HIV transmission risk through anal intercourse: systematic review, meta-analysis and implications for HIV prevention
01 Aug 2010-International Journal of Epidemiology (Oxford University Press)-Vol. 39, Iss: 4, pp 1048-1063
TL;DR: It was demonstrated that it would require unreasonably low numbers of AI HIV exposures per partnership to reconcile the summary per-act and per-partner estimates, suggesting considerable variability in AI infectiousness between and within partnerships over time.
Abstract: Background The human immunodeficiency virus (HIV) infectiousness of anal intercourse (AI) has not been systematically reviewed, despite its role driving HIV epidemics among men who have sex with men (MSM) and its potential contribution to heterosexual spread. We assessed the per-act and per-partner HIV transmission risk from AI exposure for heterosexuals and MSM and its implications for HIV prevention.
Methods Systematic review and meta-analysis of the literature on HIV-1 infectiousness through AI was conducted. PubMed was searched to September 2008. A binomial model explored the individual risk of HIV infection with and without highly active antiretroviral therapy (HAART).
Results A total of 62 643 titles were searched; four publications reporting per-act and 12 reporting per-partner transmission estimates were included. Overall, random effects model summary estimates were 1.4% [95% confidence interval (CI) 0.2–2.5)] and 40.4% (95% CI 6.0–74.9) for per-act and per-partner unprotected receptive AI (URAI), respectively. There was no significant difference between per-act risks of URAI for heterosexuals and MSM. Per-partner unprotected insertive AI (UIAI) and combined URAI–UIAI risk were 21.7% (95% CI 0.2–43.3) and 39.9% (95% CI 22.5–57.4), respectively, with no available per-act estimates. Per-partner combined URAI–UIAI summary estimates, which adjusted for additional exposures other than AI with a ‘main’ partner [7.9% (95% CI 1.2–14.5)], were lower than crude (unadjusted) estimates [48.1% (95% CI 35.3–60.8)]. Our modelling demonstrated that it would require unreasonably low numbers of AI HIV exposures per partnership to reconcile the summary per-act and per-partner estimates, suggesting considerable variability in AI infectiousness between and within partnerships over time. AI may substantially increase HIV transmission risk even if the infected partner is receiving HAART; however, predictions are highly sensitive to infectiousness assumptions based on viral load.
Conclusions Unprotected AI is a high-risk practice for HIV transmission, probably with substantial variation in infectiousness. The significant heterogeneity between infectiousness estimates means that pooled AI HIV transmission probabilities should be used with caution. Recent reported rises in AI among heterosexuals suggest a greater understanding of the role AI plays in heterosexual sex lives may be increasingly important for HIV prevention.
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Journal Article•
TL;DR: In this paper, the authors compared racial similarities and disparities in indicators of sexual health and sexual pressure in a high-risk, urban sample of young African American and Caucasian women, and found that African American women scored significantly higher on the sexual coercion subscale than Caucasian women.
Abstract: Introduction Condom self-efficacy, positive attitudes toward condom use, condom negotiation skills, HIV knowledge, and self-esteem have been associated with decreased HIV risk behavior among young women, but few studies have examined racial disparities that may exist in these sexual health indicators. Moreover, sexual pressure (inclusive of both coercive and non-coercive pressures to engage in unwanted or unprotected sex) has been understudied in women of different racial groups. Study Purpose The purpose of this study was to compare racial similarities and disparities in indicators of sexual health and sexual pressure in a high-risk, urban sample of young African American and Caucasian women. Methods A convenience sample of African American women and Caucasian women ages 19-25 ( N = 100, 50% AAW) was recruited from a local health department located in a Southeastern metropolitan area. Statistical analyses included descriptive analyses, linear, and logistic regressions. Major findings African American women reported higher self-esteem, but lower condom negotiation skills than Caucasian women. Although mean scores of sexual pressure did not differ between races, African American women scored significantly higher on the sexual coercion subscale. Condom use did not significantly differ between races. Conclusions Identifying factors that empower young minority women toward safer sexual practices is an important step in implementing effective HIV prevention interventions. Interventions that target power imbalances and gender norms in sexual relationships will benefit from addressing ways in which to increase resistance to sexual pressure in both coercive and non-coercive situations. Lastly, researchers should tailor interventions based on the social context and ensure their relevance for various racial/ethnic groups.
