The primary method of HIV transmission in the world today is through heterosexual sex. While condoms provide an effective method of prevention, many women are not able to convince their partner to use them. In many countries (including the United States) there are men who take sex as their right and do not bother to protect their partner. Often, a woman will be beaten just for suggesting their partner use a condom.

What women need is a way to protect themselves that is discreet and easy to use. Women soon may have their own secret weapon when it comes to preventing HIV transmission. Scientists at Stanford University have been working on a method that may allow women to decrease their chances of catching HIV from unsafe sex by simply inserting an inexpensive vaginal suppository once or twice a week. While the product is still a ways away from human testing, its implications for women worldwide are profound.

The technique involves using a bacterium normally present in the vagina and genetically engineering it so it expresses (makes) CD4 receptors -- one of the attachment sites for HIV to enter a cell. The virus will then attach to the bacteria instead of to the cells lining the woman's vagina. The bacteria, Lactobacillus jensenii, are found in the mucus of a healthy vagina. Researchers took the naturally occurring bacteria and enhanced it with the gene for CD4. CD4 is found on the surface of many cells, including blood cells, as well as the cells of the vaginal lining. When HIV is first introduced into the body, it looks for and attaches to CD4. If HIV first connects or attaches to the genetically "enhanced" CD4 bacteria, the virus theoretically could be made unable to attach to the woman's own cells. Researchers so far have tested this in the laboratory. They must do animal testing before they can start human trials.

Researchers have had difficulty developing methods for women to prevent HIV transmission. The microbicides and spermicides currently available or in clinical trials have not been effective in preventing transmission and are not discreet enough to prevent detection by a partner. Female condoms are even less of a secret. This new product, if proven successful, could be inserted into the vagina as a suppository once a week to protect a woman from HIV.

The research was funded by the National Institute of Health and the Contraceptive Research and Development Program of Eastern Virginia Medical School. Lead researchers are Peter P. Lee, M.D., Gary Schoolnik, M.D. and Mark Holodniy, M.D., all of Stanford University.