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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Jackson State University1, University of Mississippi Medical Center2, Binghamton University3, University of Johannesburg4, Columbia University Medical Center5, New York Blood Center6, National Institute of Water and Atmospheric Research7, Johns Hopkins University8, Harvard University9, Fenway Health10
TL;DR: The need for culturally relevant HIV prevention efforts for black MSM that facilitate communication with sexual partners especially about risk reduction strategies, including preexposure prophylaxis is suggested.
Abstract: The role of sexual networks in the epidemiology of human immunodeficiency virus (HIV) among black men who have sex with men (MSM) is poorly understood. Using data from 1,306 black MSM in the BROTHERS Study (2009-2010) in the United States, we examined the relationships between multiple sexual dyadic characteristics and serodiscordant/serostatus-unknown condomless sex (SDCS). HIV-infected participants had higher odds of SDCS when having sex at least weekly (odds ratio (OR) = 2.41, 95% confidence interval (CI): 1.37, 4.23) or monthly (OR = 1.94, 95% CI: 1.17, 3.24) versus once to a few times a year. HIV-uninfected participants had higher odds of SDCS with partners met offline at sex-focused venues (OR = 1.79, 95% CI: 1.15, 2.78) versus partners met online. In addition, having sex upon first meeting was associated with higher odds of SDCS (OR = 1.49, 95% CI: 1.21, 1.83) than was not having sex on first meeting, while living/continued communication with sexual partner(s) was associated with lower odds of SDCS (weekly: OR = 0.64, 95% CI: 0.47, 0.85; monthly: OR = 0.60, 95% CI: 0.44, 0.81; yearly: OR = 0.58, 95% CI: 0.39, 0.85) versus discontinued communication. Persons with primary/steady nonprimary partners versus commercial partners had lower odds of SDCS regardless of HIV serostatus. This suggests the need for culturally relevant HIV prevention efforts for black MSM that facilitate communication with sexual partners especially about risk reduction strategies, including preexposure prophylaxis.
26 citations
TL;DR: The investigators concluded that the risk of HIV transmission from an HIV-infected man receiving ART with a plasma HIV-1 RNA (viral load) of less than 200 copies per mL over the preceding year was, remarkably, zero, with a narrow upper 95% CI limit of 0·23 per 100 couple-years of follow-up.
26 citations
TL;DR: On-demand PrEP in high-risk MSM with TDF-FTC can be considered cost saving in France if the duration of exposure was less than 7.5 years at current drug price and 13 years at generic price.
Abstract: Objectives:We undertook the economic evaluation of the double-blind randomized ANRS-IPERGAY trial, which showed the efficacy of on-demand preexposure prophylaxis (PrEP) with tenofovir disoproxil fumarate (TDF)-emtricitabine (FTC) in preventing HIV infection among high-risk MSM.Design and methods:The
25 citations
Cites methods from "HIV transmission risk through anal ..."
...185/receptive unprotected anal intercourse during that period [13], using the IPERGAY trial results of 14 sexual partners over a 2-month period with an average number of 26 sexual acts out of which 70% were unprotected and a 0....
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TL;DR: Despite representing a small fraction of all sex acts, AI is an underestimated source of HIV transmission and increasing availability and uptake of condoms, lubricants, and pre-exposure prophylaxis for women engaging in AI could help mitigate HIV risk.
Abstract: Current evidence suggests that anal intercourse (AI) during sex work is common in sub-Saharan Africa, but there have been few studies in which the contribution of heterosexual AI to human immunodeficiency virus (HIV) epidemics has been investigated. Using a respondent-driven sampling survey of female sex workers (FSWs; n = 466) in Abidjan, Cote d'Ivoire, in 2014, we estimated AI prevalence and frequency. Poisson regressions were used to identify AI determinants. Approximately 20% of FSWs engaged in AI during a normal week (95% confidence interval: 15, 26). Women who performed AI were generally younger, had been selling sex for longer, were born in Cote d'Ivoire, and reported higher sex-work income, more frequent sex in public places, and violence from clients than women not reporting AI. Condom use was lower, condom breakage/slippage more frequent, and use of water-based lubricants was less frequently reported for AI than for vaginal intercourse. Using a dynamic transmission model, we estimated that 22% (95% credible interval: 11, 37% of new HIV infections could have been averted among FSWs during 2000-2015 if AI had been substituted for vaginal intercourse. Despite representing a small fraction of all sex acts, AI is an underestimated source of HIV transmission. Increasing availability and uptake of condoms, lubricants, and pre-exposure prophylaxis for women engaging in AI could help mitigate HIV risk.
25 citations
Cites background from "HIV transmission risk through anal ..."
...Prospective studies of the effect of sexual risk behaviors on HIV incidence are more appropriate to determine causality and there is, indeed, strong empirical evidence that AI enhances HIV risk (6)....
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...This can affect the accuracy of self-reports and AI can potentially be underestimated because of social desirability bias (6)....
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...Insertive and, particularly, receptive anal intercourse (AI) carry a well-recognized heightened risk of HIV transmission as compared with VI (3, 4), which does not substantially differ between male-female and male-male contacts (5, 6)....
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...receptive AI found them to be substantially higher than those of male-to-female VI (6)....
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Columbia University1, Fred Hutchinson Cancer Research Center2, University of North Carolina at Chapel Hill3, George Washington University4, Emory University5, Durham University6, Johns Hopkins University School of Medicine7, Harlem Hospital Center8, National Institutes of Health9, West Virginia University10
TL;DR: The results demonstrate how interpersonal and social factors may influence sustained high-risk behavior by individuals and suggest that further study of the economic issues related to HIV risk could inform future prevention interventions.
Abstract: We describe the sexual behaviors of women at elevated risk of HIV acquisition who reside in areas of high HIV prevalence and poverty in the US. Participants in HPTN 064, a prospective HIV incidence study, provided information about individual sexual behaviors and male sexual partners in the past 6 months at baseline, 6- and 12-months. Independent predictors of consistent or increased temporal patterns for three high-risk sexual behaviors were assessed separately: exchange sex, unprotected anal intercourse (UAI) and concurrent partnerships. The baseline prevalence of each behavior was >30 % among the 2,099 participants, 88 % reported partner(s) with >1 HIV risk characteristic and both individual and partner risk characteristics decreased over time. Less than high school education and food insecurity predicted consistent/increased engagement in exchange sex and UAI, and partner’s concurrency predicted participant concurrency. Our results demonstrate how interpersonal and social factors may influence sustained high-risk behavior by individuals and suggest that further study of the economic issues related to HIV risk could inform future prevention interventions.
25 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,
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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
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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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