John Imrie

Unprotected anal intercourse, risk reduction behaviours, and subsequent HIV infection in a cohort of homosexual men

Objective:A range of risk reduction behaviours in which homosexual men practise unprotected anal intercourse (UAI) has been described. We aimed to assess the extent of any reduction in HIV risk associated with these behaviours. Design:A prospective cohort study of HIV-negative homosexual men in Sydney, Australia. Methods:Men were followed up with 6-monthly detailed behavioural interviews and annual testing for HIV. The four risk reduction behaviours (behaviourally defined) examined were serosorting, negotiated safety, strategic positioning, and withdrawal during receptive UAI (UAI-R). Results:In 88% of follow-up periods in which UAI was reported, it occurred in the context of consistent risk reduction behaviours. Compared with those who reported no UAI, the risk of HIV infection was not raised in negotiated safety [hazard ratio = 1.67, 95% confidence interval (CI) 0.59–4.76] and strategic positioning (hazard ratio = 1.54, 95% CI 0.45–5.26). Serosorting outside negotiated safety was associated with an intermediate rate of HIV infection (hazard ratio = 3.11, 95% CI 1.09–8.88). Withdrawal was associated with a higher risk than no UAI (hazard ratio = 5.00, 95% CI 1.94–12.92). Patterns of UAI differed greatly according to partners serostatus. Men who reported serosorting were less likely to report either strategic positioning or withdrawal. Conclusion:Each behaviour examined was associated with an intermediate HIV incidence between the lowest and highest risk sexual behaviours. The inverse association between individual behaviours suggests that men who practise serosorting rely on this protection. The high prevalence of these behaviours demands that researchers address the contexts and risks associated with specific types of UAI.

Per-contact probability of HIV transmission in homosexual men in Sydney in the era of HAART.

Objective:The objective of this study is to estimate per-contact probability of HIV transmission in homosexual men due to unprotected anal intercourse (UAI) in the era of HAART. Design:Data were collected from a longitudinal cohort study of community-based HIV-negative homosexual men in Sydney, Australia. Methods:A total of 1427 participants were recruited from June 2001 to December 2004. They were followed up with 6-monthly detailed behavioral interviews and annual testing for HIV till June 2007. Data were used in a bootstrapping method, coupled with a statistical analysis that optimized a likelihood function for estimating the per-exposure risks of HIV transmission due to various forms of UAI. Results:During the study, 53 HIV seroconversion cases were identified. The estimated per-contact probability of HIV transmission for receptive UAI was 1.43% [95% confidence interval (CI) 0.48–2.85] if ejaculation occurred inside the rectum, and it was 0.65% (95% CI 0.15–1.53) if withdrawal prior to ejaculation was involved. The estimated transmission rate for insertive UAI in participants who were circumcised was 0.11% (95% CI 0.02–0.24), and it was 0.62% (95% CI 0.07–1.68) in uncircumcised men. Thus, receptive UAI with ejaculation was found to be approximately twice as risky as receptive UAI with withdrawal or insertive UAI for uncircumcised men and over 10 times as risky as insertive UAI for circumcised men. Conclusion:Despite the fact that a high proportion of HIV-infected men are on antiretroviral treatment and have undetectable viral load, the per-contact probability of HIV transmission due to UAI is similar to estimates reported from developed country settings in the pre-HAART era.

Why do we need randomised controlled trials to assess behavioural interventions

Merits of randomised controlled trials in behavioural and psychosocial research do not differ fundamentally from those in clinical medicine. Interventions that target behaviour are often complex and demanding, as are the requirements of good randomised controlled trials to assess their efficacy. Standardising the content and delivery of an intervention in a trial may be more challenging than justifying randomisation during informed consent. When blinding of participants and researchers to treatment allocation is impossible, it is important to minimise bias through blinded assessment of the outcome. The contribution that participant choice makes to the efficacy of an intervention is hard to measure.

HIV prevention for South African youth: which interventions work? A systematic review of current evidence

