Scientists are also investigating and testing chemical barriers, such as topical microbicides, that people can use in the vagina or in the rectum during sex to prevent HIV transmission. They also are looking at other ways to prevent transmission, such as controlling sexually transmitted diseases and modifying people's behavior, as well as ways to prevent transmission from mother to child.
A clinical trial (also clinical research) is a research study in human volunteers to answer specific health questions. Carefully conducted clinical trials are the fastest and safest way to find treatments that work in people and ways to improve health. Interventional trials determine whether experimental treatments or new ways of using known therapies are safe and effective under controlled environments. Observational trials address health issues in large groups of people or populations in natural settings.
Participants in clinical trials can play a more active role in their own health care, gain access to new research treatments before they are widely available, and help others by contributing to medical research.
For more information on current research studies that you may want to discuss with your doctor go to:
ClinicalTrials.gov: Acquired Immunodeficiency Syndrome (National Institutes of Health)
ClinicalTrials.gov: HIV Infections (National Institutes of Health)
HIV/AIDS Clinical Trials (AIDSinfo)
HIV/AIDS Vaccine Trials (AIDSinfo)
TrialScope (University of California, San Francisco)
AIDS Research Center (Bastyr University) 
