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: Although the majority of FSWs were familiar with HIV/AIDS, risky behaviors such as anal and oral sex are still in practice; this calls for education and HIV prevention campaigns focusing on risk education awareness.
Abstract: Background: Human Immunodeficiency Virus (HIV) epidemics are largely linked to high-risk populations such as female commercial sex workers (FSWs). This study assessed sexual behaviors, attitudes and knowledge of this marginalized group. Methods: We conducted a cross- sectional study on 278 selfidentified FSWs by using Respondent Driven Sampling (RDS) method in Shiraz, south of Iran, from June 2010 to March 2011. Volunteer women were interviewed in order to explore issues such as sexual behavior, sexual violence, work conditions, contraceptive methods, HIV/AIDS knowledge, HIV test, and source of HIV information. Results: The majority of participants (95.1%) knew about condoms; however, only 40.6% used condoms consistently. Despite the subject’s wide knowledge regarding modes of transmission, 61% and 40% did not use any protection with anal and oral intercourse, respectively. 21% of FSWs experienced sexual violence. Nearly half (45.2%) of them had an HIV test and more than three-quarters knew their test results. The women in our study preferred to receive their information from health workers (63%) and peer group (45.2%). Conclusion: This study sheds light on the existing knowledge and practices of this high-risk group. Although the majority of FSWs were familiar with HIV/AIDS, risky behaviors such as anal and oral sex are still in practice; this calls for education and HIV prevention campaigns focusing on risk education awareness. Efforts in addressing the problem of inconsistent condom use needs to be directed towards client specific approaches and must be regarded a top priority.
7 citations
DOI•
01 Jan 2012
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7 citations
Cites background from "HIV transmission risk through anal ..."
...Unprotected anal intercourse is a more effective means of HIV transmission than most other forms of sexual activity [Baggaley et al., 2010; Grulich & Zablotska, 2010]....
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...This makes biologic sense because unprotected anal intercourse is a more effective means of HIV transmission than most other forms of sexual activity [Baggaley et al., 2010; Grulich & Zablotska, 2010]....
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...therefore can be damaged more easily, causing bleeding during intercourse and thus providing a direct route into the bloodstream for infected sexual fluids or blood [Baggaley et al., 2010; Grulich & Zablotska, 2010]....
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...201 means of HIV transmission than most other forms of sexual activity [Baggaley et al., 2010; Grulich & Zablotska, 2010]....
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...and thus providing a direct route into the bloodstream for infected sexual fluids or blood [Baggaley et al., 2010; Grulich & Zablotska, 2010]....
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01 Sep 2014
TL;DR: Elevated levels of inflammation linked to periods of endotoxemia resulting in a significantly different immune phenotype in a subset of MSM at high risk of HIV-1 acquisition is shown.
Abstract: This study assessed cellular and soluble markers of immune activation in HIV-1-seronegative men who have sex with men (MSM). MSM immune profiles were characterized by increased expression of CD57 on T cells and endotoxemia. Endotoxin presence was linked to recent highrisk exposure and associated with elevated cytokine levels and decreased CD4/CD8 T cell ratios. Taken together, these data show elevated levels of inflammation linked to periods of endotoxemia resulting in a significantly different immune phenotype in a subset of MSM at high risk of HIV-1 acquisition.
6 citations
Cites background from "HIV transmission risk through anal ..."
...Risk factors pertaining to MSM include anal intercourse [2], differences in transmission route and kinetics of viral dissemination [3], and inadequate access to preventative health care services [4-7]....
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TL;DR: The results suggest that knowledge was variable and product use themes centered on risks of human immunodeficiency virus/sexually transmitted infections, other infections, and physical harm/damage.
Abstract: Prevalence rates indicate that receptive anal sex is increasingly part of heterosexual women’s sexual repertoire. However, there is a body of literature linking this behavior to risk for adverse sexual health outcomes. Women’s anal sexual health knowledge and awareness of behaviors associated with elevated risk have received less attention in the research literature. The aim of the current study was to examine anal sexual health knowledge and product use among heterosexual women aged 18 to 30 years. A total of 33 self-identified heterosexual women recruited from the general population participated in one of six focus groups. The results suggest that knowledge was variable. Salient sexual health themes centered on risks of human immunodeficiency virus/sexually transmitted infections (HIV/STIs), other infections, and physical harm/damage. Product-use themes included cleanliness/hygiene, comfort, and product safety. Participants expressed the desire for anal sexual health education. The results have implicat...
6 citations
TL;DR: It is concluded that, to ensure continuously safe blood systems, the bifurcation into social and medical aspects of blood supply as two separate issues needs to be moved beyond and approach social dynamics as key medical safety questions.
Abstract: The existing literature on donor screening in transfusion medicine tends to distinguish between social concerns about discrimination and medical concerns about safety. In this article, we argue that the bifurcation into social and medical concerns is problematic. We build our case on a qualitative study of the historical rise and current workings of safety practices in the Danish blood system. Here, we identify a strong focus on contamination in order to avoid 'tainted blood', at the expense of working with risks that could be avoided through enhanced blood monitoring practices. Of further significance to this focus are the social dynamics found at the heart of safety practices aimed at avoiding contamination. We argue that such dynamics need more attention, in order to achieve good health outcomes in transfusion medicine. Thus, we conclude that, to ensure continuously safe blood systems, we need to move beyond the bifurcation of the social and medical aspects of blood supply as two separate issues and approach social dynamics as key medical safety questions.
6 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
and clinical practice and the explosion of information in the scientific literature,
research results must be synthesized. Meta-analyses are increasingly used
to address this problem, and they often evaluate observational studies. A
workshop was held in Atlanta, Ga, in April 1997, to examine the reporting
of meta-analyses of observational studies and to make recommendations to aid
authors, reviewers, editors, and readers.ParticipantsTwenty-seven participants were selected by a steering committee, based
on expertise in clinical practice, trials, statistics, epidemiology, social
sciences, and biomedical editing. Deliberations of the workshop were open
to other interested scientists. Funding for this activity was provided by
the Centers for Disease Control and Prevention.EvidenceWe conducted a systematic review of the published literature on the
conduct and reporting of meta-analyses in observational studies using MEDLINE,
Educational Research Information Center (ERIC), PsycLIT, and the Current Index
to Statistics. We also examined reference lists of the 32 studies retrieved
and contacted experts in the field. Participants were assigned to small-group
discussions on the subjects of bias, searching and abstracting, heterogeneity,
study categorization, and statistical methods.Consensus ProcessFrom the material presented at the workshop, the authors developed a
checklist summarizing recommendations for reporting meta-analyses of observational
studies. The checklist and supporting evidence were circulated to all conference
attendees and additional experts. All suggestions for revisions were addressed.ConclusionsThe proposed checklist contains specifications for reporting of meta-analyses
of observational studies in epidemiology, including background, search strategy,
methods, results, discussion, and conclusion. Use of the checklist should
improve the usefulness of meta-analyses for authors, reviewers, editors, readers,
and decision makers. An evaluation plan is suggested and research areas are
explored.
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 ...
2,897 citations
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.
1,948 citations