4. Subjects must be naïve to ARV medications except for women who have received HAART for prevention of maternal to child transmission (MTCT) that meet the following criteria: HAART (defined as three medications from two classes) given for no more than six months for prevention of MTCT, Evidence of viral suppression on the HAART regimen defined as a plasma RNA level below the level of detection for the assay used by the site either during the third trimester or around the time of delivery, A minimum of six months since HAART exposure for prevention of MTCT, and Exposure to HAART for a single pregnancy only; Note: Prior treatment with Trizivir for prevention of MCTC is also permitted as long as viral suppression is documented at the time of delivery or in the last trimester, whichever is most recent.