Compared to young adults, a significantly higher proportion of the older adults were male (47.5% vs. 32.1%, p<0.001) attended rural clinics (61.1% vs. 54.7%, p<0.001), had lower CD4 count levels (p<0.001), were underweight (p<0.001) and were more likely to be enrolled in care late into their HIV infection (WHO clinical stage III/IV, p<0.001). This evidence concerns the gene CD4 and HIV infectious disease.