• AIDS-free survival [ Time Frame: Week 144 ] [ Designated as safety issue: Yes ]
  

• Direct and indirect cost of treatment per patient [ Time Frame: Week 144 ] [ Designated as safety issue: No ]
  
• Number and duration of hospitalizations [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  
• Time to and number of Grades 3 or 4 HAART-related toxicity and intolerance [ Time Frame: throughout study ] [ Designated as safety issue: Yes ]
  
• Number of HAART regimen changes [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  
• Number of Grades 1 or 2 infectious episodes [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  
• Number of courses of antibiotics used [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  
• Number of HIV-related clinical events [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  
• Virologic failure, defined as HIV viral load of 1000 copies/ml [ Time Frame: Week 24 after HAART initiation ] [ Designated as safety issue: No ]
  
• Presence of a resistance mutation in participants with virologic failure [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  
• Change of growth in Z scores [ Time Frame: study entry to Week 144 ] [ Designated as safety issue: No ]
  
• Change in CD4% and time-weighted average change [ Time Frame: study entry and Week 144 ] [ Designated as safety issue: No ]
  
• CD4 less than 10% [ Time Frame: Week 144 ] [ Designated as safety issue: No ]
  
• Average scores of the child's quality of life over time [ Time Frame: Week 144 ] [ Designated as safety issue: No ]
  
• Percentage adherence to HAART over time by pill count/weighing liquid medication bottles, self report, and questionnaire [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  
• Presence of iron deficiency anemia [ Time Frame: study entry and Weeks 24, 48, 72, 96, 120, and 144 ] [ Designated as safety issue: No ]
  
• HIV viral sequence [ Time Frame: study entry and treatment failure ] [ Designated as safety issue: No ]
  
• HIV viral replication capacity [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  
• Cytotoxic T-cell (CTL) response [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  
• Percentage of different T-cell subsets [ Time Frame: study entry and Weeks 48, 96, and 144 ] [ Designated as safety issue: No ]
  

The use of highly active antiretroviral therapy (HAART) has resulted in a significant reduction in AIDS-related deaths and complications among adults and adolescents. However, the medical management of HIV infected children remains challenging. Access to HIV treatment is limited and early treatment initiation can cause serious complications. Since there is currently no cure for HIV, a balance between treating the disease and maintaining quality of life must be weighed carefully. An evaluation to determine the appropriate time to initiate HAART is necessary to improve both quality of life and survival for HIV infected children.

This study will last 144 weeks. All participants will have a CD4 percentage (CD4%) between 15% and 24% and will be randomly assigned to either receive immediate or delayed HAART. The HAART regimen will consist of two nucleoside reverse transcriptase inhibitors, zidovudine and lamivudine. In addition, participants will also receive either one non-nucleoside reverse transcriptase inhibitor, nevirapine or efavirenz, or one protease inhibitor, ritonavir-boosted lopinavir or nelfinavir. Abacavir will replace zidovudine or lamivudine if participants experience toxicity to the regimen. Participants in the immediate treatment arm will receive HAART on Day 1 of the study regardless of their CD4%. Participants in the delayed treatment arm will receive HAART if their CD4% falls below 15 or if they develop a CDC Category C illness.

Study visits will occur every 4 weeks for the first 12 weeks and then every 12 weeks until the end of the study. Blood collection, physical exams, and medical and medication history reviews will occur at all visits. Adherence, quality of life, and lipodystrophy assessments will occur every 12 weeks for participants on HAART. Participants will be encouraged to enroll in a related substudy to examine the neurodevelopment of HIV infected children.