Before the AIDS epidemic, KS rarely occurred in the US. About 2 new cases of KS were found for every 1,000,000 people in the US each year. Now, however, most KS cases in the US develop in people infected with HIV. Kaposi sarcoma herpesvirus (KSHV), the virus that is necessary for KS to develop, is found more commonly in people infected with HIV than in the general population in the US. The weakened immunity that results from HIV increases the chance that a KSHV-infected person will develop KS.

It has been estimated that an HIV-infected person has a 20,000 times increased risk of developing KS compared with people without HIV. AIDS patients with KS increased the rate of KS in this country more than 20 times - peaking at 47 cases per million people (per year) in the early 1990s. Early in the AIDS epidemic, patients infected with HIV in the US were estimated to have a 1 in 2 chance of developing KS.

With new treatments for AIDS, KS has become less common in the US, with about 6 cases per million people each year. In the US, KS is much more common in men than in women, and it is rarely seen in children. In areas of the world (such as Africa) where KSHV and HIV infection rates are high, both endemic and HIV-associated KS are seen, and KS occurs in men, women and children.

Transplant recipients are another group that gets KS. About 1 in 200 transplant patients in the United States gets KS. This occurs primarily because they were already infected with KSHV prior to the transplant, they just don't have any symptoms. The drugs they take to suppress their immune system allow KS to develop.

Last Medical Review: 09/17/2009
Last Revised: 09/17/2009