Patient characteristics at first clinic visit overall (total) and stratified according to when and if ART was initiated.

All initiation rules are mutually exclusive. For example, if a child started ART with a CD4 count of 650 cells/mm3 and a CD4% of 19%, then he/she would be included in the column “ART at 3 or aRefers to children who initiated ART during their follow-up but did not have recorded data on both CD4% and CD4 count at the time of ART initiation.