text: what is the reason that 50% of the hiv case in the usa are african american? i heard it on npr sorry for the first answer that you received to your honest question... the reasons behind the infection rate really due lie in the use of condoms but not as ignorantly put by the previous poster. african american people are the least likely to have adequate health care and therefore not have knowledge of the transmission of the disease. it is also well documented that some aa men have at times engaged in high-risk sexual behavior with other hiv+ men (down-low) or with prostitutes. they then unknowingly bring the disease home to their gf/wife. there are many other factors that go into the descrepancy between the races but this seems to be the number one cause.