About The Study

This trial, which took place in both the U.S. and Canada, studied whether beginning a 12-month period of antiretroviral therapy (ART) immediately after contracting HIV would delay the need for permanent treatment compared to observation alone.

Study Approach

People who acquired HIV within 12 months of beginning the study were recruited. Individuals with acute (acquired in the previous 0-2 months) and early (2-12 months) HIV infection were to either be clinically observed or receive a 12-month course of ART. All participants were monitored with regular clinic visits. Regardless of how long a participant was involved in the study ART was initiated if CD4 cell count fell below 350/mm3, following the treatment guidelines at the time. The primary measure of the trial was the ART-free time from beginning the trial until initiation of permanent ART.


The study found no benefit in 12-month treatment with ART in delaying the need for a permanent regimen. The number of months before beginning permanent treatment was the same in both the immediate and observation groups (18 months). Immune function in the immediate ART group was not improved compared to the observation group.


This study supports the conclusion of several other studies that show no benefit of treatment interruption in delaying the need for permanent ART. Since the completion of this study, both the US government and World Health Organization recommend that those who test positive for HIV should begin permanent treatment immediately, regardless of CD4 count.

Principal Investigators

Here’s who is leading this study.

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