BackgroundIn South Africa, HIV prevalence among youth aged 15-24 is among the worlds highest. Given the urgent need to identify effective HIV prevention approaches, this review assesses the evidence base for youth HIV prevention in South Africa.MethodsSystematic, analytical review of HIV prevention interventions targeting youth in South Africa since 2000. Critical assessment of interventions in 4 domains: 1) study design and outcomes, 2) intervention design (content, curriculum, theory, adaptation process), 3) thematic focus and HIV causal pathways, 4) intervention delivery (duration, intensity, who, how, where).ResultsEight youth HIV prevention interventions were included; all were similar in HIV prevention content and objectives, but varied in thematic focus, hypothesised causal pathways, theoretical basis, delivery method, intensity and duration. Interventions were school- (5) or group-based (3), involving in- and out-of-school youth. Primary outcomes included HIV incidence (2), reported sexual risk behavior alone (4), or with alcohol use (2). Interventions led to reductions in STI incidence (1), and reported sexual or alcohol risk behaviours (5), although effect size varied. All but one targeted at least one structural factor associated with HIV infection: gender and sexual coercion (3), alcohol/substance use (2), or economic factors (2). Delivery methods and formats varied, and included teachers (5), peer educators (5), and older mentors (1). School-based interventions experienced frequent implementation challenges.ConclusionsKey recommendations include: address HIV social risk factors, such as gender, poverty and alcohol; target the structural and institutional context; work to change social norms; and engage schools in new ways, including participatory learning.

Condoms and seat belts: the parallels and the lessons

This paper investigates the relation between behavior adaptation and safety benefits of seat belts and whether condom promotion can be undermined by unintended changes in sexual risk perception and behavior. The comparison between 13 countries that passed seat belt laws and 4 countries without such laws shows a significant number of deaths among countries with seat belt laws. It has been suggested that drivers who wear seat belts feel safer and drive faster and more carelessly compared to those without seat belts. A model of individual risk management, postulating that every individual is comfortable with a certain level of risk and aims to balance the rewards of risk-taking against perceived hazards was developed to describe the behavior. This increase in seat belt use was then paralleled with condom use since the rise of HIV, with 3 ways in which a large increase in condom use could fail to affect transmission: 1) it appeals to risk-averse individuals who contribute little to epidemic transmission; 2) increased use of condom increases the number of transmission caused by condom failure; and 3) the increased use of condoms reflect the change in the decision of individuals from one partner to maintaining higher rates of partners and reliance on condoms. This paper, in conclusion, emphasizes the need for program development and implementation in response to this sexual behavior, particularly among developing countries.

Gay men's current practice of HIV seroconcordant unprotected anal intercourse: serosorting or seroguessing?

Abstract We explored seroguessing (serosorting based on the assumption of HIV seroconcordance) and casual unprotected anal intercourse (UAIC) associated with seroguessing. The ongoing Positive Health and Health in Men cohorts, Australia, provided data for trends in seroconcordant UAIC and HIV disclosure to sex partners. In event-level analyses, we used log-binomial regression adjusted for within-individual correlation and estimated prevalence rate ratios (PRRs) and 95% confidence intervals (95% CIs) for the association between the knowledge of a casual partners seroconcordance and UAIC. UAIC and HIV disclosure significantly increased during 2001–2006. HIV-positive men knew partners were seroconcordant in 54% and assumed it in 13% of sex encounters (42 and 17% among HIV-negative men). Among HIV-positive men, the likelihood of UAIC was higher when a partners status was known (Adjusted PRR = 5.17, 95% CI: 3.82–7.01) and assumed seroconcordant because of seroguessing (Adjusted PRR = 3.70, 95% CI: 2.56–5.35) compared with unknown. Among HIV-negative men, the likelihood of UAIC was also higher when a partners status was known (Adjusted PRR = 1.88, 95% CI: 1.58–2.24) and assumed seroconcordant (Adjusted PRR = 2.12, 95% CI: 1.72–2.62) compared with unknown. As levels of UAIC remain high, seroguessing increasingly exposes gay men to the risk of HIV infection. Because both HIV-positive and HIV-negative men often seroguess, education and prevention programs should address the fact that HIV-negative men who engage in UAI due to this practice may be at high risk of HIV infection. HIV prevention should take into account these contemporary changes in behaviors, especially among HIV-negative gay men.

DIAGNOSIS AND STIGMA AND IDENTITY AMONGST HIV POSITIVE BLACK AFRICANS LIVING IN THE UK

Individual in-depth, semi-structured interviews with 30 HIV positive Black Africans were conducted in London, UK. The interviews focused upon experiential accounts of living with HIV. The interviews were transcribed and analysed for recurrent themes using interpretative phenomenological analysis. The social context of being a Black African living in the UK emerged as an important framework within which the experience of being HIV positive was positioned. In terms of peoples accounts of their own experiences of living with HIV, diagnosis figured as an important moment in peoples lives. The majority of participants were surprised and upset upon receiving their positive antibody test results. Many reported a period of depression and social isolation. Stigma and prejudice associated with HIV also emerged as a major force shaping the daily lives of the participants. We discuss the role of identity and social context in disrupting the medical meaning of diagnostic tests.

