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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TL;DR: The epidemiology of HIV in high-income countries in 2013 depicts both the successes and challenges of HIV prevention, with stable to decreasing death rates and stable or declining trends in heterosexual populations likely attributable to the broader availability of effective treatments for HIV and relatively broad availability of antiretroviral treatment.
Abstract: Purpose of reviewThe epidemiology of HIV epidemics provides the roadmap for prioritization of programmes and serves over time to evaluate broadly the successes and challenges in prevention. The purpose of this review was to summarize recent information about the epidemiology of HIV in high-income co
66 citations
Cites background from "HIV transmission risk through anal ..."
...Changing the trajectory of the growing HIV epidemics in high-income countries will require addressing the biology of HIV transmission including acute HIV infection and transmission through anal intercourse with a viremic serodiscordant partner [15]....
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TL;DR: Enhanced understanding of the biology of enhanced rectal transmission of HIV and the focused use of antiretrovirals for prevention with culturally tailored approaches that address the potentiating social and behavioral factors associated with enhanced HIV spread among MSM are integrated.
Abstract: Men who have sex with men, including transgender women, comprise a heterogeneous group of individuals, whose sexual behaviors and gender identities may varying widely between cultures and among individuals. Their sources of increased vulnerability to HIV are diverse, including the increased efficiency of HIV transmission via unprotected anal intercourse, sexual role versatility, asymptomatic sexually transmitted infections, as well as behavioral factors that may be associated with condomless sex with multiple partners. Societal stigmatization of homosexual behavior and gender non-conformity may result in internalized negative feelings that lead to depression, other affective disorders, and substance use, which in turn are associated with increased risk taking behaviors. Social stigma and punitive civil environments may lead to delays in seeking HIV and STD screening, and later initiation of antiretroviral therapy. The iPrEX study demonstrated that chemoprophylaxis can decrease HIV acquisition in MSM, and the HPTN 052 study established the biological plausibility that earlier initiation of HAART can decrease HIV transmission to uninfected partners. Despite these advances, MSM remain among the most significantly HIV-affected population in resource rich and limited settings. New studies will integrate enhanced understanding of the biology of enhanced rectal transmission of HIV and the focused use of antiretrovirals for prevention with culturally-tailored approaches that address the potentiating social and behavioral factors associated with enhanced HIV spread among MSM.
66 citations
Cites background from "HIV transmission risk through anal ..."
...However, other data suggest that “test-and-treat” approaches could decrease HIV incidence in MSM. Individuals who are aware of their HIV status are less likely to engaging in potential transmitting behaviors64 and successful suppression of plasma viremia with HAART being associated with marked reductions in the detection of seminal HIV.65,66 Additionally, those who initiated treatment sooner in HPTN 052 had better clinical outcomes,67 and large observational studies also indicate that earlier treatment results in decreased morbidity.68 Operational questions remain, given that social stigma may result in delays in accessing testing and treatment services....
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...Receptive anal intercourse is the most efficient sexual practice transmitting HIV.(4) MSM engaging in insertive anal sex can become HIV infected, particularly if the partner has an STD, is untreated, or is uncircumcised....
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...Vernazza PL, Troiani L, Flepp MJ, et al. Potent antiretroviral treatment of HIV-infection results in suppression of the seminal shedding of HIV....
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...OF MSM SUSCEPTIBILITY Receptive anal intercourse is the most efficient sexual practice transmitting HIV.4 MSM engaging in insertive anal sex can become HIV infected, particularly if the partner has an STD, is untreated, or is uncircumcised....
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TL;DR: Focusing on 1-year and longer term transmission probabilities gives couples a better understanding of risk than those illustrated by data for a single sexual act, though long-term transmission probabilities to the negative partner in serodiscordant couples can be high, though these can be substantially reduced with the strategic use of preventive methods, especially those that include ART.
Abstract: Background The number of strategies to prevent HIV transmission has increased following trials evaluating antiretroviral therapy (ART), preexposure prophylaxis (PrEP) and male circumcision. Serodiscordant couples need guidance on the effects of these strategies alone, and in combination with each other, on HIV transmission. Methods We estimated the sexual risk of HIV transmission over 1-year and 10-year periods among male-male and male-female serodiscordant couples. We assumed the following reductions in transmission: 80% from consistent condom use; 54% from circumcision in the negative male partner of a heterosexual couple; 73% from circumcision in the negative partner of a male-male couple; 71% from PrEP in heterosexual couples; 44% from PrEP in male-male couples; and 96% from ART use by the HIV-infected partner. Findings For couples using any single prevention strategy, a substantial cumulative risk of HIV transmission remained. For a male-female couple using only condoms, estimated risk over 10 years was 11%; for a male-male couple using only condoms, estimated risk was 76%. ART use by the HIV-infected partner was the most effective single strategy in reducing risk; among male-male couples, adding consistent condom use was necessary to keep the 10-year risk below 10%. Conclusion Focusing on 1-year and longer term transmission probabilities gives couples a better understanding of risk than those illustrated by data for a single sexual act. Long-term transmission probabilities to the negative partner in serodiscordant couples can be high, though these can be substantially reduced with the strategic use of preventive methods, especially those that include ART.
65 citations
Cites background from "HIV transmission risk through anal ..."
...Lack of data on the effects of length of partnership, outside exposures, condom use and frequency and type of sex acts, on transmission risk among serodiscordant couples makes exploration of this issue difficult, although it may relate to variability in susceptibility and infectiousness [18,46]....
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...Data from couples suggest that HIV transmission risk from sex in serodiscordant couples may level off over time, regardless of ongoing exposures [18]....
