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: Analysis of sociodemographic and sexual characteristics of cisgender men who have sex with men on pre-exposure prophylaxis (PrEP) reporting transgender sexual partners found this group distinct from larger cohorts of MSM could offer new HIV prevention opportunities.
4 citations
TL;DR: The findings from this study demonstrate that condom norms can be actively established and maintained among younger gay, bisexual and other men who have sex with men (YMSM) in New Zealand and must increase YMSM's capacity, agency and skills to negotiate condom use, especially for the receptive partner.
Abstract: Background Condom promotion remains a cornerstone of HIV/STI control, but must be informed by evidence of uptake and address disparities in use. This study sought to determine the prevalence of, and demographic, behavioural and relational factors associated with, condom use during insertive and receptive anal intercourse with casual partners among younger gay, bisexual and other men who have sex with men (YMSM) in New Zealand. Methods: The 2006–2011 national HIV behavioural surveillance data for YMSM aged 16–29 years was pooled. Separately for each sexual position, frequent (always/almost always) versus infrequent condom use was regressed onto explanatory variables using manual backward stepwise multivariable logistic regression analysis. Results: Three-quarters of YMSM reported frequent condom use during insertive (76.0%) and receptive (73.8%) anal intercourse. YMSM who were exclusively insertive were more likely to report frequent condom use than versatile YMSM. Factors positively associated with frequent condom use, irrespective of sexual position were: in-person versus web-based recruitment, testing HIV negative versus never testing or testing HIV positive, having no recent sex with women, reporting two to five versus one male sexual partner in the past 6 months, reporting no current regular partner, but if in a regular relationship, reporting a boyfriend-type versus fuckbuddy-type partner, and frequent versus infrequent regular partner condom use. Pacific ethnicity and less formal education were negatively associated with frequent condom use only during receptive anal intercourse. Conclusions: The findings from this study demonstrate that condom norms can be actively established and maintained among YMSM. Condom promotion efforts must increase YMSM’s capacity, agency and skills to negotiate condom use, especially for the receptive partner.
4 citations
TL;DR: It is suggested that an association among preferential sex practices, condom use, and S. aureus colonization exists and should be investigated further.
Abstract: Purpose: The aims of this cross-sectional study were to determine the prevalence of Staphylococcus aureus nasal colonization, evaluate community-related behavioral risk factors, and utiliz...
4 citations
Cites background or result from "HIV transmission risk through anal ..."
...Likewise, the same pattern was observed in a study comparing HIV transmission risk and anal intercourse practices.(24) Baggaley et al....
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...9).(24) The hypothesis of a relationship between increased skin trauma sustained during anal intercourse and S....
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4 citations
TL;DR: The current liberal prevention strategy with programs aimed at risk reduction interventions in particular for sexual behavior and injecting drug use has been expanded by antiretroviral treatment approaches as mentioned in this paper, which was expected to keep the prevalence of infectious individuals below a certain threshold to curb self-sustaining chains of HIV infection.
Abstract: The HIV pandemic seems to be fading to some
degree—but there are regional exceptions. The current liberal prevention
strategy with programs aimed at risk reduction interventions in particular for
sexual behavior and injecting drug use has been expanded by antiretroviral
treatment approaches. It was expected to keep the prevalence of infectious
individuals below a certain threshold to curb self-sustaining chains of HIV
infections. The introduction of biomedical approaches by ART/HAART with regard
to practicing risk reduction behavior has been received as an exemption of
responsibility by certain populations who are defined as “at-risk” population.
Certain parts of the hard-to-reach, high-risk population have returned to
unsafe sex practices leading to careless behavior which in turn has promoted
the spread of HIV. This is supported by modern trends in risk societies where
with regard to HIV basic principles of ethics and tenets of the Human Rights
like “don’t harm other people” have lost any normative power. In addition, with
the support of NGOs, legal norms such as protecting the “bodily integrity of
individuals” have been ignored, allowing the “passing of HIV to partners” to
become socially acceptable behavior. As a whole, in defiance of the endeavors
of prevention applied so far, certain societies are exposed to an ongoing
spread of HIV.
4 citations
Cites background from "HIV transmission risk through anal ..."
...In respect of gay sex, the UAI poses an incremental effect for HIV transmission versus unprotected vaginal sex [44]....
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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 ...
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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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