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: Despite certain sexually transmitted infections (STI) being sufficiently prevalent among the general population in some regions that they might be considered endemic, the contribution of “key populations” (KP) to recent increases in STI prevalence and incidence has been increasingly recognized.
Abstract: Despite certain sexually transmitted infections (STI), for example, Chlamydia trachomatis, being sufficiently prevalent among the general population in some regions that they might be considered endemic, the contribution of “key populations” (KP) to recent increases in STI prevalence and incidence has been increasingly recognized [1]. The definition of who belongs to a KP has varied among normative bodies, but common features include engagement in specific practices that augment risk (e.g. multiple partners, anal sex and/or sharing needles) and social marginalization, which can concentrate the partner pool because of limited opportunities to meet partners outside of risk milieu, while limiting access to needed treatment and prevention. The UNAIDS programme includes men who have sex with men (MSM), transgender people, sex workers, people who inject drugs (PWID) as KP [2] and incarcerated persons [3-7]. Others have considered migrants to also be a KP [8-11], given their disproportionate HIV/STI burden and lack of social protection. Addressing HIV diagnosis, treatment and prevention for KP is important for their individual health, as well as that of the wider community with whom they interact. Understanding the relationship of HIV spread between KP and others is often hindered by insufficient data. Although members of KP sub-groups may have different patterns of behaviour and social mixing that influence their HIV/STI risks, their vulnerabilities are augmented by common factors (Table 1). Often, KP experience structural barriers and societal discrimination that may increase their HIV/STI vulnerability by encumbering their access to healthcare [12-17]. Moreover, structural factors may not only directly affect susceptibility (e.g. lack of access to testing or treatment), but also shape behaviours and networks (e.g. being socially marginalized limiting partner choice). In settings where behaviours are criminalized [18-20], KP members may be at increased risk for HIV because of lack of access to condoms or sterile syringes, or may engage in avoidant behaviours due to the anticipation that insensitive providers might mistreat them [21], and fear of punitive action if they disclose unapproved sexual practices. KP avoiding healthcare are less likely to benefit from routine screening for HIV/STIs, early HIV/STI therapy (delaying the benefits of treatment as prevention, aka “TasP” for their partners), and/or pre-exposure prophylaxis (PrEP). Internalized stigma and social ostracism have been linked to high rates of KP depression [22-24], anxiety and selfmedication with non-prescription substances in order to alleviate distress [25-28], which may further increase risky sexual practices. Their opportunities for gainful employment may be limited because of societal stigma, leading to sex work as their sole means of livelihood [29,30]. Financial incentives to engage in condomless sex, violence and lack of negotiating power exacerbate their vulnerability to HIV/STI. Although there are common factors affecting HIV/STI vulnerability, some unique issues enhance transmission for some KP. Anal intercourse is extremely important in facilitating HIV/STI spread in MSM and transgender women, given that anal mucosa are particularly susceptible to HIV/STI acquisition and transmission [31,32], and potentiating asymptomatic rectal STIs are common [33,34]. Although oral sex may be seen as an HIV risk reduction practice, it may potentiate the spread of other STIs, for example, Neisseria gonorrhoeae [35-38]. Natal males who engage in anal sex with other males have unique role versatility, since they can acquire infection through receptive intercourse, and then transmit as the insertive partner [39]. Similar to enhanced transmission of HIV by sharing unsterile syringes, the risks posed by anal intercourse are addressable through access to condoms and antiretrovirals for prevention. Social networks play a major role in increasing the efficiency of HIV/STI spread [40,41]. Sex workers and their partners may be at increased risk for HIV/STI [29,30,42]. The presence of sexualized venues such as brothels, bathhouses and sex-seeking social media create specific environments where HIV/STI can be efficiently spread [43,44]. These physical spaces and/or online connections [45-47] may lead to rapid partner turnover, Mayer KH et al. Journal of the International AIDS Society 2019, 22(S6):e25344 http://onlinelibrary.wiley.com/doi/10.1002/jia2.25344/full | https://doi.org/10.1002/jia2.25344
9 citations
Cites background from "HIV transmission risk through anal ..."
...Anal intercourse is extremely important in facilitating HIV/STI spread in MSM and transgender women, given that anal mucosa are particularly susceptible to HIV/STI acquisition and transmission [31,32], and potentiating asymptomatic rectal STIs are common [33,34]....
