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Journal ArticleDOI

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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Citations
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Journal ArticleDOI
TL;DR: In this article, an intervention developed through participatory crowdsourcing methods increased HIV self-testing among men who have sex with men (MSM) in four cities (Guangzhou, Shenzhen, Jinan and Qingdao).
Abstract: OBJECTIVES: An intervention developed through participatory crowdsourcing methods increased HIV self-testing among men who have sex with men [MSM; relative risk (RR) = 1.89]. We estimated the long-term impact of this intervention on HIV transmission among MSM in four cities (Guangzhou, Shenzhen, Jinan and Qingdao). METHODS: A mathematical model of HIV transmission, testing and treatment among MSM in China was parameterized using city-level demographic and sexual behaviour data and calibrated to HIV prevalence, diagnosis and antiretroviral therapy (ART) coverage data. The model was used to project the HIV infections averted over 20 years (2016-2036) from the intervention to increase self-testing, compared with current testing rates. RESULTS: Running the intervention once would avert < 2.2% infections over 20 years. Repeating the intervention (RR = 1.89) annually would avert 6.4-10.7% of new infections, while further increases in the self-testing rate (hypothetical RR = 3) would avert 11.7-20.7% of new infections. CONCLUSIONS: Repeated annual interventions would give a three- to seven-fold increase in long-term impact compared with a one-off intervention. Other interventions will be needed to more effectively reduce the HIV burden in this population.

4 citations

Dissertation
30 Oct 2017
TL;DR: For instance, the authors found that crystal methamphetamine was associated with increased rates of condomless anal intercourse (CAI), increased sexual session length was found to increase the likelihood of engagement in CAI; chemsex, use of PrEP and having an undetectable viral load (UVL) were also shown to be significant predictors of CAI.
Abstract: Substance use within the LGBTIQ community has been long established. However chemsex, the use of recreational substances within the context of sexual activity (for the purpose of enhancement), is a new and emerging area of research, particularly in Australia. Chemsex is most commonly associated with men who have sex with men (MSM) and often involves stimulants, such as crystal methamphetamine. The current study was developed in partnership with the Queensland AIDS Council to inform future health promotion. Participants were 663 MSM, the majority of whom resided in South East Queensland. Questionnaires were completed online or on paper. The questionnaire asked about demographic details, substances used in the last 12 months, sexual health details and engagement in a variety of sexual behaviours, including chemsex. Those who reported engagement in chemsex were asked further questions about these behaviours. Descriptive results provided rates of substance use within particular sub-groups. In addition, it was found that crystal methamphetamine was associated with increased rates of condomless anal intercourse (CAI); increased sexual session length was found to increase the likelihood of engagement in CAI; chemsex, use of PrEP and having an undetectable viral load (UVL) were also shown to be significant predictors of CAI. Finally, chemsex and PrEP were shown to be significantly associated with increased reporting of sexually transmitted infections. These results provide useful insight for future HIV prevention, health promotion and clinical intervention planning. Implications for chemsex participants and the wider MSM community are discussed and recommendations for future research are made.

4 citations

01 Jan 2016
TL;DR: The high prevalence of HIV among MSM in the sample compared with the general population is highlighted and the importance of testing for syphilis in the context of the HIV epidemic is confirmed as early detection may provide opportunities to prevent sexually transmitted diseases.
Abstract: Human immunodeficiency virus (HIV) continues to disproportionately affect men who have sex with men (MSM); therefore, we investigated the sociodemographic, biological, and sexual behavioral risk factors associated with HIV infection in the city of Salvador, Bahia. This study is part of the national survey Behavior, Attitudes, Practices and Prevalence of HIV and Syphilis among men who have sex with men in 10 Brazilian Cities , which is a cross-sectional survey whose participants were selected by means of the respondent-driven sampling. Exact logistic regression analysis was used to measure the association of potential risk factors with HIV infection due to an HIV prevalence lower than 10% and a small sample size (383). The prevalence of HIV was 6.3% (95%CI 3.9–8.8) and the risk factors associated with HIV infection in our adjusted final model included having never been tested for syphilis (OR = 3.1; 95%CI 1.3 – 7.3) and having more than eight sexual partners (OR = 3.3; 95%CI 1.4 – 8.1). This study highlights the high prevalence of HIV among MSM in the sample compared with the general population and confirms the importance of testing for syphilis in the context of the HIV epidemic as early detection may provide opportunities to prevent sexually transmitted diseases.

