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 findings contribute to the mapping of the demand and determinants of heterosexual men’s preferences for novel antiretroviral-based prevention in sub-Saharan Africa, and the data could aid in the differentiated design of future HIV prevention strategies using LAI PrEP in conjunction with other methods.
Abstract: Heterosexual men in South Africa are a large key population to exposure to HIV, yet preferences for HIV pre-exposure prophylaxis (PrEP) among this population have not, to date, been investigated in the literature. This paper aims to explore HIV prevention preferences among heterosexual men in urban South Africa, as well as to examine the demand and characteristics of men who favour long-acting injectable (LAI) PrEP over condoms and oral PrEP. Data were collected among 178 self-reported HIV-negative heterosexual men, who were given example products and information before being asked which they preferred. Multivariate logistic regression was used to analyse which characteristics were associated with product choice. 48% (n = 85) of participants preferred LAI PrEP, while 33% (n = 58) and 20% (n = 35) chose oral PrEP and condoms respectively. Having children (marginal effect = 0.22; 95% CI [0.01, 0.44]) or having higher risk attitude scores (marginal effect = 0.03; 95% CI [0.01, 0.06]) was significantly associated with a choice of LAI PrEP, while those who had unprotected anal intercourse (marginal effect = − 0.42; 95% CI [− 0.57, − 0.27]) and those who were concerned with protection against other sexually transmitted infections over HIV (marginal effect = − 0.42; 95% CI [− 0.60, − 0.24]) appeared less likely to prefer LAI PrEP. The results suggested a relatively high demand and theoretical acceptability for LAI PrEP among heterosexual men in urban South Africa, but there appeared to be fewer distinct predictors for the willingness to use LAI PrEP compared to studies conducted among gay and bisexual men and women. Nevertheless, the findings contribute to the mapping of the demand and determinants of heterosexual men’s preferences for novel antiretroviral-based prevention in sub-Saharan Africa, and the data could aid in the differentiated design of future HIV prevention strategies using LAI PrEP in conjunction with other methods.
11 citations
TL;DR: In this article, a survey of men who have sex with men (MSM) in the context of the HIV epidemic and other sexually transmitted infections (STI) is presented.
Abstract: Social, individual, and programmatic vulnerability of men who have sex with men (MSM) in the context of the HIV epidemic and other sexually transmitted infections (STI) is a reality in many countries. The survey Behavior, Attitudes, Practices, and Prevalence of HIV and Syphilis in Men Who Have Sex with Men in 10 Brazilian Cities selected 383 MSM in the city of Salvador, Bahia State, Brazil, using the respondent driven sampling (RDS) technique. Individual vulnerability: early sexual initiation (51%), average of eight sex partners, and unprotected receptive anal sex with casual (32%) and steady partners (45%) and positive rapid tests HIV (6.5%) and syphilis (9%). Social vulnerability: young adults (80%), black race/skin color (91%), mean monthly family income of BRL 1,000.00, and personal history of discrimination (57%). Programmatic factors: no previous HIV test (63%) and no access to lubricant gel (88%). The study showed a profile of vulnerability and the urgent need for interventions and STI prevention in the MSM population in Salvador, in addition to high prevalence rates for HIV and syphilis.
11 citations
TL;DR: Great attention to education about HAS is urgently needed in Tanzania, where this sexual practice is still regarded as a taboo and useful information is offered that could be included in sex education programmes.
Abstract: To explore ideas of truck drivers and villagers from rural Tanzania about heterosexual anal sex (HAS) and the associated health risks. Qualitative study using 8 in-depth interviews (IDIs) and 2 focus group discussions (FGDs) with truck drivers and 16 IDIs and 4 FGDs with villagers from the Morogoro region. Study participants included 24 women and 46 men. Data analysis was performed thematically employing standard qualitative techniques. Reasons why men would practice HAS included sexual pleasure, the belief that anal sex is safer than vaginal sex, alternative sexual practice, exploration and proof of masculinity. Reasons why women would practice HAS included financial need, retaining a partner, alternative for sex during menses, pregnancy prevention and beauty enhancement because HAS is believed to 'fatten the female buttocks'. Most participants believed that condoms are not needed during HAS. This was linked to the ideas that infections only 'reside in wet places' (vagina) and that the anus is not 'conducive' for condom use; condoms reduce 'dryness' and 'friction' (pleasure) and may 'get stuck inside'. The study participants reported practices and ideas about HAS that put them at risk for HIV and sexually transmitted infections. Greater attention to education about HAS is urgently needed in Tanzania, where this sexual practice is still regarded as a taboo. This study offers useful information that could be included in sex education programmes.
11 citations
TL;DR: Several lubricants were significantly associated with increased prevalence of rectal sexually transmitted infections (STI) and longitudinal studies are needed to examine any causal relationship between specific lubricants and STI acquisition.
