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: Recent trends in sexual behaviour and condom use within the region are described and their combined effects on population levels of sexual risk are assessed.
Abstract: Introduction Sexual behaviour change contributed to reductions in HIV incidence in eastern and southern Africa between 1990 and 2010. More recently, there are indications that non-regular partnerships have increased. However, the effect of these increases on population-level risks for HIV and other sexually transmitted infections could have been reduced by simultaneous increases in condom use. We describe recent trends in sexual behaviour and condom use within the region and assess their combined effects on population levels of sexual risk. Methods Nationally representative Demographic and Health Survey data on sexually active males and females (15 to 49 years) were used for 11 eastern and southern African countries (≥3 surveys for each country; 1999 to 2016) to describe trends in sexual behaviour (multiple, non-regular, and casual sexual partnerships; condom use; age at first sex). Logistic regressions tested for statistical significance of changes. Analyses were stratified by sex. Results Recent increases in multiple, non-regular, and/or casual partnerships can be found for males in 10 countries and, for females, in nine countries; five countries exhibited recent decreases in age of sexual debut. Reduction in sex without condoms with non-regular partners was observed in six countries for males and eight for females. Changes in the proportion of the overall population reporting condomless sex with non-regular partners varied between countries, with declines in six countries and increases in three. Conclusions Extensive change in sexual behaviour occurred across eastern and southern Africa during the period of scale-up of antiretroviral therapy programmes. This includes increasing multiple and non-regular partnerships, but their potential effects on population-level sexual risks were often offset by parallel increases in condom use. Strengthening condom programmes and reintegrating communication about behavioural dimensions into combination prevention programmes could help countries to meet international targets for reductions in HIV incidence.
6 citations
Cites background from "HIV transmission risk through anal ..."
...HIV infection risks are higher during anal intercourse compared with vaginal intercourse [43,44] and contributions of heterosexual anal intercourse to new HIV infections could be substantial [45,46]....
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TL;DR: Employment of a risk quantification model facilitated quantification and comparison of HIV acquisition risk across two disparate HIV serodiscordant couple cohorts.
Abstract: Background
The CHAVI002 study was designed to characterize immune responses, particularly HIV-specific T-cell responses, amongst 2 cohorts of HIV-exposed seronegative (HESN) individuals. The absence of a clear definition of HESNs has impaired comparison of research within and between such cohorts. This report describes two distinct HESN cohorts and attempts to quantify HIV exposure using a ‘HIV risk index’ (RI) model.
Methods
HIV serodiscordant couples (UK; 24, Uganda; 72) and HIV unexposed seronegative (HUSN) controls (UK; 14, Uganda; 26 couples, 3 individuals) completed sexual behavior questionnaires every 3 months over a 9 month period. The two cohorts were heterogeneous, with most HESNs in the UK men who have sex with men (MSM), while all HESNs in Uganda were in heterosexual relationships. Concordance of responses between partners was determined. Each participant’s sexual behavior score (SBS) was estimated based on the number and type of unprotected sex acts carried out in defined time periods. Independent HIV acquisition risk factors (partner plasma viral load, STIs, male circumcision, pregnancy) were integrated with the SBS, generating a RI for each HESN.
Results
96 HIV serodiscordant couples completed 929 SBQs. SBSs remained relatively stable amongst the UK cohort, whilst decreasing from Visit 1 to 2 in the Ugandan cohort. Compared to the Ugandan cohort, SBSs and RIs in the UK cohort were lower at visit 1, and generally higher at later visits. Differences between the cohorts, with lower rates of ART use in Uganda and higher risk per-act sex in the UK, had major impacts on the SBSs and RIs of each cohort. There was one HIV transmission event in the UK cohort.
Conclusions
Employment of a risk quantification model facilitated quantification and comparison of HIV acquisition risk across two disparate HIV serodiscordant couple cohorts.
