Vladimir Novitsky, from the Harvard School of Public Health, offered the audience at the International Treatment as Prevention Workshop in Vancouver a snapshot of a four-year treatment as prevention study planned for Botswana. Botswana has the highest antiretroviral therapy (ART) coverage rate in southern Africa with more than 90 percent of individuals with CD4 counts less than 350 on ART.
This study will include viral load testing as a component of evaluating individuals for ART, and Novitsky’s overview of the study occurred in the context of a debate with Jonathan Mermin of the U.S. Centers for Disease Control and Prevention about whether viral load monitoring should be a key component of implementing treatment as prevention. Novitsky pointed out that there is a population of so-called “high viremics,” a group of patients for whom viral load does not drop significantly after acute infection. Persons with a high viral load are most likely to transmit HIV infection. These same individuals are also much more likely to have a rapid decline in their CD4 counts.
Viral load will drive access to ART in this planned community-randomized trial in 30 communities. The target population with be 100,000 people ages 16 to 64. The intervention arm of the trial will have several interventions. HIV counseling and testing to identify HIV-infected persons will be followed by CD4 and viral load testing. Individuals with CD4 counts above 350 with viral loads of more than 10,000 copies will be placed on ART for prevention. There will be active linkage to HIV care and treatment, and aggressive promotion of voluntary medical male circumcision to HIV-uninfected men. Pregnant HIV-infected women will be initiated on ART during pregnancy and HIV-uninfected pregnant women will be tested again late in pregnancy. The goal is to reduce HIV incidence in adults by 50 percent over the course of the study, and to analyze the costs and the cost-effectiveness of the intervention. One of the hypotheses of the study is that targeting ART to those more likely to transmit HIV infection because of high viremia will offer a more cost-effective way to expand ART for prevention.