Science Examines HIV/AIDS Prevention, Treatment Strategies Discussed at Last Week's Conference in Mexico City

The journal Science in its Aug. 15 issue examined the "intense scrutiny" that HIV/AIDS prevention and treatment received during last week's XVII International AIDS Conference in Mexico City. Mike Cohen of the University of North Carolina-Chapel Hill at the conference said the two efforts "keep going to the altar," but "[t]hey never get married. They have to get married today."

According to Cohen and other delegates at the conference, although there have been considerable gains in HIV/AIDS treatment, such efforts have overshadowed prevention needs. Science reports that three million people in low- and middle-income countries now have access to antiretroviral drugs but that an estimated five people contract HIV for every two provided with treatment. UNAIDS Executive Director Peter Piot said, "There has not been that push for prevention as there's been for treatment," adding, "If we thought the first phase was hard, we have to prepare for even tougher times."

Science reports that a significant issue surrounding treatment and prevention is that the success of antiretrovirals in lowering viral loads and making HIV-positive people less infectious has led to the "increasing awareness that treatment is prevention, both for individuals and populations." However, "the degree to which the drugs can prevent infections has proved highly contentious," according to Science. For example, a study by the Swiss Federal Commission for HIV/AIDS concluded that couples with one HIV-positive partner do not need to use condoms to prevent HIV transmission provided that the HIV-positive person is taking antiretrovirals, has had an undetectable viral load for six months and has no other sexually transmitted infections. Kevin de Cock, head of the World Health Organization's HIV/AIDS Department, said, "It just doesn't seem like a cautious public health recommendation," adding, "I don't think anyone's shown the threshold below which people cannot transmit" HIV.

Further contention surrounding treatment and prevention at the conference, according to Science, included the degree to which ongoing treatment can prevent transmission on a population-wide scale. Although a study published in the Canadian Medical Association Journal found that treatment led to a decrease in HIV transmission in the province of British Columbia, epidemiologist Geoffrey Garnett of Imperial College London said that antiretrovirals are unlikely to have a large effect on transmission on a global scale. About 80% of HIV-positive people are not aware of their status, and of those who do, most are not eligible for no-cost treatment until their immune systems have been damaged. According to Science, this means that most HIV transmissions "occur long before people are taking the drugs."

Garnett and others encouraged HIV/AIDS researchers to embrace the notion of "combination prevention." According to Garnett, by combining treatment with preventive measures, such as condom use and male circumcision, it might be possible to create "a natural synergy." He added, "Rather than arguing for a single magic bullet, we really need to be trying to focus everything that we can on what works to realize these natural synergies" (Cohen, Science, 8/15).

Kaisernetwork.org was the official webcaster of the XVII International AIDS Conference in Mexico City. Kaisernetwork.org interviews with Science correspondent Jon Cohen during the week of the AIDS conference are available online.

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