The overall prevalence of AIDS at presentation according to the United States CDC 2014 case definition for HIV infection [29] (AOIs or CD4 cell count < 200 cells/μL) was 37.7% [38.5% in period 1, 38.4% in period 2, and 36.2% in period 3 (P = 0.74)]. Here, CD4 is linked to HIV infectious disease.