Abstract: Background Use of lubricants during anal intercourse is very common among men who have sex with men. However, few studies have evaluated associations between specific lubricants and rectal sexually transmitted infections (STIs). Methods Between July 2012 and October 2013, we conducted a cross-sectional study of men who have sex with men recruited from an urban, public sexual health clinic. In a self-administered survey, participants identified the lubricants used and frequency of lubricant use in the previous three months. Among men reporting any receptive anal intercourse (RAI) in the previous 3 months, we used multivariable binomial regression models to analyze associations between recent use of 9 specific lubricants and prevalent rectal chlamydia, rectal gonorrhea, and either rectal infection. Results Twenty-five percent of the 146 participants had rectal chlamydial infection and 21% had rectal gonococcal infection; 37% had either (chlamydial or gonococcal) infection. Three-quarters reported always or almost always using lubricant during recent receptive anal intercourse. After adjustment for age, race, human immunodeficiency virus status, and condom use, Gun Oil (adjusted prevalence ratio [aPR], 1.99; 95% confidence interval [CI], 1.04-3.80) and Slick (aPR, 3.55; 95% CI, 1.38-9.12) were significantly associated with prevalent gonococcal infection. No lubricants were significantly associated with prevalent rectal chlamydia, but in analyses of either rectal infection, precum (aPR, 1.68; 95% CI, 1.06-2.66), Vaseline (aPR, 1.70; 95% CI, 1.10-2.64), and baby oil (aPR, 2.26; 95% CI, 1.43-3.57) were all significantly associated with prevalent rectal infection. Conclusions Several lubricants were significantly associated with increased prevalence of rectal STI. Longitudinal studies are needed to examine any causal relationship between specific lubricants and STI acquisition.
11 citations
Cites background from "HIV transmission risk through anal ..."
...Some college 57 (39) Finished college 45 (31) Sexual orientation Gay or homosexual 116 (79) Bisexual 14 (10) Straight or heterosexual 2 (1) Other term 2 (1) No term 11 (8) Missing/refuse to answer 1 (<1) Sexual position preference Exclusively top 6 (4) Versatile 132 (90) Exclusively bottom 8 (6) Main partner Yes 65 (45) No 80 (55) Don't know 1 (<1) Current condom use Always/almost always 45 (31) Most of the time 35 (24) About half the time 12 (8) Sometimes, but less than half 24 (16) Never/almost never 29 (20) Missing/Refuse to answer 1 (<1) HIV status Positive 33 (23) Negative 110 (75) Missing 3 (2) Rectal chlamydia Yes 37 (25) No 109 (75) Rectal gonorrhea Yes 31 (21) No 115 (79) Either rectal infection Yes 54 (37) No 92 (63)...
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...Race* White 47 (32) Black 104 (71) Asian 6 (4) Native American 12 (8) Native Hawaiian 1 (<1) Pacific Islander 1 (<1) Other 5 (3) Ethnicity Hispanic 7 (5) Non-Hispanic 138 (95) Missing/refuse to answer 1 (<1) Education Less than high school 8 (5) Finished high school/General Educational Development (GED) 36 (25)...
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TL;DR: Women require better counselling and greater choice in prevention modalities that are effective during RVI and RAI, and more and better data are needed to explain differences in risk by world region and risk population.
Abstract: Receptive anal intercourse (RAI) carries a greater per-act risk of HIV acquisition than receptive vaginal intercourse (RVI) and may influence HIV epidemics driven by heterosexual sex. This systematic review explores the association between RAI and incident HIV among women, globally. We searched Embase and Medline through September 2018 for longitudinal studies reporting crude (cRR) or adjusted (aRR) relative risks of HIV acquisition by RAI practice among women. Of 27,563 articles identified, 17 eligible studies were included. We pooled independent study estimates using random-effects models. Women reporting RAI were more likely to acquire HIV than women not reporting RAI (pooled cRR = 1.56 95% CI 1.03-2.38, N = 18, I2 = 72%; pooled aRR = 2.23, 1.01-4.92, N = 5, I2 = 70%). In subgroup analyses the association was lower for women in Africa (pooled cRR = 1.16, N = 13, I2 = 21%) than outside Africa (pooled cRR = 4.10, N = 5, I2 = 79%) and for high-risk (pooled aRR = 1.69, N = 4, I2 = 63%) than general-risk women (pooled aRR = 8.50, N = 1). Interview method slightly influenced cRR estimates (p value = 0.04). In leave-one-out sensitivity analyses pooled estimates were generally robust to removing individual study estimates. Main limitations included poor exposure definition, incomplete adjustment for confounders, particularly condom use, and use of non-confidential interview methods. More and better data are needed to explain differences in risk by world region and risk population. Women require better counselling and greater choice in prevention modalities that are effective during RVI and RAI.
11 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 ...
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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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