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Antiretroviral Therapy Greatly Reduces HIV Transmission


Preliminary results from a multicenter clinical trial found that immediate treatment of HIV positive persons with antiretroviral therapy (ART) reduced sexual transmission of HIV to non-infected partners by 96 percent. The findings were part of a 13-site study funded by the National Institute of Allergy and Infectious Diseases at the National Institutes of Health that involved 1,700 couples in which one partner was HIV positive (with a CD4 cell count between 350-550 cells/mm3). Two of the study sites—one in Blantyre, Malawi, and another in Chiang Mai, Thailand—were led by researchers from the Johns Hopkins Bloomberg School of Public Health. 

On April 28, an independent Data and Safety Monitoring Board concluded that the trial had demonstrated a benefit of immediate antiretroviral therapy with respect to HIV transmission. The Board recommended that the primary study results be announced as soon as possible given that the findings definitively show that immediate initiation of ART reduced transmission of HIV.

“These data conclusively demonstrate that beginning HIV treatment early is a natural form of HIV prevention,” said David Celentano, ScD, MHS, principal investigator for the Thailand study site and the Charles Armstrong Chair and Professor of Epidemiology at the Bloomberg School of Public Health. “The data showed that ART can reduce HIV transmission by 96 percent, an impact that has never before been seen in the history of HIV prevention research. Further, those in the early intervention group suffered from less morbidity (bacterial infections and tuberculosis) and mortality (deaths) than those in the delayed group.”

The trial, known as HPTN 052,was designed to evaluate the optimal time to initiate ART in order to reduce morbidity and mortality in people infected with HIV/AIDS. Couples were randomized to immediately initiate ART upon enrollment or to delay initiation of treatment until two consecutive CD4 cell counts were at or below 250 cells/mm3 or when an AIDS-defining illness was diagnosed. Each couple enrolled was to be followed for at least five years.

“With the expanding services of antiretrovirals in sub-Saharan Africa, these data should strengthen our approaches for both prevention and treatment," said Taha E. Taha, MBBS, PhD, principal investigator for the Blantyre, Malawi, site and professor of Epidemiology at the Bloomberg School of Public Health.  

Media contact: Tim Parsons, director of Public Affairs, at 410-955-7619 or