AAAS meeting examines test-and-treat model's potential for fighting HIV spread, TB co-infection

Feb 23 2010

Researchers speaking at the American Association for the Advancement of Science (AAAS) meeting on Saturday, discussed how a strategy to promote universal voluntary HIV tests and early antiretroviral treatment for patients living in high-risk areas might "derail the spread of [HIV/]AIDS, a battle where a successful vaccine remains elusive," the Associated Press/Washington Post reports. "Called 'test-and-treat,' the goal is to catch new [HIV] cases early and administer therapy to reduce the amount of virus in patients' systems in an effort to prevent them from spreading the illness," the news service writes.

Though advances in antiretroviral therapies have proven successful at helping patients to live longer, "[b]y the time people start therapy they have infected most of those that they would have infected anyway, [former WHO epidemiologist] Brian Williams of the South African Centre for Epidemiological Modelling and Analysis told the annual meeting on the [AAAS]," the AP reports (Schmid, 2/21).

According to AAAS Annual Meeting News, "By testing people in high-risk regions and immediately ... putting the patients on medications that reduce their viral-loads, Williams said that public health officials could 'render HIV-infected people not infectious.'" The article also includes comments from Brown University's Kenneth Meyer and Scripps Research Institute's Dennis Burton who appeared with Williams (2/20).

"The concentration of the virus drops by a factor of 10,000 with antiretroviral treatment, resulting in 25 times the reduction of infectiousness, Williams said," CNN reports. He estimated that, with such an approach, "We could effectively stop transmission within five years." The most recent WHO and UNAIDS statistics indicated that in 2008 there were more than 33 million people living with HIV around the world, CNN reports (Landau, 2/20).

"While such an initiative would be expensive at first, costing at least $3 billion a year in South Africa alone, it would rapidly pay for itself by cutting the cost of caring for AIDS patients and reducing the economic damage caused by AIDS deaths, Dr. Williams told" the conference, the London Times reports (Henderson, 2/22).

CNN continues, "In a 2009 article in The Lancet, Williams and his colleagues at the World Health Organization advocated for broader use of antiretroviral drugs, proposing that everyone over age 15 should be tested annually for HIV, and that anyone who tests positive should begin antiretroviral treatment immediately," a concept that is beginning to attract international support, Williams said (2/20).

The AP/Washington Post adds details on several test-and-treat pilot studies to be run in New York and Washington, D.C., being led by the U.S. National Institute of Allergy and Infectious Diseases in partnership with the CDC (2/21). The London Times writes, "Two randomised trials of universal testing and treatment are to begin in South Africa shortly, and the World Health Organisation (WHO) has indicated that it will back the strategy if they prove successful" (2/22). The trials will "feed into a final decision on whether to adopt the measure as public health policy in the next two years," the Guardian reports (Sample, 2/21).

Williams presented data during the AAAS meeting on how the test-and-treat model could also "potentially avert millions of cases of HIV-related tuberculosis," Science News reports. Patients with immune systems compromised by HIV have an increased vulnerability to tuberculosis infection. "Worldwide, TB kills as many as half of all people with AIDS, according to the Joint United Nations Programme on HIV/AIDS," the magazine writes.

Williams "created a mathematical model of disease spread under different treatment strategies in sub-Saharan Africa using previously published data. For the nine countries considered, the model suggests, yearly HIV testing and immediate treatment with antiretroviral therapy would avert more than 6 million cases of TB by the year 2050," Science News writes. When treatment is delayed, the number of TB cases goes up, demonstrating the significance of early treatment with antiretrovirals, according to an unpublished study by Williams (Ehrenberg, 2/21).