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TL;DR: In this article, the authors present new paradigms and analytical methods to characterize the nonlinear behavioral dynamics within compressive and nonlinear human behaviors for HIV prevention and control in the context of social work research.
Abstract: Advancing social work research on human behaviors for HIV prevention and control calls for new paradigms and analytical methods to characterize the nonlinear behavioral dynamics within comp...
9 citations
01 Aug 2018
TL;DR: The studies recruited ‘at risk’ young people, which were variously defined as: reporting recent unprotected sex, having recently been arrested, being a crack user, having had multiple sex partners in the past year, and more.
Abstract: 74 [1,3,4,7–9,11,12,14,18–25,27,29–32,36– 41,44,45,47,49–51,55,59–62,66–68,70– 78,80,81,83,84,86–89,91–98,102–107,134] 18 [111,112,114–117,119– 126,128,130,132,133] 92 Text 16 [2,5,26,28,34,35,48,52,53,56,64,65,82,90,101,1 08,135] 4 [56,113,118,136] 19 Table 2 [58,69] 0 2 Survey response rate ≥80% 23 [2,6,8,9,15,30,32,36,45,49,52,55,69,74,76,83,93 ,94,97,101,105,107,135] 10 [109,112,115,116,119,121,125,1 26,130,133] 33 60-79% 14 [10–14,53,54,60,64,82,90,92,102,103] 3 [110,113,114] 17 <60% 13 [17,19,21,24,27,28,58,75,78,79,96,99,104] 2 [127,128] 15 NS 59 [1,3–5,7,18,20,22,23,25,26,29,31,33–35,37– 44,46–48,50,51,56,57,59,61–63,65–68,70– 73,77,80,81,84–89,91,95,98,100,106,108,134] 13 [56,111,117,118,120,122– 124,129,131,132,136] 71 ACASI = audio computer-assisted self-interview, AI = anal intercourse, CRS – cluster random sample, FTFI = face-to-face interview, NS = not specified, RCT = cluster randomised trial, RDS = Respondent driven sampling, SAQ = self-administered questionnaire, SRS = simple random sample The sum of some subgroups is greater than total number of included articles because several articles provided AI data in more than one category. Refers to non-higher risk participants recruited locally through posters, advertisements, from home visits or community venues etc. Three studies recruited ‘at risk’ young people, which were variously defined as: reporting recent unprotected sex [110,114], having recently been arrested [110], being a crack user, having had multiple sex partners in the past year.
9 citations
Cites background from "HIV transmission risk through anal ..."
...In this case, PrEP is unlikely to be the most suitable intervention....
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...PrEP may be a suitable to prevent HIV infection in sub-groups who practise AI as a routine part of their sexual practice....
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...Given that condom use during AI is reportedly frequently lower during AI than VI and that PrEP is more efficacious during AI, it may be a potent tool to protect women who practise AI....
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...Understanding the prevalence and frequency of AI practice in populations using vaginal microbicides could greatly aid development of realistic models of their effectiveness. c. Pre-exposure prophylaxis Pre-exposure prophylaxis (PrEP) is a promising HIV prevention strategy in which HIV-negative people at risk of HIV acquisition self-administer antiretrovirals orally....
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...These findings are useful in improving targeting of safe sex messaging and of prevention services such as HIV pre-exposure prophylaxis (PrEP)....
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01 Jan 2017
TL;DR: This thesis provides healthcare service providers, policy makers and clinicians with data to inform practice and public health interventions aimed at improving healthcare-seeking behaviour for STI testing and provides the first assessment of the international literature regarding the incidence of reactive arthritis after STI.
