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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01 Jan 2013
TL;DR: Addressing the expanding epidemics of HIV in MSM will require continued research, increased resources, political will, policy change, structural reform, community engagement, and strategic planning and programming, but it can and must be done.
Abstract: Epidemics of HIV in MSM continue to expand in most low, middle and upper income countries in 2013 and rates of new infection have been consistently high among young MSM. Current prevention and treatment strategies are insufficient for this next wave of HIV spread. We conducted a series of comprehensive reviews of HIV prevalence and incidence,risksforHIV,preventionandcare,stigmaanddiscrimination,andpolicyand advocacy options. The high per act transmission probability of receptive anal intercourse, sex role versatility among MSM, network level effects, and social and structural determinants play central roles in disproportionate disease burdens. HIV can be transmitted through large MSM networks at great speed. Molecular epidemiologic data show marked clustering of HIV in MSM networks, and high proportions of infections due to transmission from recent infections. Prevention strategies which lower biological risks, including those using antiretrovirals, offer promise for epidemic control, but are limited by structural factors including, discrimination, criminalization, and barriers to health care. Sub-epidemics, including among racial and ethnic minority MSM in the US and UK, are particularly severe and will require culturally-tailored efforts. For the promise of new and combined bio-behavioral interventions to be realized, clinically competent health care is necessary.. and community leadership, engagement, and empowerment are likely to be key. Addressing the expanding epidemics of HIV in MSM will require continued research, increased resources, political will, policy change, structural reform, community engagement, and strategic planning and programming, but it can and must be done. 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins AIDS 2013, 27:000‐000
15 citations
Cites background from "HIV transmission risk through anal ..."
...9), roughly 18-fold higher than for vaginal intercourse [44]....
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TL;DR: Longitudinal studies are needed to clarify the association between rectal douching and HIV and other STIs among MSM, and health education materials should inform men of the potential for increased risk of infection with rectal Douching.
Abstract: Background Men who have sex with men (MSM) are disproportionately affected by HIV and other STIs worldwide. Rectal douching, which is commonly used by MSM in preparation for anal sex, may increase the risk of HIV and other STIs by injuring the rectal mucosa. Results from individual studies reporting associations between rectal douching and HIV and other STIs among MSM are inconsistent. We performed a systematic review and meta-analysis to estimate the association between rectal douching and HIV and other STIs among MSM. Methods We searched PubMed, Embase, Scopus and Web of Science for studies published from January 1970 to November 2018. Studies that reported ORs and 95% CIs of associations between rectal douching and infection with HIV/STIs, or reported enough data to calculate these estimates, were included. We assessed risk of bias using the Newcastle-Ottawa Scale. ORs were pooled using a random effects model. Results Twenty-eight eligible studies were identified in our review, of which 24 (20 398 participants) were included in the meta-analysis. Rectal douching was associated with increased odds of infection with HIV (OR 2.80, 95% CI 2.32 to 3.39), and any STI other than HIV (including hepatitis B virus (HBV), hepatitis C virus (HCV), chlamydia, gonorrhoea, syphilis and human papillomavirus) (OR 2.46, 95% CI 1.95 to 3.11) among MSM. For specific STIs, douching was associated with increased odds of viral hepatitis (HBV, HCV) (OR 3.29, 95% CI 2.79 to 3.87), and chlamydia or gonorrhoea (OR 3.25, 95% CI 2.02 to 5.23). These associations remained significant in studies that adjusted for potential confounders. Conclusion Rectal douching may put MSM at increased risk for infection with HIV and other STIs. Longitudinal studies are needed to clarify this association, and health education materials should inform men of the potential for increased risk of infection with rectal douching.
15 citations
TL;DR: The findings suggest the need for more HIV and sexual health education targeted at heterosexuals, especially for those who go online to meet partners, and how those who meet sexual partners online attempt to assess the possible risk of acquiring HIV or STIs posed by having unprotected sex with a new partner.
Abstract: Heterosexuals' use of the Internet for meeting romantic or sexual partners is rapidly increasing, raising concerns about the Internet's potential to facilitate encounters that place individuals at risk for acquiring HIV or other sexually transmitted infections (STIs). For example, online sharing of personal information and self-revelations can foster virtual intimacy, promoting a false sense of familiarity that might accelerate progression to unprotected sex. Therefore, it is critical to understand how those who meet sexual partners online attempt to assess the possible risk of acquiring HIV or STIs posed by having unprotected sex with a new partner and decide whether to use a condom. To investigate this issue, in-depth interviews were conducted with a diverse sample of heterosexual male and female participants from large metropolitan cities who had had unprotected vaginal or anal sex with at least two partners met online in the past 3 months. With few exceptions, participants relied on faulty strategies and heuristics to estimate these risks; yet, most engaged in unprotected sex at their first meeting or very soon afterward. While some seemed to try to make a genuine effort to arrive at a reliable assessment of the HIV risk posed, most appeared to be looking for a way to justify their desire and intention to have unprotected sex. The findings suggest the need for more HIV and sexual health education targeted at heterosexuals, especially for those who go online to meet partners.
15 citations
TL;DR: Specific harm-reduction programmes are shown to have significant impacts in reducing UAI and should be scaled up among MSM in China, potentially bridging HIV to the general female population.
Abstract: Men who have sex with men (MSM) in China are highly susceptible to HIV infection and HIV prevalence among Chinese MSM is rapidly increasing in recent years. Unprotected anal intercourse (UAI) is a major contributing factor of HIV transmission. This study aims to identify factors associated with UAI among MSM in Changsha city, China. A cross-sectional survey was conducted among 642 MSM in Changsha city from July 2009 to June 2011 via a venue-based sampling method. Data on socio-demographic characteristics, sexual behaviours and utilisation of HIV/AIDS services were collected to determine the associates of UAI in MSM. Among the 642 MSM, 184 (28.7%) reported having UAI with male partners at the last sexual episode. UAI was associated with the venues where MSM met other MSM, and having unprotected sex with female partners at last the sexual episode and in the past six months. In addition, UAI was significant associated with not being exposed to HIV interventions, including free condom, lubricant, HIV testing and counselling, and peer education. MSM who have UAI practice are more likely to have unprotected sex with female; hence, potentially bridging HIV to the general female population. Specific harm-reduction programmes are shown to have significant impacts in reducing UAI and should be scaled up among MSM in China.
15 citations
Cites background from "HIV transmission risk through anal ..."
...The risk of HIV acquisition and transmission during UAI is about 18 times greater than unprotected vaginal intercourse (Baggaley et al., 2010) as the mucous membranes lining the anus and rectum are much more fragile than in vagina (Tebit, Ndembi, Weinberg, & Quinones-Mateu, 2012)....
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01 Jan 2011
TL;DR: The work of the Global Commission on HIV and the Law (GCLL) as mentioned in this paper was conducted by UNDP on behalf of UNAIDS, and the authors accept responsibility for any errors and omissions.
Abstract: These papers were written to inform the work of the Global Commission on HIV and the Law, which is convened by UNDP on behalf of UNAIDS. The content, analysis, opinions and recommendations in the papers do not necessarily reflect the views of the Commission, UNDP or UNAIDS. While the Commission’s Technical Advisory group provided review and commentary, the authors accept responsibility for any errors and omissions.
15 citations
Cites background from "HIV transmission risk through anal ..."
...Transgender women are often included as a subpopulation of MSM in epidemiological studies as many share risk factors with gay men and other MSM including penile-anal intercourse, a much more efficient mode of sexual HIV transmission than penile-vaginal intercourse [14]....
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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,
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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.
1,948 citations