Treatment-centred prevention

In their commentary ‘Remedicalizing an epidemic: from HIV treatment as prevention to HIV treatment is prevention’, Nguyen et al.[1] argue that the strong focus on ‘treatment-as-prevention’ (TASP) and other new technologies for HIV prevention signals remedicalization of HIV epidemics and a regression to the view of HIV as a medical problem best addressed by purely technical, biomedical solutions in the hands of biomedical professionals and scientists. They further question the potential of TASP to reduce HIV incidence and warn that remedicalization may come at the cost of reduced attention to the social, economic and sex inequalities which render people vulnerable to HIV infection and hinder access to HIV prevention and treatment. We agree that recent operational research findings have reinforced the momentum for TASP [2–5]. However, we wish to offer a more nuanced view of the position of TASP in the HIV prevention arsenal, its potential impact on HIV incidence and the social costs and benefits associated with implementation of TASP. We propose to replace the term and the narrowly biomedical connotation of TASP with a more holistic, inclusive notion of ‘treatment-centred prevention’ (TcP). TcP avoids ideology-based choices between old and new HIV prevention technologies, but implies combination prevention: HIV treatment as the cornerstone in synergistic programmes that offer a package of HIV prevention methods with proven effectiveness, tailored and sensitive to the local epidemiological and sociocultural contexts. HIV counselling and testing, presumptive treatment of sexually transmitted infections and medical male circumcision offer entry points for timely diagnosis and management of HIV infection. Similarly, early initiation of HIV treatment provides an opportunity for HIV-infected individuals and their partners to access biomedical and social support in their efforts to reduce the risks of HIV transmission. As Nguyen et al.[1] correctly point out, ready access to antiretroviral therapy (ART) for eligible patients is in itself not sufficient for effective HIV prevention. Even if ART coverage was near universal, the time lag between HIV infection and initiation of ART would still be at least 5–10 years for most HIV-infected individuals under the CD4 cell count ART initiation thresholds currently used in resource-constrained countries. Assuming CD4 cell counts in HIV-infected people decline at an average of 60 cells/year [6], shifting the ART eligibility criteria from 200 to 350 or 500 cells/μl would decrease the period of unsuppressed viral load by 2.5–5 years on an average. Ongoing modelling work [7] suggests that such shifts have the potential to reduce the population HIV incidence by 40–50% over a period of 10 years, especially if interventions are prioritizing population groups at high risk of HIV acquisition and transmission, such as pregnant women and their partners. In contrast to the increases in risky sexual behaviour among MSM in San Francisco, cited by Nguyen et al.[1], evidence from Uganda and South Africa suggests that the expansion of ART has led to a decreased rather than increased sexual risk taking among individuals on ART [8,9]. The commentary also states that the impact of TASP is undermined by up to two thirds of HIV transmission events occurring during acute HIV infection which is most likely to take place before ART initiation. Although such high fractions of HIV transmission events during acute HIV infection may occur in certain individuals, this is generally not true: given the short duration of the acute stage of HIV infection [10], the acute infectivity spike is ‘wasted’ on the partner from whom HIV infection was acquired, unless the newly infected individual has concurrent partners. Although the prevalence of concurrency may be larger in Africa than in other parts of the world, it rarely exceeds 25% [11–14]. Dedicated analyses, integrating behavioural, clinical and epidemiological evidence, have estimated that even under the most liberal behavioural assumptions (a different partner for every sex act), no more than 31% of new infections are due to the acute stage of HIV infection [10,15]. In line with Nguyen et al.[1], we are of the opinion that – parallel to biomedical interventions – large-scale social and structural interventions to create sustained, equitable socioeconomic environments are long overdue [16–18]. We argue, however, that TcP has the potential to enhance rather than impede social transformation, community empowerment and health systems strengthening. Any TcP trial or programme large enough to impact on HIV incidence at the population level will affect a vast proportion of HIV-infected and HIV-uninfected people – either directly or indirectly. It is, therefore, of paramount importance to actively involve the relevant communities in the processes of design, implementation and monitoring of TcP programmes. Job creation and capacity building to accommodate the increased need for ample medical, psychological and social follow-up of individuals and couples should reinforce community ownership of TcP programmes. By extension, TcP may boost the sense of community empowerment to address deeply rooted social problems, including the societal burden of HIV. Moreover, if members of the community took a central role in the monitoring and evaluation of the impact of TcP on physical health, on psychosocial and economic well being and on health systems, their feedback would enable timely improvements to the programme. Lastly, horizontal integration and concurrent health systems strengthening is key in order to generate synergies between TcP and a host of ongoing health initiatives. Specifically, positive interactions should leverage efforts to reduce HIV-related stigma and discrimination, ‘normalize’ HIV testing and ART, prevent mother-to-child transmission of HIV, improve maternal health and the well being of children affected by AIDS and prevent interpartner violence. In conclusion, TcP may be a more social and effective approach to HIV prevention than portrayed by Nguyen et al.[1]. Unlocking the full potential of TcP, however, will require social and biomedical scientists to work with – not against – each other.