4 citations

Dissertation
01 Jan 2018
TL;DR: The role of modelling in responses to the South African HIV epidemic is described and there are algorithms, such as Cluster Shuffle Pair-Matching, that offer a good compromise between speed and approximating the distribution of sexual relationships of the study-population.
Abstract: Mathematical models of the HIV epidemic have been used to estimate incidence, prevalence and life-expectancy, as well the benets and costs of public health interventions, such as the provision of antiretroviral treatment. Models of sexually transmitted infection epidemics attempt to account for varying levels of risk across a population based on diverse | or heterogeneous | sexual behaviour. Microsimulations are a type of model that can account for fine-grained heterogeneous sexual behaviour. This requires pairing individuals, or agents, into sexual partnerships whose distribution matches that of the population being studied, to the extent this is known. But pair-matching is computationally expensive. There is a need for computer algorithms that pair-match quickly. In this work we describe the role of modelling in responses to the South African HIV epidemic. We also chronicle a three-decade debate, greatly influenced since 2008 by a mathematical model, on the optimal time for people with HIV to start antiretroviral treatment. We then present and analyse several pair-matching algorithms, and compare them in a microsimulation of a fictitious STI. We find that there are algorithms, such as Cluster Shuffle Pair-Matching, that offer a good compromise between speed and approximating the distribution of sexual relationships of the study-population. An interesting further finding is that infection incidence decreases as population increases, all other things being equal. Whether this is an artefact of our methodology or a natural world phenomenon is unclear and a topic for further research.

4 citations

Journal ArticleDOI
TL;DR: In this paper, the authors locate and summarize existing literature regarding safer sex practices specific to heterosexual anal intercourse and identify promising health promotion strategies, based on Arksey and O'Malley's 2005 five-step methodology.
Abstract: Aims and objectives To locate and summarize existing literature regarding safer sex practices specific to heterosexual anal intercourse and identify promising health promotion strategies. Background Much of the literature regarding anal intercourse and safer sex is related to men who have sex with men. However, some studies suggest there are more women than men engaging in unprotected receptive anal intercourse. The risks associated with this sexual practice have been well documented, although many health care providers fail to ask about anal intercourse while addressing safer sex in the heterosexual population. Design The study was based on Arksey and O'Malley's 2005 five-step methodology. Methods A search was conducted of MEDLINE; CINAHL; PsycInfo; Cochrane; and PubMed. Databases were searched from 1990-2020. The 72 studies selected were classified according to their main area of focus. A grey literature search was also included. This scientific submission has been assessed for accuracy and completeness using the PRISMA-ScR guideline criteria (Supplementary File 1). Results The literature in this area is heterogeneous in terms of method and topic. Prevalence and incidence (n=26) in addition to sexually transmitted infection risks (n=26) related to heterosexual anal intercourse are well understood. However, there is limited information on condom use (n=6), factors that influence heterosexual anal intercourse (n=10), and health promotion strategies for this population and practice (n=4). Two websites that mentioned heterosexual anal intercourse risk reduction activities were included. Conclusions Although heterosexual anal intercourse appears to be an increasingly common sexual practice, very little is known about health promotion strategies nurses might utilize for encouraging safer sex in this population. Relevance to clinical practice Increased awareness of the prevalence and risks of heterosexual anal intercourse could enhance nurses' harm reduction strategies. Screening for sexually transmitted infections may be based on incorrect assumptions about sexual practices or due to stigma linked with anal intercourse. Reducing unprotected heterosexual anal intercourse will reduce sexually transmitted infections and their long term sequelae.

4 citations

References
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Journal ArticleDOI
04 Sep 2003-BMJ
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

Journal ArticleDOI
19 Apr 2000-JAMA
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

Journal ArticleDOI
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

Journal ArticleDOI
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

Journal ArticleDOI
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

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