Clinical trials are under way to test several drugs designed to treat human immunodeficiency virus (HIV) and AIDS (acquired immune deficiency syndrome), or infections related to the virus. One medication attacks HIV in the last stages of its life cycle, and another prevents the virus from entering healthy cells.

Clinical trials are also being conducted to test dozens of potential AIDS vaccines, although experts generally do not expect an effective vaccine to be available for many years.

Researchers also are making promising strides in the hope of protecting women from HIV. Scientists are developing a topically applied drug called a microbicide (an agent that destroys microbes) that kills the HIV virus and other sexually transmitted diseases during sex while also protecting vaginal and rectal tissue. Microbicides could be available by 2010, according to reports by the United Nations.