Evaluation of the impact of immediate versus WHO recommendations-guided antiretroviral therapy initiation on HIV incidence: the ANRS 12249 TasP (Treatment as Prevention) trial in Hlabisa sub-district, KwaZulu-Natal, South Africa: study protocol for a cluster randomised controlled trial

BackgroundAntiretroviral therapy (ART) suppresses HIV viral load in all body compartments and so limits the risk of HIV transmission. It has been suggested that ART not only contributes to preventing transmission at individual but potentially also at population level. This trial aims to evaluate the effect of ART initiated immediately after identification/diagnosis of HIV-infected individuals, regardless of CD4 count, on HIV incidence in the surrounding population. The primary outcome of the overall trial will be HIV incidence over two years. Secondary outcomes will include i) socio-behavioural outcomes (acceptability of repeat HIV counselling and testing, treatment acceptance and linkage to care, sexual partnerships and quality of life); ii) clinical outcomes (mortality and morbidity, retention into care, adherence to ART, virologic failure and acquired HIV drug resistance), iii) cost-effectiveness of the intervention. The first phase will specifically focus on the trial’s secondary outcomes.Methods/designA cluster-randomised trial in 34 (2 × 17) clusters within a rural area of northern KwaZulu-Natal (South Africa), covering a total population of 34,000 inhabitants aged 16 years and above, of whom an estimated 27,200 would be HIV-uninfected at start of the trial. The first phase of the trial will include ten (2 × 5) clusters. Consecutive rounds of home-based HIV testing will be carried out. HIV-infected participants will be followed in dedicated trial clinics: in intervention clusters, they will be offered immediate ART initiation regardless of CD4 count and clinical stage; in control clusters they will be offered ART according to national treatment eligibility guidelines (CD4 <350 cells/μL, World Health Organisation stage 3 or 4 disease or multidrug-resistant/extensively drug-resistant tuberculosis). Following proof of acceptability and feasibility from the first phase, the trial will be rolled out to further clusters.DiscussionWe aim to provide proof-of-principle evidence regarding the effectiveness of Treatment-as-Prevention in reducing HIV incidence at the population level. Data collected from the participants at home and in the clinics will inform understanding of socio-behavioural, economic and clinical impacts of the intervention as well as feasibility and generalizability.Trial registrationClinicaltrials.gov: NCT01509508; South African Trial Register: DOH-27-0512-3974.

Homosexual men in Australia: population, distribution and HIV prevalence.

OBJECTIVES To assess the size, distribution and changes in the population of homosexual and bisexual men in Australia, and the capacity of available measures to make this estimation. METHODS We used data from five sources: the Australian Study of Health and Relationships, the Gay Community Periodic Surveys, HIV Futures, the Health in Men cohort study, the Australian National HIV and AIDS Registries and the Australian Household Census. RESULTS We estimated that in 2001 there were approximately 74 000 homosexual and bisexual men in New South Wales (NSW), approximately 42 000 in Victoria and approximately 37 000 in Queensland. There was, however, some discrepancy between datasets in the estimates of the overall proportions and distribution of homosexual and bisexual men across states. We also estimated HIV prevalence rates among homosexual and bisexual men in 2001 at approximately 8% in NSW, 5% in Victoria and 4% in Queensland. There were insufficient data to estimate whether the state-specific populations of homosexual men were changing with time. CONCLUSION There are ~75% more homosexual and bisexual men in NSW than in Victoria and about twice as many as in Queensland. There are about two-thirds as many HIV-positive men in NSW as in Victoria and Queensland combined. Improved collection of population-based data on homosexuality are required.

Anal sexually transmitted infections and risk of HIV infection in homosexual men.

Background:We examined a range of common bacterial and viral sexually transmitted infections as risk factors for HIV seroconversion in a community-based cohort of HIV-negative homosexual men in Sydney, Australia. Methods:Detailed information about HIV risk behaviors was collected by interview twice yearly. Participants were tested annually for HIV, anal and urethral gonorrhea and chlamydia, herpes simplex virus types 1 and 2, and syphilis. In addition, they reported annual diagnoses of these conditions and of genital and anal warts. Results:Among 1427 enrolled participants, 53 HIV seroconverters were identified, giving an incidence of 0.78 per 100 person-years. After controlling for number of episodes of insertive and receptive nonseroconcordant unprotected anal intercourse, there were independent associations with anal gonorrhea (adjusted hazard ratio = 7.12, 95% confidence interval: 2.05 to 24.79) and anal warts (hazard ratio = 3.63, 95% confidence interval: 1.62 to 8.14). Conclusions:Anal gonorrhea and anal warts were independently associated with HIV acquisition. The added HIV prevention value of more frequent screening of the anus to allow early detection and treatment of anal sexually transmitted infections in homosexual men should be considered.