Early Treatment Cuts Spread of HIV Between Sex Partners, Study Says

In the first large-scale clinical study of its kind, U.S. researchers found that giving AIDS drugs to HIV-positive people relatively early — before their immune systems deteriorate badly — reduces their risk of transmitting the virus to their sexual partners by 96 percent.

“This new finding convincingly demonstrates that treating the infected individual — and doing so sooner rather than later — can have a major impact on reducing HIV transmission,” Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, the study sponsor, said in a news release.

The international study, which began in April 2005, included 1,763 couples, nearly all of them heterosexual, with one infected partner.  The infected partners had CD4+ T-cell levels — a key measure of immune system health — of between 350 and 550 around the beginning of the study.

(As Science reports, normal CD4 levels are above 600, and most guidelines in developed countries recommend starting treatment at levels between 350 and 500.)

The couples were randomly assigned to two groups. The infected partners in one group immediately began receiving antiretroviral medications, which are prescribed to suppress HIV.

Treatment for infected partners in the other group was delayed until the patient’s CD4 levels deteriorated to below 250 or when the patient developed an illness associated with AIDS, such as pneumocystis pneumonia.

Overall, 28 HIV infections appear to have been transmitted from one sexual partner to another— and all but one of those cases occurred in the delayed treatment group.

The study was supposed to continue until 2015 but the results were so dramatic that the researchers decided to end it early.

“This is amazing news,” Michael Sidibe, executive director of the Joint United Nations Programme on HIV/AIDS, told the Los Angeles Times. “Prevention can be a reality. The science is strong — so strong that we must use it.”


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