Clinical trials are under way to test several drugs designed to treat human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS), 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.

Scientists are developing a topically applied drug called a microbicide (an agent that destroys microbes) that kills HIV and other sexually transmitted diseases during sex while also protecting vaginal and rectal tissue. This would ensure that people are protected against HIV transmission without having to rely on the cooperation of their sexual partner. Microbicides could be available by 2010, according to reports by the United Nations.

Additional research is ongoing to investigate the structure of the HIV virus, how HIV progresses into AIDS, and to develop other potential new medications or combinations of medications that may be more effective or have fewer side effects than current antiretrovirals.