6 citations
TL;DR: In this article, the authors present a critical look at each of these commitments and make recommendations that would assist African countries in developing policies to end the HIV/AIDS epidemic in the region.
Abstract: Heads of State and Governments of the Organization of African Unity now the African Union (AU) met in April 2001 at a Special Summit held in Abuja to address the challenges of HIV/AIDS, Tuberculosis, Malaria and other related infectious diseases in Africa. In May 2006, at the Special Summit under the theme: “ Universal Access to HIV/AIDS, Tuberculosis and Malaria Services by 2010 ”, the African Union Heads of States and Governments adopted the “Abuja Call for Accelerated Action towards Universal Access to HIV/AIDS, Tuberculosis and Malaria Services in Africa” and related commitments thus reaffirming earlier commitments. In July 2013, African leaders once again gathered in Abuja for the Abuja +12 summit, which focused on the theme ‘Ownership, Accountability and Sustainability of HIV/AIDS, Tuberculosis and Malaria in Africa: Past, Present and the Future’. At the meeting, African leaders noted the tremendous progress that has been made in addressing HIV and AIDS, and made further commitments to effectively tackle the HIV epidemic on the continent. This article presents a critical look at each of these commitments and makes recommendations that would assist African countries in developing policies to end the HIV/AIDS epidemic in the region. (Afr J Reprod Health 2014; 18[3]: 34-46) Keywords : Abuja declaration; HIV infections; combination prevention; research for preventive measures; domestic resource mobilization Resume Les Chefs d'Etat et de gouvernements de l'Organisation de l'unite africaine devenue l'Union africaine (UA) se sont reunis en avril 2001, a un Sommet extraordinaire tenu a Abuja pour relever les defis du VIH / SIDA, de la tuberculose, du paludisme et d'autres maladies infectieuses connexes en Afrique. En mai 2006, lors du Sommet extraordinaire sur le theme: «Acces universel aux services du VIH / SIDA, de la tuberculose et du paludisme d'ici 2010", les chefs d'Etats et de gouvernements de l'Union africaine ont adopte l’ «Appel d'Abuja pour une action acceleree vers l'acces universel aux services du VIH / SIDA, de la tuberculose et du paludisme en Afrique » et les engagements connexes reaffirmant ainsi ses engagements anterieurs. En juillet 2013, les dirigeants africains se sont reunis une fois de plus a Abuja pour le sommet d'Abuja +12, qui portait sur le theme «La propriete, la responsabilite et la durabilite du VIH / SIDA, de la tuberculose et du paludisme en Afrique: le passe, le present et l'avenir». Lors de la reunion, les dirigeants africains ont note les progres considerables qui ont ete accomplis dans la lutte contre le VIH et le sida, et ont pris des engagements supplementaires sur un certain nombre de questions dans les moyens de lutter efficacement contre l'epidemie du VIH sur le continent. Cet article presente un regard critique sur chacun de ces engagements et fait des recommandations qui aideraient les pays africains a elaborer des politiques pour mettre fin a l'epidemie du VIH / SIDA dans la region. (Afr J Reprod Health 2014; 18[3]: 34-46)
6 citations
TL;DR: The high proportion of HIV-infected MSM in Bamako who are unaware of their HIV infection and the high prevalence of concurrent partnerships could further the spread of HIV in Bamko.
