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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Dissertation•
01 Jan 2013
TL;DR: There is an urgent need for African countries to identify MSM populations and deliver appropriate and relevant HIV prevention, treatment and care, and effective and accessible responses will benefit African MSM, and likely also enhance wider HIV control efforts.
Abstract: Introduction Men who have sex with men have been largely unrecognised within African HIV epidemics until recently. This thesis reports on three projects in Mombasa, Kenya and in Oxford that aimed to describe the burden and risk factors for HIV among MSM across sub-Saharan Africa and in Kenya specifically, and to describe patterns of sexual behaviour and partnerships relevant to individual and population HIV risk. Methods 1. cross-sectional study of HIV prevalence and risk factors among 285 MSM at enrolment to a vaccine feasibility cohort in Mtwapa, Kenya; 2. review and meta-analysis of behavioural and HIV studies in sub-Saharan African MSM until 2010 3. prospective, self-administered daily diary study of sexual behaviour among a sample of 83 IAVI vaccine feasibility cohort participants Main results HIV prevalence was 24.6% among MSM, who frequently reported transactional sex. Receptive anal sex practice, injecting drug use, concomitant STIs, homosexual exclusivity and age were independent risk factors for HIV prevalence. Prevalence studies identified high HIV burden among MSM across Africa, not associated with prevalence amongst the general adult population despite commonplace heterosexual behaviours. HIV prevalence associations with homosexual exclusivity, unprotected anal sex and transactional sex were largely consistent across different contexts. In Mombasa, prospective behaviour studies described a transactional sexual network serving both male and female clients, transaction dictating both relationship patterns and age differences between partners and condom use. Young age, homosexual exclusivity, alcohol use, religious affiliation and low earnings were associated with high risk homosexual behaviours. Heterosexual sex was commonplace, yet heterosexually active MSM had a significantly lower profile of homosexual behavioural HIV risk. Conclusions: There is an urgent need for African countries to identify MSM populations and deliver appropriate and relevant HIV prevention, treatment and care. Effective and accessible responses will benefit African MSM, and likely also enhance wider HIV control efforts.
8 citations
Posted Content•
TL;DR: In the case of C-528/13 Leger as mentioned in this paper, the Court of Justice of the European Union dealt with a blanket ban on blood donation for men who had sexual relations with other men in France.
Abstract: In the case of C-528/13 Leger [2015] commented on, the Court of Justice of the European Union dealt with a blanket ban on blood donation for men who had sexual relations with other men (MSM) in France. The Court found that such restrictions can be justified in light of specific epidemiological context and scientific knowledge available in Member States. The judgment, therefore, sheds lights on the boundaries of public health justifications, discrimination of gay and bisexual individuals, as well as the rising scope of EU sexual risk regulation. The article argues that the Court has undermined the principle of non-discrimination and shows how the matter of blood donations should have been treated instead as a prerequisite of active citizenship.
8 citations
TL;DR: CDPs for young people are likely to be cost-effective or cost-saving if they can increase condom use, since high HIV prevalence in these groups imposes a considerable health and cost burden.
Abstract: Background Prevention of sexually transmitted infection (STI) incidence in England is a high priority, particularly among young people, men who have sex with men (MSM) and black ethnic minorities. An economic evaluation of condom distribution programmes (CDPs) to reduce STI transmission is presented. Methods An economic model using a Bernoulli process estimated the number of people acquiring an STI as a function of its prevalence, transmission rate, condom use, condom failure rate and number of sexual contacts. Models were developed for young people (13–24 years), black ethnic minorities, MSM and the general English population. Effectiveness evidence came from a recent systematic review. For young people, a CDP was modelled (relative risk for condom use=1.23), along with an exploratory analysis of the impact on unintended pregnancies. For other populations, threshold analyses were used to identify the combination of costs and effect size required to make a programme cost-effective. Results The base case predicted that CDP for all young people in England could avert 5123 STI cases per annum, with an incremental cost–effectiveness ratio of £17 411. In addition, it could avert 118 pregnancies and 82 abortions and save £333 000 in associated costs. Schemes for black ethnic minorities and MSM could also be cost-effective even with relatively high costs and small effect sizes. Conclusion CDPs for young people are likely to be cost-effective or cost-saving. CDPs for other high-risk populations may also be cost-effective if they can increase condom use, since high HIV prevalence in these groups imposes a considerable health and cost burden.
8 citations
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.
8 citations
TL;DR: This study confirms the low rates of condom use, particularly in non-commercial relationship, among transgender women in Cambodia, and efforts towards education about effects of multiple, concurrent relationships, and inconsistent condom use should be reinforced.
Abstract: Globally, the prevalence of HIV among transgender women is much higher than that of the general adult population. This can be explained by the persistently low rate of consistent condom use among this population. This study was therefore conducted to explore factors associated with consistent condom use among sexually-active transgender women in Cambodia, specifically with their non-commercial partners. Data used for this study were collected as part of the National Integrated Biological and Behavioral Survey 2016. Participants were recruited from the capital city of Phnom Penh and 12 other provinces with high burden of HIV using the Respondent-Driven Sampling (RDS) method. Face-to-face interviews were conducted using a structured questionnaire. Weighted multivariate logistic regression analysis was conducted to explore independent factors associated with consistent condom use. This study included 1202 transgender women who reported having anal sex with at least one male partner not in exchange for money or gifts in the past three months. The mean age of the participants was 26.0 (SD = 7.0) years. Of the total, 41.5% reported always using condoms with male non-commercial partners in the past three months. After adjustment, the likelihood of consistent condom use was significantly higher among participants who resided in an urban community (AOR = 1.7, 95% CI = 1.1–2.6), had attained at least 10 years of formal education (AOR = 1.8, 95% CI = 1.2–2.7), perceived that they were likely or very likely to be HIV infected (AOR = 2.9, 95% CI = 2.0–4.1), reported drinking alcohol two to three times per week (AOR = 3.1, 95% CI = 1.1–8.3), reported using amphetamine-type stimulants (AOR = 1.9, 95% = 1.1–3.8) or other drugs (AOR = 7.6, 95% CI = 1.5–39.5), and reported inconsistent condom use with male commercial partners in the past three months (AOR = 4.3, 95% CI = 1.8–10.4) compared to that of their respective reference group. This study confirms the low rates of condom use, particularly in non-commercial relationship, among transgender women in Cambodia. To address these concerns, efforts towards education about effects of multiple, concurrent relationships, and inconsistent condom use should be reinforced among transgender women.
8 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