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Abstract and Introduction
Abstract
Background: Risk-reduction counselling is a standard preventive intervention, but behaviour change is difficult to sustain over the duration of HIV infection. However, primary HIV infection (PHI) is highly infectious and plays a key role in transmission - especially through dense sexual networks - but is short term, so even transient risk reduction can mitigate its high infectivity. Targeting behaviour-change interventions at recently infected individuals may be highly effective, particularly in higher risk groups. We explored the potential impact on HIV transmission-risk behaviour of PHI diagnosis in men who have sex with men (MSM).
Methods: MSM with PHI were interviewed at diagnosis and after 3 months of follow-up about their sexual behaviour in the 12-week periods before and after diagnosis and standard counselling.
Results: A total of 98 of 104 eligible MSM (94%) participated in the study, with 100% follow-up. PHI was associated with high levels of recreational drug use, low levels of condom use, high numbers of sexual partners and a history of sex work. In the 12 weeks post-diagnosis, 76% of participants eliminated risk of onward transmission entirely and, overall, there was a significant reduction in transmission-risk behaviour, with patients reporting greater condom use and fewer sexual partners. Those with continued transmission-risk behaviour were more likely to have another sexually transmitted infection (STI), use ketamine and have more sexual partners at baseline.
Conclusions: Most MSM recently diagnosed with PHI changed their behaviour to substantially reduce the risk of onward HIV transmission. Strategies are needed to (a) increase diagnoses of PHI to target prevention efforts effectively and (b) further reduce risk behaviours by targeting enhanced counselling to those most likely to continue with risk behaviours.
Introduction
HIV transmission rates in men who have sex with men (MSM) remain high in the United States of America, the United Kingdom and elsewhere in Western Europe. In both the United States of America and the United Kingdom, more than half of new HIV infections are occurring in MSM. The major HIV prevention intervention has been the promotion of risk-reduction behaviour, which was traditionally focused on uninfected persons. More recently, the focus has been changing towards earlier diagnosis of infection through 'routinized' HIV testing in multiple healthcare settings, coupled with behaviour-change counselling of those diagnosed as HIV positive. However, HIV prevention resources are limited, behaviour-change counselling interventions are costly (preventing many successful interventions from being routinely implemented) and their effects can be transient, so resources need to be focused where they will be most effective.
Prevention of onward transmission is pertinent to all stages of HIV infection. However, targeting of primary HIV infection (PHI) may be highly cost-effective in populations where it accounts for a large proportion of HIV transmission events, as it is short-lived, meaning that even transient reductions in risk behaviour can mitigate its high infectivity. In phylogenetic studies, it was found that a-quarter-to-a-half of HIV transmission may occur during PHI, as a result of high viral load, common coinfection with sexually transmitted infections (STIs) that promote HIV transmission and typically high-risk behaviour. However, effective diagnosis of PHI is resource-intensive, requiring targeted, frequent testing of high-risk groups.
Increased HIV testing through 'routinizing' of testing in healthcare settings has been advocated to reduce the prevalence of undiagnosed HIV infection and to facilitate behaviour change to reduce transmission. However, the frequency of testing is likely to be too low to increase the detection of PHI, because of its short duration. Therefore, additional targeted efforts to detect PHI in high-risk groups through high-frequency testing may be an effective component of HIV prevention - depending upon the impact of diagnosis on transmission-risk behaviour.
To assess the prevention-effectiveness of diagnosing PHI in high-risk groups, we need to consider (i) how effectively PHI cases can be identified and (ii) how much of the PHI transmission risk can be averted. We address the latter question in this study in order to understand the impact of routine counselling and care, and to identify characteristics of patients for whom this alone is insufficient.
Studying PHI is difficult, because its short duration and many missed opportunities for diagnosis limit the number of subjects that can be identified. Data on the risk behaviour of newly HIV-infected individuals before and after HIV diagnosis are limited and conflicting, so more studies are required. It is important to assess risk behaviour and quantify changes post-diagnosis, to determine the potential impact of increased detection of PHI, and to identify those most in need of assistance in reducing their transmission-risk behaviour so that counselling efforts can be targeted most effectively. Our objectives were (i) to characterize MSM diagnosed with PHI at an HIV clinic in London; (ii) to investigate whether HIV diagnosis and standard transmission risk-reduction counselling changed their sexual behaviour; and (iii) to examine risk factors associated with behaviours that pose a continued transmission risk to others, post-diagnosis.
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