2 citations
Cites background from "HIV transmission risk through anal ..."
...Because the risk of HIV transmission is substantially higher from anal sex compared to vaginal sex (Baggaley et al., 2010), women should be aware of this increased risk and educated on strategies to promote condom use....
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Dissertation•
01 Jan 2017
TL;DR: In this article, the authors focus on university students and present a theoretical framework for the development of university students' dissertations, focusing on the importance of students' academic freedom.
Abstract: .......................................................................................................................................... ii ACKNOWLEDGEMENTS ................................................................................................................ iii ACRONYMS AND ABBREVIATIONS ............................................................................................ iv TABLE OF CONTENTS .................................................................................................................... ix CHAPTER ONE: INTRODUCTION ................................................................................................. 1 1.1 Background of the study ................................................................................................................... 1 1.2 Why focus on university students? ................................................................................................... 5 1.3 Rationale and significance of study .................................................................................................. 7 1.4 Aims and Objectives of the study ..................................................................................................... 8 1.5 Theoretical Framework ..................................................................................................................... 9 1.6 Organisation of Dissertation ........................................................................................................... 11 CHAPTER TWO: LITERATURE REVIEW .................................................................................. 12 2.
2 citations
TL;DR: The most striking difference in endorsement of PAI among women was the increase in lifetime prevalence comparing the age groups of 15 to 19 years (11%) with those 20 to 24 years of age (32%), which points to a key window of exposure and to an important opportunity for sexual health education.
Abstract: In the current issue of Sexually Transmitted Diseases, Habel et al. examine the prevalence and correlates of oral sex and penile–anal intercourse (PAI) betweenmale–female partners, reporting high endorsement of these behaviors in a nationally representative sample of US adolescents and adults aged 15 to 44 years. Unsurprisingly, more than 75% of women and men reported having given and received oral sex over their lifetime, with trivial proportions (6% of women and 7% of men) using a condom at their last oral sex encounter. Lifetime male–female PAI was reported by a significant minority of both women (33%) and men (38%), among whom only 21% and 30%, respectively, used a condom at last PAI. To put these figures in context, a higher proportion of US adolescents and adults have had male– female PAI than have a Twitter account. In other words, Habel et al. highlight what is already widely known among sexual health researchers: for many women and men, male–female PAI is, simply, normal behavior. Yet despite the high lifetime endorsement of male–female PAI among US adult populations, now documented in multiple surveys, surprisingly little is known about the frequency or context in which it occurs, the prevalence of associated behaviors (e.g., use of condoms or lubricant), or about people's knowledge of PAI-specific risks of transmission of human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs). Receptive PAI is the riskiest sexual behavior for HIVacquisition due to formation of abrasions in the rectal mucosa, which also contains a high concentration of HIV-target cells. When engaging in PAI with anHIV-positive partner who is not virally suppressed, the HIVacquisition risk for the receptive partner is exacerbated by failure to use condoms, certain lubricants, and possibly presex or postsex hygiene practices (e.g., rectal douching) that could further disrupt the rectal epithelium. The bulk of evidence on PAI and HIV/STI transmission is from studies conducted among men who have sex with men. As a result, the attributable fraction of PAI for women's HIVor STI risk is not well characterized. In clinical settings, male–female PAI is often dismissed or avoided in conversations about HIV/ STI prevention. In Habel et al's work, the most striking difference in endorsement of PAI among women was the increase in lifetime prevalence comparing the age groups of 15 to 19 years (11%) with those 20 to 24 years of age (32%). This increase occurs approximately at the transition from adolescence to adulthood and points both to a key window of exposure and to an important opportunity for sexual health education. US adolescents are the population most affected by increasing STI rates (particularly adolescent females), and they experience significant barriers to accessing sexual health services. Critically, more than 50% of HIV-positive youth in the United States are unaware of their status, are therefore not virally suppressed, and have increased risk of onward transmission to HIV-negative partners. Habel et al.'s findings reinforce the need for comprehensive sex education. Adolescents should be informed—before the period of increased engagement—how to have safe and healthy PAI and how to reduce the HIV/STI risks associated with it. However, PAI is rarely included in sex education curricula – despite recommendations that it should be—and when it is, it is often the subject of protests. Valid measurement of male–female PAI is a critical first step for obtaining population-level estimates across and within age groups, which can then be used to estimate more reliable HIV/STI transmission risks associated with it. Indeed, current modeling analyses demonstrate that even if male–female PAI is relatively rare, it may still have a large impact on population-level HIV transmission dynamics in generalized epidemics. However, current models for high HIV prevalence regions in particular rely on sparse and likely incomplete data. Many epidemiological studies (which then inform
2 citations
TL;DR: Findings suggest mutual HIV-disclosure and HIV-serosorting were occurring in this population of HIV-diagnosed men, and knowledge of VL status may have impacted on disclosure to sexual partners.
