Vol. 13, No. 4 - July-August 2009Cover Art

What if there were magic pills that could effectively treat HIV infection, prevent HIV-infected individuals from transmitting the virus to others, reduce prevalence of tuberculosis, and perhaps even protect uninfected individuals from acquiring HIV? Oh wait, maybe there are. They’re called antiretrovirals (ARVs), and they have revolutionized the treatment of HIV infection.

So far, the road to developing biomedical interventions to prevent HIV infection has been a bit rockier. In his talk at the 5th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention, held recently in Cape Town, South Africa (see Everything from Cause to Cure for our report on the conference), Ronald Gray of Johns Hopkins University noted that of 29 trials evaluating the efficacy of different biomedical HIV prevention strategies, only four have shown significant success, and five have shown possible harm.

Until an effective vaccine or other HIV prevention strategy is developed, ARVs are being billed as one of the greatest hopes for controlling the global spread of HIV. One ARV-based approach to prevention is getting more HIV infected individuals on therapy. Evidence is accumulating that starting ARV treatment earlier in the course of HIV infection is beneficial. For prevention, the idea is that therapy, which efficiently and rapidly reduces viral load, could prevent those people already infected from transmitting HIV to others. This serves as the basis for the so-called test and treat strategy, which is explored in this issue (see Test and Treat on Trial).

But Stefano Bertozzi, who recently joined the Bill & Melinda Gates Foundation as HIV director, said at the IAS conference that twice as many people become HIV infected every day than are placed on treatment. In light of this, and the fact that there are still six million people who aren’t getting treatment that will die without it, Bertozzi said, “It’s really hard to imagine how [earlier treatment] could be a reality in the near future.”

Considering this, the development of other HIV prevention strategies remains a priority. ARVs will likely play a role in preventing the spread of the virus, but in the eyes of many, the development of a vaccine is an imperative. One component of vaccine development analyzed in this issue is the plethora of viral challenge models used to evaluate different vaccine approaches in non-human primates (see Looking for the Perfect Challenge). José Esparza, senior adviser on HIV vaccines at the Bill & Melinda Gates Foundation, said a vaccine is “the best hope to stop the epidemic in the poorest countries and populations in the world.”

—Kristen Jill Kresge, Managing Editor