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 results demonstrate the need for interventions designed to prevent sexual violence against gay, bisexual, and other men who have sex with men and transgender women in this population, and reduce the negative psychological and health outcomes of sexual victimization.
Abstract: This study examined experiences with sexual violence among Black African gay, bisexual, and other men who have sex with men (GBMSM) and transgender women (TGW) in townships surrounding Pretoria, South Africa. Of 81 GBMSM and TGWs interviewed, 17 reported to have experienced sexual violence perpetrated by other men. Qualitative analysis of interviews revealed the social and relational context of these experiences as well as their psychological and health consequences. The described context included single- and multiple-perpetrator attacks in private and public spaces, bias-motivated attacks, and violence from known partners. Several participants reported refusing propositions for sex as a reason for being victimized. HIV-positive individuals were overrepresented among survivors compared to the sample as a whole. Following victimization, participants described feelings of pain, fear, anger and self-blame. The results demonstrate the need for interventions designed to (a) prevent sexual violence against GBMSM and TGW in this population, and (b) reduce the negative psychological and health outcomes of sexual victimization. The discussion also highlights the need to examine more closely the link between experiences of sexual violence and risk for HIV infection.
6 citations
26 Oct 2011
TL;DR: While HIV-1 has been reported to have a shorter incubation period of 7-10years, HIV-2 is considerably longer and often less severe, which if not managed leads to the possible invasion and establishment of multiple opportunistic infections.
Abstract: Human Immunodeficiency Virus (HIV) is the causative organism of AIDS which has become one of the greatest public health challenges faced by mankind. AIDS was first identified in 1981 in Los Angeles, USA. Two types of HIV exist presentlyHIV-1 and HIV-2 (Alizon et al., 2010; Adoga et al., 2010). HIV-1 was first isolated in the early 1980s (BarreSinoussi et al., 1983) and linked as causative agent of AIDS (Gallo et al., 1984). HIV-2 which is similar to HIV-1 was later identified in the developing world (Clavel, 1987, Clavel et al., 1986), but found to be less virulent and can differ in its response to antiretroviral agents. HIV-1 is classified into three groups [M, N and O] based on the genetic diversity. Group M (major) has 10 subtypes (A-J), and Group O (outlier) represents a number of highly divergent strains (Carr et al., 1998; Jassens et al., 1997 Chen et al., 2010). Francois Simon and his group reported a group N of HIV-1. Despite the phenotypic classification of HIV-1 into subtypes, the number of sequenced isolates remains limited (Sharp et al., 1994). Both strains are spread in the same way and have the same AIDS causing consequences. While HIV-1 has been reported to have a shorter incubation period of 7-10years, HIV-2 is considerably longer and often less severe (Barre-Sinoussi, 1996; WHO, 1989). HIV infection is usually followed by a chronic progressive destruction of the immune and neurologic system (Price, 1996), which if not managed leads to the possible invasion and establishment of multiple opportunistic infections.( Lindo et al., 1998; Pozio et al., 1997) and malignancy (Schulz et al., 1996). Although on average, an infected individual spends several years without manifesting the disease, AIDS has always been certain. The time from infection to AIDS varies widely between individuals, from a few months to as many as 20 years with existing evidences accepting that 50% of individuals progress to AIDS in 7-10years and this has been accepted as the incubation period of the virus (Del Amo et al., 1998; WHO, 1994).
6 citations
Cites background from "HIV transmission risk through anal ..."
...…and blood, breast milk expressed through feeding; organ donations; sharing infected objects (needles, tattoos and piercing) which are the main vehicles through which the virus is transmitted (Kim et al., 2010; Yu et al., 2010; Suligoi et al., 2010; Pruss et al., 2010 and Baggaley et al., 2010)....
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Imperial College London1, University of London2, University of California, Los Angeles3, University of California, Davis4, University of Pittsburgh5, National Institutes of Health6, University of North Carolina at Chapel Hill7, Fred Hutchinson Cancer Research Center8, Centers for Disease Control and Prevention9
TL;DR: Receptive anal intercourse (RAI) is more efficient than receptive vaginal intercourse (RVI) at transmitting HIV, but its contribution to heterosexually acquired HIV infections among at‐risk women in the USA is unclear.
