the entire study and thus were excluded from this analysis. The remaining 1843 participants included 1365 men and 478 women. The median age of the participants was 27 years. Sixty-two percent were white, 32% were African American, and 6% were people of other races; 1184 participants (64%) were seropositive for HSV-1 at study entry. Most men and women qualified for the study by reporting 4 or more partners in the past year (66% of men, 70% of women); some reported 1 or more sexually transmitted diseases in the past year (12% of men, 19% of women); and the remainder met both criteria (22% of men, 1

Ending the Epidemic of Heterosexual HIV Transmission Among African Americans

PURPOSE To investigate concurrent sexual partnerships among heterosexual African Americans, 18 to 59 years old, in rural North Carolina. METHODS Household interviews with persons randomly selected from the NC drivers license file were conducted to identify overlap among the 3 most recent sexual partnerships. RESULTS Concurrency prevalence in the past 5 years was 53% (men) and 31% (women). Most (61%) respondents believed that a recent partner had had a concurrent partnership. Multivariate analysis revealed strong associations between concurrency and male gender, being unmarried, age of sexual debut, and incarceration of a sex partner. CONCLUSIONS Concurrent partnerships may increase rates of heterosexual HIV among blacks in the rural Southeastern United States. Future research should examine the context that supports this network pattern.