Testing, Immediately Treating HIV/AIDS Cases in Africa Could Halt Epidemic, Model Predicts

Testing all adults annually for HIV and immediately treating every person who tests positive "could virtually end the AIDS epidemic in Africa in about a decade," according to a mathematical model published Wednesday in the journal Lancet, the Washington Post reports. The "thought experiment" underscores the "usefulness of antiretroviral drugs as tools for preventing the spread of HIV infection as well as treating it" (Brown, Washington Post, 11/26). According to the AP/Google.com, this "intriguing solution" to ending the HIV/AIDS epidemic is "based on assumptions rather than data and is riddled with logistical problems."

For the study, Charlie Gilks, an AIDS treatment expert at the World Health Organization, and colleagues used data from South Africa and Malawi. In the model, people were voluntarily tested each year and immediately given antiretrovirals if they were found to be HIV-positive, even if they were not ill. Within 10 years, HIV cases decreased by 95% (Cheng, AP/Google.com, 11/25). According to the Post, under this strategy, incidence rates would decrease from 20 new cases per 1,000 people annually to one case per 1,000 people annually in about 10 years (Washington Post, 11/26). Other initiatives such as comprehensive sex education and male circumcision also were used (AP/Google.com, 11/25). The model assumed that all HIV cases were transmitted through heterosexual sex (Kahn, Reuters, 11/25). The model also assumed that HIV testing would be voluntary and that no one would be forced to start treatment. According to the Post, about 20% of HIV-positive people in developing countries are aware of their status, and this model would detect most cases (Washington Post, 11/26).

According to the researchers, the strategy would reduce the estimated number of AIDS-related deaths between 2008 and 2050 by about 50%, from about 8.7 million to 3.9 million deaths, leaving only sporadic HIV cases (AP/Google.com, 11/25). They wrote, "Although other prevention strategies, alone or in combination, could substantially reduce HIV incidence, our model suggests that only universal voluntary testing and immediate initiation of antiretroviral drugs could reduce transmission to the point at which elimination might be feasible by 2020 for a generalized epidemic, such as that in South Africa" (Reuters, 11/25).

Bloomberg reports that the study "hinges on emerging research suggesting that effective [antiretroviral] treatment can keep levels of the virus so low in people that the possibility it will spread is almost nil." Kevin De Cock, director of WHO's HIV/AIDS Department, said the findings are theoretical and that the organization is not changing its recommendations regarding HIV testing or treatment. However, he said in a statement that the "concept of antiretroviral treatment for HIV prevention is a very important, urgent thing to examine," adding, "We aim to stimulate discussion about what is probably the most important question in HIV prevention: when to start therapy?" (Lauerman, Bloomberg, 11/25).

According to experts, the cost of the strategy would peak at about $3.4 billion annually and decline after an initial investment (AP/Google.com, 11/25). In addition, the model would save money in the long term because there would be fewer HIV-positive people in need of treatment, the researchers said (Reuters, 11/25). "If we were to invest radically up front, we would have the opportunity to change the course of the epidemic," Julio Montaner -- an AIDS researcher affiliated with the University of British Columbia and the president of the International AIDS Society, who did not participate in the study -- said, adding, "What was cost effective based on patient outcomes now becomes cost averting once you add in the ability of antiretroviral therapy to reduce HIV transmission" (Goldstein, Wall Street Journal, 11/26).

WHO researcher Reuben Granich said wider HIV/AIDS treatment also would likely reduce costs associated with other diseases common among HIV-positive people, including tuberculosis and malaria (Bloomberg, 11/25). Nevertheless, the Journal reports that the strategy could encounter logistical and financial hurdles. "You can do a mathematical model, but that's different than actually testing an entire population, getting everyone who's positive into treatment and keeping them on treatment for the rest of their life," U.S. Global AIDS Coordinator Mark Dybul said (Wall Street Journal, 11/26). For example, increasing access to HIV testing and drugs could overwhelm already weak health care systems in Africa, according to the AP/Google.com. "This is not like giving someone a Tylenol," Jennifer Kates -- vice president and director of HIV policy at the Kaiser Family Foundation -- said, adding, "The idea should be explored, but it's a huge leap." Myron Cohen of the University of North Carolina said, "This is certainly beyond the bounds of the current infrastructure for many countries, but that is not a reason not to think big."

Another concern regarding the strategy is that providing every HIV-positive person with antiretrovirals could increase drug resistance. Furthermore, researchers do not yet know if it is safe to take antiretrovirals for decades; the oldest drug combinations have been around for about 12 years. Other experts also question whether the strategy might infringe on patients' rights because once an individual tests positive for HIV, he or she would be advised to begin treatment, even if they showed no symptoms. According to the AP/Google.com, "That would benefit the community, but not necessarily the patients themselves" (AP/Google.com, 11/25).

The Post reports that the model only applies to the type of epidemic seen in Southern Africa, where nearly all transmission occurs through heterosexual intercourse. Whether the findings might also apply to an epidemic in which the virus is mainly transmitted among injection drug users and men who have sex with men is not yet known. According to De Cock, WHO plans to hold a meeting early next year to examine the implications of the model (Washington Post, 11/26).

In an accompanying editorial, Geoffrey Garnett of Imperial College London said, "At best, the strategy would prevent morbidity and mortality for the population, both through better treatment of the individual and reduced spread of HIV." He added, "At its worse, the strategy will involve over-testing, over-treatment, side effects, resistance and potentially reduced autonomy of the individual in their choices of care" (Reuters, 11/25).

The study is available online.

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