Abstract: Sexually transmitted infections (STIs) are a global public health problem. Sequelae for infected individuals can be serious and STIs impose a substantial financial burden on healthcare systems. Duration of infection is one factor influencing transmission rates, and is modifiable through secondary prevention methods, namely ‘test and treat’. For this approach to be effective, at-risk individuals must choose to present for testing. New Zealand provides a useful case-study to investigate healthcare-seeking behaviour for STI testing, as incidence rates of common STIs are especially high. The aims of this thesis were to quantify healthcare-seeking behaviour for STI symptoms and assess the risk of transmission in this period, to identify the barriers to STI testing, to understand the personal drivers for getting an STI test, to examine how STI knowledge is associated with testing behaviour, and finally, to collate and critically evaluate the published evidence regarding the incidence of a lesser known sequela of STI, reactive arthritis. This thesis took a mixed method approach, employing both qualitative and quantitative methods to address the research aims. The results showed that delays in healthcare-seeking for STI symptoms were common among patients attending an inner-city Sexual Health Clinic (SHC). Almost half of people with symptoms waited longer than seven days to seek healthcare, although there were no identified predictors of delayed healthcare-seeking. Around a third of people with symptoms continued to have sex after they first thought they may need to seek healthcare. Among these individuals, infrequent condom use was reported more by those who had sex with existing sexual partners than by those who had sex with new partners. Having sex while symptomatic was statistically significantly associated with delaying seeking healthcare for more than seven days (odds ratio (OR) = 3.25, 95% CI 1.225 – 8.623, p = 0.018). Analysis of qualitative interview data revealed three types of barriers to testing. These were personal (underestimating risk, perceiving STIs as not serious, fear of invasive procedure, self-consciousness in genital examination and being too busy), structural (financial cost of test and clinician attributes and attitude) and social (concern of being stigmatised). This work also revealed several drivers for testing including crisis, partners, clinicians, routines, and previous knowledge. Knowledge of the incidence, asymptomatic nature and sequelae of STIs featured prominently in the explanations of those who undertook routine testing. However, at the same time, many of the participants felt they did not have a good knowledge base and that their school-based sex education had been lacking. STI knowledge was investigated further using quantitative methodology. Levels of STI knowledge were generally good and did not differ between a Student Health Service population and an SHC population. Individuals who had tested before had significantly better knowledge than those who were attending for testing for the first time (U = 10089.500, Z = -4.684, p < 0.001). In addition, total knowledge score was an independent predictor of having had a previous test (OR = 1.436, 95% CI 1.217-1.694, p < 0.001). Reactive arthritis can be triggered by STI, thus STI screening patients who present with reactive arthritis has the potential to identify undiagnosed infection. This thesis provides the first assessment of the international literature regarding the incidence of reactive arthritis after STI. The systematic review found only three published studies which had prospectively examined the incidence of reactive arthritis after STI. The studies reported an incidence of reactive arthritis after STI of 3.0% to 8.1% and were found to be of low to moderate quality. In conclusion, this thesis provides healthcare service providers, policy makers and clinicians with data to inform practice and public health interventions aimed at improving healthcare-seeking behaviour for STI testing. It illustrates that delayed healthcare-seeking for STI symptoms is a common behaviour in New Zealand and could potentially be contributing to STI transmission and downstream burden on the health system. This work provides evidence of the drivers of STI testing that can be promoted, and the barriers that need to be removed. Specifically, improving STI knowledge may positively impact on testing rates. Lastly, this research indicates that there is a need for more studies assessing the incidence of reactive arthritis after an STI.
8 citations
Cites background from "HIV transmission risk through anal ..."
...4 (33) Sexual orientation behaviour in women 1....
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TL;DR: Findings suggest continuing HIV risk and a need to strengthen prevention and testing among MSM and sugieren un riesgo continuado and the necesidad of fortalecer the prevención and the testeo entre HSH in the costa pacífica of Ecuador.
Abstract: We assessed HIV and STI prevalence, risk behaviors and factors associated with HIV infection in men who have sex with men (MSM) in Guayaquil, Ecuador. Respondent-driven sampling was used to recruit 400 MSM in 2011–2012. Participants completed a computer-assisted self-interview and provided blood samples. Statistical analysis accounted for differential probability of selection and for recruitment patterns. HIV prevalence was 11.3 %, HSV-2 30.2 %, active syphilis 6.9 % and hepatitis B 1.2 %. In the previous 12 months, 84 % of MSM reported casual male sex partners and 25 % sex work. Only 48 % of MSM consistently used condoms with male partners and 54 % had ever been tested for HIV. Of 17 % of MSM reporting a female partner, consistent condom use was 6 %. HIV infection was associated with age 25 or older, active syphilis and homosexual self-identification. Findings suggest continuing HIV risk and a need to strengthen prevention and testing among MSM.
8 citations
Cites background from "HIV transmission risk through anal ..."
...A versatile role during anal intercourse was found to be the most prevalent in our study; which has been previously cited as a rising practice among Latin American MSM [25] and may play a role in enhancing the efficiency of HIV spread [26, 27]....
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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.
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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.
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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,
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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
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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.
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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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