Abstract: Background Concurrent male-male sexual partnerships have been understudied in sub-Saharan Africa and are especially important because human immunodeficiency virus (HIV) prevalence and acquisition probability are higher among men who have sex with men (MSM) than among heterosexual men and women. Methods We conducted a respondent-driven sampling survey of 552 men who have sex with men in Bamako, Mali from October 2014 to February 2015. Eligibility criteria included 18 years or older, history of oral or anal sex with another man in the last 6 months, residence in or around Bamako in the last 6 months, ability to communicate in French. Results HIV prevalence was 13.7%, with 86.7% of MSM with HIV unaware of their infection. Concurrent male-male sexual partnerships were common, with 60.6% of MSM having a concurrent male sexual partnerships or believing their sex partner did in the last 6 months, and 27.3% having a concurrent male sexual partnerships and believing their sex partner did in the last 6 months. Over half (52.5%) of MSM had sex with women, and 30.8% had concurrent male partnerships and sex with a woman in the last 6 months. Concurrency was more likely among MSM with limited education, telling only MSM of same-sex behaviors, high social cohesion, and not knowing anyone with HIV. Conclusions The high proportion of HIV-infected MSM in Bamako who are unaware of their HIV infection and the high prevalence of concurrent partnerships could further the spread of HIV in Bamako. Increasing testing through peer educators conducting mobile testing could improve awareness of HIV status and limit the spread of HIV in concurrent partnerships.
6 citations
TL;DR: AI is commonly practised and condom use is inconsistent among Swazi FSW, but knowledge that AI increases HIV acquisition risk low, with only 10% identifying AI as the riskiest sex act.
Abstract: Introduction
As HIV is very effectively acquired during condomless receptive anal intercourse (AI) with serodiscordant and viremic partners, the practice could contribute to the high prevalence among female sex workers (FSW) in eSwatini (formerly known as Swaziland). We aim to estimate the proportion reporting AI (AI prevalence) among Swazi FSW and to identify the correlates of AI practice in order to better inform HIV prevention interventions among this population.
Methods
Using respondent-driven sampling (RDS), 325 Swazi FSW were recruited in 2011. We estimated the prevalence of AI and AI with inconsistent condom use in the past month with any partner type, and inconsistent condom use during AI and vaginal intercourse (VI) by partner type. Univariate and multivariable logistic regression models were used to identify behavioural and structural correlates associated with AI and AI with inconsistent condom use.
Results
RDS-adjusted prevalence of AI and AI with inconsistent condom use was high, at 44%[95% confidence interval (95%CI):35–53%]) and 34%[95%CI:26–42%], respectively and did not vary by partner type. HIV prevalence was high in this sample of FSW (70%), but knowledge that AI increases HIV acquisition risk low, with only 10% identifying AI as the riskiest sex act. Those who reported AI were more likely to be better educated (adjusted odds ratio(aOR) = 1.92[95%CI:1.03–3.57]), to have grown up in rural areas (aOR = 1.90[95%CI:1.09–3.32]), have fewer new clients in the past month (aOR = 0.33[95%CI:0.16–0.68]), and for last sex with clients to be condomless (aOR = 2.09[95%CI:1.07–4.08]). Although FSW reporting AI in past month were more likely to have been raped (aOR = 1.95[95%CI:1.05–3.65]) and harassed because of being a sex worker (aOR = 2.09[95%CI:1.16–3.74]), they were also less likely to have ever been blackmailed (aOR = 0.50[95%CI:0.25–0.98]) or been afraid to walk in public places (aOR = 0.46[95%CI:0.25–0.87]). Correlates of AI with inconsistent condom use were similar to those of AI.
Conclusions
AI is commonly practised and condom use is inconsistent among Swazi FSW. Sex act data are needed to determine how frequently AI is practiced. Interventions to address barriers to condom use are needed, as are biomedical interventions that reduce acquisition risk during AI.
6 citations
Cites background from "HIV transmission risk through anal ..."
...HIV is very effectively transmitted by condomless anal intercourse with serodiscordant and viremic partners[4], with a meta-analysis on finding that women may have an 18-fold higher HIV acquisition risk during receptive condomless AI compared to condomless vaginal intercourse[5]....
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...Despite a well-recognized heightened risk of transmission during condomless AI[5], we found no association between AI practice and HIV infection and an inverse association with syphilis infection in this cross-sectional sample....
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...Prospective studies are more appropriate to determine causality and there is indeed strong evidence that AI enhances HIV risk in women[5]....
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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.
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
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authors, reviewers, editors, and readers.ParticipantsTwenty-seven participants were selected by a steering committee, based
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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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