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...4% per act of unprotected receptive anal sex based on a meta-analysis [18]....
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...025] [18] Risk ratio associated with HIV transmission risk modifiers (rj) [95% CI] Positive partner taking ART 0....
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TL;DR: The association between ATS use and HIV infection among MSM and amphetamine‐type stimulants is summarized.
Abstract: Introduction : HIV infections and the use of amphetamine-type stimulants (ATS) among men who have sex with men (MSM) have been increasing internationally, but the role of ATS use as a co-factor for HIV infection remains unclear We aimed to summarize the association between ATS use and HIV infection among MSM Methods : We conducted a systematic search of MEDLINE, EMBASE, GLOBAL HEALTH and PsycINFO for relevant English, peer-reviewed articles of quantitative studies published between 1980 and 25 April 2013 Pooled estimates of the association – prevalence rate ratios (PRR, cross-sectional studies), odds ratio (OR, case-control studies) and hazard ratio (HR, longitudinal studies), with 95% Confidence Intervals (CI) – were calculated using random-effects models stratified by study design and ATS group (meth/amphetamines vs ecstasy) We assessed the existence of publication bias in funnel plots and checked for sources of heterogeneity using meta-regression and subgroup analysis Results : We identified 6710 article titles, screened 1716 abstracts and reviewed 267 full text articles A total of 35 publications were eligible for data abstraction and meta-analysis, resulting in 56 records of ATS use Most studies (31/35) were conducted in high-income countries Published studies used different research designs, samples and measures of ATS use The pooled association between meth/amphetamine use and HIV infection was statistically significant in all three designs (PRR=186; 95% CI: 157–217; OR=273; 95% CI: 216–346 and HR=343; 95% CI: 298–395, respectively, for cross-sectional, case-control and longitudinal studies) Ecstasy use was not associated with HIV infection in cross-sectional studies (PRR=115; 95% CI: 088–149; OR=304; 95% CI: 129–718 and HR=248; 95% CI: 142–435, respectively, for cross-sectional, case-control and longitudinal studies) Results in cross-sectional studies were highly heterogeneous due to issues with ATS measurement and different sampling frames Conclusions : While meth/amphetamine use was significantly associated with HIV infection among MSM in high-income countries in all study designs, evidence of the role of ecstasy in HIV infection was lacking in cross-sectional studies Cross-sectional study design, measurement approaches and source populations may also be important modifiers of the strength and the direction of associations Event-specific measure of individual drug is required to establish temporal relationship between ATS use and HIV infection HIV prevention programmes targeting MSM should consider including interventions designed to address meth/amphetamine use Keywords: HIV; amphetamine-type stimulants; MSM; systematic review; meta-analysis; risk behaviour; meth/amphetamine; ecstasy To access the supplementary material to this article please see Supplementary Files in the column to the right (under ‘Article Tools’) (Published: 2 February 2015) Citation: Nga Thi Thu Vu et al Journal of the International AIDS Society 2015, 18 :19273 http://wwwjiasocietyorg/indexphp/jias/article/view/19273 | http://dxdoiorg/107448/IAS18119273
64 citations
Cites background from "HIV transmission risk through anal ..."
...In relation to ecstasy, where reported effects include improved sexual performance and satisfaction [13,14], participants also reported enhanced sensuality rather than sexuality [17] and increased feelings of intimacy and emotional closeness [20,21]....
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...Ecstasy has also been reported to increase feelings of sensuality and emotional closeness [20,21]....
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TL;DR: The purpose of this review is to examine existing evidence regarding the role of innate and cellular components of the oral cavity in HIV infection and how HIV infection may drive systemic hyper-immune activation in these patients.
Abstract: Mucosal surfaces account for the vast majority of HIV transmission. In adults, HIV transmission occurs mainly by vaginal and rectal routes but rarely via oral route. In contrast, pediatric HIV infections could be as the result of oral route by breastfeeding. As such mucosal surfaces play a crucial role in HIV acquisition, and spread of the virus depends on its ability to cross a mucosal barrier. HIV selectively infects, depletes, and/or dysregulates multiple arms of the human immune system particularly at the mucosal sites, and causes substantial irreversible damage to the mucosal barriers. This leads to microbial products translocation, and subsequently hyper-immune activation. Although introduction of antiviral therapy (ART) has led to significant reduction in morbidity and mortality of HIV-infected patients; viral replication persists. As a result, antigen presence and immune activation are linked to “inflammaging” which attributes to a pro-inflammatory environment and the accelerated ageing process in HIV patients. HIV infection is also associated with the prevalence of oral mucosal infections and dysregulation of oral microbiota, both of which may compromise the oral mucosal immunity of HIV-infected individuals. In addition, impaired oral immunity in HIV infection may predispose the patients to periodontal diseases which are associated with systemic inflammation and increased risk of cardiovascular diseases. The purpose of this review is to examine existing evidence regarding the role of innate and cellular components of the oral cavity in HIV infection and how HIV infection may drive systemic hyper-immune activation in these patients. We will also discuss current knowledge on HIV oral transmission, HIV immunosenescence in relation to the oral mucosal alterations during the course of HIV infection and periodontal disease. Finally, we discuss oral manifestations associated with HIV infection and how HIV infection and ART influence the oral microbiome. Therefore, unraveling how HIV compromises the integrity of the oral mucosal tissues and innate immune components of the oral cavity and its association with induction of chronic inflammation are critical for the development of effective preventive interventions and therapeutic strategies.
64 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.
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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.
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and clinical practice and the explosion of information in the scientific literature,
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authors, reviewers, editors, and readers.ParticipantsTwenty-seven participants were selected by a steering committee, based
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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
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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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