Global health: Persuasive evidence on HIV policy.


In the tragic story of the global HIV/AIDS epidemic, one glimmering light is anti­ retroviral therapy. This treatment involves a combination of at least three drugs that sup­ press HIV, and it prevents progression of the infection to AIDS and death. As emergency investment to fight HIV/AIDS evolves into a long­term response, it remains crucial to measure the direct and indirect benefits of HIV treatment to sustain investment. Two studies published in Science (Tanser et al. and Bor et al.) show a large increase in the overall pop­ ulation life expectancy and a decrease in new cases of HIV infection after expanded use of antiretroviral therapy in South Africa (Fig. 1). That antiretroviral therapy greatly increases the survival of individuals with HIV has been known since the 1990s. Global scale­up of this therapy, however, started in 2004, following large investments by the US President’s Emer­ gency Plan for AIDS Relief (PEPFAR) and the Global AIDS Program (GAP). Since then, antiretrovirals have been given to more than 8 million people worldwide (Fig. 2), leading to millions of life­years saved — an unprec­ edented public­health success story. Studies of HIV­discordant couples (in which one partner has HIV and the other doesn’t) have shown that if the HIV­infected partner receives antiretroviral therapy, transmission rarely occurs. The most compelling confirma­ tion of this observation was a multi­country phase III clinical trial (HIV Prevention Tri­ als Network 052), in which antiretrovirals decreased the risk of sexual transmission of HIV between couples by 96%. These studies, however, involved motivated patients with high levels of adherence to treatment. The Science papers add a unique perspec­ tive on the benefits of antiretroviral therapy on life expectancy and transmission at a gen­ eral population level. The studies investigate a meticulously characterized population of more than 101,000 individuals from house­ holds in a 434­square­kilometre surveillance area in rural KwaZulu­Natal, South Africa. Between 2000 and 2011, the households were surveyed twice a year for birth and death data by the Africa Centre for Health and Popula­ tion Studies in KwaZulu­Natal. A subset of these individuals was serially tested for HIV to estimate the rates of new HIV infections. Starting in 2004, Tanser and colleagues’ map­ ping of individual household location, local HIV prevalence and the proportion of HIV­ infected individuals in specified geographi­ cal areas who were receiving antiretrovirals (antiretroviral­therapy coverage) allowed them to discern whether living in an area with better coverage was associated with lower risk of acquiring HIV infection. Both studies demonstrate the profound impact of antiretroviral­therapy coverage at a population level. Bor and colleagues show that expansion of therapy programmes increased the overall adult life expectancy by 11.3 years in KwaZulu­Natal. Tanser et al. estimate that in communities in which 30–40% of those infected with HIV were taking antiretrovirals, uninfected individuals were 38% less likely to acquire HIV than those in communities in which the therapy was less widespread. Population studies such as these, which involve individuals who may have much lower drug adherence than those participating in carefully controlled clinical trials, are a powerful complement to clinical trials. They give us a sense of impact in the ‘real world’. The reality is that the new studies focus on a fairly specific real world — one in which HIV prevalence was staggeringly high, allowing detection of the impact of therapy on overall adult life expectancy. Nonetheless, the stud­ ies are persuasive in the larger landscape of global HIV. Several other countries in south­ ern and eastern Africa that also have a high prevalence of HIV could expect to see similar results. In 2012, 25 countries saw a decline of more than 50% in new HIV infections. This decrease was due to multiple factors, but undoubtedly antiretroviral therapy played a pivotal part. These data, therefore, should persuade policy­makers to sustain or increase invest­ ment in this form of therapy. Global aid funds are constricting or staying stable, whereas health needs are persisting or expanding. It is clear from the two studies that for regions of high HIV prevalence, including South Africa, greater investment in antiretroviral Figure 1 | A woman with HIV infection in KwaZulu-Natal, South Africa. ZI V K O R EN /P O LA R IS /E YE V IN E

DOI: 10.1038/495452a

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@article{JohnStewart2013GlobalHP, title={Global health: Persuasive evidence on HIV policy.}, author={Grace John-Stewart}, journal={Nature}, year={2013}, volume={495 7442}, pages={452-3} }