Abstract: We assessed attitudes to disclosure to new sexual partners and association with sexual behaviours among HIV-diagnosed gay, bisexual, and other men who have sex with men (GBMSM) in the UK Antiretrovirals, Sexual Transmission Risk and Attitudes (ASTRA) study in 2011-12. Among 1373 GBMSM diagnosed with HIV for ≥3 months and reporting sex in the past three months (84% on antiretroviral therapy (ART), 75% viral load (VL) ≤50c/mL), 56.3% reported higher sexual disclosure ("agree" or "tend to agree" with "I'd expect to tell a new partner I'm HIV-positive before we have sex"). GBMSM on ART with self-reported undetectable VL had lower disclosure than those on ART without self-reported undetectable VL and those not on ART. Higher sexual disclosure was associated with higher prevalence of CLS in the past three months; this was due to its association with CLS with other HIV-positive partners. Higher sexual disclosure was more common among GBMSM who had CLS with other HIV-positive partners only (72.1%) compared to those who had higher-risk CLS with HIV-serodifferent partners (55.6%), other CLS with HIV-serodifferent partners (45.9%), or condom-protected sex only (47.6%). Findings suggest mutual HIV-disclosure and HIV-serosorting were occurring in this population. Knowledge of VL status may have impacted on disclosure to sexual partners.
2 citations
Dissertation•
01 Jan 2018
TL;DR: The Role of CS1 Fibronectin in HIV-1 Infection of α4β7 + T Lymphocytes is studied to establish a causative mechanism and establish a causal relationship between CS1 and HIV infection.
Abstract: The Role of CS1 Fibronectin in HIV-1 Infection of α4β7 + T Lymphocytes
2 citations
References
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TL;DR: A new quantity is developed, I 2, which the authors believe gives a better measure of the consistency between trials in a meta-analysis, which is susceptible to the number of trials included in the meta- analysis.
Abstract: Cochrane Reviews have recently started including the quantity I 2 to help readers assess the consistency of the results of studies in meta-analyses. What does this new quantity mean, and why is assessment of heterogeneity so important to clinical practice?
Systematic reviews and meta-analyses can provide convincing and reliable evidence relevant to many aspects of medicine and health care.1 Their value is especially clear when the results of the studies they include show clinically important effects of similar magnitude. However, the conclusions are less clear when the included studies have differing results. In an attempt to establish whether studies are consistent, reports of meta-analyses commonly present a statistical test of heterogeneity. The test seeks to determine whether there are genuine differences underlying the results of the studies (heterogeneity), or whether the variation in findings is compatible with chance alone (homogeneity). However, the test is susceptible to the number of trials included in the meta-analysis. We have developed a new quantity, I 2, which we believe gives a better measure of the consistency between trials in a meta-analysis.
