Before the onset of the AIDS epidemic, diseases such as Kaposi's sarcoma were extremely rare in the United States; for example, the rate of Kaposi's sarcoma was about 40 - 120 per year (0.2 to 0.6 per million population). During the AIDS epidemic up to 1999, CDC had recorded 46,684 definite cases of the disease.

Similarly, there had been just 107 cases of Pneumocystis carinii pneumonia reported in the United States, whereas the AIDS epidemic resulted in 166, 368 cases up to 1999.

Prior to the AIDS epidemic, there had been 32 cases of disseminated infection with the Mycobacterium avium complex but the AIDS epidemic resulted in 41,873 cases up to 1999