The NNTI per new HIV infection detected according to the CD4 of the interviewed index cases was 5.5 (22/4), 6.3 (19/3), 5.2 (23/5), and 2.9 (41/14) for CD4≤200, 201–350, 351–500, and >500 cells/mm3, respectively. This evidence concerns the gene CD4 and HIV infectious disease.