Unprotected Anal Intercourse, Risk Reduction Behaviours, and Subsequent HIV Infection in a Cohort of Homosexual Men

Fengyi Jin; June Crawford; Garrett P Prestage; Iryna Zablotska; John Imrie; Susan C Kippax; John M Kaldor; Andrew E Grulich


AIDS. 2009;23(2):243-252. 

In This Article

Abstract and Introduction

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 partner's 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.

Soon after the onset of the HIV epidemic in homosexually active men, unprotected anal intercourse (UAI) was identified as the main mode of HIV acquisition.[1,2,3] In response, gay communities in developed countries embraced the concept of 'safe sex', and there were dramatic reductions in UAI[4,5,6,7] and HIV transmission.[8,9,10]

Approximately 25 years later, homosexual men's behavioural response to the risk of HIV transmission has evolved considerably. In general, the proportion of men reporting 'unsafe sex', often measured as UAI with casual partners, has increased since the mid-1990s,[7,11] but at the same time recognition of a range of so-called 'risk reduction behaviours' has emerged. The risk is 'reduced' in that it is perceived to be lower than the highest risk activity (receptive UAI with an HIV-positive partner) but higher than having no UAI. From an HIV-negative man's perspective, there are at least four patterns of UAI behaviour in which he may believe he lowers his risk of HIV acquisition. First, in serosorting, UAI is practised only with partners believed to be HIV negative.[12,13,14] Second, in negotiated safety, a particular form of serosorting, UAI is restricted to an HIV-negative partner with whom a steady regular relationship is formed.[15,16] Third, in strategic positioning, the HIV-negative man takes only the insertive role in UAI.[17] Fourth, in withdrawal, the HIV-negative man engages in receptive UAI (UAI-R) only where ejaculation inside his rectum does not occur.[18]

Despite the relatively widespread and increasing practice of some risk reduction behaviours,[12,19,20] there is no published information from prospective studies on the risk of these behaviours. In this report, we describe the relationship between specific types of UAI, risk reduction behaviours, and HIV infection in a cohort of homosexual men in Sydney, Australia.


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