Abstract: Problem Receptive anal intercourse (RAI) is more efficient than receptive vaginal intercourse (RVI) at transmitting HIV, but its contribution to heterosexually acquired HIV infections among at-risk women in the USA is unclear. Method of study We analysed sexual behaviour data from surveys of 9152 low-income heterosexual women living in 20 cities with high rates of HIV conducted in 2010 and 2013 as part of US National HIV Behavioral Surveillance. We estimated RAI prevalence (past-year RAI) and RAI fraction (fraction of all sex acts (RVI and RAI) at the last sexual episode that were RAI among those reporting past-year RAI) overall and by key demographic characteristics. These results and HIV incidence were used to calibrate a risk equation model to estimate the population attributable fraction of new HIV infections due to RAI (PAFRAI ) accounting for uncertainty in parameter assumptions. Results Receptive anal intercourse prevalence (overall: 32%, city range: 19%-60%) and RAI fraction (overall: 27%, city range: 18%-34%) were high overall and across cities, and positively associated with exchange sex. RAI accounted for an estimated 41% (uncertainty range: 18%-55%) of new infections overall (city range: 21%-57%). Variability in PAFRAI estimates was most influenced by uncertainty in the estimate of the per-act increased risk of RAI relative to RVI and the number of sex acts. Conclusion Receptive anal intercourse may contribute disproportionately to new heterosexually acquired HIV infections among at-risk low-income women in the USA, meaning that tools to prevent HIV transmission during RAI are warranted. The number of RVI and RAI acts should also be collected to monitor heterosexually acquired HIV infections.
6 citations
Cites methods from "HIV transmission risk through anal ..."
...Uniform ranges of plausible values were specified for each parameter (ie prior parameter range) based on the unadjusted 95% CI of the estimates from NHBS data (overall and by demographic or risk group) when available and sourced from the literature otherwise (1) CIRi,j=1− 2 �...
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Dissertation•
01 Mar 2015
TL;DR: The association between environmental stress and adequate adherence was attenuated among women ≤35 years and among women ≥45 years and interventions to improve adherence and ensure levels ≥95% must address stress and promote adaptive coping strategies to reduce or eliminate hazardous alcohol use.
Abstract: This cross-sectional study sought to: “Determine the association between stress, depression and ART adherence among women living with and accessing care for HIV in Toronto, Ontario, between 2007 and 2012”. Using OCS data, logistic regression models were used to identify covariates of (≥95%) adequate adherence and mediators and moderators in the association between stress and adherence. Among 307 women, 34.5% and 65.5% had poor and adequate adherence, respectively. Women with poor versus adequate adherence had more reports of hazardous alcohol use, stress events and depressive symptoms. No hazardous alcohol use (aOR=2.20, 95%CI:1.124.32) and fewer stress events (aOR=0.56, 95%CI:0.33-0.94) were associated with increased odds of adequate adherence. The association between environmental stress and adequate adherence was attenuated among women ≤35 years (aOR=0.73, 95%CI:0.56-0.94) versus ≥45 years (aOR=0.51, 95%CI:0.34-0.77). Interventions to improve adherence and ensure levels ≥95% must address stress and promote adaptive coping strategies to reduce or eliminate hazardous alcohol use.
6 citations
Cites background from "HIV transmission risk through anal ..."
...5 [4-25] 16[6-28] (n=106) 12[3-22] (n=190) 0....
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...3% Clinical Characteristics Hepatitis C Time since HIV diagnosis (years) 11 [6-17] No 267 89....
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Journal Article•
TL;DR: In this paper, the authors examined the practices of anal intercourse and dry sex within a cohort of female sex workers in Kenya, focusing on the prevalence and perceived risk of the practices, demographic and behavioural correlates, and association with sexually transmitted infections (STI).
Abstract: Objective: To examine the practices of anal intercourse and dry sex within a cohort of female sex workers (FSWs) in Kenya, focusing on the prevalence and perceived risk of the practices, demographic and behavioural correlates, and association with sexually transmitted infections (STI). Methods: A survey was conducted among FSWs in Meru, Kenya, with 147 participants randomly sampled from an existing cohort of self identified FSWs. Results: 40.8% of participants reported ever practising anal intercourse and 36.1% reported ever practising dry sex. Although the majority of women surveyed believed anal intercourse and dry sex to be high risk practices for HIV infection compared with vaginal sex, about one third of women reported never or rarely using condoms during anal intercourse, and about 20% never or rarely using condoms during dry sex. Reported consistent condom use was lower with both of these practices than with penile-vaginal intercourse. Anal intercourse was associated with experience of recent forced sexual intercourse, while dry sex was not. Anal intercourse was almost always initiated by clients, whereas dry sex was likely to be initiated by the women themselves. Sex workers reported charging higher fees for both practices than for vaginal intercourse. Both practices were associated with reported symptoms and diagnoses of STI. Conclusions: Both anal intercourse and dry sex were common in this sample, and although perceived as high risk practices, were not adequately protected with condom use. Education and other interventions regarding these high risk sexual behaviours need to be translated into safer practices, particularly consistent condom use, even in the face of financial vulnerability.
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