Science Magazine Examines HIV Prevention Strategies

• Circumcision: A recent study of 3,000 HIV-negative men in South Africa found that circumcision can reduce by about 65% the risk of men contracting HIV through sexual intercourse with women. Similar circumcision studies are under way in Kenya and Uganda;
  
  
• Treating Pre-Existing Herpes Infection: A study conducted about five years ago in four African cities found that a pre-existing herpes infection increased the risk of HIV transmission. Connie Celum with the University of Washington in Seattle is leading two international trials of acyclovir, which is used daily to treat herpes, to see whether suppressing herpes can prevent HIV transmission. If the drug works, it could affect the HIV/AIDS pandemic because more than 80% of HIV-positive adults are co-infected with herpes;
  
  
• Antiretroviral Drugs: Other prevention trials are focusing on whether antiretrovirals might be helpful in preventing HIV transmission. The HIV Prevention Trials Network, sponsored by NIH's National Institute of Allergy and Infectious Diseases, recently launched a study of antiretroviral treatment involving 1,750 couples worldwide;
  
  
• Microbicides: Five efficacy trials of vaginal microbicides are currently under way, and one study is examining microbicides that can be placed in the rectum. Researchers also are looking into incorporating antiretrovirals such as tenofovir into microbicides;
  
  
• Early Detection: Scientists also are looking at ways to improve HIV detection at early stages of infection, when the risk of transmission is highest;
  
  
• Diaphragms: Another study is looking at how the diaphragm and a lubricant can help prevent HIV transmission. Nancy Padian with the University of California-San Francisco, who is conducting studies of the diaphragm in Zimbabwe and South Africa, said the device might help prevent the virus from reaching the cervix and endocervix, where most female infections occur;
  
  
• Gels: Other scientists are conducting a study in Kenya to discover whether wiping the penis with an ethanol-based gel can prevent transmission of HIV, herpes and other sexually transmitted diseases;
  
  
• Antidepressants: A researcher in San Francisco will launch a study this fall that will evaluate the impact of antidepressants on HIV transmission. Previous studies have indicated a connection between depression in men who have sex with men and risky sexual behavior (Cohen, Science, 8/12).