Assessment of the consistency of effects across studies is an essential part of meta-analysis. Unless we know how consistent the results of studies are, we cannot determine the generalisability of the findings of the meta-analysis. Indeed, several hierarchical systems for grading evidence state that the results of studies must be consistent or homogeneous to obtain the highest grading.2–4
Tests for heterogeneity are commonly used to decide on methods for combining studies and for concluding consistency or inconsistency of findings.5 6 But what does the test achieve in practice, and how should the resulting P values be interpreted?
A test for heterogeneity examines the null hypothesis that all studies are evaluating the same effect. The usual test statistic …
45,105 citations
TL;DR: A checklist contains specifications for reporting of meta-analyses of observational studies in epidemiology, including background, search strategy, methods, results, discussion, and conclusion should improve the usefulness ofMeta-an analyses for authors, reviewers, editors, readers, and decision makers.
Abstract: ObjectiveBecause of the pressure for timely, informed decisions in public health
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authors, reviewers, editors, and readers.ParticipantsTwenty-seven participants were selected by a steering committee, based
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improve the usefulness of meta-analyses for authors, reviewers, editors, readers,
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17,663 citations
TL;DR: The problem of making a combined estimate has been discussed previously by Cochran and Yates and Cochran (1937) for agricultural experiments, and by Bliss (1952) for bioassays in different laboratories as discussed by the authors.
Abstract: When we are trying to make the best estimate of some quantity A that is available from the research conducted to date, the problem of combining results from different experiments is encountered. The problem is often troublesome, particularly if the individual estimates were made by different workers using different procedures. This paper discusses one of the simpler aspects of the problem, in which there is sufficient uniformity of experimental methods so that the ith experiment provides an estimate xi of u, and an estimate si of the standard error of xi . The experiments may be, for example, determinations of a physical or astronomical constant by different scientists, or bioassays carried out in different laboratories, or agricultural field experiments laid out in different parts of a region. The quantity xi may be a simple mean of the observations, as in a physical determination, or the difference between the means of two treatments, as in a comparative experiment, or a median lethal dose, or a regression coefficient. The problem of making a combined estimate has been discussed previously by Cochran (1937) and Yates and Cochran (1938) for agricultural experiments, and by Bliss (1952) for bioassays in different laboratories. The last two papers give recommendations for the practical worker. My purposes in treating the subject again are to discuss it in more general terms, to take account of some recent theoretical research, and, I hope, to bring the practical recommendations to the attention of some biologists who are not acquainted with the previous papers. The basic issue with which this paper deals is as follows. The simplest method of combining estimates made in a number of different experiments is to take the arithmetic mean of the estimates. If, however, the experiments vary in size, or appear to be of different precision, the investigator may wonder whether some kind of weighted meani would be more precise. This paper gives recommendations about the kinds of weighted mean that are appropriate, the situations in which they
4,335 citations
TL;DR: The viral load is the chief predictor of the risk of heterosexual transmission of HIV-1, and transmission is rare among persons with levels of less than 1500 copies of HIV -1 RNA per milliliter.
Abstract: Background and Methods We examined the influence of viral load in relation to other risk factors for the heterosexual transmission of human immunodeficiency virus type 1 (HIV-1). In a community-based study of 15,127 persons in a rural district of Uganda, we identified 415 couples in which one partner was HIV-1–positive and one was initially HIV-1–negative and followed them prospectively for up to 30 months. The incidence of HIV-1 infection per 100 person-years among the initially seronegative partners was examined in relation to behavioral and biologic variables. Results The male partner was HIV-1–positive in 228 couples, and the female partner was HIV-1–positive in 187 couples. Ninety of the 415 initially HIV-1–negative partners seroconverted (incidence, 11.8 per 100 person-years). The rate of male-to-female transmission was not significantly different from the rate of female-to-male transmission (12.0 per 100 person-years vs. 11.6 per 100 person-years). The incidence of seroconversion was highest among ...
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TL;DR: A theoretical strategy of universal voluntary HIV testing and immediate treatment with ART, combined with present prevention approaches, could have a major effect on severe generalised HIV/AIDS epidemics.
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